Pilot study on the functional relevance of single versus double toe transfer in monodactyly: Analysis on functional integration and grasping

Monodactyly is a rare congenital anomaly of the upper limb, characterized by the presence of an isolated thumb. Although toe-to-hand transfer is a well-established surgical reconstructive procedure, there are currently no universally accepted guidelines clearly defining the optimal number of digits to be transferred. The aim of this pilot study is to evaluate whether performing a double toe transfer offers a significant functional advantage over a single toe transfer. We collected seven cases which were divided into two groups based on the number of digits transferred. All patients underwent the same standardized surgical and rehabilitative protocol. During follow-up, the motor patterns of each patient and the integration of the transferred digits during grasping were systematically evaluated. In our series, while double toe transfer has enhanced grasp and function by providing a three-digit pinch, a single transferred toe combined with a structured thumb appeared able to perform most daily activities. The second transferred digit has often shown to be stiffer as compared to the first toe transfer, limiting function while increasing donor site morbidity and operative time. Careful preoperative assessment of residual anatomy and spontaneous grasp strategies should guide surgical planning to maximize functional integration and minimize unnecessary morbidity. This study highlights the need for a selective, patient-specific approach in toe-to-hand transfer reconstruction in children affected by monodactyly.