Repair of Flexor Digitorum Profundus to Distal Phalanx: A Biomechanical Evaluation of Four Techniques

Abstract

Many techniques for repair of the flexor digitorum profundus to the distal phalanx show excessive gapping with variable clinical results. The purpose of this study was to test the biomechanical characteristics of an anchor-button (AB) technique, as compared to 3 other techniques. Twenty-four fresh-frozen human cadaveric fingers were randomized to 4 groups, 6 in each: group 1, 2-strand Bunnell suture button pullout technique; group 2, modified Kessler suture and 2 retrograde anchors; group 3: locking Krakow suture with 2 retrograde anchors; group 4, AB technique incorporating a 2-part repair, consisting of a locking dorsal Krakow suture with 2 retrograde anchors and a locking palmar Krakow suture fixed with a button. Tendon-to-bone gapping was measured after cyclical loading. Ultimate load to failure was measured at the end of 500 cycles. The AB technique resulted in significantly less gapping when compared to the other techniques. It also resulted in a significantly stronger repair compared to all the other groups with an average load to failure comparable to the native tendon-to-bone interface. The AB repair might allow for early active postoperative motion after repair of flexor digitorum profundus avulsion injuries and tendon reconstruction procedures; however, the soft tissue effects of this multistrand technique are unknown in clinical repairs.