Subclinical Partial Attritional Rupture of the Flexor Digitorum Profundus as an Etiology of Atraumatic Trigger Finger

Background. Trigger finger is a relatively common clinical entity. The etiology is most often attributable to stenosing tenosynovitis though traumatic cases have been described. When trigger finger is associated with an underlying flexor tendon rupture, previous cases have reported a clear association with overt laceration or previous trauma. Methods. We present the case of a 23-year-old male active duty military service member who presented with a characteristic history and clinical exam consistent with trigger finger. The symptomatic onset was gradual, with no history of inciting trauma. Results. Given symptomatic persistent triggering following failure of conservative management to include cortisone injections, the patient was taken for open A1 pulley release. Intraoperatively, the triggering was found to be attributable to a partial attritional rupture of the small finger flexor digitorum profundus tendon. Tendon debridement, tubularization, and A1 and partial A2 pulley releases were performed with subsequent resolution of triggering. Conclusion. We present the rare case of subclinical atraumatic attritional rupture of the FDP tendon to the small finger as a cause of clinically apparent trigger finger. This is an important consideration as the hand surgeon must be prepared to address more atypical pathologies.