Biomechanics of the intact and surgically repaired proximal interphalangeal joint collateral ligaments.

Collateral ligament injuries to the proximal interphalangeal joint are common. When the collateral ligament is completely ruptured, surgical repair may be required. The strength of the lateral collateral ligaments of the proximal interphalangeal joint was examined using axial distraction on an electrohydraulic testing apparatus. Eighty-five fresh human adult cadaver fingers were assessed; 38 intact ligaments were first examined. The strength of the native ligament was 162.5 N. Forty-seven ligament repair preparations were tested: suture repair (27.8 N), pull-out wire repair (35.9 N), and repair using a Mitek suture anchor (38.4 N). The breaking strength of the intact ligaments was significantly greater than that of any repair. All repaired ligaments failed at the site of the repair. The ligaments repaired by the pull-out wire and Mitek anchor technique were significantly stronger than those repaired with the suture technique.