Correlation between femoral offset,rotation center and leg length discrepancy after total hip arthroplasty based on digital analysis
10.12200/j.issn.1003-0034.20230313
- VernacularTitle:基于数字化分析全髋关节置换术后股骨偏心距及旋转中心与下肢不等长的相关性研究
- Author:
Mao-Yong LI
1
;
Wei CAO
;
Pei-Xin SHA
;
Xu-Dong SUN
;
Shi-Yuan HUANG
;
Kuan-Xin LI
;
Heng ZHANG
Author Information
1. 蚌埠医学院第一附属医院骨科组织移植安徽省重点实验室蚌埠医学院,安徽 蚌埠 233004
- Keywords:
Total hip arthroplasty;
Femoral offset;
Rotation center height;
Leg length discrepancy;
3D reconstruction
- From:
China Journal of Orthopaedics and Traumatology
2024;37(4):381-386
- CountryChina
- Language:Chinese
-
Abstract:
Objective CT scans combined with Mimics software were used to measure femoral offset(FO),rotation center height(RCH)and lower leg length discrepancy(LLD)following total hip arthroplasty(THA),and the relationship between FO,RCH and LLD after THA is discussed.Methods Retrospective analysis was performed on 40 patients with unilateral THA who met standard cases from October 2020 to June 2022.There were 21 males and 19 females,18 patients on the left side and 22 patients on the right side,aged range from 30 to 81 years old,with an average age of(58.90±14.13)years old,BMI ranged from 17.3 to 31.5 kg·m-2withan average of(25.3±3.4)kg·m-2.There were 30 cases of femoral head necrosis(Ficattype Ⅳ),2 cases of hip osteoarthritis(Tonnis type Ⅲ),2 cases of developmental hip dislocation combined with end-stage osteoarthritis(Crowe type Ⅲ),and 6 cases of femoral neck fracture(Garden type Ⅳ).Three-dimensional CT reconstruction of pelvis was taken preoperative and postoperative,and three-dimensional reconstruction model was established after processing by Mimics software.FO,RCH and LLD were measured on the model.The criteria for FO reconstruction were as follows:postoperative bi-lateral FO difference less than 5 mm;the standard for equal length of both lower limbs was as follows:postoperative LLD differ-ence less than 5 mm.Results Bilateral FO difference was positively correlated with LLD(r=0.744,P＜0.00l).Chi-square test was performed between the FO reconstructed group and the non-reconstructed eccentricity group:The results showed that the i-sometric ratio of lower limbs in the FO reconstructed group was significantly higher than that in the FO reconstructed group(x2=6.320,P=0.012).The bilateral RCH difference was significantly negatively correlated with LLD(r=-0.877,P＜0.001).There is a linear relationship between bilateral FO difference and bilateral RCH difference and postoperative LLD,and the lin-ear regression equation is satisfied:postoperative LLD=0.038x-0.099y+0.257(x:postoperative bilateral FO difference,y:post-operative bilateral RCH difference;Unit:cm),F=77.993,R2=0.808,P=0.009.Conclusion After THA,LLD increased with the increase of FO and decreased with the increase of RCH.The effect of lower limb isometric length can be obtained more easily by reconstruction of FO.There is a linear relationship between the bilateral FO difference and the bilateral RCH difference after THA and LLD,and the regression equation can provide a theoretical reference forjudging LLD.
