Longitudinal Tear of the Central Slip Causing Painful and Unusual Snapping of the Finger: A Case Report.

The most common cause for catching or snapping in the finger is stenosing tenosynovitis, that is, trigger finger. Although less common, snapping can also occur as a result of extensor mechanism injury. Among these injuries, sagittal band rupture is most common and leads to snapping at the metacarpophalangeal joint. Snapping at the proximal interphalangeal (PIP) joint is rare with only 4 reported cases; reported mechanisms of PIP joint snapping include retinacular ligament injury or tendon impingement. We present a unique case of painful finger snapping at the PIP joint as a result of longitudinal tear of the central slip, leading to sudden subluxation of one-half of the central slip and conjoint lateral band with flexion of the PIP joint.