The aim of this cadaver study was to identify the change in position of the sciatic nerve during arthroplasty using the posterior surgical approach to the hip. We investigated the position of the nerve during this procedure by dissecting 11 formalin-treated cadavers (22 hips: 12 male, ten female). The distance between the sciatic nerve and the femoral neck was measured before and after dislocation of the hip, and in positions used during the preparation of the femur. The nerve moves closer to the femoral neck when the hip is flexed to > 30° and internally rotated to 90° (90° IR). The mean distance between the nerve and femoral neck was 43.1 mm (standard deviation (sd) 8.7) with the hip at 0° of flexion and 90° IR; this significantly decreased to a mean of 36.1 mm (sd 9.5), 28.8 mm (sd 9.8) and 19.1 mm (sd 9.7) at 30°, 60° and 90° of hip flexion respectively (p < 0.001). In two hips the nerve was in contact with the femoral neck when the hip was flexed to 90°.

This study demonstrates that the sciatic nerve becomes closer to the operative field during hip arthroplasty using the posterior approach with progressive flexion of the hip.

Cite this article: Bone Joint J 2015;97-B:1056–62.

Introduction Kirschner wire (K-wire) pinning is a widely accepted technique for fixation of distal radius fractures. Potential exists for injury to the soft tissues. This cadaveric study evaluates the safety of percutaneous pinning of distal radius fractures using a technique of intrafocal placement of K-wires.

Methods Three K-wires (1.6 mm diameter) were inserted percutaneously into 18 cadaveric wrists 18 mm proximal to the radial styloid. A radial wire was placed between the first and second extensor compartments. A dorso-radial wire was placed proximal to Lister’s tubercle. A dorsoulnar wire was placed between the fourth and fifth compartments. The wrists were dissected along the wires to the bone.

Results The superficial radial nerve (SRN) was pierced twice (11%), the abductor pollicis longus six times (33%), the extensor pollicis brevis and the extensor carpiradialis brevis once (6%). Extensor pollicis longus (EPL) was entered five times (28%), the fourth compartment four times (22%) and the fifth compartment once (6%). Only four wrists (22%) escaped injury to any important structure.

Conclusions The incidence of SRN injury by percutaneous insertion of K-wires is similar to that reported for the mini-open approach of around 12%. Rupture of EPL has been reported at around two percent. Aetiology of rupture is unclear and a K-wire that is subsequently removed may not increase the risk of rupture.