Extra-articular subcutaneous "inverted king post-truss" ligament reconstruction for severe swan neck deformity (snapping finger).

A swan neck deformity (SND) can be well tolerated for a long time, until the appearance of a disabling "snapping finger". In its most advanced condition, the other hand is needed to initiate finger flexion. We propose a technique of extra-articular, subcutaneous ligament reconstruction with an "inverted king post-truss" configuration use in roofs and to reinforce railway bridges. An artificial ligament (MaxBraid™ polyethylene surgical suture, 5 metric, Biomet) makes a figure of eight between transosseous tunnels in the proximal and middle phalanges, crossing over top of the A3 pulley. We limited our series to severe SND cases with "snapping finger". We excluded isolated SNDs without functional disability. Eleven patients were followed for 3.4 years on average. The cause was an acute injury 8 times (7 balloon accidents), rheumatoid arthritis 2 times and overuse once (saxophone). Only one case was a poor outcome of mallet finger. The 11 patients were reassessed by a telephone survey. Two patients underwent reoperation: one for a ligament rupture, the other one for a knot that became untied. One patient had a suspected late rupture but without recurrence of the disabling snapping finger. The 11 patients considered themselves improved by the intervention. Nine patients did not notice any difference between their operated finger and the contralateral side. Return to manual activity was possible once the skin had healed. The technique is simpler than the spiral oblique retinacular ligament (SORL) reconstruction technique described by Thomson-Littler and also less demanding because it does not involve the distal interphalangeal joint. It requires only a short incision in the volar crease of the proximal interphalangeal joint. No tendon or ligament is sacrificed. Neither postoperative immobilization nor lengthy physical therapy is needed. Complications can be avoided by selecting the appropriate artificial ligament material and careful knot tying.