Surgical Reconstruction of Type IV Hypoplasia of the Thumb (Floating Thumb) in Infants: A Retrospective Analysis of Functional Outcomes and Radiographic Alignment.

BACKGROUND Congenital hypoplasia of the thumb type IV, also known as floating thumb, is a condition in which 2 small phalanges are attached to the hand with a thin skin bridge. Surgical management options for this condition vary from amputation to flap reconstruction. MATERIAL AND METHODS This retrospective study analyzed 11 infants with congenital hypoplasia of the thumb type IV who underwent surgical reconstruction using a modified vascularized polydactylous hallux flap. The study included 6 male and 5 female infants, aged 6 to 24 months. Functional evaluations and radiographic studies were conducted postoperatively. RESULTS All 11 patients underwent the complete surgical protocol. Successful vascular and nerve anastomoses were performed during the initial procedure, ensuring sufficient blood supply and neural connectivity to the transferred toes. The second operation showed promising outcomes, including improvements in thumb opposition, grasp strength, and overall function. Postoperative assessments demonstrated satisfactory radiographic alignment and no major complications during the follow-up period. CONCLUSIONS The modified vascularized polydactylous hallux flap reconstruction is a viable surgical option for managing congenital hypoplasia of the thumb type IV in infants. This technique effectively restores thumb opposition, grasp strength, and overall hand function, with satisfactory radiographic alignment and minimal complications. The study findings support the efficacy and safety of this surgical approach in addressing this rare congenital anomaly.