[Extensor tenodesis to the retinaculum extensorum: anatomic and biomechanical study].

INTRODUCTION The extensor tenodesis is a direct dynamic tenodesis which is activated by wrist flexion due either to hand weight or flexor carpi radialis. This tenodesis is usually performed to the distal radius, but it is possible to fix EDC (extensor digitorum communis) to the retinaculum extensorum. MATERIAL AND METHODS Biomechanical study concerned 12 anatomical subjects (24 wrists). The biometric and radiological analysis of retinaculum displacement distalwards was made under low (1 kg) and moderate (6 kg) pulling. Surgical clips were placed on the proximal and distal limits of the retinaculum in order to study their positions on roentgenograms. RESULTS Average width of the retinaculum was 19 mm. Average movement under 1 kg drive was 6 mm and 8.6 mm under 6 kg drive. X-rays showed that the proximal border of the retinaculum was always located proximally to the wrist rotate centre, whatever the traction. DISCUSSION We found the same anatomical features described by different authors, except for the width of the retinaculum. Our study suggests that the retinaculum is strong enough to support a surgical tenodesis.