The Effect of Core Suture Knot Location on the Mechanical Properties of Flexor Tendon Repaired With Modified Kessler...

A robust suture technique is essential to permit early mobilization after flexor tendon repair. It requires sufficient contact between two lacerated tendon ends. However, the core suture knot, which is embedded commonly between these two ends in many repair techniques, impedes the contact of tendon ends and possibly hinders tendon healing. This study aimed to identify the biomechanically optimal location for the core suture knot embedded outside the junction of lacerated tendon ends in a modified Kessler repair.

Two canine flexor digitorum profundus tendons were used to exhibit the proportion of cross-sectional area occupied by the suture knot. Forty canine flexor digitorum profundus tendons were repaired using a modified Kessler technique with the core suture knot embedded in various locations. The gliding properties and repair strength of the repaired tendons were investigated.

A knot of 4-0 core suture occupied approximately 24% of the tendon's cross-section. The repaired tendons with the core suture knot embedded in the volar side demonstrated larger gliding resistance and greater work expenditure than those with the core suture knot placed between the lacerated tendon ends or embedded in the radial or dorsal side of the tendon during the identical cycles of repeated gliding. Moreover, the dorsal embedding of the core suture knot resulted in an increase of load for 2-mm gap formation and ultimate load relative to the other locations.

The biomechanically optimal location of the core suture knot in a modified Kessler repair was under the dorsal surface of flexor tendon.

The embedding of the core suture knot in the dorsal side could facilitate the early postoperative mobilization and the healing of repaired flexor tendon.