INTERFERENCE SCREWS FOR STABILISATION OF THE DISTAL RADIOULNAR JOINT

Abstract

Purpose: Injury to the distal radioulnar joint can result in ulna sided wrist pain and instability. Stabilisation of the distal radioulnar ligaments described by Adams and Berger uses a tendon graft run along the anatomical course of the distal radioulnar ligaments from the lip of the radial sigmoid notch to the fovea of the ulna. The graft wraps around the ulna head and is fixed with a simple suture; this can be challenging for the surgeon and requires a considerable length of tendon. The length of graft required could be reduced by fixing the graft directly to the ulna. Alternative fixation methods when the graft is short would include bone anchors and interference screws.

We therefore compared the fixation strength achieved with simple suture, by bone anchor and by interference screw (Mini Bio-suture Tack and 3mm Biotenodesis interference screw, Arthrex, UK).

Methods: Four ulna bones were harvested along with four corresponding tendons. Tendons were divided into 2mm wide strips and run through a 3.5mm hole in the ulna. Maximum load was measured after fixing the tendon with 1) simple suture, 2) a bone anchor, and 3) an interference screw. Paired data was tested with the paired T-test and Wilcoxon test.

Results: Maximum load recorded was highest for the Mini Bio-Suture Tack bone anchor (99.28 ± 47.39) followed by the simple suture method (96.23 ± 24.14 N), and the Biotenodesis interference screw (46.90 ± 11.29). Differences approached significance when comparing simple suture fixation with interference screws (p=0.02/0.068).

Conclusions: No study has investigated the use of interference screws to secure two tendons in one graft tunnel. Previous work using a single graft and a single tendon has consistently shown that interference screws are superior to other methods of fixation. However, when performing Adam’s procedure for stabilisation of the distal radioulnar joint suturing the tendon together or using a bone anchor provide the greatest fixation strength. This might be due to loss of the interference effect when placing two grafts in the tunnel.