通过回顾性分析带血管腓骨移植(FVFG)治疗股骨头坏死(AVN)的随访资料，探讨FVFG术后股骨头塌陷的高危时间窗和危险因素，为临床进一步优化FVFG术后随访和康复锻炼计划提供可靠依据。

筛选2006年1月至2012年12月在上海市第六人民医院行FVFG治疗的AVN病例共307髋。入组标准：①年龄18～55岁；②AVN Ficat-Arlet Ⅱ～Ⅲ期；③按计划进行随访且抵达随访终点。排除标准：①术后继发感染、排异等严重并发症；②未按计划随访、随访资料不全或抵达随访终点前失访。记录入组病例的年龄、性别、AVN诱因、AVN单双侧、AVN分期及术后股骨头有无塌陷并对以上数据采用单因素和多因素Logistic回归分析FVFG术后股骨头塌陷进展的危险因素。

共收集215例307髋病例，平均随访时间(51±26)个月，其中股骨头塌陷未进展率为84.7%(260髋)，股骨头塌陷进展率为15.3%(47髋)。股骨头塌陷发生在术后3～24月，其中25%发生在术后3月内，50%在术后6月内，75%在术后15月内。单因素和多因素Logistic回归分析提示，年龄≥ 40岁(P＝0.021)和Ficat-Arlet Ⅲ期AVN(P＝0.003)是FVFG术后股骨头塌陷进展的危险因素。

FVFG是一种有效的AVN保髋治疗方法。术后15月内是FVFG术后股骨头塌陷的高危时间窗，年龄较大和Ficat-Arlet Ⅲ期是其风险因素；此类病人在FVFG术后应缩短随访时间间隔，减轻锻炼强度。

To evaluate the risk factors and duration of femoral head collapse after free vascularized fibular graft (FVFG) for the treatment of avascular necrosis of femoral head (AVN).

Data of the patients who underwent FVFG for the treatment of AVN between January 2006 and December 2012 at Department of Orthepedics, Shanghai Sixth People’s Hospital were studied retrospectively. Inclusion criteria : age between 18 to 55 years, AVN of Ficat-Arlet stage II~III, follow-up according to the plan and reach the end-point. Exclusion critera: severe complications, being failed to follow up on schedule, incomplete data. Univariate and multivariate Logistic regression analyses were used to analyze the risk factors for the progression of femoral head collapse after FVFG. Age, gender, causes of AVN, sides of AVN, stages of AVN and presence of femoral head collapse were recorded.

A total of 215 cases (307 hips) with a mean follow-up duration of (51±26) months were included in the study. Femoral heads of 260 hips (84.7%) did not collapse at the last follow-up, and femoral head collapse was observed in the remaining 47 hips (15.3%). Femoral head collapse was observed between three months and 24 months after the operation, and the first, second, and third quartile of the time point of femoral head collapses following the operation were three months, six months after operation, and 15 months after the operation, respectively. The results of univariate and multivariate binary logistic regression analyses demonstrated that age ≥ 40 years (P=0.021) and AVN of Ficat-Arlet stage III (P=0.003) were the risk factors of femoral head collapse after FVFG for AVN.

FVFG could provide excellent outcomes for the treatment of AVN. The risk duration of femoral head collapse after FVFG for AVN is within postoperative 15 months, and the risk factors are age≥40 years old and Ficat-Arlet stage III. For the patients with risk factors, the follow-up interval should be shortened, and the rehabilitation exercise intensity should be reduced.