TRANSPOSITION OF THE LATERAL SLIPS OF THE APONEUROSIS IN TREATMENT OF LONG-STANDING " BOUTONNIERE DEFORMITY " OF THE FINGERS By IVAN MATEV Institute of Reconstructive Surgery, Sofia, Bulgaria RUPTURE of the central slip of the digital extensor expansion in the region of the proximal interphalangeal joint accounts for loss of active middle phalanx extension and occurrence of typical deformity. The associated discomfort and pain in the middle and distal joints reduce the working capacity of the hand. Treatment of the characteristic "boutonniere deformity" is one of the difficult and controversial problems in reconstructive surgery of the hand. Late suture, in my experience, has not been effective even in small separations. Because of the contraction of the extensor muscle, the two ends of the slip could be approximated only provided the fibres inserted to the base phalanx were detached. The proximal phalanx, however, remained in strong hyperextension, which was difficult to overcome. Free tendon or fascial graft is no more encouraging, the main reasons being the presence of permanent contraction of the extensor muscle and dislocation of the tendon graft on flexion of the middle phalanx. Suture together of the separated lateral slips constitutes a method which may bring about favourable results in recent injuries. In inveterate lesions the lateral slips are shortened from the long-standing intrinsic muscle contracture, and can be approximated only under strong tension, which restricts middle and distal phalanx flexion. The operative management as proposed by Fowler (1956) is the only one which restores active extension in the middle joint (two cases from my series), provided there is no articular rigidity and the dorsal skin is in good condition. My experience shows that success in the surgical management of deformities of the middle and distal joints depends on the following points : (I) the creation of an independent extensor of the middle phalanx, and (2) lengthening of the lateral slips. The treatment we have adopted in the past four years in long-standing "boutonniere deformity" is as follows. The dorsal skin of the entire middle phalanx is dissected as a rectangular flap. By means of additional skin incisions along the dorsolateral surfaces of the distal and proximal phalanges, two triangular flaps are tailored (Fig. i), thus exposing the distal half of the proximal phalanx and the proximal half of the distal phalanx. The lateral slip of the aponeurosis on one side is divided opposite the midpoint of the middle phalanx. It is reflected proximal to the transverse fibres of the aponeurosis. The other lateral band is severed at a more distal point, immediately distal to the distal joint, and is reflected up to the proximal interphalangeal joint (Fig. 2). The surgical manoeuvre of the volar displaced lateral slips brings about a mild correction of the proximal joint flexion contracture. Next, the first band is passed through a slit in the proximal portion of the central extensor slip and fixed, with fully corrected proximal joint, to the base of the middle phalanx, periosteum, and soft tissues. Passing of the band through a cleft in the common extensor prevents lateral dislocation on flexing 281
282 BRITISH JOURNAL OF PLASTIC SURGERY the digit. The second band crosses the dorsum of the middle phalanx and is sutured to the distal cut end of the first with the distal phalanx in extension. This procedure provides for the lengthening of the aponeurosis in its distal portion and corrects hyperextension contracture of the terminal phalanx (Fig. 3). With a view to achieving this goal, detachment and distal moving of the distal joint FIG. I FIG. 2 FIG. 3 Fig. i.--scheme of skin incisions. Fig. 2.--The lateral portion of the aponeurosis on one side is cut along the middle aspect of the medial phalanx, and on the other side just above the distal joint. Fig. 3.--Scheme showing transposition of the lateral bands with lengthening of their distal half. The lateral band on one side is left acting as extensor of the terminal phalanx. The passing of the other band through a cleft in the upper portion of the central slip obviates dislocation when the digit is flexed. capsule may occasionally prove necessary. The distal end of the second band is fixed to the distal portion of the first. In involvement of the index or little finger, the ulnar and radial bands respectively are divided (the latter are thicker than the others and more adequate for suturing). This is done because in two cases (one index and one little finger) the operation was limited to division and transposition of one band to the middle phalanx; the deformity in the distal joint was satisfactorily corrected and further surgical treatment was not justified. Suture with oooo silk on an atraumatic needle proved to be most satisfactory. Post-operative immobilisation is maintained for twenty days with the metacarpophalangeal joint in 45 degrees flexion and extension of the interphalangeals. Rehabilitation is carried out for several weeks after the operation. Only patients treated according to the method described and with a follow-up
TREATMENT OF LONG-STANDING " BOUTONNIERE DEFORMITY " OF FINGERS 283 period exceeding six months are included in the review. The follow-up period is from eight months to three years, the average being one year and nine months. Three patients sustained glass cut injuries ; in one the lesion was closed, in another one there was an open fracture of the proximal phalanx, whereas the FIG. 4 Case I. A 23-year-old female student with a boutonnihre deformity due to a glass cut wound. Examination at the time of operation (29th September 196o ) revealed mild rigidity in the medial joint and strong in the distal one. FIGS. 5 and 6 Condition at the check examination two years and nine months after the operation--the ulnar slip is transposed to the medial phalanx and the radial one is elongated, and left to act as extensor of the distal phalanx. remainder suffered various types of lacerated skin injuries without involvement of bone. In three patients there was considerable scarring of the dorsal skin. All had a slight or moderate degree of flexion deformity of the proximal joint, and moderate or marked hyperextension deformity of the distal joint. Despite pre-operative corrective exercises, all patients showed deformity of the distal joint at operation, and four of the middle joints in addition. The mean time lapse between the day of sustaining the trauma and surgical intervention was nine months.
284 BRITISH JOURNAL OF PLASTIC SURGERY All operations were performed under local anmsthesia. In extension of the middle joint, the central slip defect ranged between i and 2½ cm. The ulnar slip was transposed to the middle phalanx in eight fingers (three right index, two right middle, and three left middle fingers), and the radial only once (right_~little finger). FIG. 7 Case 2. A 35-year-old electrician sustained a lacerating wound. Moderate rigidity in the medial and distal joints at the time of surgery (i2th January 1961). A slight limitation of flexion in the proximal interphalangeal joint is present, due to a previous injury. The ulnar slip only was cut and transposed to the medial phalanx. Case 2. FIGS. 8 and 9 The condition at the last follow-up examination two years and five months after the operation. As already pointed out, in two cases one slip only was operated upon, since the division of one of the aponeurotic lateral parts alone exerted a satisfactory effect on the distal phalanx hyperextension. Correction of the deformity was achieved in six of the nine patients reported, and function in the middle and distal joints was restored. Three of the results are illustrated (Figs. 4 to I2). The somewhat decreased extension force of the end
TREATMENT OF LONG-STANDING " BOUTONNIERE DEFORMITY " OF FINGERS 285 phalanx exerts no unfavourable effect on the function and working capacity of the hand. Of the remaining three patients of the present series, one achieved correction of the flexion contracture of the middle phalanx, but the hyperextension deformity FIG. IO Case 3. A 26-year-old technician sustained a lacerating injury of the third and fifth fingers of the right hand in a motorcar accident. At the time of surgery there was moderate rigidity in the medial and strong rigidity in the distal joint of the third finger. FIGS. I I and I2 Condition of the same finger eight months after the operation. Transposition of the ulnar slip to the medial phalanx performed together with elongation of the radial slip. The latter assumes the function of extensor of the terminal phalanx. of the distal phalanx due to laxity of the stitches was converted into flexion. Resuture of the aponeurosis was done in this area with a good outcome. As far as the last two patients are concerned, only the hyperextension contracture of the distal phalanx was corrected. The condition in the middle joints was
286 BRITISH JOURNAL OF PLASTIC SURGERY unsatisfactory because of the articular rigidity and considerable scarring due to the original trauma. The unfavourable result obtained was anticipated. CONCLUSION Although only a small number of patients have been treated, the results obtained provide sufficient ground for laying emphasis on the two advantages of the operation: (i) there is no need for tendon grafting, (2) sound correction is achieved of severe hyperextension rigidity involving the distal interphalangeal joint. REFERENCE FOWLER, S. B. (1956). Quoted by S. BunneU. " Surgery of the Hand," 3rd ed: Philadelphia and London : J. B. Lippincott. Submitted for publication, July I963.