[CLINICAL RESEARCH OF POSTOPERATIVE DEVIATION SECONDARY TO THUMB DUPLICATION RESECTION].

OBJECTIVE: To study the causes and treatment of postoperative deviation secondary to thumb duplication resection.

METHODS: Between February 2007 and June 2013, 32 cases (33 thumbs) of postoperative deviation secondary to thumb duplication resection were treated, and the clinical data were retrospectively analyzed. There were 13 males and 19 females, aged 2-34 years (median, 8 years). The left thumbs were involved in 7 cases, the right thumbs in 24 cases, and bilateral thumbs in 1 case. Of 33 thumbs, 2 were rated as type II, 4 as type III, 10 as type IV, 7 as type V, and 10 as type VII according to Wassel classification. The average time between duplicated thumb resection and admission was 6.5 years (range, 1-29 years). Nine thumbs only had ulnar deviation of the metacarpophalangeal (MP) joint; 8 thumbs only had radial deviation of the interphalangeal (IP) joint; 10 thumbs only had ulnar deviation of the IP joint; and 6 thumbs had ulnar deviation of the MP joint combined with radial deviation of the IP joint. The mean deviation degree of the MP joint was 32.3 (range, 20-40*), and the mean deviation degree of the IP joint was 42.5° (range, 30-110°). Operation methods were chosen specially according to the deformity, including remnant bone or cartilage resection, restoring normal alignment, and soft tissue balance.

RESULTS: All wounds got first stage healing and there was no complication associated with operation. Postoperative follow-up period ranged from 6 to 70 months (mean, 34 months). The skeleton alignment of the thumbs was improved on the X-ray images; all osteotomy got union at 5-10 weeks (mean, 6 weeks). Deviation was completely corrected in 31 thumbs; the preoperative deviation degree was too large to correct completely in 2 thumbs with a postoperative deviation degree of 10°. The motion degree was similar to that at preoperation in 13 thumbs; the motion degree decreased in 20 thumbs, which did not affect the function of the thumbs. Nineteen cases (20 thumbs) were followed more than 2 years, there was no recurrence of deviation and all thumbs developed well, but the size of affected thumb was smaller than that of the contralateral side in 14 cases (14 thumbs).

CONCLUSION: Getting good result and preventing postoperative deviation for thumb duplication resection acquires appropriate preoperative design, reconstruction of the insertion of the abductor poll icis brevis, transposition of the flexor and extensor pollicis longus insertion, and essential osteotomy play important roles in preventing postoperative deviation after thumb duplication resection. Individualized treatment plan for deviation should be made according to the degree and the cause of deviation.