Capsular injuries of the proximal interphalangeal joint.
Although capsular injuries of the PIP joints are common, their management is frequently complicated. Successful treatment must begin with a detailed history because reviewing the mechanism of injury may provide information relevant to the pathomechanics of the capsular disruption and facilitate making an accurate diagnosis. Grades I and II volar plate and collateral ligament sprains represent the vast majority of PIP joint injuries. They are best treated with a short period of dorsal splinting followed by supervised mobilization. Although splinting is also applicable for grade II sprains associated with instability and most grade III sprains, the initial period of immobilization should be longer. The prognosis for recovery is generally good, although some residual tenderness or joint stiffness are common complications. Dorsal capsular injuries, if unrecognized, result in deformity rather than instability. The majority of these injuries can also be treated by closed means, but they require more prolonged immobilization and more commonly result in reduced mobility than volar plate and collateral ligament injuries. Capsular injuries that are compound, irreducible, or associated with a large intraarticular fracture can result in serious problems. Frequently, these injuries require primary surgical treatment, particularly in the case of the irreducible dislocation, which always requires surgery. An exception to the generally poor prognosis of these injuries is the irreducible volar dislocation because the central tendon remains intact permitting early postoperative joint mobilization. A chronic dislocation or late instability are fortunately not common sequela of capsular injuries; however, when they do occur, surgery is required.