The volar anatomy of the distal radius--an MRI study of the FCR approach.

Introduction: Fractures of the distal radius are one the commonest orthopaedic injuries. Recent advances in implant technology have seen a dramatic rise in the number of fractures treated with volar locked plates, as they permit accurate peri-articular reconstruction. The surgical approach along the bed of flexor carpii radialis (FCR) tendon encounters a number of key soft tissue and neurovascular structures during the dissection to the fracture plane. The aim of this study was to describe the exact position of such structures involved (and hence at risk) during the FCR approach.

Methods: 100 adult MRI scans were reviewed. The relationships between the brachioradialis tendon (BR), flexor carpi radialis (FCR) tendon, flexor pollicis longus (FPL) tendon, median nerve (MN) and radial artery (RA) were measured.

Results: The male to female ratio was 35:65. Average age was 39. FCR tendon was 7.4 mm (SD 1.46) from the RA and 7.01 mm (SD 2.37) from the MN. The distance between BR and RA was significantly different between male and female (5.06 mm vs. 4.1 mm, p=0.034).

Conclusion: This study highlights the precise nature of the surgical anatomy involved in dissection to the fracture site. Vigilance is needed during the initial steps of the FCR-bed approach to avoid damage to the radial artery and median nerve which lie in close proximity. If the approach is extended to include a brachioradialis tenotomy, we suggest this should be made under direct vision, given its relationship with the radial artery.