Clinical Characteristics and Distribution of Thumb Polydactyly in South China: A Retrospective Analysis of 483 Hands.

PURPOSE:This study was intended to characterize the epidemiological features of thumb polydactyly (TP) in South China. METHODS:Clinical records were retrieved from 1 central hospital in South China to identify the patients with a definite diagnosis of TP from January 2004 to January 2017. The cases were classified by their x-ray appearance. The data collected included sex, age at first operation, reoperation, family history, unilateral/bilateral polydactyly, right/left hand involvement in unilateral cases, classification of polydactyly, and the presence of associated congenital anomalies. RESULTS:A total of 428 patients with a definite diagnosis of TP were identified (278 males and 150 females) involving 483 cases, 373 unilateral and 55 bilateral. A syndrome or associated congenital anomaly was found in 26 (18 unilateral and 8 bilateral cases). A dominant thumb, larger and more developed, was observed in 448 hands (93%), and was the ulnar thumb in 433. Owing to postoperative complications, 31 thumbs (6.4%) underwent reoperation. The average interval from initial surgery to reoperation was 4.8 years. CONCLUSIONS:Thumb polydactyly had a male predominance in this Chinese cohort, mostly occurring on the right hand with an ulnar dominant thumb. Bilateral cases had a higher incidence of associated anomaly and positive family history than unilateral cases. The need for additional surgery for TP might occur as late as 4.8 years after primary surgery. TYPE OF STUDY/LEVEL OF EVIDENCE:Therapeutic IV.