The SLAC wrist: Scapholunate advanced

collapse pattern of degenerative arthritis

Four thousand wrist x-ray films were reviewed to establish the pattern of sequential changes indegenerative arthritis of the wrist. After eliminating all other arthritides, we studied 210 cases ofdegenerative arthritis. The most common pattern (57%) was arthritis between the scaphoid,lunate, and radius; 27% of cases occurred between the scaphoid, trapezium, and trapezoid; acombination of these two patterns occurred in 15%. Twenty operations were performed on 19patients with the scapholunate advanced collapse pattern. Eighteen of 19 patients had less painpostoperatively and none required pain medication. Flexion-extension and radial-ulnar deviationmotions showed considerable improvement after the operation. (J HAND SURG 9A:358-65, 1984.)

H. Kirk Watson, M.D., and Frederick L. Ballet, M.D., Hartford and New Haven,

Degenerative arthritis of the wrist occurs

in specific patterns. Not only are there repetitive pat-terns, but the sequence and progression within thesepatterns is repetitive and consistent. More than 4000wrist x-ray films were analyzed and all findings of non-inflammatory degenerative changes were computerizedfor area of initial change, progression of degeneration,degree of joint narrowing, evaluation of sclerosis, andrelated patterns of change between different carpaljoints. All cases of inflammatory arthritis wereexcluded.

The most common form of human wrist arthritis istermed the "SLAC" (scapholunate advanced collapse)pattern. This repetitive sequence of degenerative~hange is based on and caused by articular alignmentproble.ms between the scaphoid, the lunate, and theradius.

Painful and debilitating.SLAC wrist can be recon-structed.1, ~ This reconstruction consists of limited ar-throdesis of the wrist combined with a silicone rubber(Silastic; Dow Coming Corporation, Midland, Mich.)implant.

From the Connecticut Combined Hand Service, Hartford Hospital,University of Connecticut, Newington Children’s Hospital, Hart-ford, and Yale University, New Haven.

Received for publication March 8, 1983; accepted in revised formAug. 1i, 1983.

Reprint requests: H. Kirk Watson, M.D., 85 Jefferson St., Hartford,CT 06106.

¯ 1/3 joint space narrowing :.~¯ 1/3-~-,-2/3 space narrowing¯ complete space narrowing¯ sclerosis¯ osteophytes¯ cysts¯ reversal of normal

radial concavity

Fig. 1. Areas of the wrist were numbered andfrom this list of degenerative arthritic changesby area for each x-ray examination.

358 THE JOURNAL OF HAND SURGERY

9A, No. 31984 wrist: Pattern of degenerative arthritis 359

Fig. 2. A, Earliest degenerative changes of any large series of wrist arthritis will be noted at tip ofradial styloid and outer distal aspect of scaphoid (area I). B,, There is invariably a sharpening normal curve of radial styloid and a similar sharp prominence occurring on scaphoid.

Fig. 3. A, Degenerative process progresses from the tip of the styloid to the articular surfacebetween radius and styloid (area 2). B, By the time complete narrowing has occurred in the radiusand scaphoid, significant osteophytes are often present in area 1. Radius-lunate joint is normal.

and methods

order to determine which specific areas in the

consistently demonstrated degenerative arthritis,than 4000 x-ray films were reviewed. The films

were sc, reened initially for changes in the anteropos-

terior projection. Lateral x-ray films were used forfurther analysis and substantiation. For purposes ofcomputerization, the wrist was divided into multiple

The360 Watson and Ballet HAND SU

Table I. Slac wrist reconstruction procedures

Inv Assoc AgePt side dx Dom (yr)

1 L R 712 R R 59

3 R R4 L R5 R R6 R R

7 L8 R9 L Sc fx

10 L Sc fx

11 R12 R

Bones fused

C-H-L-T3C-H-L-T3

Bone graftsite

RR

61 C-H-L-% I65 C-H-L-T3 R70 C-H-L-T3 R56 C-L R

R 34R 55L 43R 42

R 55R 59

13 L R 5914 R R 59

15 R Osteomyel R 60

16 L R 3817 R R 4418 L R 4919 R R 58

20 L R 28

C-H-L-T3 RCoL RC-H-L-T> prox pole sc RC-L. C-prox pole sc, R

C-dis pole scC-H-L-T3 RC-H-L-T~ R

C-H-L-T3 RC-H-L R

C-L R

C-H-L-T3 R

Silsca

+

+

+

+

+

+

+

+

+

+

(Prev pr)

+

+

+

+

Pt = patient; Inv side = involved side; Assoc dx = associatedL = lunate; h = hamat~; T~ = triquetrum; R = radius; I = iliacteomyetitis; Prev pr = previous procedure.

areas. The results of the film reviews were then placedin their appropriate computerized area (Fig. 1). Thiswas done to demonstrate the common degenerative pat-terns of the wrist.

Twenty operative procedures in 19 patients were per-formed on a specific in~ercarpal joint pattern, the SLACwrist, and were evaluated at long-term follow-up. Eigh-teen patients were right-handed and one was left-handed and the average age was 52.9 years, with arange Of 28 to 71 years. Thirteen of the SLAC wristreconstructions consisted of a limited arthrodesis of thewrist with a Silastic scaphoid replacement, three werereconstructed by limited arthrodesis alone, and fourwere treated by Silastic scaphoid replacement alone(Table I). Follow-up ranged from 4 months to 9.5years. The standard evaluation at follow-up includedrange of motion, grip strength, employment status, andsubjective assessment. All patients with arthritis fromother causes and those with arthritis between thescaphoid, trapezium, and trapezoid we/’e excluded from

the study, the latter group having been reportedelsewhere.

diagnosis: Dora = dominance; Sil sca= silastic scaphoid; FU = follow-up; C =crest; Sc fx == scaphoid fracture; prox pole sc = proximate pole of scaphoid; Osteomyel

Results of x-ray film evaluation

Review of 4000 x-ray films of the hand andrevealed 210 patients with unequivocal dearthritis of the wrist. Of these, 141 demonstratedvolvement in area 1 (Fig. 2, A andB), merit in area 2 (Fig. 3,A andB) and 21 in area

4, A andB). The changes inareas 1, 2, andthe SLAC pattern and were seen in 120 of thereviewed. The SLAC pattern demonstratedcommon pattern of degenerative wrist arthritis

x-ray film reviews demonstrated that arthritisbegins at the most radial portionjoint between the styloid process of the radiusradial-most portion of the scaphoid articularwaist level. The changes then progress to affect;radioscaphoid articular surface and include themal pole of the scaphoid and radial fossa. The

space is lost, sclerosis then develops,cysts appear later, and, occasionally,

distal radioarticular concavity is seen. The dearthritic process usually jumped to thejoint. In reviewing almost 4000 x-ray films, we

The,ND 9A, No. 3

I984 SLAC wrist: Pattern of degenerative arthritis 361

ap: C =~; Osteomyel

nd and

onstrated

t area 3d3of the:ed the~ritis and~ritis

dius and

0 affectie the[’heophytes~ning

13

satE:

Occupationwork status

;: .’.orer, samesame

advertiser, samesalTle

agent, samesame

samesame

worker, different~rofessor, same

samerentai sales, same

department,sameteacher, same

Commen~

Dystrophy--respondedto stress program

Dystrophy--respondedto stress program

Infection

Nonunion C-L-TRadial bone graft

worker, same Dislocated scaphoidreplaced

samesame

same

that the radius-lunate joint is almost neverThe "triscaphe" joint changes (scaphoid,and trapezium) alone represented 14% (area

Fig. 1) and other nonscaphoid-related changesup the remaining 3%.

technique

objective in treatment of the SLAC wrist is tothe wrist so that the lunate will transmit the

of the functioning hand through the preservedjoint. This is accomplished by capitate-

arthrodesis with or without inclusion of the ha-and triquetrum bones. The scaphoid is excised

with a Silastic implant. A dorsal vans-incision is made at the level of the radial styloid

superficial radial nerve and dorsal veins areThe extensor pollicis longus and extensor

radialis longus and brevis are identified and re-A transverse incision is made in the capsule at

of the capitate-lunate joint. All cartilage isthe adjacent surfaces of the lunate, capi-

hamate, and triquetral articulation with a dentalHigh-speed burs are not recommended sincenecrosis can interfere with healing. A 3-

centimeter incision is made 1-inch proximal to the firstincision, running it from the level of Lister’s tubercledorsally just palmar to the first dorsal extensor com-partment. A tiny longitudinally aligned periosteal ar-tery is always present between the first and secondcompartments. An incision is made along this arteryand a subperiosteal dissection made, exposing 1.5 to 2cm of the dorsal radius under the first and second exten-sor compartments. A window of this size is cut with.an osteotome and a No. 2 curette is used to obtain:sufficient cancellous bone for grafting. Trabecular bone:measuring 0.5 to 1 cm is left to support the distalradioarticular surface. Pins 0.045 inch in diameter arepassed from the capitate to the lunate, from the tri-quetrum to the lunate, from the hamate to the lunate,and from the hamate to the triquetrum. Bone from theradius is packed with a dental tamp between the de-nuded bones. The scaphoid is removed while protectingthe radial and palmar ligaments and is replaced by aSilastic prosthesis. The old style Silastic scaphoid pros-thesis is preferred. Reshaping of the scaphoid prosthe-sis is occasionally necessary. Postoperative care in-cludes a long-arm bulky dressing with a posterior plas-ter splint applied from above the elbow to the finger-tips. One week later a long-arm cast is applied, cover-ing the thumb to its tip and holding the index and longfingers in the intrinsic-plus position. The ring and smallfingers are excluded from plaster immobilization. Afterthe fourth week a short-arm thumb spica is applied,with all fingers excluded. After 6 weeks the pins, whichhave been cut off beneath the skin, are removed underlidocaine (Xylocaine) anesthesia by pressing the pinsthrough the skin and extracting them. Depending uponthe appearance of the x-ray films, a simple, removablepalmar splint may be indicated for an additional 10days.

Clinical results

At an average follow-up of 2,~ months, no patientshad found it necessary to change their vocations post-operatively because of problems in the wrist. Eighteenof the 19 patients experienced less pain postoperatively.In no instance did follow-up x-ray films demonstratedegenerative changes in the radius-lunate joint ~r othercarpal joints that had not undergone arthrodesis. Twocases of postoperative dystrophy occurred but re-sponded to a stress program. One nonunion was suc-cessfully treated with repeat radial bone grafting. OneSilastic scaphoid was dislocated but was replaced with-out subsequent problems. One deep infection necessi-tated removal of the Silastic scaphoid. This occurred inthe only patient who complained of continued postop-erative pain. Several months after removal of the

362 Watson and BalletThe

HAND SUR,

Fig. 4, A-B. Narrowing and deepening of radius-lunate joint is accompanied by complete loss ofcapitate-lunate articular cartilage (area 3), with full-width cartilage in radius-lunate joint.

Table II. Results of slac reconstruction

Duration ofsymptoms

Pt preop. (mo)Pain l Surgery

1 24 No No2 8 No Yes3 48 No Yes4 36 No Yes5 60 No Yes6 35 No Yes7 4 No No8 12 No Yes

9 240 No Yes10 12 No Yes11 30 No Yes12 18 No Yes13 18

14 24 No Yes15 636 No Yes16 10 No17 72 No Yes18 360 No Yes19 12 No Yes20 24 No Yes

Grip (kg)Follow-up

x-ray Op. Nonop.

’" No DJD 20 40No DJD 25 29No DJD 30 28No DJD 28 33No DJD 26 37

22 34No DJD 26 45No DJD 18 23

No DJD 19No DJD *No DJD Good NormalNo DJD 14No DJD 12

No DJD 40 40No DJD 14 16

No DJD 26 32No DJD 30 45No DJD 22 18No DJD 30 38

Subjecnve assessment i~

LessLessLessLess LessLess - Less~’

Less E~More Less:Less

LessLessLessLess"Able to knit

crochet now"LessNone

LessLessNoneLess

Less

DJD .= degenerative disease; ROM = range*Normal but weaker than the other side.~’Opposite sides, the same patient.

of motion.

~e

SURGER, SLAC wrist: Pattern of degenerative arthritis 3639A, No. 3

May 1984

~:Fb, "~.’-k. Preoperative film appears to demonstrate a com-

~:pletely destroyed wrist, but analys~s reveals an advanced

SLAC wrist with involvement basically in areas 1, 2, and 3,with preservation of the radius-lunate joint. There is a largecyst in the radius.

7ssessment

ROM

Less

LessLessLessLess , :EqualLessEqual

EqualLessLessEqual

~nit and~OW" "!

More

EqualLessEqualMore

Fig. $B. Arthrodesis of capitate-lunate-hamate-triquetral0ints and Silastic scaphoid produces a wrist that articulates at

its radius-lunate joint and is asymptomatic, even with heavyloading.

the patient underwent another operation inwhich the scaphoid was reimplanted successfully. No

required medicine for pain at the time offollow-up examination (Table II). The extension-

arc of motion as well as the radial-ulnar devia-

Fig. 5, C-D. Patient is pleased with this asymptomatic rangeof motion. The cyst was ignored and has begun to decrease insize.

Fig. 6. Anteroposterior x-ray film shows long-term result ofSLAC wrist deformity treated with limited carpal fusion andS!ilastic scaphoid implant.

364 Watson and Ballet The JouHAND

Table III. SLAC reconstruction and range of motion

Radial-ulnar deviation (degrees)Patient

Extension-flexion (degrees)

Nonop. Op.I Nonop.

20/16 28/2410/20 30/4015/45 36/558/25 20/400/20 18/359/32 34/45

ll/28 19/3315/25 25/456/24 ¯

15/10 30/4010/25 35/4512/40 t16/42 t15/30 20/30

1 20/25 50/352 30/20 64/603 45/38 72/754 30/40 60/505 30/52 65/766 35/45 55/667 45/25 70/738 40/40 80/6o9 9/42 ¯

10 53/45 65/85II 25/25 85/70127 37/40 ?137 40/45 #14 30/40 50/6015 60/50 65/80 21/50 21/55Too early to test preoperative range ofmotion1617 60/50 80/80 25/30 25/4518 -65/70 55/45 15/30 20/4519 35/65 50/70 15/38 28/4020 60/60 55/55 40/28 35/45

*Above elbow amputation."~Opposite sides, the same patient.

tion arc of motion showed marked improvement post-

operatively and are documented in Table III.

Discussion

In this series we observed that 57% of all wrists withdegenerative arthritis initially showed involvement ofthe scaphoid and radius followed by the capitate andlunate, in a pattern we have labeled the SLAC wrist.Our x-ray study revealed that degenerative changes firstoccur between the tip of the radial styloid and the

.scaphoid and then progress along the scaphoradialjoint. The radius-lunate joint is spared as the process

.:progresses to the capitate-lunate joint. Reconstructionof the SLAC wrist is based on our observation that theradius-lunate joint is not affected even in late cases ofdegenerative arthritis. The radius-scaphoid joint is themost susceptible to degeneration because of its ellipticalshape. The radius-lunate joint is protected because ithas a more spherical shape. By fusing the capitate..

lunate joint and replacing the scaphoid with the pros-.thesis, all of the wrist load is assumed through theradius-lunate joint and to a minimal degree through theprosthetic scaphoid-radius joints. Fusion of the hamateto the triquetrum does not seem to affect the eventualrange of motion and does enhance healing of the inter-carpal arthrodesis (Fig. 5). When the Silastic scaphoid

prostheses is left out of the procedure, the restingmoves to a position of radial deviation. This doeshinder the functional loading but we believescap’hoid prosthesis improves wrist alignmentfunction. Reconstruction of SLAC wrist is indicatedsymptomatic degenerative arthritis of the SLACthat does not respond to a program ofmanagement. SLAC reconstruction is not designedsystemic arthritis or inflammatory conditions.past, proximal carpectomy has been used to treatwrist. After resection of the lunate, thescends to articulate with the distal articularthe radius. Even though;the cartilage on the

capitate has been reported to be satithat the proximal capitate has ature than has the lunate and does not fit welllunate’s spheroidal fossa on the radius.we have found the proximal capitate in thesedevoid of good cartilage, which comp;omises the itional result of the procedure.

Conclusions

Most degenerative arthritis of the wrist

articulation of the scaphoid-radius, a jointa major role of the load in wrist function. The.tion of the lunate-radius appears to be spared

The JournalD

No. 3984 SLAC wrist: Pattern of degenerative arthritis

frequently observed to be intact even in ad-

cases of degenerative arthritis. On the basis ofobservations we devised the SLAC wrist recon-

ion and our results demonstrate that all but oneexperienced less pain postoperatively. In addi-

wri--.: motion improved in all patients treated by~rocedure and no patient found it necessary to

vocations postoperatively (Fig. 6).

-2FERENCES

Vatson HK, Hemptson RF: Limited wrist arthrodesis,I: The triscaphoid joint. J HAND SUR6 5:320-7,

t80Watson HK, Goodman ML, Johnson TR: Limited wristarihredesis. Part II: Intercarpal and radial carpal combi-lat;d::~. J HAND SUR66:223-33, 1981

2Rechnasel K: Arthrodesis of the wrist. Acta Orthop;cand 42:441, 1971

~f L, Copin G, Forster JP: Wrist arthrodesis, critical:study, appropo of 28 cases. Ann Chir 23:81-8, 1969: Bertheussen K: Partial carpal arthrodesis as treatment of

local degenerative changes in the wrist joints. ActaOrthop Scand 52:629-31, 1981

6. Peterson HA, Lipscomb PR: Intercarpal arthrodesis.Arch Surg 95:127-34, 1967

7. Campbell CJ, Keokam T: Total and subtotal arthrodesisof the wrist. J Bone Joint Surg [Am] 46:1520-33, 1964

8. Schwartz S: Localized fusion at the wrist joint. J BoneJoint Surg [Am] 49:1591-6, 1967

9. Ricklin P: LeArthrodese radiocarpiene partielle. AnnChir 30:909-11, 1976

10. Cockshott WP: Pisiform hamate fusion. J Bone JointSurg [Am] 51:778-80, 1969

11. Swanson AB: Silicone rubber implants for the replace-ment of the carpal scaphoid and lunate bones. Orth0pClin North Am 1:299-309, 1970

12. Carstan M, Eiken O, Andren L: Osteoarthritis of thetrapezioscaphoid joint. Acta Orthop Scand 39:354-8,1968

13. Crosby EB, Linscheid RL, Dobins JH: Scaphotrapezialtrapezoid arthrosis. J HAND SURG 3:223-34, 1978

14. Patterson AC: Osteoarthritis of the trapezioscaphoidjoint. Arthritis Rheum 18:375-9, 1975

esting wristdoes not

~elievenment

esigned~ns. Inxeatapitatesurfaceradius and

Capitate-radius arthrodesis: An alternativemethod of radiocarpal arthrodesis

Arthrodesis of the wrist may be indicated for a variety of conditions and can be achieved by many

techniques. We have had experience with radiocarpai arthrodesis by fusion of the capitate to theradius after a modified proximal row carpectomy. The common feature in our 10 patients was aflexion deformity of the wrist. In five of the patients it~vas the result of spastic posturing. Five ofthe patients had a variety of other conditions. Primary arthrodesis occurred in all patients andthe cosmetic improvement was appreciated by all patients. Functional improvement seemed to bemost related to the preoperative condition. The follow-up evaluation averaged 5.4 years with arange from 6 months to 11 years. (J HAND SURG 9A::365-69, 1984.)

Dean S. Louis£ M.D., Fred M. Hankin, M.D., and W. H. Bowers, M.D/,Ann Arbor, Mich., and Asheville, N.C.

;11 into

:ases tos the

~ins att

articula’

this load

mrthrodesis involving the radius and the

is a time-honored procedure that has been ac-

the Hand Service, Section of Orthopaedic Surgery, UniversityMedical Center, Ann Arbor, Mich.

publication June 6, 1983; accepted in revised form July

aests: Dean S. Louis, M.D., C4002, Box 054, University. Ann Arbor, MI 48109.

complished by many techniques? -~ The variety oftechniques that have been used to obtain arthrodesis inthis area reflects the varied indications for the proce-dure. In addition, limited intercarpal arthrodesis hasfound applicability in certain cases of established inter-

carpal ligamentous disruption),In a carefully selected group of patients, we have

found that arthrodesis of the capitate to the radius hascertain ’distinct advantages. A review of the literature

THE JOURNAL OF HAND SURGERY 365