股骨近端形态和髋关节置换术后下肢不等长的关系

目的为评估股骨近端形态与髋关节置换术后下肢不等长是否相关，本文研究了股骨髓腔闪烁指数(CFI)对髋关节置换术后下肢不等长(LLD)情况的影响。 方法选取2012年至2019年间进行单侧无骨水泥首次全髋关节置换术患者作为研究对象，纳入标准：单侧手术；无神经功能症状；使用生物型假体；初次手术；术侧无存在髋关节病变。排除标准：患侧或对侧存在髋臼发育不良及髋关节间隙破坏；患侧或对侧存在股骨近端畸形；术前下肢不等长大于2 cm；骨折的患者；患侧旋转中心距对侧距离大于3 mm，最后纳入研究235例患者。回顾性分析这些患者的年龄、性别、身体质量指数(BMI)、术前疾病和影像学资料和术后下肢不等长情况；根据患者髓腔形态将患者分为3组，并对比这3组患者下肢不等长性。计量数据满足方差齐性的多组资料间比较采用方差分析，两两比较采用事后检验LSD-t检验；计数资料组间比较采用卡方检验，单项有序分类变量资料采用Kruskal-wallis H检验，两两比较采用Nemenyi法比较。 结果总共纳入患者235例，所有患者CFI的平均值为(4.3±1.2)；根据股骨髓腔形态进行分组后各组对比结果性别、身体质量指数、术前诊断、假体股骨头颈长类型、髋臼旋转中心与泪滴连线距离、股骨头中心至假体远端的垂直距离，差异均无统计学意义(P>0.05)。香槟型髓腔的患者年龄较其他两组小，差异具有统计学意义(P<0.05)；香槟型髓腔的患者LLD差异较其他两组明显大(P<0.05)；烟囱型髓腔的患者股骨柄假体打入深度较香槟型组更深(P<0.05)；烟囱型髓腔的股骨头中心至小转子上缘的垂直距离较香槟型短，差异有统计学意义(P<0.05)；详细比较3组患者的LLD情况，3组间比较差异有统计学意义(P<0.05)，进一步两两比较，香槟型的LLD大于烟囱型(P<0.05)，余两两比较差异均无统计学意义(P>0.05)。 结论香槟型髓腔(CFI高)的患者术后患侧肢体过长的可能性较大，烟囱型髓腔(CFI低)患者术后患侧肢体短缩的可能性较大。

Relationship between proximal femur morphology and unequal length of lower limbs after total hip arthroplasty

ObjectiveTo evaluate the relationship between proximal femur morphology and leg-length discrepancy (LLD) after hip replacement and study the effect of femoral medullary scintillation index (CFI) on LLD after hip replacement. MethodsPatients who underwent unilateral first total hip arthroplasty without bone cement from 2012 to 2017 were selected as study subjects. Inclusion criteria: unilateral surgery; no neurological symptoms; use of biotype prosthesis; primary surgery; no hip lesion on the operative side. Exclusion criteria: acetabular dysplasia and hip space destruction in the affected or contralateral side; proximal femur deformity on the affected or contralateral side; preoperative lower extremity unequal size of 2 cm; patients with fractures; the distance between the rotatory center of the affected side and the contralateral side over 3 mm. Finally, 235 patients were included in the study. Age, sex, body mass index (BMI), preoperative disease and imaging data, and postoperative lower extremity disparity were retrospectively analyzed. The patients were divided into three groups according to the shape of the medullary cavity, and the lower limb length of the patients in the 3 groups was compared. Variance analysis was used for the comparison between multiple groups of data satisfying homogeneity of variance, and LSD-t test was used for pair-wise comparison. The intergroup comparisons for count data were analyzed by chi-square test, single ordered variable data were analyzed by Kruskal-Wallis H test, and paired comparison was analyzed by Nemenyi method. ResultsA total of 235 patients were included, and the mean CFI value of all patients was (4.3±1.2). After grouping according to the morphology of femoral bone marrow cavity, there was no statistically significant difference in gender, body mass index, preoperative diagnosis, type of prosthetic femoral neck length, distance between acetabular rotation center and tear drops, or the vertical distance between femoral head center and distal prosthesis among the groups (P>0.05). The age of patients with champagne medullary cavity was smaller than that of the other two groups (P<0.05). LLD of patients with champagne medullary cavity was significantly different than that of the other two groups (P<0.05). The insertion depth of femoral stem prosthesis in patients with chimney-type medullary cavity was deeper than that in patients with champagne-type medullary cavity (P<0.05). The vertical distance from the center of the femoral head to the upper margin of the lesser trochanter in the chimney-type medullary cavity was shorter than that in the champagne type (P<0.05). The LLD status of patients in the three groups was compared in detail, and the difference between the three groups was statistically significant (P<0.05). The paired comparison showed that the LLD of champagne type was greater than that of chimney type (P<0.05), while the remaining paired comparison showed no statistically significant difference (P>0.05). ConclusionThe patients with champagne medullary cavity (high CFI) are more likely to have longer limbs on the affected side, while the patients with chimney medullary cavity (low CFI) are more likely to have shorter limbs.