A biomechanical study of the reconstruction of the forearm interosseous membrane with the graft substitute

Abstract

Objective To study the abilities of 3 graft tissues to linit proximal radial displacement compared with the native interosseous membrane (IOM) of the forearm. Methods Twelve biomechanics models harvested from fresh-frozen cadaveric forearms were mounted on testing machine. The specimens were tested under 100 newtons of constant axial load with the elbow and wrist in neutral rotation. Proximal displacement of the radius relative to the capitellum was measured. With the radial head excised specimens were first tested with the IOM intact. The IOM was then sectioned and central band IOM reconstruction were performed on each specimen using the following tissues: palmaris longus tendon, flexor carpi radialis (FCR) tendon, and achilles tendon allograft. Ten loading cycles were performed with each test configuration. The increase in proximal displacement between the first and 10th loading cycles represented the elongation of the graft. Results Mean proximal radial displacements were (3.02±3.56) mm (intact IOM), (6.78±4.12) mm (palmaris longus tendon), (5.08±6.78) mm (FCR tendon), (4.13±4.73) mm (achilles tendon allograft), all means were significantly different from each other. Mean graft elongations were (0.31±2.12) mm (intact IOM), (1.82±3.26) mm (palmaris longus tendon), (1.72±4.37) mm (FCR tendon), (0.36±2.89) mm (achilles tendon allograft). All means were significantly different from each other with the exception of means for palmaris longus tendon vs. FCR tendon and achilles tendon allograft vs. intact IOM. Conclusion No graft reconstruction limited proximal radial displacement as effectively as the native IOM. Of the 3 graft tissues the achilles tendon allograft is the best choice if IOM reconstruction is considered for treatment of an Essex-Lopresti injury. Key words: Forearm interosseous membrane; Reconstruction; Graft substitute; Biomechanics