Finger sprains and jamming injuries often occur when the fingers are hyperextended, with the thumb and index finger being the most commonly affected. After dislocation, the phalanx shifts dorsally, and the metacarpal head protrudes toward the palmar side, resulting in a hyperextended joint deformity. The index finger may also exhibit ulnar deviation and semi-flexion deformity of the interphalangeal joint. Manual reduction often fails after joint dislocation. In thumb dislocations, the metacarpal head perforates the palmar joint capsule, and its neck becomes trapped between the longitudinally torn capsule. Sometimes, the sesamoid bone or the flexor pollicis longus tendon may also become lodged between the articular surfaces, making reduction difficult. In index finger dislocations, the metacarpal head ruptures the joint capsule from the proximal end of the volar plate, which then becomes trapped between the articular surfaces. The metacarpal neck is also pinched between the flexor tendons and lumbrical muscles on both sides, further complicating reduction.

bubble_chart Treatment Measures

First, attempt manual reduction. If unsuccessful, proceed with surgical reduction by retracting the tissue clamped around the metacarpal neck, reducing the metacarpal head, and immobilizing in flexion for 3 weeks.