COMPARISON OF GLIDING RESISTANCE AT THE PARTIALLY LACERATED FLEXOR TENDON – A2 PULLEY INTERFACE USING THREE DIFFERENT CIRCUMFERENTIAL SUTURING TECHNIQUES

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 50%. The Silfverskiold circumferential techniques is stronger than the Halsted repair or a running suture, but there is currently no comparison of gliding resistance, which is probably more important than tensile strength for partial lacerations.

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

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 gliding resistance and friction coefficient with the Silfverskiold technique were 1.3 times that of the other two techniques (P< 0.001).

Conclusion: The Silfverskiold technique leads to higher friction at the tendon-pulley interface and may not be an ideal treatment for partial flexor tendon lacerations.