richard kuipers von lande - anzcvsoldwebsite.anzcvs.org.au/surgery_assets... · 2018-09-11 ·...

Incongruency and Osteotomies for

Elbow Disease

! Richard Kuipers von Lande

Overview (1)

In talking about osteotomies we must address several interlinked questions… - Is incongruency an issue? !- If so how should we measure it? !- What osteotomies can be performed

and how will they work?

Overview (2) - questions

• What is the role of incongruency in development canine elbow disease?

• Is osteotomy helpful in treatment of; – Primary ED in the dog with abnormal

mechanics? – Medial compartment pathology by altering

mechanics (normal or abnormal)?

Outline

Defining ED, with special reference to FCP - pathogenesis of ED and FCP - role of incongruence in FCP !Measurement of Incongruence - current methods of measurement - limitations and current understanding !Osteotomies - types - methods - changes that result - clinical results and complications

“Can’t be far really…”

Definitions (1)

ED has been recognized in dogs since the 1960s !“Elbow arthrosis caused by fragmented coronoid process (FCP), osteochondrosis (OC[D]), ununited anconeal process articular cartilage anomaly, and/or joint incongruency is the manifestation of inherited canine elbow dysplasia” International Elbow Working Group (IEWG) 1993

Definitions (2)

“Elbow Joint incongruency which refers to malalignment of the joint surfaces of the elbow has been proposed as a key factor in the pathogenesis of FCP and various surgical procedures have been devised to treat the proposed incongruency. However the precise characterization of incongruency present in cases of FCP has not been reported consistently” FCP in the dog: is there a role for incongruency? Gemmill and Clements JSAP 2007

Pathogenesis (1)

The coronoid process develops from the same ossification centre as the the proximal ulna (Guthrie et al 1992a), and does not develop from a separate ossification centre as reported by Olsson and Tirgari in the 1970s

“An important result of the study was that no histological evidence was found at any age to suggest that the medial coronoid process of the ulna is a separate centre of ossification.” Guthrie et al 1992 Res Vet Sci

Pathogenesis (2)

FCP cha rac te r i zed by f i s su r i ng and fragmentation of cartilage and bone over the craniolateral aspect of the medial coronoid process. Cartilage erosion over the MC process and medial aspect of the humeral condyle may occur without discrete coronoid fragmentation. !FCP may represent a specific lesion within a wider spectrum of pathology affecting both the coronoid and medial compartment, hence the term medial compartment disease

Pathogenesis (3)Some authors reported histological lesions consistent with OCD (Grondalen 1981, Wolschrin 2005), however most studies have not supported this and rather suggest osteochondral fracture. !Danielson, Fitzpatrick et al 2006 performed histopathology on coronoids removed by subtotal coronoidectomy (SCO) and found lesions consistent with a non healed osteochondral fragment. !!!!! Histopath sites Microdamage Microfractures below AC Fibrous tissue filling gap

!So why has the coronoid fractured?

Pathogenesis (4)

Traumatic coronoid lesions have been reported in adult dogs (Yovich and Read) and when treated with excision appear to result in less OA than in younger dogs !“Removal of a traumatically fractured portion of the medial coronoid process in two adult dogs resulted in a rapid return to soundness. Elbow function in both dogs remained normal on long-term follow-up.” Yovich and Read

!i.e. possibly that the spectrum of pathology seen in young dogs is not solely due to the FCP.

Incongruency (1)

Incongruency is therefore proposed as one mechanism leading to FCP (Samoy et al 2006). Wind 1982 proposed incongruency may lead to disproportionate weigh bearing through the medial compartment leading to pathology. Osteochondral fragmentation has been noted after experimental fracture malreduction in rabbits (Llina et al 1993), and is consistent with microfractures seen.

Incongruency (2)

Concurrent FCP and incongruency seen in BMD !Gemmill et al 2005 reported a strong association between FCP and incongruency

Incongruency (3) RUI

Relative undergrowth of radius with respect to ulna! step defect (Wind 1982, Morgan at al 2000) = radioulnar incongruence (RUI)

Incongruency (4)

Wind 1986 described the gross anatomy and measured the proximal ulna (PU) compared to total ulna and radial length

Incongruency (5)

Wind found that FCP was primary in heavy breeds (not sighthounds) and was correlated to relative increase in length of the PU. !PU correlated to larger trochlear for larger humerus.


Relative undergrowth of radius:ulna proposed ! step defect (Wind 1982, Morgan at al 2000) = radioulnar incongruence (RUI)

– Cadaver studies support incr loading of MC when radius shortened (Preston et al 2001)

!Studies of normal loading and loading after radial shortening by Preston (2000 and 2001) using methyl methacrylate which fills void (non contact) areas. The contact areas can then be assessed and stains applied


Figure 2—Photograph of articulated forelimb of a dog within the material testing system under an axial compressive load. The triceps brachii myotendinous unit was simulated by attaching an adjustable turnbuckle from the proximal humeral metaphysis to a contoured bone plate attached to the olecranon.

Figure 4—Photographic view of the radial articular surface of the elbow joint (radial view). Notice black paint on the radial and distal ulnar contact areas (arrows). A = Ulna. B = Radius.


Figure 4—Photograph of joint cast of control specimen before radial shortening or ulnar ostectomy. Notice the continuity of the contact areas of the radial (R) and ulnar (U) surfaces. !From Preston et al 2000

Figure 5—Photograph of joint cast of control specimen after radial shortening but before ulnar ostectomy. Notice loss of continuity of the contact areas of the radial (R) and ulnar (U) surfaces.



– Cadaver studies support incr loading of MC when radius shortened (Preston et al 2001) !

– Premature radial shortening ! coronoid fractures (MacPherson et al 1992, Robins 1987)


MacPherson, Lewis et al reported on n=4 in which FCP occurred in n=3 secondary to humeroradial subluxation due to premature closure of the distal radial physis. A dynamic PUO with pin was then performed with ulna shortening along with FCP excision, with “encouraging long-term results” Images from MacPherson et al 1992

In 1987 Robins reported in AVP on n=36 cases of distal radial GP closure. 18/36 had fractures involving one or both coronoids.


MacPherson, Lewis et al reported on n=4 in which FCP occurred in n=3 secondary to humeroradial subluxation due to premature closure of the distal radial physis. A dynamic PUO with pin was then performed with ulna shortening along with FCP excision, with “encouraging long-term results” Images from MacPherson et al 1992



– Cadaver studies support incr loading of MC when radius shortened (Preston et al 2001)

– Premature radial shortening ! coronoid fractures (MacPherson et al 1992, Robins 1987)

But…

– Gross mismatch not often observed !

Relative shortening proposed (temporal at some point in growth)…not necessarily present later

Incongruency (10) HUI

• Wind suggested underdevelopment of the trochlear notch in relation to humerus (HUI) that could result in increased stress to UAP and MC. – Larger prox ulna in affected breeds – underdevelopment

could ! incongrunency (Wind 1986)


• Wind suggested underdevelopment of the trochlear notch in relation to humerus (HUI) that could result in increased stress to UAP and MC. – Larger prox ulna in affected breeds – underdevelopment

could ! incongrunency (Wind 1986) !

– Decreased radius of curvature of ulna notch seen in Rottis cf GHs(Collins et al 2001) and in BMDs cf Rhodesian Ridgebacks (Viehmann et al1992) = bicentric concave H-U incongruency


From Collins et al 2001 AJVR


• Wind suggested underdevelopment of the trochlear notch in relation to humerus (HUI) that could result in increased stress to UAP and MC. – Larger prox ulna in affected breeds – underdevelopment could

! incongrunency (Wind 1986) !

– Decreased radius of curvature of ulna notch seen in Rottis cf GHs(Collins 2001) and in BMDs cf Rhodesian Ridgebacks (MacPherson 1992) = bicentric concave H-U incongruency !

– The presence of concurrent MC with UAP (25/155 – Meyer-Lindenberg et al 2006) may support, however in 17/25 no incongruence seen


FIG 2. Mediolateral (A) and craniolateral-caudomedial (B) oblique radiographs of the left elbow joint of a five-year-old German shepherd dog. Besides an ununited anconeal process and moderate to severe osteoarthritis, a fragmented medial coronoid process of the ulna (arrows) is clearly visible From Meyer-Lindenberg JSAP 2006


FIG 3. Arthroscopic picture of the left elbow joint of a two-year-old mixed-breed dog. (A) In addition to the clearly ununited anconeal process (X), (B) a fragmented medial coronoid process (*) in the area of the radioulnar joint could be identified. 1 Cartilage of medial coronoid process of the ulna; 1# cartilage of the ulna; 2 cartilage of the medial humeral condyle; 3 cartilage of the lateral humeral condyle. (X) UAP, (*) FMCP From Meyer-Lindenberg JSAP 2006

Incongrueny (16) HUI

• But…arguments against HUI – Mismatch may be normal in humans and dogs (Preston

2000) !– Dynamic positional changes may occur – radiographs have

not traditionally been taken under weight bearing conditions, only for cadaver research studies

!– The MC also supports more weight in normal dogs –

physiological incongruence? (Maierl et al 2000)…see later

Incongruency (17)

!A third form of incongruence has also been proposed (Fitzpatrick and Yeadon, Vet Surg 2009)

– In this form the curvature of the radial head is different from that of the MC. Mismatch in musculotendoinous development ! biceps force which is essentrically located. Flexion ! conversion to supination! shear along radial incisive. The authors proposed the BURP procedure.

!– Pull of biceps (Hulse VCOT 2010 after Fitzpatrick) was

investigated anatomically;***NEW*** Thought to result in shear consistent with the theory

Incongruity (18) In summaryThree forms of elbow incongruency are proposed or known; 1. Proximodistal radioulnar incongruence = length mismatch 2. Closed radius of curvature of ulnar notch relative to humeral

condyle = bicentric concave H-U incongruency 3. Rotational radioulnar incongruence – mismatch in curvatures

of the radial head and MCP ! shear forces

Incongruity (19) In summary

“…[incongruity] is now considered a herditary cause of elbow dysplasia and a factor contributing to the progression of degenerative joint disease after surgical treatment of affected elbows” Dominque Griffon, Surgical diseases of the Elbow Tobias and Johnson, 2011

The end is in sight…

Measuring Incongruity (1)

Radiographs are unreliable for incongruency below 2mm (Murphy et al 1998, Mason et al 2002) !Elbow position affects detection (90 or 135 degrees are standard for most studies) and simulated weight bearing reduces incongruency !…some incongruency is physiological?

Measuring Incongruency (2)Arthroscopy – can detect incongruency (Beale 2002, Fitzpatrick 2004) but reliability questioned.

– In vivo 1-2mm is generally detected but variation between evaluators (Blond 2005).

– In addition placement of an arthroscope may create or disguise incongruity. !

The article by Samoy et al (2012) compared normal, FCP and FCP with incongruent elbow dogs with excellent images ***NEW*** Images at left from Samoy et al 2012

Griffon (WVOC 2010) suggested a protocol including examination in neutral position at 135 degrees (standing angle) and no supination or pronation (first described by Wagner 2007) see following protocol

Measuring Incongruency (4)CT has become well established;

– Transverse CT can detect some incongruency. Saggital and coronal (dorsal) images through reconstruction (rCT) also helpful

!– rCT has shown high level of reliability and low intraobserver

variability for MCD (Gemmill 2006 cadaver study). A similar cadaver study showed incongruity could also be measured (Gemmill 2005)

!– A retrospective of naturally occurring FCP showed correlation

between affected elbows and incongruency …but not present in all cases.

Incongruency appears at apex not at base – Kramer conversely showed incongruency at base

Therefore a complex incongruency likely present

Measuring Incongruency (5)Limb position is important:

– House 2009 concluded that “Limb position [supination and pronation] must be controlled when performing CT evaluation of elbows for incongruity. 3-D imaging appears to be less affected by limb position than conventional 2-D analysis when assessing radioulnar incongruence.”

!Images from House et al 2009 showing determination of reference points on 2D and 3D CT images !– Griffon proposed a standard protocol for

2D CT imaging of elbow at 135 degrees in dorsal recumbency (Tobias and Johnson 2011) after Cook&Cook, Holsworth et al and Wagner et

Images from Chpt 52 Surgical diseases of the Elbow. In: Tobias and Johnson 2011

Measuring Incongruency (5)• Most recently 3D CT has proved useful;

– A 3D CT study by Bottcher et al (2009) concluded “Estimation of positive and negative RUI based on 3D surface models of the radioulnar articulation mimics gross inspection in a noninvasive manner, the latter being the ultimate gold standard for definitive diagnosis of any radioulnar step. The proposed technique is precise, reliable, and repeatable in vitro”

!!!!– Eljack, Bottcher et al 2013 then went one step further 3D CT

models of cadaver FLs fitted with spheres the sensitivity and specificity was 0.94 and 0.89 respectively . Fitting a sphere to the trochear notch significantly improves diagnostic accuracy

with RUI

Measuring incongruency (6)

Fig 3. Measurement of relative position of the radius with respect to the ulna. Two parallel planes (white) orthogonal to the long axis (gray dotted line) of the 3-dimensional (3D) model of the aluminum rod were manually positioned, 1 at the most proximal point of the radius (black open arrow) and 1 at the most proximal point of the ulna (white open arrow). The distance of those 2 planes (black short arrow) measured perpendicular to the long axis of the aluminum rod (gray dotted line) defined the proximodistal position of the radius relative to the ulna. From Bottcher et al 2012

Figure 1 Process of constructing and fitting a sphere to the trochlear notch. (A) Selection of surface points along the sagittal ridge of the trochlear notch using a paint brush type tool within ParaView. (B) Extraction of the point cloud and transfer of the 3D-coordinates of the selected points to a MATLAB script, calculating the best fitting sphere, where the majority of the points lies on the surface of the calculated sphere. (C) Combination of the generated sphere and the radial and ulnar models. From Eljack, Bottcher et al 2013


MRI – Considered to have limited use in small joints and with complex

articulations such as the elbow, but improved resolution and contrast MR arthrography. MRI can detect cartilage.

– Has been used to assess FCP (Snaps et al 1999) and at least one UAP case but use to assess incongruency remains limited.

!– Janach et al has published in the AJVR2006, concluding that “the

degree of incongruity increases with increasing body weight”, however this may be a reflection of physiological incongruity present in humans (see later)

dGEMRIC and T2 mapping appears to predict cartilage GAG content and similar to hips can help predict outcome (Conzemius WVOC 2010). Low T1 represent low GAG content

Nearly there, not far to go [up]

Osteotomies (1)Dynamic Proximal Ulna osteotomy (DPUO)

– Thompson and Robins 1995, Bardet and Bureau 1996, Ness 1998 !– Results in slight shortening of ulna but also rotation !

relieves abnormal loading of the MC Images at right from Thompson and Robins 1995 !– Preston (2000 and 2001) concluded that “Proximal radial

shortening, which creates articular step incongruity, changes the location and size of the radioulnar contact areas. Dynamically stabilized ulna ostectomies [with pin] proximal to the radioulnar ligament restore contact patterns in vitro”

…will pin limits rotation ? Irritation to triceps Image at left from Preston et al 2001

Osteotomies (2)Dynamic Proximal Ulna osteotomy (DPUO)

– More recently shown to mimic PAUL? – Bottcher et al showed in 2013 that DPUO resulted in reduction of

RUI and prevention of a focal contact area at the MCP. This was not an axial shift but rather a complex 3D rotation of the proximal ulna segment .

Figure 3 Superimposed preoperative (white) and follow-up (orange) 3D model of the radioulnar joint cup of a typical elbow while matching the radius of both models showing the malalignment of the proximal ulnar segment after dynamic proximal ulnar osteotomy (DPUO) (same elbow shown in Fig 1). (A) View from caudal, illustrating varus deformity. (B) View from medial illustrating significant caudal tipping of the proximal segment at the level of the osteotomy. (C) View from proximolateral onto the lateral coronoid process illustrating widening of the lateral radioulnar joint space because of axial rotation of the osteotomized ulnar segment. Images and text from Bottcher et al 2013

Osteotomies (3)

Figure 2 Preoperative (left) and follow-up (right) 3D model of the radioulnar joint cup color-coded based on the subchondral joint space width (SJSW) measurements for a typical elbow (red indicating a narrow SJSW). Orientation of the images in respect to the alignment of the proximal radius was aimed to match each other. Preoperative collapse of subchondral joint space at the medial coronoid process (MCP) (red area) is relieved after dynamic proximal ulnar osteotomy (DPUO), while the focal area of small SJSW at the caudolateral aspect of the radial head moves craniomedially indicating some realignment of the humeral condyle after DPUO. Images and text from Bottcher et al 2013

Osteotomies (4) UAP

Excision; between 90 and 50% owner satisfaction, and 60% and 84% normal in flexion and extension respectively (Roy VCOT 1994, Sjostrom Vet Clin Nth Am 1998). No force plate studies. !Lag screw; Fox, Burbridge and Bray showed (n=10), 6/10 fused but small numbers !Ulna osteotomy; • Sjostrom VCOT 1995 (n=21) 15 fused, 17 dogs had good

outcome. • In another study 21/23 elbows improved but only 5/23 fused

(Turner VCOT 1998)

Osteotomes (5) UAP

Ulna osteostomy and internal fixation; • Krotscheck reported n=4 (VCOT 2000) all healed.

!• Recently Pettitt published a multicenter UK trial (Vet

Surg 2012) looking at osteotomy vs osteotomy AND internal fixation (n=47 elbows, 44 dogs). 14/28 osteotomy alone healed, vs 16/19 osteotomy and int fixation. Osteotomy and lag screw! better fusion, uncertain if this results in better clinical outcome. ***NEW ***

Osteotomies (6)So what about PUO for FCP? Recent ACVS presentation… !Prospective Randomized Clinical Study of Proximal Ulnar Ostectomy in Dogs with FCP. Ursula Krotscheck, Rory James Todhunter, Jeremy J. Rawlinson, Margret S. Thompson, Hussni O. Mohammed.

FCP artroscopic fragment removal (n=16) vs removal and PUO (n=16) randomized. Vert GRFs measured as well as modified Outerbridge scores. No diff preop, significant diff at 0 and 1 months postop, but by 12months no significant differences. !“PUO with IM pin did not significantly affect outcome in FCP”

Osteotomies (7)

But there are concerns about DPUO – Significant postop morbidity (Meyer-Lindenberg 2001) – Also proposed progressive collapse of medial joint space

after osteotomy! accelerated loss of cartilage and actual INCREASE loading of medial joint

!Subtotal coronoidectomy (Fitzpatrick at al 2009) has a reasonable success and may work in a similar manner by removing the incongruent area and reducing humeroulnar loading.

Osteotomies (8)

• When apex of the medial portion of the MC affected then SCO can be used to address incongruence.

• Often severe cart loss humerus in present and other procedures could be considered– The BURP procedure was proposed by

Fitzpatrick (VOS 2009, and later Vet Surg 2009), to treat cartilage malacia or fissures of radial incisive of the medial portion of MC. Also proposed for juvenile dogs , bilateral pain but minimal changes.

– While Hulse (VCOT 2010) confirmed the apparent shear force there is also evidence that cutting the biceps and or brachialis tendon(s) may! lameness (as in a study of 11 Greyhounds reported by Schraff in Vet Surg 2009).

Mapping Elbow forces…a little history

Images from Preston 2001, Mason 2005 and Cuddy et al 2012

!!With improvements in technology normal elbow forces have been mapped initially using methyl methacrylate to show contact (Preston 2001), then pressure maps using micro-thin tactile array sensor (Mason 2005) and more recently using Fiduciary arrays (Cuddy and Pozzi 2012). This has allowed changes from osteotomies to be reported

Osteotomies (9)Rather than treating underlying incongruency osteotomies may shift loading and pressures of the joint, allowing unloading of the medial compartment and relieving intraosseus pressure (pain?). !High tibia wedge osteotomies are used successfully in the treatment of unicompartmental knee OA in humans (Nagel et al 1996) !SHO developed by Shultz (UC Davis)

Humeral Osteotomies (1)

Humeral osteotomies(Fujita et al 2003, Mason et al 2008) propose to shift the transarticular loading from predominantly the medial aspect to the lateral aspect.

– Humeral sliding osteotomies (SHO) achieve a change in loading (Mason 2008) – 25% for 4mm and 28% for 8mm- but humeral wedge osteotomies do not to a significant degree

– Fujita found significant changes in contact areas for both wedge AND sliding humeral osteotomies using methyl methacrylate

– In addition there is a DECREASE of the radial head weigh bearing contact – long term effects uncertain? Images from Fujita and Mason

Sliding Humeral osteotomy (SHO)

Initially 34.5% complications until LP fixation. Case series of 59 limbs by Fitzpatrick Vet surg 2009. Av age in this series 46 mnths. If > 1yr/o and lameness then 31% have cartilage eburnation (as reported by Vermote VCOT 2010 in dogs >6 years). Radiographically these older dogs appear similar clinically to younger dogs, but the distribution of lesions very different in young where eburnation only 3%, and fissures and non-displaced fragments much higher (23 and 45% respectively)

!With refinement in technique 19% complication, 5% serious. The addition of a 4mm locking screws in prox fragment where shear concentrates has helped decr serious complications. Images from Fitzpatrick 2009

Sliding Humeral osteotomy (SHO)

No kinematic studies performed to date in peer viewed literature but Fitzpatrick (WVOC 2010) reported that PVF increased from 85.6% of normal preop to 97.5% @ 12 weeks postop…but stressed that low numbers low !VAS lameness was not significantly different postop but elbow pain score significantly lower. !In 59 humeri / 49 dogs; catastrophic fractures (n=2 ) within first week, multiple screw breakage (n=5 +2), and single screw breakage (n=3) !Only 4 dogs had arthroscopic / necrospy follow-up 6-17months postop and all had fibrocartilage or hyaline cartilage coverage of previously eburnated areas Images from Fitzpatrick 2009

Sliding Humeral osteotomy (SHO)Custom 8 hole plates used (NGD) with Combi holes for either locking or standard screws.

– Most distal and most proximal holes drilled first, drill kept in position 8 to rotate plate into best position.

– Proximal 2,3,4 holes drilled and locking screws placed. – 6, 7 overlong non-locking screws. – Osteotomy made and drill guide removed from 8 with

tightening of 6,7! translation of osteotomy. – 1 and 5 locking screws placed. – Drill in 8 removed and other side of combi hole used as

locking screw. – 6,7 replaced with shorter cortical screws.

Proximal Abducting Ulna Osteotomy (PAUL)

Tepic PAUL course, Munich 2011 and website 2012 By 2012 about 300 cases by Pfeil (since 2007) and 30 colleagues (since 2010 in Europe). Since 2009 PAUL with [3 versions of] an ALPS locking plate by Kyon. !

– By straightening the leg axis with a lateraling and valgus osteomtomy ! off loads med joint and loads lateral joint (initially no published work to support this but in vitro demonstration shown as part of PAUL course 2011).


Andreas Gutbrod, Tomas Guerrero - normal front limb loaded by a weight in a vertical compression frame before and after osteotomy. 3mm step/6 deg angulation plate used with pressure sensors within transverse slits cut in the bones subchondrally (in vitro demonstration shown as part of PAUL course 2011).

!!!!!

Images from in vitro demonstration

PAUL course


Effects; – 1. ulna angulated (plate + bone curvature) - paw lateralized

(+) – 2. distal ulna internally rotated (bone twist) - paw externally

rotated (+) supinated – see Cuddy (Vet Surg 2012) rotational osteotomy paper

– 3. transverse step at osteotomy (? effects) and lastly – 4. opening gap at osteotomy (?effects) –

Guerrero PAUL course 2011 Munich

!Complications not well reported – Anodised titanium so infections <1%, claimed no implant

failures with ALPS system


Two recent ACVS abstracts may help… !The Effect of a Proximal Abducting Ulnar Osteotomy on Intra-Articular Pressures of the Incongruent Canine Elbow Ex Vivo. Marina J. McConkey, Ursula Krotscheck, Dominick Valenzano, Alexander Wei, Ting Li, Marjolein van der Meulen. Cornell University, Ithaca, NY

!“An incongruent canine elbow has decreased medial contact area and increased medial contact pressure compared to the normal elbow. The PAUL plate significantly decreases contact area, mean and peak contact pressure in the medial elbow compartment and may be an effective treatment for MCD.”


Two recent ACVS abstracts may help… !Clinical Experience with PAUL in the patient with elbow disease. Aldo Vezzoni, Med. Vet, DECVS, Clinica Veterinaria Vezzoni srl, Cremona, Italy In this preliminary study, PAUL was carried out in n=32 elbows of 29 dogs Follow-up at 2mnths (100%) 6 mnths (64%) and 12mnths (52%) • The majority of the dogs (78%) improved (great or moderate

improvement) postoperatively, while 19% did not improve and one case deteriorated (8-year-old Lab with very severe OA and plate breakage two months after surgery). NB owner assessment, 4 categories, by telephone

• Nine (28%) cases had minor complications (screw breakage, seromas) , 12.5% repeat surgery.

• After the introduction of the new PAUL plate, no plate loosening or breakage was noted in subsequent cases.


!!!!!!!!!!!!!!!

Images from PAUL course 2011 Munich


!!!!!!!!!!!!!!

KYON PAUL plates and locking drill guides

Humeral (external) rotating osteotomy

Gutbrod and Guerrero (PAUL course 2011) reported on a rotating humeral osteotomy.

– A 15 degree rotation resulted in changes to the location of Peak pressure and centre of pressure as measured with force centres in elbows of cadaver specimens; !!!!!!!

Images from in vitro demonstration PAUL course, Munich 2011

Humeral (external) rotating osteotomyGutbrod and Guerrero subsequently reported in Vet Surg 2012 ***NEW*** !!!!!!!Figure 4 CT images were reconstructed at the level of the subchondral osteotomy in the radius and ulna and true to scale images of the force map were superimposed using the marking on the sensor drawn during testing. The peak pressure location and the center of pressure were determined to be situated over the ulna or the radius. Peak pressure location is indicated by a red box, center of pressure is indicated by a yellow circle

Humeral (external) rotating osteotomyResults: Peak pressure location and center of pressure shifted 37.5 ± 15.9% and 21.5 ± 6.8% laterally after ERHO (P < .001 for both). Both were situated over the subchondral bone of the ulna in neutral position and over the radius after rotation in all 8 specimens (P < .001). Pressure measured in the ulnar part of the osteotomy was reduced from 58.7 ± 9.1% to 27.1% after ERHO (P < .001). Contact area, peak and mean contact pressure, and total force did not vary significantly between conditions. Conclusion: ERHO shifts the peak pressure location and the center of pressure laterally, toward the radial head and reduced the pressure acting on the ulna. The lateral shift of peak pressure may be beneficial in dogs with medial compartment disease.

– This may achieve the same results as SHO without complications, and without reducing contact area, but has yet to be trialed clinically and gait tested.

The last word…“in humans the humeroulnar joint has been proven to be physiologically incongruent in the unloaded state by methyl methacrylate casts and distribution of subchondral mineralization. Under loading the incongruous notch is spread apart by the humerus and contact areas merge in the depth of the notch, and the joint become congruous on heavy loading” Many CT congruencey studies in dogs are performed in the unloaded state.

!!!!Am I chasing shadows? How do I know how much incongruency is abnormal at arthroscopy or on CT? !The degree and nature of physiological incongruency has yet to be determined and will become more important to define as CT and MR become more refined for diagnostic use in ED

And the final, final word?

Take your ice axe!

Acknowledgements

Based partly on the review by Gemmill et al 2006 with the addition of subsequent literature from the journals; !Gemmill and Clements. JSAP 48, 361-368, 2007 !Griffon. Surgical Diseases of the elbow. In: Veterinary Surgery Small Animal. Ed Tobias and Johnson, 2011 !Articles - Veterinary Surgery VCOT !Worth. PAUL procedure. Patron’s Day CPD notes 2012

richard kuipers von lande - anzcvsoldwebsite.anzcvs.org.au/surgery_assets... · 2018-09-11 ·...

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