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66 Total ankle replacement (TAR)
Contents
Indications and Contraindications for TAR
First-Generation Total Ankle Replacements
Second-Generation of Total Ankle Replacements
Results of First- and Second-Generation TARs
Modern TAR Designs (Third-Generation TARs)
The TAR Learning Curve
Modern TAR Designs: Promising Results
Future Insights
References
66.1 Indications and Contraindications for TAR
66.1.1 Indications
Total ankle replacement (TAR) is an alternative to ankle arthrodesis for the treatment of end-stage ankle
osteroarthritis (OA) in select patients with advanced painful arthropathy of all three main etiologies: primary,
post-traumatic, and secondary. One of the main advantages of TAR compared with ankle arthrodesis is
preservation of functional range of motion (ROM) which is sacrificed in ankle fusion. Improved ROM allows
patients to better perform activities of daily living and possibly regain athletic activities.
The ideal candidate for TAR is an older (middle- to old-aged), reasonably mobile patient with no significant
co-morbidities, a normal or low body mass index, adequate bone stock, a well-aligned and stable hindfoot,
good soft tissues conditions, and no neurovascular impairment of the lower extremity.
Another indication for TAR is bilateral end-stage ankle OA. Bilateral ankle fusion may not be the most
appropriate treatment option given its significant detrimental effects on gait and functional status of patients.1
This is particularly important to consider in patients with secondary OA due to hemochromatosis or
hemophilia. Furthermore, in patients with previously performed subtalar, triple, and/or midfoot fusion the2,3
tibiotalar fusion would completely “stiffen” the hindfoot, while the TAR may preserve functional motion. It has
been shown that the clinical outcome of TAR when combined with hindfoot fusion is comparable to that of
ankle replacement alone.4
66.1.2 Contraindications
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The relative contraindications for TAR are severe osteoporosis, history of osteomyelitis, diffuse
osteonecrosis, or significant bone defect on the tibial and/or talar site. Previous long-term therapy with
steroids or immunosuppressive substances may also reduce bone quality, resulting in compromised
osteointegration of prosthesis components. Further relative contraindications for TAR include heavy physical
work, medium level of sports activities (eg, tennis, jogging, and downhill ski), high body mass index,
diabetes, and smoking.
Significant preoperative varus or valgus deformity (>10°) has also been seen as a contraindication for TAR.
Doets et al found that preoperative deformity in the frontal plane is difficult to correct, causing instability and
subluxation of the bearing, which may result in the prosthesis failure. Wood and Deakin observed in their5
study including 200 STAR implants that preoperative varus or valgus deformity >15° may cause edge
loading of the mobile bearing. Therefore, they stated that this may be a relative contraindication for TAR.6 7
However, the preoperative hindfoot deformity should not be an absolute contraindication, as long as
additional realignment procedures (supramalleolar and/or calcaneal osteotomies, ligament reconstruction,
subtalar fusion) may correct the deformity. Karantana et al did not observe any differences in functional8-11
outcome and prosthesis component survivorship between patients with and without preoperative deformities
as long the deformity was addressed at the time of prosthesis implantation. Daniels et al demonstrated12,13
that correction of moderate to severe varus deformities is possible and results in good functional outcome
and stability of prosthesis components. Kim et al reported that the clinical outcome of TAR performed in14
ankles with preoperative varus deformity >10° is comparable with that of neutrally aligned ankles.15
However, the simultaneous surgical procedures addressing the preoperative deformity are necessary to
achieve good results.15
The absolute contraindications for TAR include:
Neuroarthropathy (Charcot foot)
Non-manageable hindfoot malalignment
Massive joint laxity (eg, patients with Marfan disease)
Highly compromised periarticular soft tissues (eg, in patients with posttraumatic OA who underwent
several previous surgeries)
Severe sensomotoric dysfunction of foot/ankle
Active soft-tissue or bony infection
Additionally, TAR should not be considered as the first-choice therapy in patients with a high level of
functional demand (eg, contact sports).
While many authors suggest that previous ankle infection is an absolute contraindication for TAR, we do16-20
not confirm this idea. In a series of 17 consecutive patients who underwent HINTEGRA TAR, we achieved
good functional results and did not observe any recurrence of infection (unpublished data). Eichinger et al
and Espinosa and Klammer also recommend TAR in patients with ankle OA due to previous infection.21,22
In several studies, avascular necrosis of the talus has been identified as an absolute contraindication for
TAR. However, it should be considered that some prosthesis designs offer the possibility to use the17,23-29
revision talar component. Also custom made components may be used replacing the whole body of talus.30
66.2 First-Generation Total Ankle Replacements
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Since the 1970s, ankle arthrodesis has been recognized as having limitations regarding complication rate
and functional outcome. In most articles addressing TAR history, the study by Lord and31-33 22,31,32,34-38
Marotte is described as the first clinical study with TAR patients.39
However, Muir et al described in 2002 outcome results in a 71-year-old male who underwent talar dome
resurfacing with a custom Vitallium implant for post-traumatic OA in 1962. The clinical examination at40
40-year follow up showed mild hindfoot malalignment with slightly decreased ROM (25° plantar flexion),
AOFAS score of 85, no pain, and no activity limitation.40
In their study, Lord and Marotte used an inverted hip stem, which was implanted into the tibia. After the39
talus had been completely removed, they implanted a cemented acetabular cup in the calcaneus. This
procedure was performed in 25 consecutive patients and only seven patients reported satisfaction
postoperatively. Twelve of the 25 arthroplasties failed, and therefore the authors did not recommend the41
further use of this prosthesis design. At the time, the authors recognized the complexity of ankle41
biomechanics and concluded that a simple hinge prosthesis system with plantar flexion and dorsiflexion
would be insufficient to mimic the normal ankle joint. Overall, the majority of first-generation prostheses41
were eventually withdrawn from the market because of high failure rates with subsidence, continued patient
pain, or progressive alignment deformities.
The research published by these original investigators led to the development of the first-generation of
TARs. These included:
, a semi-constrained prosthesis type introduced in 1973St. Georg-Buchholz ankle prosthesis, a two-component, constrained implant with aImperial College of London Hospital prosthesis
polyethylene tibial component 42,43
(Howmedica prosthesis), one of the first early ankle prostheses where a specialIrvine Ankle TARtalus anatomy was regarded, with the prosthesis designers performed anatomical measurements of
32 tali to establish the morphology of talus 44
, a non-constrained so-called “ball-and-socket” (spherocentric) prosthesis thatRichard Smith TAR
was introduced in 1975 45
, a very constrained prosthesis type Conaxial Beck-Steffee ankle prosthesis 46
, a non-constrained cemented prosthesis including the high densityNewton ankle implantpolyethylene tibial and Vitallium talar components
, an unconstrained, two-component total ankle design.Bath-Wessex TAR, a highly congruent two-component design including a polyethylene tibial component withMayo TAR
cement fixation 47,48
, a single-axis, two-component TAR designOregon ankle prosthesis, a two-component semi-constrained cemented implant that includedThompson-Richard prosthesis
a polyethylene tibial component with a concave articular surface and a lip on each side 1,49
, developed by a bioengineer and an orthopaedic surgeon New Jersey or Cylindrical TAR 50
66.3 Second-Generation of Total Ankle Replacements
Based on research demonstrating the high complication and failure rates and lack of patient satisfaction with
the first-generation of TARs, a second-generation was developed, including:
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The (Depuy), the first of a new generation of ankle prostheses, has beenAgility ankle prosthesis
used since 1984. The Agility has been approved by the FDA and is currently the most widely used51
ankle prosthesis in the United States, and with more than 20 years of implantations, it has the longest
follow up of any fixed-bearing TAR. The Agility ankle prosthesis is a semi-constrained,52
two-component prosthesis consisting of a titanium tibial and cobalt-chromium talar component. For
improved osseous integration, both components have a sintered titanium bead surface. As this
prosthesis is a two-component system, a modular polyethylene insert is locked into the tibial
component. In 2007, the Agility LP Total Ankle System was introduced with some modification of its
design. All improvements were designed after careful analysis of published data to improve the52
outcome and avoid mid- and long-term complications. The new prosthesis features include: a
redesigned broad-based talar component (to avoid subsidence of the tibial component, especially in
patients with nonunion of tibiofibular syndesmosis), the ability to mix and match component sizes to
match native anatomy, and a front-loading polyethylene (easier surgical technique for exchange of
insert).52
The is the first reported three-component prosthesis with aBuechel-Pappas ankle prosthesis
mobile bearing. It is the evolution of the first-generation New Jersey ankle prosthesis. In the first38,50
Buechel-Pappas design (Mark I), the anterior-posterior constraint between the tibial and mobile
bearing components was removed. This shallow sulcus design allowed more ROM without
compromising the intrinsic sagittal stability of the ankle replacement. Postoperative complications
included delayed wound healing, reflex sympathetic dystrophy, deep infection, mobile bearing
subluxation, talar component subsidence, severe bearing wear, malleolar fracture, and osteolysis.
Analysis of complications from using this prosthesis led to modifications resulting in the Mark II
Buechel-Pappas prosthesis. This new design (also known as the deep sulcus design) included two
fins, a thicker meniscal component, and deeper sulcus with a gap in the plastic.
The (STAR) was developed as a two-component,Scandinavian Total Ankle Replacementanatomic, unconstrained resurfacing ankle prosthesis with congruent parts covering the medial and
lateral facet joints. Since 1986, the tibial part of the STAR prosthesis has included a polyethylene53
component. This modification was performed to minimize rotational stress at the implant-bone53
interface. The current design of the STAR prosthesis is a congruent, cylindrical, three-component
prosthesis. Initial osseous integration of the prosthesis is secured by a single fin on the talar side and
by two cylindrical fins on the tibial side. Both metallic components have hydroxyapatite coated
surfaces. The STAR prosthesis, one of the most popular TARs used in Europe, has one of the longest
histories in ankle replacement surgery, with several modifications made during its clinical use.54
66.4 Results of First- and Second-Generation TARs
The majority of first-generation TAR designs were two-component prostheses that used cement fixation on
both the talar and tibial sides. The reason for cement fixation was simple: in the 1970s cementless fixation
had not been widely used in knee and hip prostheses and cement fixation led to acceptable early component
stability. However, an extremely high complication rate was observed with increased incidence of loosening,
wide osteolysis, subsidence, and mechanical failure of prosthesis components.
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Cement fixation required a larger bone resection. Therefore, bone quality at the cement-bone interface was
not optimal, as the main load transfer occurred on the weaker methaphyseal bone. Most TARs included a
polyethylene concave tibial and a metal convex component for the talus, usually made using cobalt chrome
alloy. Both types of prostheses – constrained and unconstrained – were available at that time. One design
feature of most first-generation TAR designs was a tibial component that was significantly larger than the
talar. The idea was to allow physiological dorsi-/plantar flexion ROM as well as axial rotation. However, due
to low intrinsic stability, significant increases in shear forces occurred. This was especially true in patients
with chronic ligamental instability which resulted in prosthesis loosening early on.
Most clinical studies addressing outcomes in patients who underwent first-generation TAR were case reports
or studies including between 20 to 40 patients. Another critical factor was the short follow-up periods55
reported (mostly 5 years or less). Patient satisfaction with first generation TAR was reciprocally proportional
to the length of follow-up and varied between 19% and 81%.55
Generally, the clinical results of first-generation TAR were highly discouraging. The alarmingly high
prosthesis component failure rate along with other complications like wound healing and unacceptable
functional results were the reasons that foot and ankle surgeons were advised to use ankle fusion as the
primary treatment option for ankle OA. Failure analysis of first generation TARs showed that only29,48,56-60
significant improvements in prosthetic design, change of fixation (elimination of use of cement), and
improved anatomical access would change arthroplasty outcomes.61
An analysis of the main failure reasons of the first-generation TAR designs was crucial for the development
of the second-generation ankle prostheses. More conservative and sparing bone cuts and the elimination of
bone cement have significantly improved problems with component loosening. New biologic interfaces with
special porous coatings for bony ingrowth and/or adding of hydroxyapatite were investigated as another
possible method to ensure the primary prosthesis fixation. To reduce subsidence, second-generation62,63
ankle prostheses were designed to increase the surface area of the metallic components. Increased surface
area sought to decrease the average local contact pressure and pressure peaks during gait.
The three main second generation TAR designs – Agility, Buechel-Pappas, and STAR prostheses – have
been implanted with encouraging mid- and long-term results. Positive clinical results, high patient64
satisfaction, and acceptable survivorship of prosthesis components presented at national meetings and
published in orthopaedic literature led to rethinking that ankle fusion may not be the only one reasonable
treatment option for patients with severe ankle OA. The continued critical review of second-generation
implant failures and biomechanical studies provided important data that led to the development of modern
TAR designs.
66.5 Modern TAR Designs (Third-Generation TARs)
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The was developed between 1994 and 1996 by Michel Bonnin. This TARSalto Total Ankle 65
represents the third-generation of cementless meniscal-bearing designs. The tibial component has a
flat surface toward the mobile bearing, allowing its free translation and rotation. The 3-mm medial rim
is designed to avoid insert impingement against the medial malleolus. For osseous integration, the
component has a keel and a fixation peg. The specific shape of the talar component mimics the
natural talar geometry with the anterior width being wider than the posterior, and the lateral flange
having a larger curvature radius than the medial. The mobile bearing is manufactured from
ultra-high-molecular-weight polyethylene (UHMWPE) and has full congruency with the talar
component in flexion and extension. All components are available in three sizes.65
The is an unconstrained, three-component system that provides inversion-eversionHINTEGRA TAR
stability and was designed in 2000 by Beat Hintermann, Greta Dereymaeker, Ramon Viladot, and
Patrice Diebold. The mobile bearing provides axial rotation and normal flexion-extension mobility.66-68
The HINTEGRA TAR includes two metallic components and an ultrahigh-density polyethylene mobile
bearing. The non-articulating surfaces have a porous coating with 20% porosity and are covered by
titanium fluid and hydroxyapatite. The tibial component has a flat, 4-mm thick loading plate with
pyramidal peaks against the tibia. Additional stability may be achieved by fixation with two screws.
The talar component is conically shaped with a smaller radius medially than laterally, mimicking the
normal anatomy of talus. It has 2.5-mm high rims on each side that ensure stable positioning and
guide the anteroposterior translation of the mobile bearing. The anterior shield of this component
increases primary bone support, especially in cases with weaker bone, and may prevent the
adherence of scar tissue and avoid restriction of ROM in cases with arthrofibrosis.67
The was developed by Pascal Rippstein, Peter Wood, and Chris Coetzee. ThisMobility Ankle System
is a three-component Buechel-Pappas type prosthesis with a short, conical tibial stem. The talar
component of the Mobility implant resurfaces the superior dome of the talus, while the medial and
lateral aspects of the talus remain untreated (unlike the Buechel-Pappas prosthesis). The talar
component has a central, longitudinal sulcus and two fins, enhancing its intrinsic stability. The
non-articulating surfaces are porous coated with a titanium spray.
The was developed in 1987 and first implanted in 1989 by a French design group.Ramses TAR 69,70
The Ramses TAR is a three-component, semi-constrained prosthesis with the high-density mobile
bearing. Initially, a cemented fixation of prosthesis was used between 1980 and 2000.70
Since its introduction in 1975, the has undergone many modifications toTNK total ankle replacement
address the material of the components (stainless steel, polyethylene, alumina ceramic), coating
(without/with hydroxyapatite), and fixation (cement/cementless fixation). Currently, this is the only
TAR design containing alumina ceramic components. While the studies by the designer reported
favorable results using the third-generation TNK prosthesis, independent studies addressing71,72
TAR results in patients with rheumatoid OA show less promising results.73,74
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The is a further development of the Buechel-Pappas-typeAnkle Evolutive System (AES) TAR
prosthesis. This design has a modular stem and allows hemi-replacement of the medial tibiotalar and
talofibular joints. This prosthesis has been widely used in England and France, and has also75 76,77
been introduced in Norway. Recent studies of the AES TAR reported a high rate of osteolytic78
lesions. It is still unclear whether the osteolysis process is a result of failure of the hydroxyapatite79-82
coating of the metal components or failure of the mobile bearing. As a result of independently
published results showing high osteolysis rate, the AES prosthesis has been withdrawn from the
market.83
The was developed in the late 1990s by Leardini et al. This prosthesis is aBOX TAR
three-component implant with metal components fixed to the proximal talus and the distal tibia and
interposed UHMWPE meniscal bearing. The biomechanical development of this prosthesis type has
been well documented in the literature by its designers.84-86
The is a two-component prosthesis designed for cementless implantation between 1985ESKA ankle
and 1989. The following features were included to improve biomechanics of the replaced ankle:87,88
cementless implantation and porous-structured implant surface for faster osteointegration, shear force
reduction by shape design of both metallic components, and easy replacement of the polyethylene
without disturbing prosthesis anchoring. Because of the ridge-like shaping and its transverse87,88
anchoring peg in both metallic components, a lateral or in special cases, medial malleolar approach
has to be used for implantation.87
Other modern TAR designs include:
, a three-component prosthesis allowing rotation around each of theGerman Ankle Systemthree possible movement axes
, a non-constrained Buechel-Pappas type design with aAlphanorm Total Ankle Replacement90° tibial stem without inclination
, which has a titanium coating and is optionally available withTARIC Total Ankle Replacementan additional hydroxyapatite coating
, a fixed-bearing, two-component total ankle system with a modular stem systemINBONE TARfor both metallic components
66.6 The TAR Learning Curve
It has been shown that there is a steep learning curve associated with performing TAR. The following
intraoperative complications have been commonly reported:
Medial and/or lateral malleolar fractures
Laceration to the tendons (posterior tibial tendon, flexor digitorum/hallucis longus)
Nerve injures (deep/superficial peroneal nerve) 89-92
The influence of surgeon experience on complication rates in patient receiving the Agility prosthesis was
examined by Saltzman et al. The perioperative records of the first 10 cases of nine surgeons with different91
training levels were recorded. The authors did not identify any specific training method that significantly
decreased complication rates.91
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Myerson and Mocked performed a retrospective radiographic and chart review of 50 arthroplasties
performed by the same surgeon using the Agility prosthesis. Patients were divided into two groups due to90
surgeon’s experience, each including 25 patients. The number of minor wound complications decreased
from six in the first group to two in the second group. Also, the number of intraoperative fractures was
different in favor of the second group (five vs. two fractures). The nerve or tendon lacerations (n=4) all
occurred in the first group. Regarding the overall decreased complication rate in the second group of 25
patients, the authors stated that there was a notable learning curve in TAR performance.90
A similar study with 50 patients who underwent Agility TAR was performed by Schuberth et al. In this93
study, patients were also divided into two 25-patient groups. There was a significantly decreased rate of the
following complications with increased surgeon experience: medial and lateral fractures, major revisions, and
malpositioning of prosthesis components. Schutte and Louwerens reported their initial results obtained in93
49 patients who received a STAR prosthesis. The following intraoperative complications were detected: six92
fractures of the medial and two of the lateral malleolus, three fractures of the distal tibia, one injury of the
peroneal nerve, and two malpositions of the tibial and two of talar components. Based on these numbers,
the authors concluded that TAR should be performed only by an experienced orthopaedic foot and ankle
surgeon.92
The aforementioned studies addressed intraoperative complications in patients receiving second-generation
TARs. Similar studies have been conducted for patient groups receiving third-generation TARs.89-92 89,94
Lee et al addressed the perioperative complications in the 25 initial patients to receive the HINTEGRA
prosthesis and compared these results with those from a subsequent 25 cases. In the first group,89
perioperative complications occurred in 60% of all cases, while in the second group, only five complications
(20%) were observed. All major complications (deep infection and aseptic loosening) occurred in the first
group. The rate of minor complications (fractures, minor wound problem, nerve/tendon injuries, and
heterotopic ossifications) significantly decreased in the second group. However, the authors were unable to
show a decrease in the number of malpositioning of prosthesis components as a result of increased surgeon
experience. The same working group compared the perioperative complication of the HINTEGRA total89
ankle system with the MOBILITY total ankle system. The authors did not find any differences in94
perioperative complications between the two total ankle systems, but medial malleolar fractures did occur
more frequently when using the MOBILITY prosthesis.94
Recently, Reuver et al addressed short-term results of TARs performed in low-volume arthroplasty centers.
In total, 64 TARs were performed using Salto implants between 2003 and 2007 at four low-volume95
centers. Fifty-five patients (59 ankles) were reviewed at a mean follow up of 36 months. Seven ankles had to
undergo revision surgery – two revision arthroplasties and five fusions – because of loosening, and two
cases of deep infection resulting in a survivorship of 86% at final follow up. Significant pain relief and
functional improvement were observed in this review, as assessed using VAS and AOFAS score. The
authors felt confident that results of TAR performed in low-volume centers are comparable to most
high-volume centers. However, the survival of implanted components was significantly lower, especially
regarding the relatively short follow up.95
In summary, despite the encouraging results reported by studies using modern third-generation TAR, we
believe, that TAR should be limited to foot and ankle orthopaedic surgeons with special training and
adequate experience in arthroplasty techniques.
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See for more on the use of TAR in painful ankle arthrodesisSpecial Situations for Total Ankle Replacement
and simultaneous bilateral TAR.
66.7 Modern TAR Designs: Promising Results
Stengel et al performed a systematic review and meta-analysis to address the efficacy of TAR with
meniscal-bearing implants. The following inclusion criteria were defined for this study: a minimum sample96
size of 20 subjects, at least 1 year of follow up, and a clinically relevant study endpoint. In total, 18 studies
with 1,086 patients were included in the review. Most patients experienced significant functional
improvement (average 45.2 points using standardized 100-point ankle and hindfoot scores) and a mild
increase of ROM (mean increase = 6.3%, 95% CI, 2.2% - 10.5%). Weighted complication rates ranged from
1.6% (deep infection) to 14.7% (impingement). Secondary surgeries were necessary in 12.5% of all patients.
Ankle fusions were required in 6.3% of patients due to implant failure, resulting in 1- and 5-year survivorship
of 96.9% (95% CI, 94.9% - 98.8%) and 90.6% (95% CI, 84.1% - 97.1%), respectively. The data of this
meta-analysis showed that TARs using current three-component designs provide an acceptable benefit-risk
ratio. However, the results should be interpreted with caution due to non-optimal methodological quality,
sample sizes, and short follow ups.96
SooHoo et al compared reoperation rates following ankle fusion and TAR using California’s hospital
discharge database. A total of 4,705 ankle fusions and 480 TARs were included in the review during the97
10-year study period (1995 through 2004). It was shown that patients who underwent TAR had an increased
risk of periprosthetic infection. The rates of major revision surgery after TAR were 9% at 1 year and 23% at 5
years compared with 5% and 11% following ankle fusion. However, TAR was shown to have advantages in
terms of functional results.97
In another study from 2004, SooHoo and Kominski performed cost analyses of TAR compared to ankle
fusion. The authors performed a thorough literature review to identify possible outcomes and their98
probabilities following ankle fusion versus TAR. They found that TAR generated total expected lifetime
treatment costs of $16,568, which is $6,990 more than costs following ankle fusion. Furthermore, TAR had
an incremental cost-effectiveness ratio in the reference case of $18,419 for each quality-adjusted life year
gained.98
In 2007, Haddad et al performed a systematic literature review addressing the intermediate and long-term
outcomes of interest in TAR and ankle fusion. In total, 10 studies including 852 TAR patients and 3999
studies including 1,262 with ankle fusion were analyzed. The authors showed that 38% of patients had
excellent postoperative results, 30.5% had good results, 5.5% had fair results, and 24% had poor results.
The corresponding values in patients who underwent ankle fusion were 31%, 37%, 13%, and 13%,
respectively. The 5- and 10-year survivorship for TAR was 78% (95% CI, 69.0% - 87.6%) and 77% (95% CI,
63.3% - 90.8%), respectively. The revision rate in patients with TAR and ankle fusion was 7% (95% CI, 3.5%
- 10.9%) and 9% (95% CI, 5.5% - 11.6%), respectively. The main reasons for revision surgery were
component loosening and subsidence in the TAR group and non-union in the fusion group. The results of
this study suggest that the intermediate outcome is comparable in both procedures.99
In 2010, Gougoulias et al performed a systematic review of the literature to address the outcome of TAR
implants currently in use. In total, 13 Level IV peer-reviewed studies were included, reporting the outcome100
of 1,105 TARs:
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234 Agility
344 STAR
153 Buechel-Pappas
152 HINTEGRA
98 Salto
70 TNK
54 Mobility implants
Postoperatively, a remarkable portion of patients still had residual pain (range, 27% - 60%). Also, superficial
wound complications and deep infection were often reported, with rates up to 14.7% and 4.6%, respectively.
Overall failure rate at 5 years had a wide range, 0% and 32%. In general, most patients experienced
significant functional improvement as assessed by the AOFAS score. However, the postoperative
improvement of ROM was relatively small (0° - 14°). Therefore, the patients should be informed that
significantly improved ROM is not one of the postoperatively expected benefits of TAR.100
Recently, Slobogean et al compared preference-based quality of life in patients with end-stage ankle OA
treated with TAR or ankle fusion. The quality of life of 107 subjects was assessed using health state101
values derived from SF-36 (SF-6D transformation). The mean baseline SF-6D health state value in the TAR
group was 0.67 (95% CI, 0.64 – 0.69) and in the ankle fusion group 0.66 (95% CI, 0.63 – 0.68). At 1 year
follow up, both groups had significant and comparable improvements with 0.73 for the TAR group (95% CI,
0.71 – 0.76) and 0.73 for the ankle fusion group (95% CI, 0.70 – 0.76).101
To date, there has been no clear evidence in the literature that three-component TAR designs are superior
compared with two-component designs. Also, the high-quality comparative studies addressing102,103
postoperative outcomes in patients who underwent TAR vs. ankle fusion are rare. There has been only one
prospective, controlled, comparative surgical trial performed including both patient cohorts. Future104
high-quality prospective, randomized, controlled studies would significantly help to establish the clinical
practice guidelines needed for surgeons to make a correct decision about treatment choice.104-108
66.8 Future Insights
TAR is increasingly gaining acceptance as a valuable option for treating patients with end-stage ankle OA.
Current reports of this procedure show consistently good to excellent mid-term results with significant pain
relief, good functional outcomes, and high patient satisfaction. The high failure rate of the100,109,110
first-generation ankle prostheses has been thoroughly analyzed and the TAR designs have been
significantly improved. Current fixation techniques without cement have become the gold standard using
“biological surfaces” (eg, introduction of hydroxyapatite in the 1990s) for better osseous integration of
metallic prosthesis components.110,111
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1.
2.
3.
4.
5.
6.
7.
8.
9.
One of the main principles of TAR surgical technique is preserving adequate bone stock. It has been111
widely recognized, with regard to bone resection, that less is more. An extensive bone resection may
drastically limit the revision surgery in case of failure of the TAR, especially on the talar side. Also, the bone
resection for implantation of prosthesis components should consider the anatomical inner structure of bone
and especially trabecular microarchitecture for optimal load transfer. The optimal load transfer is very111
important because this would avoid pathologically increased pressure peaks, which may cause loosening
and subsidence of components. Therefore, the load transfer on a tibial component that incorporates
circumferential bony support may be superior to that of a stemmed component in the long term.110
Furthermore, the natural articular geometry of the ankle should be considered during the design of any ankle
prostheses.
Modern implants try to retain the radius of the curvature of the talus, resulting in improved and a more
natural ROM. The modern TAR is not only a resurfacing procedure of the osteoarthritic ankle but also a111
restoration of normal biomechanics of the entire hindfoot. If necessary, additional surgeries should be110
performed to achieve the appropriate ligamental and osseous balancing of the hindfoot. Failure to8-10,110
correct hindfoot alignment or undercorrection of hindfoot deformity can cause a significant increase of
translation forces and movements during gait. Especially in patients with remaining valgus misalignment, this
may lead to prosthesis failure because valgus misalignment is tolerated more poorly than varus.110
In conclusion, TAR with current devices, equipment, and techniques has improved considerably over the
past several decades to show that the ankle fusion is no longer the “gold standard” treatment for all patients
with severe end-stage ankle OA. Future biomechanical and clinical studies addressing the outcomes and
biomechanical properties of TAR should be continued with the aim of improving current TAR designs.
66.9 References
Barg,A., Knupp,M., and Hintermann,B.: Simultaneous bilateral versus unilateral total ankle
replacement: A patient-based comparison of pain relief, quality of life and functional outcome. J Bone
Joint Surg Br, 92:1659-1663, 2010.
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26th Annual Summer Meeting of the American Orthopaedic Foot & Ankle Society, 2010
66.10 AES Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
more
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The Ankle Evolutive System (AES) TAR is a further development of the Buechel-Pappas-type prosthesis.
This design has a modular stem and allows hemi-replacement of the medial tibiotalar and talofibular joints.1
This prosthesis type has been widely used in England and France and has also been introduced in2,3
Norway. While some studies show promising functional results, this prosthesis has experienced significant4
problems relating to osteolysis and has been withdrawn from the market.17
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One of the first reports addressing the outcome in patients who underwent AES TAR is a study by Patsalis.5
This study included 15 AES TAR patients with an average short-term follow up of 8.5 months. Three
malleolar fractures were observed intraoperatively. Two replaced ankles had to be revised, while the
remaining 13 patients showed significant functional improvement as assessed by the AOFAS score.5
In 2005, a short-term study by the designers of the AES prosthesis outlined the suggested surgical
technique and reported good preliminary results.6
Henricson and Ågren addressed the influence of preoperative hindfoot alignment on secondary surgery after
TAR. The patient cohort included 109 STAR, 62 Buechel-Pappas, and 22 AES TARs. The mean follow-up7
time in the whole patient group was 4.2 years.Two cases with instability requiring additional surgery (one
case with preoperative varus and one case with preoperative valgus deformity) were observed in the AES
TAR group. No revision surgeries addressing prosthesis loosening were necessary.7
Brooke et al presented two cases with valgus malalignment following TAR using an AES prosthesis. They8
performed a fibula lengthening osteotomy to regain the anatomical alignment and to avoid pathological
increases in wear. In both cases, good clinical and radiographic results were achieved. Kharwadkar and8
Harris published a report of two cases using the AES tibial component as a revision component in patients
with failed STAR prostheses. The hybrid AES-STAR revision procedures were performed at 4 and 7 years9
following the primary STAR prosthesis implantation. The mid-term results were satisfactory, with no
restriction of daily activities.9
Dahabreh et al published a case report with a patient having revision surgery due to extrusion of a metal
radiological marker. The exchange of polyethylene insert was performed 9 months after the initial TAR10
using an AES implant. During revision surgery, the insert was found to be intact without fracture. Morgan10
et al presented 2.5 years' follow-up results in a female patient who had poliomyelitis as a child and had been
treated with the AES prosthesis because of a painful, degenerate ankle with preoperatively significant varus
deformity. The patient showed a satisfactory functional outcome with a well-aligned replacement ankle and11
no evidence of loosening or osteolysis around prosthesis components.11
Anders et al reported their mid-term results in 94 patients who underwent AES TAR between 2002 and
2007. One patient was deceased, leaving 93 ankles for evaluation at a mean follow up of 3.5 years. There12
were five intraoperative malleolar fractures, which were all secured with screws. One patient was revised
after 5.5 years due to loosening of both metallic components, and two patients with loosening of the tibial
component were pending revisions. In an additional three cases osteolysis, around the component was
seen. Two ankles were revised due to fixed varus or valgus deformity. In one patient, an ankle fusion was
performed because of a fracture of the distal tibia. Two patients were revised for deep infection. Overall, the
cumulative 5-year survivorship with revision for any reason was 90%. In summary, the authors stated that
mid-term results in their patient cohort were promising.12
Morgan et al presented the outcomes of 38 consecutive patients who were treated with AES TAR between
2002 and 2004. All patients were reviewed clinically and radiographically at a minimum follow up of 413
years. Most patients presented with significantly improved function and pain relief. Two replaced ankles were
converted to ankle fusion resulting in a cumulative 6-year survivorship of 94.7% (95% CI, 80.3% - 98.7%).
Ten patients presented with edge-loading, of whom nine had corrective surgery. In nine patients significant
osteolysis around the prosthesis components was seen. Because of non-progressive symptoms no further
revision surgeries were suggested.
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1.
2.
3.
4.
5.
6.
7.
Despite high patient satisfaction, the authors reported some concerns about an observed high rate of
osteolysis. The reported high rate of osteolysis in patients who underwent AES TAR has been confirmed13
by other studies. Besse et al reported mid-term results of their prospective study including 51 AES implants
performed from 2003 to 2006. All patients were reviewed at a mean follow-up of 40 months. Eighty-two14
percent of all patients had good functional outcome showing a significant postoperative improvement of
AOFAS score. In two patients, replaced ankles were converted to ankle fusion because of talar component
subsidence and mechanical dislocation. Although the functional outcome and patient satisfaction were
comparable to other results published in studies using other third generation prostheses, significant
osteolysis with the AES TAR was more frequent with risk of subsidence. As a consequence, the authors
stopped implantation of this prosthesis type and recommended a preventive grafting for severe osteolysis.14
The comparably high osteolysis rate was also seen in a study by Koivu et al reviewing 130 consecutive AES
implants performed between 2002 and 2008. Radiolucent lines or osteolytic lesions were seen on plain15
radiographs in 48 ankles (37%). Marked osteolytic lesions were found in 27 ankles (21%). The talar
component migrated in nine ankles; in an additional two ankles, a shift of the tibial component was observed.
Of the 27 ankles with marked osteolysis, 16 underwent revision surgery resulting in a revision rate of 15.5%.
The contents of the osteolysis cavities were used for microbiological and histological analysis. The
histological findings were interpreted as a foreign-body reaction. The authors concluded that the use of AES
implants should be avoided until the reason and extent for the problem of osteolysis has been solved.15
Rodriguez et al observed a high frequency of delayed appearance of osteolysis (77%) in 18 ankles replaced
with AES prosthesis at the mean follow-up of 39.4 months.16
In summary, recent studies of the AES TAR reported a high rate of osteolytic lesions. It is still unclear13-16
whether the osteolysis process is a result of failure of the hydroxyapatite coating of the metal components or
failure of the mobile bearing. As a result of independently published results showing high osteolysis rate, the
AES prosthesis has been withdrawn from the market.17
66.10.1 References
Hintermann,B.: Current designs of total ankle prostheses, in Hintermann,B. (ed), Total ankle
arthroplasty. Historical overview, current concepts and future perspectives. Wien , Springer, 2004, pp.
69-100.
Goldberg,A.J., Sharp,R.J., and Cooke,P.: Ankle replacement: current practice of foot & ankle
surgeons in the United kingdom. Foot Ankle Int, 30:950-954, 2009.
Besse,J.L., Colombier,J.A., Asencio,J., Bonnin,M., Gaudot,F., Jarde,O., Judet,T., Maestro,M.,
Lemrijse,T., Leonardi,C., and Toullec,E.: Total ankle arthroplasty in France. Orthop Traumatol Surg
Res, 96:291-303, 2010.
Fevang,B.T., Lie,S.A., Havelin,L.I., Brun,J.G., Skredderstuen,A., and Furnes,O.: 257 ankle
arthroplasties performed in Norway between 1994 and 2005. Acta Orthop, 78:575-583, 2007.
Patsalis,T.: Die AES-Sprunggelenksprothese: Indikation, Technik und erste Ergebnisse. Fuss
Sprungg, 2:38-44, 2004.
Asencio,J. and Leonardi,C.: Ankle Evolutive System prosthesis: a simple, accurate, and reliable
specific concept for primary and revision surgery. Tech Foot & Ankle, 4:119-124, 2005.
Henricson,A. and Agren,P.H.: Secondary surgery after total ankle replacement. The influence of
preoperative hindfoot alignment. Foot Ankle Surg, 13:41-44, 2007.
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9.
10.
11.
12.
13.
14.
15.
16.
17.
Brooke,B.T., Harris,N.J., and Morgan,S.S.: Fibula lengthening osteotomy to correct valgus
mal-alignment following total ankle arthrplasty. Foot Ankle Surg,epub ahead of print, 2009.
Kharwadkar,N. and Harris,N.J.: Revision of STAR total ankle replacement to hybrid AES-STAR total
ankle replacement-a report of two cases. Foot Ankle Surg, 15:101-105, 2009.
Dahabreh,Z., Gonsalves,S., Monkhouse,R., and Harris,N.J.: Extrusion of metal radiological marker
from a total ankle replacement insert: a case report. J Foot Ankle Surg, 45:185-189, 2006.
Morgan,S.S., Brooke,B., and Harris,N.J.: Is there a role for total ankle replacement in polio patients?:
A case report and review of the literature. Foot Ankle Surg,epub ahead of print, 2009.
Anders,H., Kaj,K., Johan,J., and Urban,R.: The AES total ankle replacement: A mid-term analysis of
93 cases. Foot Ankle Surg, 16:61-64, 2010.
Morgan,S.S., Brooke,B., and Harris,N.J.: Total ankle replacement by the Ankle Evolution System:
medium-term outcome. J Bone Joint Surg Br, 92:61-65, 2010.
Besse,J.L., Brito,N., and Lienhart,C.: Clinical evaluation and radiographic assessment of bone lysis of
the AES total ankle replacement. Foot Ankle Int, 30:964-975, 2009.
Koivu,H., Kohonen,I., Sipola,E., Alanen,K., Vahlberg,T., and Tiusanen,H.: Severe periprosthetic
osteolytic lesions after the Ankle Evolutive System total ankle replacement. J Bone Joint Surg Br,
91:907-914, 2009.
Rodriguez,D., Bevernage,B.D., Maldague,P., Deleu,P.A., Tribak,K., and Leemrijse,T.: Medium term
follow-up of the AES ankle prosthesis: High rate of asymptomatic osteolysis. Foot Ankle Surg,
16:54-60, 2010.
Smith,T.W. and Stephens,M.: Ankle arthroplasty. Foot Ankle Surg, 16:53, 2010.
66.11 Alphanorm Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The Alphanorm TAR was developed by Professor Tilmann in Germany and has been used since 1996. The1
Alphanorm prosthesis is a non-constrained Buechel-Pappas type design with a 90° tibial stem without
inclination. The prosthesis is made out of cobalt chrome alloy with a titanium coating. The medial and lateral2
talar surfaces are not replaced during component implantation, thus preventing inversion and eversion.
Before developing the Alphanorm TAR for use, the designer had experience with the TRP prosthesis, New
Jersey prosthesis, and STAR prosthesis between 1976 and 1998.3,4
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4.
To date, there are no published studies available from Professor Tilmann or others addressing clinical
outcomes or surgical technique of the Alphanorm TAR.
66.11.1 References
Tillmann,K.: Endoprostheses of the ankle joint. Indications, development, current status and trends.
Orthopade, 32:179-186, 2003.
Gougoulias,N.E., Khanna,A., and Maffulli,N.: History and evolution in total ankle arthroplasty. Br Med
Bull, 89:111-151, 2009.
Tillmann,K., Schaar,M., Schaar,B., and Fink,B.: Ergebnisse von OSG-Endoprothesen bei
rheumatoider Arthritis: Eine klinische und pedobarographische Untersuchung. Fuss Sprungg, 1:56-65,
2003.
Feldman MH, Rockwood J (2004) Total ankle arthroplasty: a review of 11 current ankle implants. Clin
Podiatr Med Surg, 21, 393--406.
66.12 BOX Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
more
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The BOX TAR was developed from a collaborative effort of the Rizzoli Orthopaedic Institute (Drs. Giannini,
Catani, Leardini) in Italy and Oxford University (Dr. O'Connor) in England in the late 1990s. This
non-constrained, mobile-bearing prosthesis is a three-component implant with metal components fixed to the
proximal talus and the distal tibia and interposed UHMWPE meniscal bearing. The upper UHMWPE surface
is concave, not flat is in previous designs. The biomechanical development of this prosthesis type has been
well documented in the literature by its designers. Original research studies by the designers of this1-3
prosthesis focused on movement and stability of the ankle and sought to provide detailed understanding of
the role of the ligaments in controlling and limiting joint movement.
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In 2001 Leardini developed a geometrical model of the intact human ankle complex that established the
basic principles for design of a new total ankle prostheses. Seven lower leg specimens were prepared for1
passive flexion analysis using a stereophotogrammetric system. It was shown that the geometry of the
articular surface of the ankle is strictly related to that of the ligaments. Therefore, the author stated that the
ideal TAR design should be based on ligament compatibility and the careful reconstruction of ligaments
should be performed in any foot and ankle surgery to recreate the normal kinematics and mechanics of the
ankle. A four-bar linkage model was developed from this initial study that also showed that both rolling and1
sliding motions take place at the talocrural joint.
In 2004 Leardini et al described the BOX TAR design and rationale, including compatibility to the
physiological function of surrounding ligaments. The designers aimed to reproduce physiological ankle2
mobility with the following design features:
Spherical convex tibial component
Talar component with radius of curvature in the sagittal plane longer than that of the natural talus
Fully conforming meniscal bearing.
Preliminary results from their study of two female patients demonstrated the feasibility of their surgical
technique. Reggiani et al developed a finite element model to address the BOX TAR analysis during the2
stance phase of gait. Overall kinematics, contact pressures, and ligament forces were analyzed during3
both, passive (eg, virtually unloaded) and active (eg,stance phase of gait) conditions. The authors showed
that this prosthesis design could allow the necessary ROM and constrain the motion of the prosthetic
components, especially the mobile bearing.3
Affatato et al have used a four-station knee joint simulator to address meniscal wear of the BOX TAR mobile
bearing. The knee wear simulator was able to reproduce load-motion patterns comparable to those of a4
replaced ankle. Tests of three specimens showed a linear penetration of 0.0178, 0.0081, and 0.0339 mm per
million-cycle. The linear penetration observed in this study was comparable to that found in
ceramic-to-polyethylene or metal-to-polyethylene couplings.4
Two years later, Affatato et al performed a comparative study of wear behavior in the BOX TAR between an
in vitro simulation and retrieved prostheses. Three retrieved mobile bearings were available from revision5
surgeries performed 24, 24, and 9 months after the initial TAR surgery. Visual and microscopic observations,
analyses, and Raman crystallinity-based measurements showed similarity between the patterns generated
experimentally using a four-station knee joint simulator and those seen in retrievals with similar wear
duration.5
Ingrosso et al performed gait analysis in BOX TAR patients by a stereophotogrammetric system with eight
M2-cameras. The study included 10 patients with a follow-up of 6 and 12 months after the surgery. Normal6
patterns and ROMs were observed in all 10 patients at both follow-ups.6
Giannini et al presented short-term results in 51 patients who were treated with a BOX TAR. The minimum7
follow-up in this study was 24 months. All patients showed significant functional improvement as assessed
by the AOFAS score. A revision arthroplasty had to be performed In one patient because of lateral
impingement, resulting in a 3-year cumulative survivorship of 97%. The main indication for this procedure7
was stage III ankle OA (with subtotal or total disappearance or deformation of joint space) with preserved or
restored ankle anatomy.8
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6.
7.
8.
In summary, the design process and biomechanical properties of the BOX TAR have been documented in
detail. The designers claim that it maintains complete congruency during the entire arc of motion and1-3
closely resembles normal ankle biomechanics. Studies addressing the wear behavior in this prosthesis
design have significantly contributed to the understanding of modern three-part prostheses. The4,5
short-term results are promising, with high satisfaction among treated patients, good functional results, and a
low revision rate. However, all aforementioned studies were performed by one of designers of this7
prosthesis; therefore, further study by independent groups should be performed. Long-term results have to
provide evidence on their clinical success.
66.12.1 References
Leardini,A.: Geometry and mechanics of the human ankle complex and ankle prosthesis design. Clin
Biomech (Bristol , Avon ), 16:706-709, 2001.
Leardini,A., O'Connor,J.J., Catani,F., and Giannini,S.: Mobility of the human ankle and the design of
total ankle replacement. Clin Orthop Relat Res, 424:39-46, 2004.
Reggiani,B., Leardini,A., Corazza,F., and Taylor,M.: Finite element analysis of a total ankle
replacement during the stance phase of gait. J Biomech, 39:1435-1443, 2006.
Affatato,S., Leardini,A., Leardini,W., Giannini,S., and Viceconti,M.: Meniscal wear at a
three-component total ankle prosthesis by a knee joint simulator. J Biomech, 40:1871-1876, 2007.
Affatato,S., Taddei,P., Leardini,A., Giannini,S., Spinelli,M., and Viceconti,M.: Wear behaviour in total
ankle replacement: a comparison between an in vitro simulation and retrieved prostheses. Clin
Biomech (Bristol , Avon ), 24:661-669, 2009.
Ingrosso,S., Benedetti,M.G., Leardini,A., Casanelli,S., Sforza,T., and Giannini,S.: GAIT analysis in
patients operated with a novel total ankle prosthesis. Gait Posture, 30:132-137, 2009.
Giannini,S., Romagnoli,M., O'Connor,J.J., Malerba,F., and Leardini,A.: Total ankle replacement
compatible with ligament function produces mobility, good clinical scores, and low complication rates:
an early clinical assessment. Clin Orthop Relat Res, 468:2746-2753, 2010.
Giannini,S., Buda,R., Faldini,C., Vannini,F., Romagnoli,M., Grandi,G., and Bevoni,R.: The treatment
of severe posttraumatic arthritis of the ankle joint. J Bone Joint Surg Am, 89 Suppl 3:15-28, 2007.
66.13 ESKA Ankle Prosthesis
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
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OrthopaedicsOne Articles
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1.
2.
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The ESKA TAR is a non-constrained, fixed-bearing, two-component prosthesis that was designed in
Germany for cementless implantation between 1985 and 1989. It has a shallow groove on the talar1,2
component that is congrous to the ultra-high-molecular-weight polyethylene (UHMWPE) bearing fixed to the
tibial prosthesis. The following features were included to improve the biomechanics of the ankle
replacement:
Cementless implantation and porous-structured implant surface for faster osteointegration
Shear force reduction and rotational force control by shape design of both metallic components
Easy replacement of the polyethylene without disturbing prosthesis anchoring.1,2
Because of the ridge-like shaping and its transverse anchoring peg in both metallic components, a lateral
approach with fibular osteotomy or in special cases, a medial malleolar approach is used for component
implantation.3
In 2001, the prosthesis designer, Dr. Rudigier, published short-term results of 56 patients treated with the
ESKA prosthesis since 1990. Forty of 56 patients were reviewed at a minimum follow up of 1 year. All4
patients experienced significant pain relief, improved ankle ROM and ability to walk, and showed functional
improvement as assessed by the Kofoed ankle score. In two cases, deep infection led to prosthesis removal
and conversion to ankle fusion. Another patient showed painful progressive ossification of the joint capsule
resulting in ankle fusion. The same patient cohort was again reviewed at a longer follow up and the results4
were published in another two studies. The authors reported a significant improvement of the Kofoed3,5
ankle score from 37.6 points preoperatively to 90.4 points postoperatively. Of 12 TARs performed 10-155
years before, 8 (67%) remained in situ (2 early deep infections, 2 aseptic loosenings). In 20 implants
inserted 5-10 years before, 3 were revised, leaving 17 (85%) in situ functioning well. None of the implants
with a follow-up of 1-5 years failed. No results from independent authors have been published.
In summary, the limited studies performed by ESKA prosthesis designers reported favorable mid-term
results with improved ankle ROM, pain relief, and ability to walk long distances postoperatively. However,3-5
the authors conceded that this surgery should be limited to only highly experienced foot and ankle surgeons
due to the demanding lateral approach with fibular osteotomy. As with the BOX TAR, published results have
come from only the prosthesis designers. Thus additional, independent analyses of ESKA efficacy are
needed.
66.13.1 References
Rudiger,J.: Ankle replacement by the cementless ESKA endoprosthesis. Tech Foot & Ankle,
4:125-136, 2005.
Rudiger,J., Menzinger,F., and Grundei,H.: 14 Jahre Erfahrungen mit der zementfreien
ESKA-Sprunggelenksendoprothese. Fuss Sprungg, 2:65-75, 2004.
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3.
4.
5.
1.
Rudigier,J.: Ankle replacement by the cementless ESKA endoprosthesis. Tech Foot & Ankle,
4:125-136, 2005.
Rudigier,J., Grundei,H., and Menzinger,F.: Prosthetic replacement of the ankle in posttraumatic
arthrosis: 10-year experience with the cementless ESKA ankle prosthesis. Eur J Trauma, 27:66-74,
2001.
Rudigier,J., Menzinger,F., and Grundei,H.: 14 Jahre Erfahrungen mit der zementfreien
ESKA-Sprunggelenksendoprothese. Fuss Sprungg, 2:65-75, 2004.
66.14 German Ankle System
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
more
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The German Ankle System is a three-component prosthesis allowing rotation around each of the three
possible movement axes. The talar component of this prosthesis includes side borders to keep the mobile1
bearing in position, which may prevent inlay dislocation. Both metallic components have BONIT© coating
(porous coating with titanium plasma sprayed surface and an additional layer of calcium phosphate) to
ensure the proper osteointegration. The system includes an option for computer-assisted implantation
surgery.
Richter et al performed the robotic-guided surgical approach on a cadaver and compared the results with
those obtained using a HINTEGRA prosthesis. The authors found that the German Ankle Prosthesis had1
smaller effect on resulting forces and torques during partial weight-bearing passive ankle motion than the
HINTEGRA prosthesis. However, to date no clinical results from patients treated with this prosthesis type1
are available, raising some concern regarding the interpretation of obtained data in the study by the
designer.
66.14.1 Reference
Richter,M., Zech,S., Westphal,R., Klimesch,Y., and Gosling,T.: Robotic cadaver testing of a new total
ankle prosthesis model (German Ankle System). Foot Ankle Int, 28:1276-1286, 2007.
OrthopaedicsOne Articles
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66.15 HINTEGRA Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
more
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The HINTEGRA Total Ankle Replacement (TAR) is an unconstrained, three-component system that provides
inversion-eversion stability and was designed in 2000 by Beat Hintermann, Greta Dereymaeker, Ramon
Viladot, and Patrice Diebold. The mobile bearing provides axial rotation and normal flexion-extension
mobility. The HINTEGRA TAR includes two metallic components and an ultrahigh-density polyethylene1-3
mobile bearing. The non-articulating surfaces have a porous coating with 20% porosity and are covered by
titanium fluid and hydroxyapatite.
The tibial component has a flat, 4-mm thick loading plate with pyramidal peaks against the tibia. Additional
stability may be achieved by fixation with two screws. The talar component is conically shaped with a smaller
radius medially than laterally, mimicking the normal anatomy of talus. It has 2.5-mm high rims on each side
that ensure stable positioning and guide the anteroposterior translation of the mobile bearing. The anterior
shield of this component increases primary bone support, especially in cases with weaker bone, and may
prevent the adherence of scar tissue and avoid restriction of ROM in cases with arthrofibrosis.2
The HINTEGRA TAR has been used since 2000 in Europe, since 2004 in Canada and Korea, and since
2005 in Brazil. The use of this prosthesis is also documented in National Arthroplasty Registers of4-7
Finnland, Sweden, Norway, and New Zealand.8 9 10 11
In the current literature there are numerous studies addressing clinical outcome and biomechanical
properties of the HINTEGRA TAR, published by the designer. In 2004, Hintermann et al published the first
study reporting HINTEGRA design rationale, surgical technique, and short-term results of the first
consecutive 122 ankles in 166 patients. All patients were reviewed at a mean follow up of 19 months.12
Eight ankles had to undergo revision surgery, four because of loosening of at least one component, one
because of dislocation of the mobile bearing, and three for other reasons. All revisions were successful.
Most patients experienced significant functional improvement postoperatively, as assessed by the AOFAS
score; 68% were pain free at latest follow up. The clinically and radiographically measured ROM was 39°
and 37°, respectively. Tibial components were stable in all reviewed ankles; in two ankles a slight migration
of the talar component was observed. Similar results were published in a study by Valderrabano and12
Hintermann, including 125 HINTEGRA implants.13
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In 2006, Hintermann et al presented mid-term results of 271 HINTEGRA TARs performed in 261 patients
between 2000 and 2004. The mean follow-up was 36 months with a range between 12 and 64 months.14
Intraoperatively, four malleolar fractures occurred, which all healed within 6 weeks. Five ankles (1.8%) had
to be converted to ankle fusion. Thirteen talar and two tibial components were later revised. In total, 39
revision surgeries (eg, open arthrolysis, lengthening of Achilles tendon, ligament reconstruction) were
necessary to address late postoperative complications.14
Kim et al compared the outcome and complications of HINTEGRA TAR with and without hindfoot fusion. In15
total 60 ankles with HINTEGRA implants and subtalar or triple fusion were compared to a control group of
288 ankles treated with TAR alone. The mean follow up was 39.5 months. The authors found that the clinical
outcome of TAR when combined with hindfoot fusion (subtalar or triple fusion) is comparable to that of ankle
replacement alone. Therefore, the authors recommended that hindfoot fusion should be performed
simultaneously with TAR in cases when indicated.15
Recently, Barg et al published clinical observation studies addressing clinical and radiological outcomes in
patients who underwent HINTEGRA TAR because of end-stage osteoarthritis (OA) due to hemophilia or16
hemochromatosis. In both patient cohorts, favorable outcomes with significant pain relief and functional17
improvement were observed, demonstrating TAR as a reliable option treatment.16,17
Valderrabano et al addressed the sporting and recreational activity of patients with end-stage ankle arthritis
before and ankle TAR. The authors recommended specific Sports Frequency Score. A clinical evaluation18
was performed preoperatively and at a mean follow up of 2.8 years in 147 patients (152 ankles). All patients
experienced significant functional improvement as assessed by the AOFAS score. After TAR, patients with
sports activities had a higher AOFAS score. The three most frequent sports activities after TAR were hiking,
biking, and swimming.18
Daniels et al published their results for 32 TARs in patients with significant preoperative varus talar
deformities. In all patients, cementless, mobile-bearing, three-part component prostheses had been used:19
26 HINTEGRA, four Mobility, and two STAR implants. A satisfactory radiographic correction was obtained in
the most cases (30 ankles) at a mean follow up of 17 months. In 24 ankles, additional procedures after TAR
were required to obtained a plantigrade foot.19
Lee et al addressed perioperative complications of HINTEGRA TAR in their 50 initial cases. The same20
author presented two case reports addressing HINTEGRA TAR in patients following revascularization of
avascular necrosis of the talar body. The authors stated that in patients with avascular necrosis of the21
talus, healing of necrotic bone by creeping substitution TAR is a valuable option.21
Kim et al described clinical outcome of TAR in 23 patients with moderate to severe varus deformity and
compared results to those in 22 patients with neutral alignment. All patients were reviewed at a mean22
follow-up of 27 months and showed substantial pain relief and functional improvement in both groups as
assessed by VAS and AOFAS score, respectively. Failure of the implant with conversion to ankle fusion
occurred in one case in each group. The authors stated that the TAR is a valuable treatment for severe
ankle OA, including patients with hindfoot misalignment. However, the appropriate additional procedures to
address the deformity are necessary to obtain good clinical results including prosthesis stability and ROM.22
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Recently, Bai et al compared clinical outcome and revision rate after TAR between patients with
posttraumatic and primary OA. Sixty-seven consecutive TARs were performed using HINTEGRA23
prosthesis in 65 patients between 2005 and 2007. All patients were divided into two groups: posttraumatic
OA group (37 ankles) and primary OA group (30 ankles). At a mean follow-up of 38 months the clinical
(AOFAS score, ROM) and radiographic outcome were comparable. However, the incidence of postoperative
complications was significantly higher in the posttraumatic OA group.23
Valderrabano et al published a series of studies addressing muscle biomechanics and muscle rehabilitation
in patients with severe ankle OA who underwent TAR. A prospective study performed including 1524-27
patients who were reviewed preoperatively and postoperatively in 3-month intervals up to 1 year showed that
TAR surgery may improve muscle biomechanics as assessed by torque measurement and EMG intensity.24
However, in most patients the muscle rehabilitation was not complete at a follow up of 1 year.24
Müller et al used a Heidelberger foot and ankle analysis model to address the 3D kinematics and foot and
ankle shape in 12 patients who underwent HINTEGRA TAR. The authors detected some decreased ROM28
after ankle replacement compared with contralateral ankles free of degenerative changes. However, these
differences did not affect the gait kinematics, showing TAR may be able to preserve ROM which, in turn,
may avoid or at least decelerate the degenerative changes in adjacent joints.28
Lee et al investigated static and dynamic postural balance after TAR using HINTEGRA in 30 patients and
compared the results to an age- and sex-matched control group. The authors showed that patients who29
underwent TAR have a higher degree of dynamic postural imbalance. Some motor control deficits were also
detected in the TAR group. The authors stated that more intensive postoperative balance training may
decrease the observed deficits.29
In conclusion, the mid-term results in patients with HINTEGRA TAR are favorable. However, most12,14
clinical studies have been published by the designer. Comparable studies by independent authors and
studies with longer follow-ups should be performed.
66.15.1 References
Valderrabano,V., Pagenstert,G.I., and Hintermann,B.: Total ankle replacement - three-component
prosthesis. Tech Foot & Ankle, 2:84-90, 2005.
Hintermann,B. and Barg,A.: The HINTEGRA total ankle arthroplasty, in Wiesel,S.W. (ed), Operative
Techniques in Orthopaedic Surgery Lippincott Williams & Wilkins, 2010, pp. 4022-4031.
Hintermann,B.: Surgical techniques, in Hintermann,B. (ed), Total ankle arthroplasty: Historical
overview, current concepts and future perspectives. Springer , Wien New York, 2005, pp. 105-126.
Kim,B.S., Choi,W.J., Kim,Y.S., and Lee,J.W.: Total ankle replacement in moderate to severe varus
deformity of the ankle. J Bone Joint Surg Br, 91:1183-1190, 2009.
Gougoulias,N.E., Khanna,A., and Maffulli,N.: History and evolution in total ankle arthroplasty. Br Med
Bull, 89:111-151, 2009.
Goldberg,A.J., Sharp,R.J., and Cooke,P.: Ankle replacement: current practice of foot & ankle
surgeons in the United kingdom. Foot Ankle Int, 30:950-954, 2009.
Besse,J.L., Colombier,J.A., Asencio,J., Bonnin,M., Gaudot,F., Jarde,O., Judet,T., Maestro,M.,
Lemrijse,T., Leonardi,C., and Toullec,E.: Total ankle arthroplasty in France. Orthop Traumatol Surg
Res, 96:291-303, 2010.
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24.
25.
26.
27.
Skytta,E.T., Koivu,H., Eskelinen,A., Ikavalko,M., Paavolainen,P., and Remes,V.: Total ankle
replacement: a population-based study of 515 cases from the Finnish Arthroplasty Register. Acta
Orthop, 81:114-118, 2010.
Henricson,A., Skoog,A., and Carlsson,A.: The Swedish Ankle Arthroplasty Register: An analysis of
531 arthroplasties between 1993 and 2005. Acta Orthop, 78:569-574, 2007.
Fevang,B.T., Lie,S.A., Havelin,L.I., Brun,J.G., Skredderstuen,A., and Furnes,O.: 257 ankle
arthroplasties performed in Norway between 1994 and 2005. Acta Orthop, 78:575-583, 2007.
Hosman,A.H., Mason,R.B., Hobbs,T., and Rothwell,A.G.: A New Zealand national joint registry review
of 202 total ankle replacements followed for up to 6 years. Acta Orthop, 78:584-591, 2007
Hintermann,B., Valderrabano,V., Dereymaeker,G., and Dick,W.: The HINTEGRA ankle: rationale and
short-term results of 122 consecutive ankles. Clin Orthop Relat Res, 424:57-68, 2004.
Valderrabano,V. and Hintermann,B.: HINTEGRA-Sprunggelenkprothese: Präliminäre Resultate der
ersten 125 Fälle. Fuss Sprungg, 2:7-16, 2004.
Hintermann,B., Valderrabano,V., Knupp,M., and Horisberger,M.: The HINTEGRA ankle: short- and
mid-term result. Orthopade, 35:533-545, 2006.
Kim,B.S., Knupp,M., Zwicky,L., Lee,J.W., and Hintermann,B.: Total ankle replacement in association
with hindfoot fusion: Outcome and complications. J Bone Joint Surg Br, 92:1540-1547, 2010.
Barg,A., Elsner,A., Hefti,D., and Hintermann,B.: Haemophilic arthropathy of the ankle treated by total
ankle replacement: a case series. Haemophilia, 16:647-655, 7-1-2010.
Barg,A., Elsner,A., Hefti,D., and Hintermann,B.: Total Ankle Arthroplasty in Patients with Hereditary
Hemochromatosis. Clin Orthop Relat Res, 7-28-2010.
Valderrabano,V., Pagenstert,G., Horisberger,M., Knupp,M., and Hintermann,B.: Sports and recreation
activity of ankle arthritis patients before and after total ankle replacement. Am J Sports Med,
34:993-999, 2006.
Daniels,T.R., Cadden,A.R., and Lim,K.: Correction of varus talar deformities in ankle joint
replacement. Oper Tech Orthop, 18:282-286, 2008.
Lee,K.B., Cho,S.G., Hur,C.I., and Yoon,T.R.: Perioperative complications of HINTEGRA total ankle
replacement: our initial 50 cases. Foot Ankle Int, 29:978-984, 2008
Lee,K.B., Cho,S.G., Jung,S.T., and Kim,M.S.: Total ankle arthroplasty following revascularization of
avascular necrosis of the talar body: two case reports and literature review. Foot Ankle Int,
29:852-858, 2008.
Kim,B.S., Choi,W.J., Kim,Y.S., and Lee,J.W.: Total ankle replacement in moderate to severe varus
deformity of the ankle. J Bone Joint Surg Br, 91:1183-1190, 2009.
Bai,L.B., Lee,K.B., Song,E.K., Yoon,T.R., and Seon,J.K.: Total ankle arthroplasty outcome
comparison for post-traumatic and primary osteoarthritis. Foot Ankle Int, 31:1048-1056, 2010.
Valderrabano,V., Nigg,B.M., von,T., V, Frank,C.B., and Hintermann,B.: J. Leonard Goldner Award
2006. Total ankle replacement in ankle osteoarthritis: an analysis of muscle rehabilitation. Foot Ankle
Int, 28:281-291, 2007.
Valderrabano,V., von Tscharner,V., Nigg,B.M., Goepfert,B., Frank,C.B., and Hintermann,B.:
Unterschenkel-Muskelatrophie bei Arthrose des oberen Sprunggelenks und deren Rehabilitation nach
Implantation einer Sprunggelenksprothese. Fuss Sprungg, 5:33-43, 2007.
Valderrabano,V., Hintermann,B., von,T., V, Gopfert,B., Dick,W., and Nigg,B.M.: Muscle biomechanics
in total ankle replacement. Orthopade, 35:513-520, 2006.
Valderrabano,V., Nigg,B.M., von,T., V, Stefanyshyn,D.J., Goepfert,B., and Hintermann,B.: Gait
analysis in ankle osteoarthritis and total ankle replacement. Clin Biomech (Bristol , Avon ),
22:894-904, 2007.
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Muller,S., Wolf,S., and Doderlein,L.: [Three-dimensional analysis of the foot following implantation of
a HINTEGRA ankle prosthesis: evaluation with the Heidelberg foot model]. Orthopade, 35:506-512,
2006.
Lee,K.B., Park,Y.H., Song,E.K., Yoon,T.R., and Jung,K.I.: Static and dynamic postural balance after
successful mobile-bearing total ankle arthroplasty. Arch Phys Med Rehabil, 91:519-522, 2010.
66.16 INBONE Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The INBONE TAR is a fixed-bearing, two-component total ankle system. A special feature of this ankle1,2
design is a modular stem system for both metallic components. The tibial stem has the ability to be extended
by adding more modular segments. The stem of the talar component may be short and limited to the talar
body. However, in cases where subtalar fusion has to be performed or for greater stability, the talar stem
may be extended across the subtalar joint.
To date, there are limited reports in the literature on clinical and radiographic outcomes in patients who
received INBONE TAR. The designer of the prosthesis has performed more than 240 INBONE TARs and3,4
data have been collected in preparation for publication. There are also no biomechanical studies available5
that address the kinematics and biomechanical properties of this prosthesis design.
66.16.1 References
Deorio,J.K. and Easley,M.E.: Total ankle arthroplasty. Instr Course Lect, 57:383-413, 2008.
Cracchiolo,A., III and Deorio,J.K.: Design features of current total ankle replacements: implants and
instrumentation. J Am Acad Orthop Surg, 16:530-540, 2008.
Reiley,M.A.: Total ankle arthroplasty with bone defects. Foot Ankle Spec, 2:32-34, 2009.
Reiley,M.A.: INBONE total ankle replacement. Foot Ankle Spec, 1:305-308, 2008.
Ellis,S. and Deorio,J.K.: The INBONE total ankle replacement. Oper Tech Orthop, 20:201-210, 2010.
OrthopaedicsOne Articles
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66.17 Mobility Ankle System
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The Mobility Ankle System, developed by Pascal Rippstein, Peter Wood, and Chris Coetzee, is a
three-component Buechel-Pappas type prosthesis with a short, conical tibial stem. The talar component of
the Mobility implant resurfaces the superior dome of the talus, while the medial and lateral aspects of the
talus remain untreated (unlike the Buechel-Pappas prosthesis). The talar component has a central,
longitudinal sulcus and two fins, enhancing its intrinsic stability. The nonarticulating surfaces are porous
coated with a titanium spray.
Goldberg et al reported results of their questionnaire-based survey sent to all Consultant members of the
British Orthopaedic Foot & Ankle Society. The Mobility prosthesis was the most commonly used prosthesis1
among 62% of all surgeons in the United Kingdom.1 The use of this prosthesis has also been documented in
the Swedish Ankle Arthroplasty Register and New Zealand Ankle Arthroplasty Register. The Swedish2 3
Ankle Arthroplasty Register included a total of 531 total ankle replacements (TARs) with 23 Mobility
prostheses implanted since 2005. No peri- or postoperative complications with the Mobility prosthesis were2
observed in the Swedish cohort. The New Zealand Ankle Arthroplasty Register included a total of 202 TAR2
with a mean follow-up of 6 years.3 Twenty-nine patients in this registry underwent Mobility prosthesis; no
failures were observed in this study.3
Recently, Wood et al published early results from their prospective study that included 100 Mobility implants
performed in 96 patients between 2003 and 2005.4 At a minimum follow up of 5 years, a total of five ankles
(5%) had to undergo revision surgery -- two ankle fusions and three revision arthroplasties -- resulting in 3-
and 4-year survivorship of 97% (95%CI, 91% -- 99%) and 93.6% (95%CI, 84.7% -- 97.4%), respectively. In
14 ankles a radiolucent line or osteolytic cavity was observed. However, only in five ankles was it more than
10 mm in width. The authors presented encouraging short-term results which are comparable to those
obtained using other modern three-component prostheses.4
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1.
2.
3.
Naal et al addressed habitual physical activity and sports participation before and after TAR in 137
consecutive patients with 155 implants. One hundred one ankles were available for the review at a mean5
follow up of 44 months, 54 of them were Mobility implants. The percentage of patients who were active in
sports did not change after the TAR (62.4% preoperatively and 66.3% postoperatively). The most common
sports activities after TAR were swimming, cycling, and fitness/weight training. The authors registered high
functional improvement in their patient cohort as assessed by AOFAS scores. No association was found
between sports participation, increased physical activity level, and the appearance of periprosthetic
radiolucencies.5
Thermann et al reported a single case of a 58-year-old patient who underwent Mobility TAR and tibialis
posterior tendon transfer for ankle osteoarthritis (OA) and drop foot deformity. Postoperative radiographs6
showed a medial malleolus fracture despite intraoperative pinning with the Kirschner wires. However, the
fracture completely healed after 8 weeks. Three years after the primary procedure, the patient was
asymptomatic and had a stable ankle joint with 5° dorsiflexion and 20° plantar flexion.6
Goldberg et al reported two cases of early failure in patients who underwent Mobility TAR due to component
malposition. In both cases, the talar component was inserted back to front, as was the polyethylene insert,7
requiring ankle fusion in the first case and revision arthroplasty in the second case. The authors emphasized
the need for adequate training of foot and ankle surgeons for performing TARs. They also suggested that
designers have a responsibility to improve marketing and education for surgeons using their products to
minimize incidents of incorrect use.7
Espinosa et al generated two finite element models of TAR prostheses (Agility and Mobility) to investigate
the misalignment of prosthesis components on joint contact pressures. The authors have shown that the8
highly congruent mobile-bearing design of Mobility prosthesis may result in more evenly distributed contact
pressures than the less congruent two-component Agility prosthesis. However, in both design the
misalignment of prosthesis components may lead to pathologically increased contact stresses.8
Bell and Fisher investigated polyethylene wear in Mobility and Buechel-Pappas prostheses using a modified
knee prosthesis simulator. The authors showed that wear in the two models was comparable and that the9
wear rate for both designs significantly increases with the inclusion of an anterior/posterior displacement in
the kinematic inputs, simulating malalignment of prosthesis components.9
In conclusion, the Mobility TAR has been in general use since 2003 in Europe, Australia, New Zealand,
South Africa, and Canada. In the United States a multicenter FDA trial including this prosthesis type is
running.10
66.17.1 References
Goldberg,A.J., Sharp,R.J., and Cooke,P.: Ankle replacement: current practice of foot & ankle
surgeons in the United kingdom. Foot Ankle Int, 30:950-954, 2009.
Henricson,A., Skoog,A., and Carlsson,A.: The Swedish Ankle Arthroplasty Register: An analysis of
531 arthroplasties between 1993 and 2005. Acta Orthop, 78:569-574, 2007.
Hosman,A.H., Mason,R.B., Hobbs,T., and Rothwell,A.G.: A New Zealand national joint registry review
of 202 total ankle replacements followed for up to 6 years. Acta Orthop, 78:584-591, 2007.
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4.
5.
6.
7.
8.
9.
10.
Wood,P.L., Karski,M.T., and Watmough,P.: Total ankle replacement: the results of 100 mobility total
ankle replacements. J Bone Joint Surg Br, 92:958-962, 2010.
Naal,F.D., Impellizzeri,F.M., Loibl,M., Huber,M., and Rippstein,P.F.: Habitual physical activity and
sports participation after total ankle arthroplasty. Am J Sports Med, 37:95-102, 2009.
Thermann,H., Gavriilidis,I., Longo,U.G., and Maffulli,N.: Total ankle arthroplasty and tibialis posterior
tendon transfer for ankle osteoarthritis and drop foot deformity. Foot Ankle Surg,epub ahead of print,
2009.
Goldberg,A.J., Sharp,B., and Cooke,P.: Early failure in total ankle replacements due to component
malposition: a report of two cases. Foot Ankle Int, 30:783-787, 2009.
Espinosa,N., Walti,M., Favre,P., and Snedeker,J.G.: Misalignment of total ankle components can
induce high joint contact pressures. J Bone Joint Surg Am, 92:1179-1187, 2010.
Bell,C.J. and Fisher,J.: Simulation of polyethylene wear in ankle joint prostheses. J Biomed Mater Res
B Appl Biomater, 81:162-167, 2007.
Deorio,J.K. and Easley,M.E.: Total ankle arthroplasty. Instr Course Lect, 57:383-413, 2008.
66.18 Ramses Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The Ramses TAR was developed in 1987 and first implanted in 1989 by a French designer group. The1,2
Ramses TAR is a three-component, semi-constrained prosthesis with a high-density mobile bearing. Initially,
cemented fixation of the prosthesis was used between 1980 and 2000.
A total of approximately 350 TARs using the Ramses TAR have been performed by the inventing group.
Mendolia et al reported long-term results in 69 patients who underwent Ramses TAR between 1989 and
1993. In seven cases, the replaced ankle had to be converted to an ankle arthrodesis (four ankles for pain2
without loosening and three ankles for clinical and radiographic loosening). In an additional five cases, a
second surgery was performed (two cases with mobile bearing ankle replacement and three cases with
revision arthroplasties).2
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2.
3.
4.
5.
Delagoutte performed a retrospective analysis of 110 TARs between 1991 and 1998. This was a3
multicenter study including 22 hospitals. Three different TAR types were used in this study: Ramses (n=66,
60%), LCS (n=36, 33%), and STAR (n=8, 7%) prosthesis. The follow up varied in this study between 3 and
37 months. In general, the postoperative functional results were less favorable, with no postoperative
improvement in dorsiflexion. In two patients with Ramses prostheses, revision surgery was necessary to
address prosthesis loosening.3
Use of the Ramses prosthesis has been listed in 11 of 202 TARs mentioned in the New Zealand national
joint registry. Two failures in this patient cohort were reported.4 4
In conclusion, the mid- and long-term results in patients who underwent Ramses TAR are not satisfactory
due to high revision rates of 18% and 34% at 2 and 10 years, respectively. The number of pain free patients
also has equaled the number of patients with remaining pain.5
66.18.1 References
Mendolia,G. and Talus Group: The Ramses ankel replacement: design-surgical technique result,
results in first 38 cases. The French Orthopedic Web Journal (available at: www matrise-orthop com),
2007.
Mendolia,G., Coillard,J.Y., Cermolacce,C., and Determe,P.: Long-term (10 to 14 years) results of the
Ramses total ankle arthroplasty. Tech Foot & Ankle, 4:160-173, 2005.
Delagoutte,J.P.: Retrospective analysis of 110 ankle prostheses. Eur J Orthop Surg Traumatol,
12:198-205, 2002.
Hosman,A.H., Mason,R.B., Hobbs,T., and Rothwell,A.G.: A New Zealand national joint registry review
of 202 total ankle replacements followed for up to 6 years. Acta Orthop, 78:584-591, 2007.
Michael,J.M., Golshani,A., Gargac,S., and Goswami,T.: Biomechanics of the ankle joint and clinical
outcomes of total ankle replacement. J Mech Behav Biomed Mater, 1:276-294, 2008.
66.19 Salto Total Ankle Prosthesis
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
OrthopaedicsOne Articles
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The Salto Total Ankle Prosthesis was developed between 1994 and 1996 by Michel Bonnin. This total1
ankle replacement (TAR) is the third generation of cementless meniscal-bearing designs. The tibial
component has a flat surface that faces the mobile bearing, allowing free translation and rotation. The 3 mm
medial rim is designed to avoid insert impingement against the medial malleolus. For osseous integration,
the component has a keel and a fixation peg. The specific shape of the talar component mimics the natural
talar geometry - the anterior width is wider than the posterior width and the lateral flange has a larger
curvature radius than the medial. The mobile bearing is manufactured from UHMWPE and has full
congruency with the talar component in flexion and extension. All components are available in three different
sizes.1
In 2008, Leszko et al performed an in vivo kinematics study of the Salto TAR in 20 patients using
fluoroscopy and a 3D-to-2D registration technique. The motion of the prosthesis was described in terms of2
clinical rotations and as rotation about the helical axis. Among the clinical rotations, the dorsi-/plantarflexion
was the most dominant with a mean ROM of 9.2 degrees. The anterior-posterior translation of the mobile
bearing was measured at 1.5 mm and 2.3 mm for gait and step-up, respectively.2
The first clinical study on the Salto prosthesis was published in 2004 by the prosthesis designer. Bonnin et1
al implanted 98 consecutive Salto prostheses between 1997 and 2000. Ninety-three implants in 91 patients
were reviewed clinically and radiographically at a mean follow-up of 35 months. Most patients were pain free
and showed a significant functional improvement as assessed by AOFAS score (from 32.2 to 83.1 points).
Two prostheses had to be converted to ankle fusion, resulting in survivorship of over 95% at 68 months. In1
the following 2 years, 22 additional Salto implants were performed, as published by Weber et al, who
included a total of 115 implants in their study. At a mean follow up of 22 months, four ankles had to undergo3
revision surgery.3
Recently, Bonnin et al presented survivorship at 7 to 11 years in a retrospective review of 98 TARs
performed between 1997 and 2000. Six replaced ankles had to be converted to ankle fusion and an4
additional 18 ankles underwent reoperation without ankle fusion (10-year survivorship 65% with 95% CI of
50% to 80%). The most common complications requiring additional surgery were bone cysts (11 ankles),
fracture of polyethylene (5 ankles), and unexplained pain (3 ankles).4
Furthermore, Bonnin et al addressed the sports activity level of 145 patients who underwent Salto TAR
between 1997 and 2005. Ankle function was assessed using the Foot Function Index and Foot and Ankle5
Ability Measurement. In most cases, replaced ankles were reported to have normal (15.2%) or nearly normal
(60.7%) function. Participation in sports and recreational activities was analyzed only in the osteoarthritis
(OA) group (100 patients), but not in patients with rheumatoid arthritis. While most patients participated in
some sport activities, a return to impact sports was rarely possible.5
In conclusion, the mid-term results of the Salto TAR are promising. However, the only clinical reports come4
from the prosthesis designer. In the United States, a modified design of the Salto TAR is approved for use in
patients with ankle OA. This fixed-bearing design includes a titanium tibial component with a highly6
conforming polyethylene articulating insert. However, to date no clinical studies reporting results of this6
prosthesis are available.
66.19.1 References
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2.
3.
4.
5.
6.
Bonnin,M., Judet,T., Colombier,J.A., Buscayret,F., Graveleau,N., and Piriou,P.: Midterm results of the
Salto Total Ankle Prosthesis. Clin Orthop Relat Res, 424:6-18, 2004.
Leszko,F., Komistek,R.D., Mahfouz,M.R., Ratron,Y.A., Judet,T., Bonnin,M., Colombier,J.A., and
Lin,S.S.: In vivo kinematics of the salto total ankle prosthesis. Foot Ankle Int, 29:1117-1125, 2008.
Weber,M., Bonnin,M., Columbier,J.A., and Judet,T.: Erste Ergebnisse der
SALTO-Sprunggelenkendoprothese: Eine französische Multizenterstudie mit 155 Implantaten. Fuss
Sprungg, 2:29-37, 2004.
Bonnin,M., Gaudot,F., Laurent,J.R., Ellis,S., Colombier,J.A., and Judet,T.: The Salto Total Ankle
Arthroplasty: Survivorship and Analysis of Failures at 7 to 11 years. Clin Orthop Relat Res, 7-1-2010.
Bonnin,M.P., Laurent,J.R., and Casillas,M.: Ankle function and sports activity after total ankle
arthroplasty. Foot Ankle Int, 30:933-944, 2009.
Yalamanchili,P., Donely,B., Casillas,M., Ables,A., and Lin,S.S.: Salto Talaris total ankle replacement.
Oper Tech Orthop, 18:277-281, 2008.
66.20 Special Situations for Total Ankle Replacement
Takedown of Painful Ankle Fusion and Total Ankle Replacement
Simultaneous Bilateral Total Ankle Replacement
66.20.1 Simultaneous Bilateral Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
Some patients may present degenerative changes on both ankles concurrently. In such patients, an1
appropriate treatment may be bilateral total ankle replacement (TAR).
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3.
There is limited information in the current literature about the outcome of simultaneous bilateral TAR.
Karantana et al published a case series including five consecutive simultaneous bilateral TARs performed
between 2002 and 2006 using the STAR prosthesis. The mean follow-up in this patient cohort was 462
months, with a range between 26 and 65 months. Two patients had delayed wound healing. In one patient, a
stress fracture of medial malleolus was seen 10 weeks postoperatively and treated nonoperatively in an
Aircast splint for 6 weeks. At the latest follow-up, all patients experienced significant pain relief and
presented with good functional outcome and reported excellent satisfaction relating to their experience.2
Barg et al recently compared pain relief, quality of life, and functional outcome of 23 simultaneous bilateral
TARs with that of 46 matched unilateral TARs. After 4 months, patients with simultaneous bilateral TAR had3
a higher pain level and worse functional outcome and quality of life as assessed by using AOFAS and SF-36
scores, respectively. However, the observed differences disappeared at the 1- and 2-year follow-up.3
In summary, the two available clinical studies suggest that simultaneous bilateral TAR under one anesthetic
can be offered to patients with bilateral severe ankle OA. However, further studies including more patients2,3
with clinical and radiographic review at longer follow-up should be performed to prove the safety and efficacy
of this procedure.
References
Valderrabano,V., Horisberger,M., Russell,I., Dougall,H., and Hintermann,B.: Etiology of ankle
osteoarthritis. Clin Orthop Relat Res, 467:1800-1806, 2009.
Karantana,A., Martin,G.J., Shandil,M., and Dhar,S.: Simultaneous bilateral total ankle replacement
using the S.T.A.R.: a case series. Foot Ankle Int, 31:86-89, 2010.
Barg,A., Knupp,M., and Hintermann,B.: Simultaneous bilateral versus unilateral total ankle
replacement: A patient-based comparison of pain relief, quality of life and functional outcome. J Bone
Joint Surg Br, 92:1659-1663, 2010.
66.20.2 Takedown of Painful Ankle Fusion and Total Ankle
Replacement
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Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
Ankle fusion as a treatment option for end-stage ankle osteoarthritis (OA) has been reported as the “gold
standard”. Most patients who undergo ankle fusion experience significant early pain relief postoperatively.1
However, many patients with an ankle fusion develop long-term degenerative changes in adjacent joints.1-3
This progressive development of degenerative changes may require addition fusion surgery, eg, subtalar2,4
fusion.5
A nonunion or malunion of an ankle fusion is an uncommon but severe post-surgical complication. In1
patients with painful nonunited or malunited ankle arthrodesis, takedown of the arthrodesis and subsequent
implantation of a total ankle prosthesis may be a treatment option.
Newton performed three total ankle replacements (TARs) using the Newton Ankle Implant in patients with
nonunion of a prior ankle fusion. The initial ankle fusion was performed because of avascular necrosis of6,7
the talus. In one patient, four unsuccessful fusion attempts were performed. All three implants failed,
requiring one prosthesis revision and two lower leg amputations. Therefore, the author stated that TAR
should not be performed in patients with a previously failed ankle fusion.6,7
In 2004, Greisberg et al published a retrospective study of 23 procedures in 22 patients to review takedown
of ankle fusion and conversion to TAR using the Agility prosthesis. At a mean follow-up of 30 months, 188
patients (19 ankles) were available for clinical and radiological review. In three patients, a lower leg
amputation was performed because of significant residual pain. In the remaining 16 ankles, a significant
functional improvement was detected as assessed by the AOFAS score. Thus, in this study a remarkable
rate of postoperative complications with a failure rate of 42.1% was reported. However, the authors
suggested that this procedure is a viable alternative to amputation, primarily in patients with a definable
source of pain and who have not had previous malleolar resection during the initial ankle fusion.8
Between 1999 and 2004, Hintermann et al performed 29 conversions of painful ankle fusion to TAR in 27
patients using the HINTEGRA TAR. At a mean follow up of 56 months, most patients (82.7%) were9,10
satisfied with results and showed significant pain relief and functional improvement as assessed using VAS
and AOFAS scores, respectively. One ankle had to be revised because of persistent pain and significant
loosening of the talar component. All but one tibial component were stable; the talar component was found to
have migrated in four ankles but was asymptomatic in two of them.9,10
Atkinson et al published a case report addressing clinical outcome and gait analysis following conversion of
tibiotalocalcaneal fusion to TAR using HINTEGRA implants. Two years after the conversion to TAR, the11
patient was subjectively delighted with her increased mobility and functional improvement. The objective
results of her gait analysis, which included comfortable walking pace, stride length, and cadence, showed a
trend toward normalization of gait mechanics.11
In 2010, Barg and Hintermann published the detailed technique of this procedure. The absolute12
contraindications for the procedure include:
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6.
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8.
9.
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11.
Clubfoot deformity
* Non-manageable hindfoot deformity
* Highly comprised soft tissues and large scars on the medial side
* Severe vascular and/or neurological deficiency
* Active osteomyelitis and/or deep infection
* Chronic pain syndrome existing over years
* Neuropathic disorders (Charcot arthropathy).12
This procedure may be used with some restrictions (relative contraindications) in the following cases:
* Previous fibulectomy
* Long-standing immobilization
* More than 3 cm shortening of the affected leg
* High demands for physical and sports activities
* Diabetic syndrome without polyneuropathy.12
In conclusion, current studies show favorable mid-term results after conversion to TAR in patients with
painful ankle arthrodesis. However, this procedure is technically more demanding that primary TAR and9-11
should be limited to foot and ankle surgeons with adequate experience in primary TAR. Additionally, careful
preoperative planning and selection of patients are very important factors in achieving a good clinical
outcome.
References
Nihal,A., Gellman,R.E., Embil,J.M., and Trepman,E.: Ankle arthrodesis. Foot Ankle Surg, 14:1-10,
2008.
Coester,L.M., Saltzman,C.L., Leupold,J., and Pontarelli,W.: Long-term results following ankle
arthrodesis for post-traumatic arthritis. J Bone Joint Surg Am, 83-A:219-228, 2001.
Plaass,C., Knupp,M., Barg,A., and Hintermann,B.: Anterior double plating for rigid fixation of isolated
tibiotalar arthrodesis. Foot Ankle Int, 30:631-639, 2009.
Fuchs,S., Sandmann,C., Skwara,A., and Chylarecki,C.: Quality of life 20 years after arthrodesis of the
ankle. A study of adjacent joints. J Bone Joint Surg Br, 85:994-998, 2003.
SooHoo,N.F., Zingmond,D.S., and Ko,C.Y.: Comparison of reoperation rates following ankle
arthrodesis and total ankle arthroplasty. J Bone Joint Surg Am, 89:2143-2149, 2007.
Newton,S.E., III: Total ankle arthroplasty. Clinical study of fifty cases. J Bone Joint Surg Am,
64:104-111, 1982.
Newton,S.E.: An artificial ankle joint. Clin Orthop Relat Res, 142:141-145, 1979.
Greisberg,J., Assal,M., Flueckiger,G., and Hansen,S.T., Jr.: Takedown of ankle fusion and conversion
to total ankle replacement. Clin Orthop Relat Res, 424:80-88, 2004.
Hintermann,B., Barg,A., Knupp,M., and Valderrabano,V.: Conversion of painful ankle arthrodesis to
total ankle arthroplasty. J Bone Joint Surg Am, 91:850-858, 2009.
Hintermann,B., Barg,A., Knupp,M., and Valderrabano,V.: Conversion of painful ankle arthrodesis to
total ankle arthroplasty. Surgical technique. J Bone Joint Surg Am, 92 Suppl 1 Pt 1:55-66, 2010.
Atkinson,H.D., Daniels,T.R., Klejman,S., Pinsker,E., Houck,J.R., and Singer,S.: Pre- and
postoperative gait analysis following conversion of tibiotalocalcaneal fusion to total ankle arthroplasty.
Foot Ankle Int, 31:927-932, 2010.
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12.
1.
2.
3.
Barg,A. and Hintermann,B.: Takedown of painful ankle fusion and total ankle replacement using a
3-component ankle prosthesis. Tech Foot & Ankle, 9:190-198, 2010.
66.21 TARIC Total Ankle Replacement
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
more
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The TARIC TAR was developed by Schill in Germany and has been used since 2006. The TARIC1
prosthesis has a titanium coating and is optionally available with an additional hydroxyapatite coating. The
tibial component has two fixation pegs. Before creating the TARIC TAR, the designer had experience with2
the TRP and STAR prostheses.3
Currently, there are no studies available addressing clinical outcomes or surgical technique of the TARIC
TAR.
66.21.1 References
Schill,S., Rehart,S., and Fink,B.: Endoprothetik am rheumatischen oberen Sprunggelenk: Historie und
Zukunftsperspektive. Fuss Sprungg, 4:98-105, 2006.
Gougoulias,N.E., Khanna,A., and Maffulli,N.: History and evolution in total ankle arthroplasty. Br Med
Bull, 89:111-151, 2009.
Schill,S., Biehl,C., and Thabe,H.: Ankle prostheses. Mid-term results after Thompson-Richards and
STAR prostheses. Orthopade, 27:183-187, 1998.
66.22 TNK Total Ankle Replacement
OrthopaedicsOne Articles
Page of 357 372
This article is taken wholly from, or contains information that was originally published by the
American Orthopaedic Foot and Ankle Society.
more
Section editors and authors for Orthopaedia may have edited its content or added new information. The use
of information from the American Orthopaedic Foot and Ankle Society should not be construed as support
for or endorsement by that organization for any new information added by Orthopaedia members, or for any
editing of the original content.
Learn about the AOFAS
The TNK prosthesis was developed by Dr. Takakura in Japan in 1975. It is currently the only total ankle
prosthesis with alumina ceramic components. The third generation of this device has shown promising
results in reports by the designer, but these have not been results have not been duplicated by others.
In 1988, Takakura et al reported a comparative study of cemented metal and uncemented ceramic TNK
ankle prostheses.1 Both types were two-component prostheses with high-density polyethylene fixed to the
tibial component. Before 1980, the authors implanted 30 cemented stainless steel prostheses (first
generation); after 1980 they used 9 cemented and 30 uncemented ceramic prostheses (second generation).
The mean follow-up time for cemented and uncemented total ankle replacements (TARs) was 8.1 and 4.1
years, respectively.
Patients who underwent TAR with an uncemented prosthesis were 67% more satisfied than those who
underwent the procedure with a cemented prosthesis (27%). Five metal TARs and one ceramic TAR had to
be revised (five arthrodeses and one revision arthroplasty).1
The initial encouraging results were not maintained in another study by the same working group, published
in 2004. Significant loosening and subsidence of the prosthesis were observed in most patients with the2
first-generation TAR (stainless steel prosthesis). The second-generation TAR (ceramic prosthesis) was
implanted in 60 ankles between 1980 and 1991 (in 12 ankles, cement fixation was used). However,
loosening and significant subsidence occurred in most patients within 5 years after the surgery.
In 1991, the ceramic prosthesis (second generation) was modified by adding bead-formed alumina coated
with hydroxyapatite (third generation). Between 1991 and 2001, this prosthesis type was used in 70 ankles.
The mean follow up in this patient group was 5 years. In three patients, the replaced ankle had to be2,3
fused (one case with deep infection, two cases with severe subsidence of talar component). Overall results
were excellent or good in the most patients (52 ankles). The patient satisfaction rate was higher in patients
with osteoarthritis (OA) compared with patients with rheumatoid OA.2,3
OrthopaedicsOne Articles
Page of 358 372
The TNK prosthesis has been used for treatment of rheumatoid OA with poor clinical and radiographic
outcomes, as shown in two studies. Nishikawa et al reviewed 26 patients (six patients received bilateral4,5
TAR) with rheumatoid OA who were treated with a TNK prosthesis between 1984 and 2000. At a mean
follow up of 72 months 27 ankles in 21 patients were reviewed. Three ankles had to undergo revision
surgery. Nine patients reported their outcome as excellent or good, but patients complained about residual
pain in 13 ankles. A high rate of radiolucency was observed in this patient cohort: migration of the tibial
component in 13 ankles and collapse of the talus in nine.4
Nagashima et al reported results of 21 TARs performed in 19 patients between 1998 and 2002 using the
TNK prosthesis. Hybrid-type fixation (talus component cemented, tibial component not cemented) was used5
in 15 of 21 cases, while both components were cemented in the remaining cases. Early postoperative
complications included two patients with delayed wound healing and one patient with deep infection. In 11 of
21 ankles, significant radiolucency lines were observed. Most patients experienced pain relief and functional
improvement; however, postoperative improvement of ROM directly correlated with preoperative ROM.5
Shinomiya et al performed 20 TARs using TNK prosthesis in 18 selected patients with rheumatoid OA
between 1988 and 1996. All patients were reviewed at a mean follow up of 8 years, with a range of 5 to 126
years. All patients experienced substantial pain relief and showed functional improvement superior to those
who underwent ankle arthrodesis in the same period. No conversions to ankle fusion or revision
arthroplasties were necessary in this cohort. However, a radiolucent line was observed in all replaced ankles
at the final follow up. The authors stated that TAR may be useful in young patients with rheumatoid OA,
considering their better postoperative quality of life.6
Shi et al developed a special hydroxyapatite augmentation for bone atrophy in TAR for rheumatoid patients
receiving a TNK prosthesis. This specially designed hydroxyapatite coating was used in 16 ankles (147
patients) and results were reviewed at a mean follow up of 23 months. More than half of all ankles showed a
radiolucency zone between hydroxyapatite and the tibial component on radiographs at the final follow up.
However, no significant changes of coating position were registered; also, no significant subsidence was
noted. The authors suggested that this new technique using hydroxyapatite may increase the primary
implant fixation to the bone, especially in patients with rheumatoid OA and showing significant bone atrophy.7
Recently, Tsukamoto et al reported a case using a custom-made alumina ceramic total talar component for
treatment of collapse of the talar body in one patient who received a TNK prosthesis. The revision surgery8
was performed in a 56-year-old female patient 4 years after the initial TAR. The authors achieved substantial
pain relief and functional improvement especially regarding walking ability. This case report demonstrated a
feasible revision treatment in patients with failed TAR.8
In summary, since its introduction in 1975, the TNK prosthesis has undergone many modifications to
address the material of the components (stainless steel, polyethylene, alumina ceramic), coating
(without/with hydroxyapatite), and fixation (cement/cementless fixation). Currently, this is the only TAR
design with alumina ceramic components. While the studies by the designer reported favorable results using
the third-generation TNK prosthesis, independent studies addressing TAR results in patients with2,3
rheumatoid OA show less-promising results.4,5
66.22.1 References
OrthopaedicsOne Articles
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1.
2.
3.
4.
5.
6.
7.
8.
Takakura,Y., Tanaka,Y., Sugimoto,K., Tamai,S., and Masuhara,K.: Ankle arthroplasty. A comparative
study of cemented metal and uncemented ceramic prostheses. Clin Orthop Relat Res, 252:209-216,
1990.
Takakura,Y., Tanaka,Y., Kumai,T., Sugimoto,K., and Ohgushi,H.: Ankle arthroplasty using three
generations of metal and ceramic prostheses. Clin Orthop Relat Res, 424:130-136, 2004.
Tanaka,Y. and Takakura,Y.: [The TNK ankle: short
- and mid-term results]. Orthopade, 35:546-551, 2006.
Nishikawa,M., Tomita,T., Fujii,M., Watanabe,T., Hashimoto,J., Sugamoto,K., Ochi,T., and
Yoshikawa,H.: Total ankle replacement in rheumatoid arthritis. Int Orthop, 28:123-126, 2004.
Nagashima,M., Takahashi,H., Kakumoto,S., Miyamoto,Y., and Yoshino,S.: Total ankle arthroplasty for
deformity of the foot in patients with rheumatoid arthritis using the TNK ankle system: clinical results
of 21 cases. Mod Rheumatol, 14:48-53, 2004.
Shinomiya,F., Okada,M., Hamada,Y., Fujimura,T., and Hamada,D.: Indications of total ankle
arthroplasty for rheumatoid arthritis: evaluation at 5 years or more after the operation. Mod
Rheumatol, 13:153-159, 2003.
Shi,K., Hayashida,K., Hashimoto,J., Sugamoto,K., Kawai,H., and Yoshikawa,H.: Hydroxyapatite
augmentation for bone atrophy in total ankle replacement in rheumatoid arthritis. J Foot Ankle Surg,
45:316-321, 2006.
Tsukamoto,S., Tanaka,Y., Maegawa,N., Shinohara,Y., Taniguchi,A., Kumai,T., and Takakura,Y.:
Total talar replacement following collapse of the talar body as a complication of total ankle
arthroplasty: a case report. J Bone Joint Surg Am, 92:2115-2120, 9-1-2010.