An evaluation of a clinical method to assess malunion of little finger metacarpal fractures.

This study assessed the reliability, responsiveness and validity of two clinical measurements for the assessment of malunion of little finger metacarpal neck and shaft fractures. Both compared the relative lengths of the ring and little fingers in the injured and contralateral hands. One measurement was taken with the metacarpophalangeal joints extended (straight-MCP), and the other with them flexed to 90 degrees (90-MCP). Ninety-five percent of the differences between the relative lengths of the ring and little fingers in the two hands of 50 normal subjects were less than 3mm and the 95% limits of agreement for repeat measurements (intra-observer reproducibility) was +/- 1 mm for both measurements. Both measurements were significantly altered in a group of 218 patients with a past history of a metacarpal shaft or neck fracture. Although both measurements correlated with the patient's assessment of the cosmetic result (p = 0.01), neither measurement correlated with the severity of palmar angulation of the fracture at presentation. It is concluded that these measurements are reliable and responsive, but their validity is uncertain.