Iatrogenic Injuries in Percutaneous Pinning Techniques for Fifth Metacarpal Neck Fractures.

BACKGROUND: There is little information regarding anatomic structures at risk during closed percutaneous treatment of fifth metacarpal neck fractures. This study evaluates a variety of common percutaneous techniques with the hypothesis that each approach presents unique risks to tendons and neurovascular structures.

METHODS: Seven cadaveric hands were used for this study. The senior author, a board-certified hand surgeon with more than 20 years of experience, used a mini-C arm to pass 1.6-mm Kirschner wires (K-wires). The 4 percutaneous techniques employed were anterograde, retrograde, cross-pinning, and transverse fixations. Meticulous superficial dissection was carried out, with fixation from all 4 techniques left in place, to identify any tendons or neurovascular structures penetrated by the K-wires.

RESULTS: All techniques demonstrated penetration of at least 1 adjacent structure. The anterograde technique showed penetration of the extensor carpi ulnaris tendon in 5 out of 7 cadavers. In the retrograde approach, the K-wire impaled either the extensor digitorum communis or the extensor digitorum minimi tendons in 4 out of 7 cadavers. The transverse pinning technique exhibited injury to the dorsal cutaneous ulnar nerve in 2 of the specimens. In the retrograde cross-pin technique, there were 2 penetrations of the digital branch of the dorsal cutaneous ulnar nerve.

CONCLUSIONS: None of the described percutaneous techniques for treating fifth metacarpal neck fractures eliminate the potential for damage to surrounding tendons or nerves. Each technique has at risk structures that the treating surgeon should be aware of in order to anticipate potential complications and counsel patients accordingly.