Introduction
Thumb hypoplasia is a condition of congenital underdevelopment of the thumb. It accounts for approximately 5% to 15% of congenital hand disorders [1].
It occurs equally among both genders. In over half of the cases, both thumbs are affected, while among one-sided hypoplastic patients the right thumb is reported to be more commonly involved [2].
Blauth’s classification is the most used categorization. The principle of hypoplastic thumb reconstruction is to address each abnormal clinical element. [3]
Type I thumbs have minimal shortening and narrowing. Type II thumbs have thumb-index web space narrowing, hypoplasia intrinsic thenar muscles, and metacarpal joint instability. Type IIIA thumbs have type II features plus extrinsic tendon abnormalities and hypoplastic metacarpal with a stable carpometacarpal joint. Type IIIB thumbs have type IIIA features plus partial metacarpal aplasia with an unstable carpometacarpal joint. Type IV thumbs are floating thumbs, and type V thumbs are absent thumbs.[4]
Case historyA 23-year-old male patient comes to the rheumatology clinic for a bilateral restriction in opposition movement especially when using a pen or razor. The clinical examination revealed a bilateral inability to use the interphalangeal joint of the thumb and toes with a mild weakness in grip strength.