A Case Report of Complex Dislocation of the Metacarpophalangeal Joint of the Little Finger

Abstract

Dorsal dislocation of the MP joint of the finger is a relatively rare injury. The most common digit involved is the index finger. We presented a case with complex dislocation of the MP joint of the little finger which was thought to be quite rare. This case involved a 52-year-old man who injured his little finger by hyperextension. Closed reduction failed and open reduction was carried out with the dorsal approach. Operative findings revealed that the structures obstacled closed reduction were volar plate and bilateral collateral ligaments which tightened the volar plate bilaterally. From our previous experiences and this case, we concluded that the main structure blocking the closed reduction in the complex dorsal dislocation of the MP joint is not a special structure described by Kaplan (FDC, lumbrical muscle, natatory ligament and superficial transverse metacarpal ligament), but volar plate connecting with deep transverse metacarpal ligament and collateral ligament which tightened the volar plate.From these cases, the dorsal approach is recommended because it is easier to confirm the blocking structures and to reduce the dislocation. Also the neurovascular bundle is not as likely to be damaged.This mechanism reduces the surgical exposure. It is difficult to confirm the mechanism using the volar approach and the neurovascular bundle is more easily damaged during this exposure.The dorsal approach is recommended because it gives full exposure of the volar plate, it is easier to use for open reduction and there is no risk of damaging the neurovascular bundle.