To explore the effects of femoral flexion angle and tibial plateau tilt angle on the range of motion after total knee arthroplasty.

A total of 387 cases of total knee arthroplasty in department of orthopaedic, Longtan Hospital from January 2014 to December 2016 were retrospectively analyzed. Sex, age, body mass index, number of replacement joints, operation time, preoperative joint activity, preoperative maximum flexion, preoperative Hospital for Special Surgery (HSS) score, preoperative pain score, accompanying disease, personal history, rehabilitation intervention time, pain score of the postoperative first day, tibial plateau tilt angle, femoral prosthesis flexion angle of patients were recorded, paired t-test was used to compare the data in the measurement group. The independent sample t test was used to compare the joint activity of the patients in the one-year postoperative period. The other parameters were the rank correlation analysis and multiple regression analysis of the independent variables. The correlation between the above indexes and the knee range of motion over 90° at one year after the operation.

The preoperative HSS score was (47±10), and the HSS score at one year after operation was (87±6), the difference was statistically significant (t =15.820, P <0.01). The preoperative joint mobility was (86±7)°, and the postoperative joint mobility was (106±9)°, the difference was statistically significant (t =6.058, P <0.01). The Pearson correlation showed that there was a positive correlation between sex, preoperative joint activity, maximum flexion, preoperative HSS score, tibial plateau posterior truncation angle and knee joint activity (P <0.05). The age, body mass index, number of replacement joints, intraoperative bleeding, preoperative assessment of pain, hypertension, diabetes, rehabilitation intervention There was a negative correlation between time, pain score on the postoperative first day, femoral prosthesis flexion degree and joint activity (P <0.05), and there was no significant correlation between operation time, smoking, drinking and postoperative knee joint activity (P >0.05). The multiple linear stepwise regression analysis showed that the posterior tibial plateau angle, the femoral prosthesis flexion angle, the preoperative pain score, and the preoperative joint movement were independent factors affecting the joint activity one year after the knee joint replacement (P <0.05).

There is a negative correlation between the flexion angle of the femoral prosthesis and the degree of joint activity after total knee replacement, and the angle of tibial plateau posterior truncation is positively correlated with the degree of joint activity after total knee replacement.