Congenital sporadic clinodactyly of the index finger is uncommon and has not been specifically investigated in previous reports. In this paper, we report on 10 cases with this deformity to investigate its clinical features and to document the results following a closing wedge osteotomy. The study demonstrated that clinodactyly of the index finger is a unique entity. It is unilateral, with male predominance. It is commonly associated with brachydactyly but is not associated with systemic anomalies or mental retardation. Finally, the study showed that the side of angulation of the index finger is consistently to the radial side. The closing wedge osteotomy technique obtained a satisfactory correction of the angulation in all patients (the mean preoperative angulation was 44 degrees and the mean postoperative angulation was 13 degrees). The cosmetic outcome was considered acceptable in 9 cases. In the remaining patient, the operated index finger appeared too short compared with the other fingers. We now believe that it was not appropriate to do a closing wedge osteotomy for all cases of sporadic clinodactyly of the index finger, and we have designed a new approach of management based on 3 factors: the severity of angulation, the age of the patient, and the relative degree of brachydactyly of the index finger compared with the adjacent middle finger.