Central slip tenotomy for the treatment of chronic mallet finger: an anatomic study.

PURPOSE

Tenotomy of the central slip, described by Fowler, can clinically improve chronic distal interphalangeal joint (DIP) extensor lag secondary to mallet finger (terminal tendon disruption). The goal of this study is to evaluate the potential of central slip tenotomy to restore DIP joint extension.

METHODS

A mallet deformity was reproduced in 15 fresh-frozen cadaver fingers after the extensor tendon insertion was sectioned over the DIP joint. A suture anchor inserted at the terminal insertion was then secured to the extensor tendon over the middle phalanx to reconstruct the extensor mechanism. A 500-g weight attached to the proximal extensor tendon applied extensor tension. Central slip tenotomy was then performed. DIP extensor lags before and after tenotomy were recorded.

RESULTS

After sectioning of the terminal tendon over the DIP joint the average amount of extensor tendon lag produced was 45 degrees. After central slip tenotomy was performed the average amount of extensor lag correction was 36 degrees (range, 30 degrees-46 degrees).

CONCLUSIONS

Several clinical studies have shown that central slip tenotomy is an effective treatment for chronic mallet finger but may not fully restore DIP joint extension. Our data suggest that patients with a pre-existing extensor lag of greater than 36 degrees may not achieve full extension from central slip tenotomy, although extensor lags of up to 46 degrees may be corrected.