DEFORMITIES OF THE HAND INCIDENTAL TO PATHOLOGICAL CHANGES OF THE EXTENSOR AND INTRINSIC MUSCLE MECHANISMS

Abstract

1. Metacarpophalangeal joints in extreme hyperextension of long duration in conjunction with absent intrinsic muscles may he treated expediently by joint fusion. 2. Metacarpophalangeal joints with less severe hyperextension and with functioning intrinsic muscle mechanism can be improved by the adequate excision of collateral ligaments, freeing of all dorsal tissues, and stripping of the volar plate. The heavy deep dorsal fascia in particular must be excised. 3. When the intrinsic strength of the index finger is being restored in the absence of contractures, it is advisable to replace weak lumbrical and volar interosseus muscles, as well as a weak first. dorsal interosseus. This strengthens volar abduction and gives a strong pinch. 4. If the dorsal hood is destroyed and the joint is affected, fibrous ankylosis or osseous fusion gives a desirable end result. 5. If the dorsal hood is intact and the extensor tendons are destroyed, it is desirable to correct the extension contracture by adequate excision of scar tissue and collateral ligaments, followed by the replacement of the extensor tendons. 6. In burns, a fixed button-hole deformity can be changed to a mallet deformity for better flexion,—that. is, for a golfer, if other reconstructive measures cannot be done. In old burns, it is important occasionally to maintain a slight button-hole deformity if this position is consistent with a specific occupation,—that is, for a piano player. 7. Fusion of the middle or distal interphalangeal joints is a useful procedure for irreparable flexion or extension deformities. 8. The intrinsic-plus hand, due to contracture of the intrinsic muscle mechanism, can be improved by advancing the intrinsic muscles in the metacarpal region or by sectioning the lateral bands opposite the proximal interphalangeal joints. 9. It is necessary to differentiate a contracture of the intrinsic muscles and fascia, contracture of the lateral bands in the digit only, contracture of both the extensor mechanism and lateral hands, and changes in the digits due to pathological joint changes resulting in hyperextension.