Dorsal surgical approaches to the proximal interphalangeal joint: a comparative anatomic study.

PURPOSE: Adequate exposure of the articular surface of the head of the proximal phalanx is essential for reduction of intra-articular fractures of the proximal interphalangeal (PIP) joint. We compared the articular exposure obtained by a dorsal extensor-tendon splitting (Swanson), an extensor tendon-reflecting (Chamay), and an extensor mechanism-sparing approach.

METHODS

The PIP joints of 24 digits from 6 fresh-frozen cadaveric specimens were randomly assigned to 1 of 3 dorsal surgical exposures: an extensor tendon-splitting, extensor tendon-reflecting, or extensor mechanism-sparing approach. The exposed surface was painted with methylene blue and the PIP joints were disarticulated to reveal the distal articular surface of the proximal phalanx. Using 3-dimensional digital mapping, we calculated the percentage of the exposed dyed surface area to the total surface area and compared the 3 approaches.

RESULTS

The mean percent exposed joint surface area for the extensor tendon-splitting, extensor tendon-reflecting, and extensor mechanism-sparing approaches were 41%, 52%, and 16%, respectively. Each approach provided a significantly different percentage of articular PIP joint surface area from the other 2.

CONCLUSIONS

The amount of articular surface visualized using 3 dorsal approaches to the PIP joint must be weighed against the amount of extensor mechanism violated. Exposure of the articular surface by the extensor mechanism-sparing approach to the PIP joint allowed nearly a third of the exposure gained by the extensor tendon-reflecting exposure. Although the extensor tendon-reflecting technique revealed the greatest amount of surface, nearly 50% of the proximal phalanx articular surface remained inaccessible as long as the collateral ligaments were intact.

CLINICAL RELEVANCE: Understanding the limitations inherent in dorsal exposure of the PIP joint may help guide the surgical approach for the individual patient.