The effect of asymmetric core suture purchase on gap resistance of tendon repair in linear cyclic loading

To evaluate the biomechanical properties of an asymmetric core suture for tendon repair.

Sixty porcine flexor tendons were repaired with 3 different 4-strand sutures using different core suture purchases: 2 sets of identical purchases of 10 mm, 2 sets of asymmetric purchases (8 mm proximal/distal stump and 12 mm distal/proximal stump), and 2 sets of identical purchases of 12 mm. The tendons were subjected to the cyclic loading for 20 cycles. The number of tendons with gaps at each cycle, elongation of gap area between tendon ends and tendon segment, gap formation forces, and ultimate strengths were recorded.

Tendons repaired with the asymmetric core suture purchases had the smallest gaps during cyclic loading. The elongation of gaps and tendon segments were significantly smaller than those with symmetric suture purchase of 10 or 12 mm. The asymmetric core suture repair had significant higher gap resistance forces than the symmetric suture repair at the final loading cycle.

A 4-strand core suture repair with asymmetric purchases on the tendon stumps generated greater gapping resistance than that with an equal length of suture purchase.

The asymmetric core suture purchase may be a practical measure to improve gapping resistance and fatigue strength when the suture purchase meets essential length requirements.