Proximal Interphalangeal Joint Dislocation

History and Physical Exam

Because injuries to the hand are common, athletes may initially disregard PIP trauma as simply a “jammed” finger and delay seeking medical attention. A thorough assessment and accurate diagnosis are important first steps to avoid chronic defects and disability. The history of injury should include the setting of injury, specifically the sports, position, and mechanism. Next, a typical pain assessment should uncover both the immediate and the persistent symptoms, including any change in this pattern over time. Typically, the athlete will describe pain, swelling, and paresthesias over the affected joint. Ultimately, the information most likely to lead to diagnosis is a description of dysfunction, what the player can and cannot do since the injury occurred.

A thorough physical exam of the entire upper extremity on both the injured and the uninjured side is ideal. When focusing on the PIP joint, inspection of the hand in the relaxed and clenched positions may help reveal any deformity. Certain acute PIP dislocations may result in characteristic phalanx deformities, such as swan-neck and boutonniere. The swan-neck deformity occurs when the PIP joint is hyperextended and the distal interphalangeal (DIP) joint is flexed, while the boutonniere deformity is the opposite, occurring with flexion of the PIP and extension of the DIP, a result of avulsion at the extensor digitorum communis tendon.

Normal range of motion at the PIP joint is 100° of flexion and 0° of extension. Accurate assessment relies on isolating the joint by holding the DIP just distal to the site being examined. Tenderness, swelling, and weakness over the affected PIP joint are common. Rupture of a tendon, ligament, or intraarticular fragment can manifest as limitation in active and resisted flexion and extension. Perform passive hyperextension to determine volar plate integrity, and apply varus and valgus stress to assess the collateral ligaments. The Elson test evaluates for rupture of the extensor tendon central slip at the base of the proximal phalanx, which leads to the boutonniere deformity mentioned above. With the finger over the edge of a table and the PIP joint at 90°, a positive test yields weakness against resisted extension and hyperextension of the DIP. A neurovascular exam of the finger is an essential part of the complete exam.

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