Ulnar drift

LETTERS TO THE EDITOR Ulnar drift To the Editor: In the September issue an original communication from Mr. Harrison 1 has prompted questions and comments. On page 88 under "The intrinsic snap," it is stated that the index finger is provided with additional stability through the first interosseous muscle and by the support given by the middle or long finger. Wouldn't the stability through the second dorsal interosseous muscle and the support given by the adjacent ring finger provide the long finger with the same stability? In Fig. 7 on page 90 is demonstrated the attachment of the extrinsic extensor tendon to the base of the proximal phalanx. If this attachment were secured with the interphalangeal joints extended, then flexion of these joints would be impossible. If secured with these joints flexed, then interphalangeal joint extension could only be achieved through the action of the intrinsics. If subsequent intrinsic contractures became severe, releases, such as described by Littler,2 could not be performed without taking away all voluntary extension of the interphalangeal joints. If, however, fibrosis of the intrinsics rendered them fixed length cords of sufficient length so that intrinsic plus was not extreme, then through the "tenodesis effect" they could cause interphalangeal JOlllt extension as the metacarpophalangeal joint extended. (As the loop attachment through the proximal phalanx extended this phalanx, interphalangeal joint extension necessarily would follow.) What has been the author's experience and observation in regard to interphalangeal joint extension following the loop attachment to the proximal phalanx? When the metacarpophalangeal joint is near full flexion, the loop attachment to the proximal phalanx does not seem to be in a position which would prevent ulnar subluxation of the extrinsic extensor tendon from the ]lead of the metacarpal. As pointed out by Zancolli,4 even normal transverse laminae are not capable of maintaining centralization of the extrinsic extensor tendon when the finger is in full flexion. It is then the fibrous tissue proximal to the transverse laminae which keeps this tendon centralized. It would appear that the correction of ulnar drift in the long finger is because the author divides the ulnar intrinsic tendon of .the long finger and transfers the ulnar intrinsic tendon of the index finger to the long finger. The loop attachment to the proximal phalanx could provide dorsal support for the extensor tendon during partial flexion.

REFERENCES 1. Harrison, S. H.: The importance of middle or long finger realignment in ulnar drift, J. Hand Surg. 1: 87-91, 1976.

2. Littler, J. W.: Tendon transfers and arthrodesis in com-

bined median and ulnar nerve paralysis, J. Bone Joint Surg. 31A: 228, 1949. 3. Boyes, J. H.: Bunnell's surgery of the hand, ed. 5, Philadelphia, 1970,1. B. Lippincott Co., p. 329. 4. Zancolli, E.: Structural and dynamic basis of hand surgery, Philadelphia, 1968, J. B. Lippincott Co., p. 7. Reply To the Editor: Thank you for your comments. To take your first comment. The second interosseous apparently does not provide sufficient stability to prevent ulnar drift of the middle finger, whereas the first interosseous does do this for the index finger. The index finger often is stable when there is a large erosion present, but the middle finger will nearly always show a medial shift. In regard to your comment on the extensor loop operation, this is sutured with the metacarpophalangeal joint fully extended and the proximal interphalangeal joint fully flexed, and there is no interference with the movement of these joints. I note your comment in regard to intrinsic contractures, but some years ago, in conjunction with Prof. Bywaters, I did an investigation on the intrinsic muscles in rheumatoid arthritis to disprove that there was fibrosis present, and this was confirmed absolutely and reconfirmed in Gothenberg at a later date. There has so far been no interference with interphalangeal extension following the extensor loop operation. I have now done the extensor loop operation on over 300 patients, and it has always achieved centralization of the extensor tendon over the metacarpophalangeal joint. It does not normally interfere with flexion or extension, at either the metacarpophalangeal joint, or at the proximal interphalangeal joint, but one has to always bear in mind that these joints are periodically affected by the rheumatoid arthritic process and are potentially liable to stiffness. Stewart H. Harrison, F.R.C.S. (Eng.), F.R.C.S. 1, Dorset Road, Windsor, SL4 3BA, England

John E. Micks, M.D. 2300 S. Hope St., Suite 500 Los Angeles, Calif. 90007 248

THE JOURNAL OF HAND SURGERY

May, 1977

Vol. 2, No.3, p. 248