Reattachment of Flexor Digitorum Profundus Avulsion: Biomechanical Performance of 3 Techniques

PurposeTo investigate whether inclusion of the volar plate in repair of flexor digitorum profundus avulsions increases the strength of the repair and resists gapping.MethodsCadaveric fingers (n = 18) were divided into 3 equal groups. The first technique involved 2 micro-suture anchors only (A). The second used only volar plate repair (VP). The third group was a hybrid, combining a micro-suture anchor with volar plate augmentation (AVP). Specimens were loaded cyclically to simulate passive motion rehabilitation before being loaded to failure. Clinical failure was defined as 3 mm of gapping, and physical failure as the highest load associated with hardware failure, suture breakage, anchor pullout, or volar plate avulsion.ResultsGapping throughout cycling was significantly greater for the A group than VP and AVP with no difference detected between VP and AVP groups. Gapping exceeded 3 mm during cycling of 3 A specimens, but in none of the VP or AVP specimens. Load at clinical and physical failure for A was significantly lower than for VP and AVP, whereas no difference was detected between VP and AVP.ConclusionsIn this cadaveric model, incorporating the volar plate conferred a significant advantage in strength, increasing the mean load to physical failure by approximately 100 N.Clinical relevanceAccording to previous biomechanical studies, current reconstructive strategies for flexor digitorum profundus zone I avulsions are not strong enough to withstand active motion rehabilitation. We demonstrated the potential use of volar plate augmentation and the prospective advantageous increase in strength in this cadaveric model. In vivo performance and effects on digital motion are not known.