Flexor pollicis longus (FPL) tendon hypoplasia: A case report and literature review

Abstract

An 18-year-old female presented with long-standing inability to flex her left thumb. MRI of the left thumb revealed flexor pollicus longus (FPL) tendon hypoplasia, and subsequent ultrasound of the bilateral thumbs confirmed a left-sided hypoplastic FPL tendon. Structural integrity of the left FPL tendon was confirmed during surgical examination under anesthesia. Multiple congenital anomalies of the FPL have been described, but FPL tendon hypoplasia and its appearance on imaging are rarely reported. This case demonstrates the diagnosis of FPL tendon hypoplasia on MRI, ultrasound, and surgical examination under anesthesia; and demonstrates the importance of including this entity in the differential diagnosis for impaired thumb flexion.

Congenital Bilateral Anomaly of the Flexor Pollicis Longus Tendon Without Thenar Atrophy: A Case Report

“…However, some connections and anomalies are difficult to visualize at imaging and should be proven by surgical exploration. 1,4,9,11 The treatment with a tendon transfer by using the tendon of the FDS muscle of the ring finger is an option. In this case, postoperative planned physiotherapy is strongly advised.…”

“…However, some connections and anomalies are difficult to visualize at imaging and should be proven by surgical exploration. 1,4,9,11…”

“…2,3 Most cases document unilateral absence of the FPL tendon, with or without associated anomalies, thenar atrophy, or abnormal osseous structures. 1,4,5 However, bilateral absence of the FPL tendon is a rare phenomenon. Only a few cases have been reported, 1 of them with a familial appearance, other associated with more anomalies or thenar atrophy.…”

Agenesis of flexor pollicis longus without thenar hypoplasia: a case report and literature review

“…The flexor pollicis longus (FPL) muscle acts to flex the thumb at the interphalangeal joint (IPJ) and is innervated by the anterior interosseous nerve, which is a branch from the median nerve [ 1 ]. FPL agenesis is very rarely reported in the literature and its association with normal thenar muscles is even rarer [ 2 ].…”