Irreducible Volar Rotatory Subluxation of the Proximal Interphalangeal Joint of the Finger.

We describe 4 cases of irreducible volar rotatory subluxation of the proximal interphalangeal (PIP) joint of the finger that required open reduction. All of the patients had radiographically proven (in lateral-view radiographs) volar rotatory subluxation of the PIP joint, without fracture. The causes of irreducibility were interposition of the lateral band about the condyle of the middle phalanx in 2 cases, interposition of the collateral ligament in 1 case, and scarring of the injured central slip in 1 case. Rupture of the collateral ligament of one side was found in all cases. Acceptable results were provided with all cases after restoration of the collateral ligaments and the damaged parts. Accurate early diagnosis by careful physical examination and obtaining true lateral radiographs of the PIP joint is important.