Copyright 1986 by The Journal of Bone and Joint Surgery. Incorporated

Limited Triscaphoid Intercarpal Arthrodesisfor Rotatory Subluxation of the Scaphoid*

BY H. KIRK WATSON, M.D.S’, JAIYOUNG RYU, M D.~, AND EDWARD AKELMAN, M.D.,

HARTFORD, CONNECTICUT

From the Connecticut Combined Hand Surgery Service:

Hartford Hospital. Hartford: Universio’ of Connecticut. Farmingvm; ,Vewin,°~ ton Children’s Hospital. Newington:

and Yale University, New Haven. Connecticut: and the UniversiO’ of Massachusetts. Worcester, Massachusetts

ABSTRACT: Rotatory subluxation of the scaphoid isa well known lesion that is relatively common and results~n instability of the wrist. It has been well accepted thatbecause of the subluxation of the scaphoid, degenerativechanges in the wrist may develop rapidly, and for thatreason correction of the subluxation in its early stages

is indicated.Over the past thirteen years, many cases of rotatory

subluxation of the scaphoid in various stages of the path-ological process have been successfully treated with atriscaphoid arthrodesis of the wrist (fusion of the scaph-old, trapezium, and trapezoid) at the Connecticut Com-bined Hand Surgery Service. A follow-up of thirtypatients with an average length of follow-up of threeyears and eleven months is described. From this exper-ience, a classification system and treatment plans foreach type of rotatory subluxation of the scaphoid have

evolved.

In 1934, mid-carpal subluxation was brought to theattention of the medical community by Mouchet and Belot,but on.ly recently has a heightened interest developed in thatand other positional abnormalities of the carpal bones~7.

Several papers have described various regimens for treat-ment of the lesions classified under the term rotatory sub-luxation of, the scaphoid~"3’~9.’-t" They include cast im-mobilization, closed or open reduction with or without pin-ning, capsular reefing, reconstruction or substitution of lig-aments, limited intercarpal arthrodesis, proximal rowcarpectomy, and total arthrodesis of the wrist. No usefulclassification of the rotatory abnormalities and no consistentplan of treatment for the different degrees of severity ofthose lesions has been suggested to date. One purpose ofthis paper is to propose such a classification, and four classesof rotatory subluxation of the scaphoid (Table I) are pos-tulated. Our second purpose is to show what results wereobtained with triscaphoid arthrodesis in the treatment of

rotatory subluxation of the scaphoid.The concept of a limited intercarpal arthr0desis is not

new. In 1946 Sutro first reported on arthrodesis of the scaph-

* This article was accepted for publication prior to July 1. 1985. Noconflict-of-interest statement was requested from the authors.

+ 85 Jefferson Street, Suite 501. Hartford, Connecticut 06106.+, Hand Surgery Service, Department of Orthopaedic Surgery. Texas

Tech University ~chool of Medicine, 4800 Alberta Avenue. El Paso, Texas

7~905-1298.

old, trapezium, and trapezoid in the treatment of non-unionof a scaphoid fracture, and it was first suggested as treatmentof rotatory subluxation of the scaphoid by Peterson andLipscomb in 1967. We have given preliminary reports ofits use in the treatment of several lesions, including certain

disease-, andinstabilities of the wrist~, degenerative joint "Kienb6ck’s disease’-t. Others have recently reported on itsuse for rotatory subluxation of the scaphoid, but the resultsof a longer follow-up tha~ is contained in their report areneede:d:. In this report we give our results with follow-up

averaging nearly four years.

Material

,One hundred and forty-seven patients have had thetriscaphoid arthrodesis to be described for rotatory sublux-ation of the scaphoid during the period from February 1972to June 1985. Follow-up of two years or more was availablein forty-three of the fifty-one patients who were operatedon before May 1983. The large number of patients (ninety-

six) *ho were seen after that date is attributable to. theincrease in referrals because of our cited publicationstg"2t.

Eight of the fifty-one patients were not available for follow-up and have been excluded from this report: one was d__ead,another was severely disoriented, and six patients could notbe found. Of the remaining forty-three patients, four haddynamic rotatory subluxation of the scaphoid (our Type I),twenty had static rotatory subluxation of the scaphoid (Type2), and six patients had rotatory subiuxation of the scaphoidwith degenerative arthritic changes (Type 3). The degen-erative changes in all six patients were limited to the tri-scaphoid joints (between the scaphoid, trapezium, andtrapezoid). Excluded from the report are thirteen patientswith Type-4 involvement: twelve with Kienb6ck’s diseaseand one with lateral dislocation of the trapezium. Those

thirteen patients have been reported on previously-. Thepresent report therefore deals with thirty patients, seventeenof whom were male and thirteen, female. The ages at thetime of operation ranged from sixteen to sixty-nine. Thedominant hand was involved in twenty-three patients. Theduration Of symptoms before the arthrodesis ranged from 42one month to ten years (average, two years and five months).The: average length of follow-up was three years and elevenmonths (range, two to almost twelve years). Eight patientshad follow-up of longer than five years, and their resultswere compared with those in the other twenty-two patients.

346 H.K. WATSON, JAIYOUNG RYU.. AND EDX, VARD AKELMAN

Classification

Type l : dynamic rotato~.’ subluxation of the scaphoid(four wrists in this series) is diagnosed when symptoms andsigns of instability exist with no radiographic abnormality;that is, stress radiographs, arthrograms, and cineradiographsare normal~5’~6. There is a history of pain in the wrist, usuallylasting for at /east six months. The pain usually is worseon activity and afterward, and it is not completely relievedby rest. The patients usually have a decreased range ofmotion of the wrist, particularly of flexion. There is ten-derness over the scaphoid (in the anatomical snuff-box)indicative of periscaphoid synovitis. The so-called scaphoidtest is positive. For this test, the examiner places his or herfingers (of the same hand as that to be examined) posterior.to the dorsal end of the patient’s radius and his or her thumbon the tuberosity (distal pole) of the scaphoid. The exam-iner’s other hand deviates the patient’s wrist first ulnarwardand then radialward. Normally, in ulnar deviation the scaph-old assumes a position in line with the forearm, and in radialdeviation it lies nearly perpendicular to the axis of the fore-arm. As the examiner presses on the scaphoid tuberositywith his or her thumb while moving the patient’s wrist fromulnar deviation to radial deviation, the examiner obstructsthe motion of the scaphoid from assuming a transverse po-sition. If there is instability, the proximal pole of the scaph-old will displace dorsally out of the elliptical radial fossa.

TABLE I

CLASSIFICATION OF ROTATORY SUBLUXATION OF THE SCAPHOID

Type 1: dynamic

Type 2: static

Type 3: degenerative

Type 4: secondary

Rotatory subluxation of the scaphoid with noradiographic evidence of abnormality

Rotatory, subluxation of the scaphoid withradiographic findings of scapholunatedissociation, foreshortening of the scaphoid.a wide scapholunate joint, a ring sign,overlapping of the scaphoid and capitate.and an increased scapholunate angle

Type 1 or Type 2 with concomitantdegenerative arthritic changes

Rotatory subluxation of the scaphoid secondary,to Kienb6ck’s disease, scaphoid non-union,or other causes

Th:is displacement is accompanied by significant pain. Somemid-carpal dorsal displacement also may occur. Comparisonof the two sides is important, and the examiner shoulddevelop experience with this test in many patients withnormal wrists.

Type 2: static rotatory subhtxation of the scaphoid(tw,enty wrists in this series) is diagnosed when the historyand findings on physical examination are similar to thosein Type 1. but more severe. In addition, there usually is ahistory of an acute injury,, and the radiographs reveal thetypical signs of rotatory subluxation of the scaphoid (Figs.1-A and I-B). It should be emphasized that the only dif-

FIG. I-A FIG. l-BFigs. 1-A and l-B: Static rotatory subluxation of the scaphoid is demonstrated.Fig. l-A: Posteroanterior radiograph demonstratine a definite foreshortenin~ of the scaphoid, a rin~ si_on, a wide gap (dissociation) between the

scat~hoid, and the lunate, and excessive overlappin,_, o~" the scaphoid and the cat’irate. ~ ~Fie. l-B: Lateral radiograph demonstrating the s~caehoid in a well flexed position. As a resuit of the subluxation, the scapholunate an~le exceeds the

normal limit, which is 70 degrees. The an,,le is 81 degrees in this wrist. Because of the scapholunate dissociation, the lunate usually ~torsi~lexes androtates so that its concavity tilts dorsally, producing a so-called DISI (dorsiflexed intercalated-seement instabilitv/ pattern, but occasionally there is VISI (volar intercalated-segment instability) pattern. ~ " -

LIMITED TRISCAPHOID INTERCARPAL ARTHRODESIS 347

ference between Types 1 and 2 is the presence of radio-graphic changes of rotatory subluxation of the scaphoid.Occasionally asymptomatic patients have similar radio-graphic findings secondary to ligament hypermobility.

Type 3." rotato~ subluxation of the scaphoid with con-comitant degenerative changes (six wrists in this series) diagnosed on the basis of a history similar to that in eitherType 1 or Type 2, but the symptoms are usually more severe,their duration often is longer, and the patient is older. Theremost often is swelling as well as severe tenderness over thescaphoid, and the range of motion of the wrist invariablyis decreased in all directions. The scaphoid test is positive.Degenerative changes are present most commonly betweenthe radius and scaphoid as well as in the scaphoid-capitateand scapholunate joints (that is, the SLAC wrist [scapho-lunate advanced collapse pattern])~8’2° (Fig. 2), or in thescaphoid-trapezium and scaphoid-trapezoid joints~9"-° (Figs.3-A and 3-B). We will be discussing only wrists in whichdegeneration was confined to the latter joints. Triscaphoidarthrodesis is contraindicated if there is degeneration be-tween the scaphoid and the radius.

Type 4: seconda~ rotator, subluxation of the scaph-oid, while excluded from this report, designates a secondaryrotatory subluxation of the scaphoid because of other carpallesions such as a collapsed wrist due to Kienbrck’s disease~-~

or non-union of the scaphoid.

Treatment

The two main indications for the triscaphoid arthrodesisare, first, that the rotatory.subluxation of the scaphoid bedemonstrable clinically and radiographically. Second, indynamic subluxation, the duration of symptoms and theirseverity must be sufficient to justify the procedure, and areasonable period of conservative therapy must have beenfollowed unsuccessfully. A third indication is the devel-opment of arthritic changes at the triscaphoid joints; how-ever, if the d.egenerative changes involve the radioscaphoidjoint, triscaphoid arthrodesis should not be done.

The operative technique and postoperative care for thearthrodesishave been described previously~9’2°. It should beemphasized that the position of the scaphoid must be suchthat its long axis, viewe.d laterally, lies at approximately 45degrees to the long axis of the forearm. The most frequentmajor technical error is positioning the scaphoid in line withthe forearm instead of at the recommended angle. This willresult in significant limitation of range of motion of the wristbecause of the incongruous alignment of the surface of thescaphoid in relation to the articular surface of the radius.

Results

The average length of follow-up for the thirty wristsin this report was three years and eleven months, with arange from two years to eleven years and nine months. Noneof the thirty patients changed their vocational or avocationalactivities after the operation. Four patients had only mildpain during use of the wrist, and there was an ache afteractivity only following vigorous exercise or heavy manual

FIG. 2

Rotatory subtuxation of the scaphoid rapidly produces degenerative ar-thritis of the wrist. The first changes occur between the distal part of thescaphoid and the styloid process of the radius, followed by changes allalong .the joint between the scaphoid and the radius. Finally, the jointbetween the capitate and the lunate becomes involved. The pattern outlinedis the most common form of degenerative arthritis of the wrist and is calledSLAC ~scapholunate advanced collapsed) wrist. Once the degenerativechanges occur m other than the triscaphoid joints, triscaphoid arthrodesisalone cannot solve the problem, and the SLAC wrist-reconstruction pro-cedure is indicated~s’-’°.

work. We analyzed the ranges of motion and grip strengthswith the patients divided into two groups: those with morethan five years of follow-up and those with two to five yearsof follow-up. We did not find any significant difference inthese two groups, so our results will be discussed for allthirty wrists together.

At the time of follow-up, the average grip strength onthe operative side was thirty-one kilograms, representing 92per cent of that on the opposite, normal side. The maximumdifference in grip strength was twenty-two kilograms. Nine’/teen patients had a difference in grip strength of zero to fivekilograms. Only five patients had a difference in gripstrength exceeding ten kilograms.

The .average extension of the wrist that had been op,~erated on was 55 degrees, 75 per cent of that on the un-affected side. The average flexion on the treated side was68 degrees, 84 per cent of that on the contralateral side.The; average radial deviation of the involved side was 12degrees, representing 55 per cent of the range on the con-

348 H.K. WATSON, JAIYOUNG RYU, AND EDWARD AKELMAN

FIG. 3-A FIG. 3-BFigs. 3-A and 3-B: Degenerative arthritis is evident in the triscaphoid joint space, with obvious rotatory subluxation of the scaphoid.Fig. 3-A: The radiocarpal joints can be seen to be free from degenerative changes. There is some joir~t-space narrowin2 between the capitate and

the lunate.Fig. 3-B: Lateral radiograph demonstrating associated rotatory subluxation of the scaphoid with a scapholunate angle of almost 90 degrees as well

as an advanced DISI pattern.

tralateral side, and the average ulnar deviation was 28 de-grees, 73 per cent of that on the contralateral side. The lossof extension was more tl~an 30 degrees in four patients, 20to 30 degrees in eight, and 10 to 20 degrees in fourteen.The loss of flexion exceeded 30 degrees in only two patientsand was more than 20 degrees in eleven. There was nostatistically significant correlation between the decrease ingrip strength, duration of symptoms before operation, andlength of follow-up.

No patient had significant pain during the range-of-motion examination at follow-up, and the radiographs of allpatients at the time of follow-up demonstrated solid fusionof the three bones at the site of arthrodesis. No degenerativechange in the remaining intercarpal joints or in the radio-carpal joint was demonstrated in any patient (Fig. 4). performed ninety-six additional triscaphoid arthrodeses be-tween May 1983 and June 1985, and the results to datehave been consistent with the results in this report.

Complications

No patient had an infection, non-union, or delayedunion. Three patients had mild to moderate dystrophicchanges after the operation, but all responded well to phys-ical therapy.

Discussion

Rotatory subluxation of the scaphoid is a common typeof instability in the wrist and usually is troublesome anddifficult to treat, Appropriate treatment is indicated becausedegenerative changes in the wrist often will develop.

FIG. 4.

A follow-up radiograph made almost twelve years after arthrodesis dem-onstrates solid fusion of the triscaphoid joint and no degenerative changesof the carpus.

LIMITED TRISCAPHOID INTERCARPAL ARTHRODESIS 349

We have treated the various types of rotatory sublux-ation of the scaphoid with a triscaphoid arthrodesis (fusionof the scaphoid, trapezium, and trapezoid) over the lastthirteen years, and thirty such wrists had a successful resultafter an average follow-up of approximately four years.Wrists with more than five years of follow-up did not showany deterioration of the result compared with wrists that hadtwo to five years of follow-up, which suggests that the long-term results of the arthrodesis are durable. Theoretically,degenerative arthritis of one or more of the unfused inter-carpal joints or of the radiocarpal joint might be anticipatedsequelae, but our radiographic examinations did not dem-onstrate that complication (Fig. 4). No patient in this studyand none of the many more recently operated on (hut notyet reported) have required surgery for degenerative changesin or about the involved wrist.

At the time of the last follow-up, our patients had anaverage grip strength of thirty-one kilograms, approximately90 per cent of the contralateral grip strength. The averagepostoperative ranges of motion of the wrist were extensionof 55 degrees (73 per cent of the contralateral side), flexionof 68 degrees (84 per cent of the contralateral side), radialdeviation of 12 degrees, and ulnar deviation of 28 degrees.All of the arthrodeses healed solidly, and at the time offollow-up no degenerative changes were found in any ofthe wrist joints other than those that had been present pre-operatively. All thirty patients returned to their vocational

and avocational activities shortly after the operation. There-fore, in our experience, arthrodesis seems to be a successfulprocedure. The decrease in the range of motion of the in-volved wrist, mostly in radial deviation, is acceptable anddoes not compromise function.

From this experience, we classified rotatory subluxa-tion of the scaphoid in four types (Table I). Type 1 (fourwrists in our series) is a dynamic type in which no radio-graphic abnormality is present despite clinical symptomsand signs. Conservative treatment with immobilization isindicated initially, but triscaphoid arthrodesis may be con-sidered if, despite the treatment, the symptoms are persistentor increase over a minimum period of six months. Type 2(twenty wrists) has typical radiographic findings of rotatorysubluxation of the scaphoid along witti the clinical findings,and triscaphoid arthrodesis is indicated. Type 3 (six wrists)demonstrates degenerative changes. Triscaphoid arthrodesisis indicated only when the degenerative change is limitedto the distal periscaphoid joints and does not involve theradioscaphoid joint. If a degenerative process is present inany other carpal or radiocarpal joint, triscaphoid arthrodesisalone is contraindicated. Treatment for such wrists will bemore extensive, and was discussed in our previouspapers~9’2°. Type 4 is a secondary rotatory subiuxation ofthe scaphoid which usually occurs due to Kienb6ck’s dis.-ease. it was described in one of our previous papers on thatspecific subject2~.

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