Biomechanical comparison of three epitendinous suture patterns as adjuncts to a core locking loop suture for repair of canine flexor tendon injuries

Objective: To determine the effects of different epitendinous sutures (ES) in addition to core locking-loop (LL) sutures on the mechanical properties and gap formation in a canine cadaveric tendon model. Study design: Experimental, ex vivo, biomechanical study. Sample population: Seventy-two cadaveric superficial digital flexor tendon specimens. Methods: Superficial digital flexor tendon specimens were divided into four groups (n = 18): sharply transected and repaired with LL, LL + simple continuous ES, LL + Silfverskiöld cross-stitch ES, and LL + interlocking horizontal mattress ES. Constructs were loaded to monotonic failure. Failure modes, gapping, yield, peak, and failure forces were analyzed. Significance was set at P <.05. Results: Yield, peak, and failure forces increased by 2.5-fold, two-fold, and twofold, respectively when ES groups were compared with core LL suture patterns alone (P <.0001). Resistance to 1- and 3-mm gap formation was greater in ES groups compared with core LL constructs alone (P <.0001). No differences in yield, peak, failure force, or gapping were observed among ES patterns (P >.827). Conclusion: Adding an ES reduced gap formation and increased yield, peak, and failure forces of tenorrhaphies. No difference was detected between the epitendinous patterns tested in this study. Clinical significance: The addition of an ES seems more relevant than the specific type of pattern to improve the biomechanical properties of flexor tendon repairs. In vivo studies are warranted to determine the biological implications of the patterns tested here.