Idiopathic Rupture of the Extensor Pollicis Longus Tendon due to Carpometacarpal Joint Arthritis of the Thumb: A Case Report

Abstract

The most common cause of extensor pollicis longus (EPL) tendon rupture is a distal radius fracture; however, spontaneous EPL tendon rupture also shows a high frequency of occurrence, which cannot be ignored. A retrospective study of 27 EPL ruptures suggested that trauma or iatrogenic causes account for more than half of the cases, but spontaneous rupture is also considered an important etiological factor 1 . The etiology of spontaneous EPL tendon rupture includes systemic or local steroid injections, tenosynovitis, synovitis, rheumatoid arthritis, and repetitive wrist motions 2 .This report presents a case of idiopathic EPL tendon rupture in a patient who was a daily laborer with repetitive wrist motion. No cases of EPL rupture caused by mechanical attrition due to an osteophyte caused by progression of carpometacarpal (CMC) arthritis, rather than the generally known etiology involving repetitive wrist motions, have been reported yet. Herein, we provide the case report and a review of the literature. A spontaneous rupture of the extensor pollicis longus (EPL) tendon is associated with rheumatoid arthritis, fractures of the wrist, systemic or local steroids, and repetitive and excessive abnormal motion of the wrist joint. Various causes of spontaneous rupture of the EPL tendon have been reported, but EPL rupture due to carpometacarpal (CMC) arthritis has not been reported. We had a case of an idiopathic rupture of the EPL tendon due to CMC joint arthritis of the thumb. The patient had no predisposing factors including trauma or steroid injection. The ruptured tendon was operated. During the surgery, both ends of the ruptured EPL tendon were found around the dorsum of the first CMC joint, and an osteophyte was observed in the dorsal aspect of the first CMC joint. The osteophyte was removed and an extensor indicis proprius tendon transfer was performed. Three monthss post-surgery, the patient was satisfied.