2023, Vol. 27 ›› Issue (27): 4291-4296

Digital measurement of femoral valgus angle and femoral posterior condyle angle in elderly people over 60 years old in northern China and comparison with young and middle-aged population

Li Jiawei1, 2, Li Canran1, He Yujie1, Wu Chao1, Jin Feng3, Zhang Kai4, Li Xiaohe1   

Abstract: BACKGROUND: Total knee arthroplasty is an effective treatment for end-stage osteoarthritis of the knee. The femoral valgus angle and femoral posterior condyle angle are important parameters for preoperative evaluation, and selecting the proper angle for osteotomy will be beneficial to the reconstruction of the force line of the lower limb and the stability of the prosthesis after surgery. Therefore, the study of femoral valgus angle and femoral posterior condyle angle is of great significance for the precise osteotomy of total knee arthroplasty.  
OBJECTIVE: To measure the femoral valgus angle and femoral posterior condyle angle in different age groups of elderly people in Inner Mongolia Autonomous Region and to understand the distribution of these two parameters in different age groups.
METHODS: A total of 175 patients receiving lower extremity vascular examination from January 2018 to December 2021 in The Affiliated Hospital of Inner Mongolia Medical University and The Second People’s Hospital of Ulanqab were selected in this study. They were divided into four groups: < 60 years old (group A, n=41), 60-69 years old (group B, n=52), 70-79 years old (group C, n=41), and > 80 years old (group D, n=41). The CT data of the lower extremity blood vessels of the patients were collected. Mimics 21.0 software was used to reconstruct 3D model and rotate to standard orthostatic position. Simulated lower limb X-ray films were used to measure the femoral valgus angle. CT cross-section was used to measure the femoral posterior condyle angle. The SPSS 25.0 software was used to analyze the difference of two parameters among different age groups, and difference of two parameters between sexes in the same age group and the correlation between the two parameters and age.
RESULTS AND CONCLUSION: (1) For the same gender, the femoral valgus angle of groups A and B was smaller than that of groups C and D (P < 0.05). For male patients, the femoral posterior condyle angles in groups A and B were smaller than those in groups C and D (P < 0.05). For female patients, the femoral posterior condyle angle in group A was smaller than that in groups C and D (P < 0.05), and that in group B was smaller than that in group D (P < 0.05). (2) In the same group, there was no significant difference in femoral valgus angle and femoral posterior condyle angle between men and women (P > 0.05). (3) Pearson correlation analysis showed that femoral valgus angle and femoral posterior condyle angle were positively correlated with age, and the correlation coefficients were 0.31 and 0.46, respectively (P < 0.01). (4) The results confirm that when performing total knee arthroplasty for elderly people, the effect of age on femoral valgus angle and femoral posterior condyle angle should be considered. Preoperative CT examination of the lower extremity and 3D reconstruction measurement are recommended to clarify the femoral valgus angle and femoral posterior condyle angle for individualized osteotomy.

Key words: total knee arthroplasty, elderly, femoral valgus angle, femoral posterior condyle angle, three-dimensional digital measurement