Irreducible volar subluxation of the proximal interphalangeal joint due to radial collateral ligament interposition: case report and review of literature.

Irreducible volar subluxation should be considered when assessing a patient with flexion deformity of the proximal interphalangeal finger joint (PIPJ). Primary assessment requires careful examination of the collateral ligaments and extensor tendon. Preoperative imaging such as ultrasound and MRI can help identify the interposed structures and plan the subsequent operation. Although rare, irreducible volar subluxation due to radial collateral ligament interposition is an important entity to be aware of. Prompt and appropriate management can prevent joint stiffness and loss of function.