[Injuries of the proximal interphalangeal joint].

BACKGROUND: Injuries of the proximal interphalangeal joint (PIP joint) are common. They are frequently underestimated by patients and initial treating physicians, leading to unfavorable outcomes. Basic treatment includes meticulous clinical and radiological diagnosis as well as anatomical and biomechanical knowledge of the PIP joint. TREATMENT: In avulsions of the collateral ligaments and the palmar plate with or without involvement of bone, nonoperative treatment is preferred. Operative stabilization is reserved for large displaced bony fragments or complex instabilities. In central slip avulsion or rupture, osseous refixation, suture, or reconstruction is common and nonoperative treatment is limited to special situations like minimally displaced avulsions. In basal fractures of the middle phalanx, elimination of joint subluxation and restoration of joint stability are priority. If the fragments are too small for fixation with standard implants, therapeutic alternatives include refixation of the palmar plate, dynamic distraction fixation, percutaneous stuffing, or replacement by a hemihamate autograft. Early motion is initiated regardless of the treatment regime. Undertreatment leads to persistent swelling, instability, and limited range of motion, which are difficult to treat. Contributing factors are unnecessary immobilization, immobilization in more than 20° flexion or transfixation by K-wires. For residual limitations, nonoperative treatment with physiotherapists and splinting is first choice. Operative treatment is reserved for persistent flexion/extension contractures persisting for more than 6 months, as well as reconstructions in boutonniere and swan neck deformity and salvage procedures for destroyed joints.