Application of the nail ridge formation for the wassel type I and type II thumb duplication with connected nail

Objective To report the clinical outcome for Wassel Type I and Ⅱ thumb duplication with connected nail by excising the extra digit and reconstructing of nail ridge with the flap from the ablated digit. Methods 63 polydactyly of the thumbs in 61 patients with connected nail were treated the procedure by excising of the inferior phalangeal bones and nails and straightening the IP joint by orthroplasty or wedge osteotomy and reconstructing the nail ridge with the flap from the extra digit. The patients were followed up postoperatively for the assessment of thumb′s appearance and function by using the modified TADA scoring. Results All cases acquired primary wound healing and 55 of 63 cases were followed up for 6 months to 4 years. The nails were flat and the width were more than 80% of the contralateral side. Symmetric nail lunula was found in 46 thumbs (80.7%) as well as symmetric nail ridge in 40 thumbs (70.1%), but 50 thumb′s nail grooves were not obvious (87.7%). All incisions were made at the lateral of thumbs and no scars were found in the finger pulps. Except mild IP joint deviation was found in 6 thumbs, the others were roughly normal. The range of motion of the IP joint was more than 45° in all cases. Modified TADA scoring result: 52 fingers were excellent and 5 were good. Conclusions Satisfactory surgical outcome and better parental acceptance can be obtained after the procedures of excising the extra digit and forming of nail ridge, including aesthetics appearance, unaffected sense of touch with finger pulp intact and good mobility of the joint. Key words: Wassel Type Ⅰ and Ⅱ thumb; Connected nail; Surgery; Nail ridge formation