EFFECT OF THE CIRCUMFERENTIAL SUTURE TECHNIQUE ON THE FRICTION COEFFICIENT FOLLOWING FLEXOR TENDON REPAIR: IN VITRO STUDY ON TURKEY TENDONS

Abstract

Introduction: Treatment of a partial laceration in zone 2 of a flexor tendon is controversial. Although the intact part of a partially lacerated tendon is sufficient to sustain normal physiological forces, conservative management can lead to triggering, entrapment and rupture. Surgical repair is advocated for lacerations deeper than 60%. The Silfverskiold and Halsted techniques for peripheral repair use more suture material and have been shown to be stronger than a simple running suture. Currently there are no comparison of gliding resistance between different circumferential suture techniques, which is more important than tensile strength for partial lacerations.

Aim: The purpose of this study was to compare friction coefficient and gliding resistance at the flexor tendon – A2 pulley interface using three different circumferential repair techniques.

Method: Thirty long flexor tendons from long digit of turkey foot, along with the equivalent of A2 pulley were harvested. The tendons were lacerated to 50% and ten each were subjected to a Silfverskiold, Halsted or a running suture. All experiments were carried out for intact and lacerated tendon at 30, 50 and 70 degrees of flexion and two load settings of 2 N and 4 N. Gliding resistance was measured as the difference between forces recorded at the two ends of the tendon and the friction coefficient was measured using this formula, μ = Ln[(F2/F1)]/Ø.

Results: The Halsted repair was associated with a 100% increase in gliding resistance and friction coefficient relative to the intact tendon, compared to 80% for the Sil-fverskiold repair and 60% for a running suture (p=0.05). The running suture was technically the easiest.

Conclusion: We recommend a simple running suture for peripheral repair of partial flexor tendon lacerations, where surgical repair is advocated.