In human, the flexor pollicis longus (FPL) is an important muscle for function of the hand. Thumb aplasia and hypoplasia represent a large spectrum of deficiencies. One of the variants of type I thumb hypoplasia is the absence or hypoplastic of FPL tendon without deficiency of other thenar muscle. Although rare, we found several literatures reporting the cases. In treating pediatric thumb disease especially for this condition, we have to carefully diagnose the problem to set our goal of treatment.
Materials and methods
We presented a case of 8-year-old male with bilateral inability to flex both thumbs at the interphalangeal (IP) joint. His parents realized this condition after he was involved in school activity. On physical examination, we concluded that the patient has absence of FPL and proceeded for reconstruction with tendon transfer from 4th flexor digitorum superficialis (FDS) and dorsal capsule release.
We performed surgery and postoperatively observed the active movement of IP joint. The treatment improved the active flexion of the IP joint around 60 degrees.
The absence of IP crease is one of the clear signs of FPL absence or hypoplasia. The usage of dorsal capsule release and tendon transfer in treating FPL absence or hypoplasia without any other thenar anomalies is proven to be adequate and feasible