Metacarpophalangeal portal safety. An anatomical study.

AIM: To quantify the risk of dorsal innervation injury when performing direct metacarpophalangeal joint portals of the second to fifth fingers.

MATERIAL AND METHOD: An anatomical study of 11 upper limbs of fresh corpses was carried out. After placing them in a traction tower, the metacarpophalangeal portals were developed on both sides of the extensor tendon. The dorsal sensory branches were dissected and the distances between the portal and the nearest nerve were measured by a digital caliper. The portals of all the fingers were compared globally to assess the safest finger and two to two radial and ulnar portals were compared in each of the fingers to assess the safest portal within each finger.

RESULTS

The overall comparison of all portals and fingers showed that the third finger is the safest in any of its portals, while the ulnar side of the second and radial of the fourth are the portals with the highest risk of nerve injury (P=8.96·10-5). Comparing two to two of the radial and ulnar portals in each of the fingers showed that the ulnar portal is safer than the radial on the fourth finger (P=.042), while the radial is safer than the ulnar on the fifth finger (P=.003).

CONCLUSIONS

The third finger was the safest to perform metacarpophalangeal portals, while the ulnar side of the second finger and radial side of the fourth had the highest risk of nerve injury.