Effect of Bite Distance of an Epitendinous Suture from the Repair Site on the Tensile Strength of Flexor Tendon Constructs in a Canine Cadaveric Laceration Model

Introduction: Blood supply and preventing gap formation <3 mm are critical factors for successful tendon repair. Peripheral epitendinous sutures (ES) increase biomechanical stability of primary repairs by 10 to 50% over core sutures alone.

Objective: To evaluate effect of bite distance of an interlocking horizontal mattress epitendinous suture (IHMES) from the repair site on tensile strength of tendon repairs.

Materials and Methods: Canine cadaveric superficial digital flexor tendons (SDFTs) specimens were randomly allocated into four groups (18 SDFT/group). Transverse tenotomy was performed, and SDFTs repaired with a locking-loop (LL) or 3 LL constructs with IHMES suture bites placed 5 (LL + 5 ES), 10 (LL + 10 ES), or 15 (LL + 15 ES) mm from the transection site. Constructs were loaded to failure. Load at 1- and 3-mm gapping, yield, peak and failure loads, and failure mode were evaluated.

Results: Mean ± SD yield force and failure load for LL constructs were significantly lower than for IHMES constructs. Load at 1- and 3-mm gapping was significantly higher when IHMES was used. Increasing bite distance significantly increased construct strength (LL + 5 ES, 134.4 ± 26.1 N; LL + 10 ES, 151.0 ± 16.8 N; and LL + 15 ES, 182.1 ± 23.6 N), compared with strength for LL alone. Failure mode differed significantly among constructs when IHMES was used.

Discussion/Conclusion: Addition of IHMES to LL constructs increased ultimate tensile strength by 2.5 times and significantly reduced gap formation compared with results for LL alone. Increasing IHMES bite distance increased yield force by 2.1, 2.3, and 2.7 times for bites placed 5, 10, and 15 mm from the tenotomy. Positioning IHMES at a greater distance from the repair site provided superior biomechanical strength for tendon repairs.

Acknowledgment: No proprietary interest or funding provided for this study.