跖侧入路截骨延长治疗先天性第四跖骨短小症

Metatarsal lengthening by callus distraction for congenital brachymetatarsia:a plantar approach for osteotomy

[目的]探讨牵张成骨术治疗先天性第四跖骨短小症的效果,并介绍跖侧入路截骨的优点。[方法]2008年6月～2010年3月,共治疗先天性第四跖骨短小症15例。均为女性;年龄18～34岁,平均23.5岁。15例病人共有22根跖骨短小,其中8例为单侧第4跖骨短小,5例为双侧第4跖骨短小,2例为单侧同足有第1和第4跖骨短小。跖骨短缩1.5～2.5 cm,平均2 cm。在影像增强器的帮助下,采用足背侧安装Orthofix单边延长支架,跖侧入路截骨。随访时间8～24个月,平均12个月。所有跖骨都延长到满意的长度,延长骨痂完全钙化。[结果]延长长度12～24 mm,平均18 mm,延长百分比25.8%～48.7%,平均32.6%。骨延长指数(延长1 cm需要的时间)为52 d/cm～85.8 d/cm,平均63.5 d/cm。按照美国足踝矫形外科协会(the american orthopedic foot and ankle society,AOFAS)的功能评判标准,平均AOFAS评分为89.6分,10例优,3例良,2例可。每个足趾延长后足背遗留直径1 mm点状瘢痕4个,足底切口为线性瘢痕,长2 cm,对功能无任何影响。全部患者对延长的结果和足外观满意。并发症包括:延长跖骨成角4例,对延长足外观无影响;跖趾关节间隙缩窄13例,活动度减小,这是影响AOFAS评分的主要因素,随时间延长而明显改善。[结论]跖侧入路截骨延长治疗先天性第四跖骨短小症能使短小的跖骨恢复到满意的长度,遗留足背瘢痕小,对应的足趾功能恢复好,是一种值得推荐的好方法。

[ Objective ] To analysis the outcome of metatarsal lengthening by callus distraction for congenital brachymeta- tarsia via the plantar approach for osteotomy. [ Methods] From June 2008 - March 2010, distraction lengthening was per- formed in 22 metatarsals of 15 patients at our department. Among the patients, there were 8 patients with unilateral deformity and 5 bilateral, the other 2 cases with multiple brachymetatarsia of the first and fourth rays in same foot. All the patients were female aged from 18 to 34 （ average 23.5） years old. The average shortness of involving metatarsal than normal was 18mm by the X - ray meter. Although most patients had thick and painful callosities under adjacent metatarsal head, their main complaint was the cosmetic appearance of foot. Under the fluoroscopic guide, four mini half - pins in one line were directly drilled into the involved metatarsal in dorsal aspect, then the Orthofix fixator were mounted the half - pins. The osteotomy between the second and third pinhole were performed via plantar approach inside 2 - cm incision. After one week latency, distraction was started at the rate of O. 25mm twice daily. Radiographs were taken every 2 - week until distraction stopped and a satisfactory length was gained. The external fixator and pins were removed without anesthesia after callus maturation. Average follow -up period was 12 （range, 8 to 24） months. [ Results] There were merely four small spot - scar of half - pin insertion left in dorsal side of involved foot. At fi- nal follow-up, the mean lengthening was 18mm （12 to 20mm, 32. 6% ） . The lengthening index （time cost by average 1 cm） was 63.5d/cm （52 to 85. 8 d/cm） . All patients were satisfied with the appearance of lengthened toes. There were 10 excellent result, 3 good, 2 fair, according to AOFAS score. [ Conclusion] Distraction lengthening via the plantar osteotomy approach for treating the congenital brachymetatarsia has low morbidity and limited complications, and can restore normal appearance of foot.