Influence Of Lower-limb Mechanical Axis On The Curative Effect Of Medial High Tibial Osteotomy For Knee Osteoarthritis

Objective: To investigate the influence of the ratio of the medial tibial plateau width(the distance between the medial edge of the tibial plateau to the intersection point of the tibial plateau tangent line and the lower-limb mechanical axis)to the total tibial plateau width on the therapeutic efficacy of high tibial osteotomy(HTO)on the medial side for knee osteoarthritis.Methods: This study retrospectively analyzed information of 278 patients who underwent medial HTO for knee osteoarthritis with varus deformity,including 113 males and 165 females(mean age of 56.51 ±8.60 years)from January 2015 to December 2019.The Tinetti gait and balance assessment tool and the Kujala score were the primary means of evaluation.The Visual Analogue Scale(VAS)and the Knee Society Scoring System(KSS)for the evaluation of knee joint function were used as auxiliary tools to comprehensively evaluate the influence of the lower-limb mechanical axis on the curative effect of medial HTO for knee osteoarthritis.Results: After adjusting for potential confounding factors(age,gender,BMI,lateral orientation),the degree of lower limb force line correction has a non-linear relationship with gait balance and patellofemoral joint function after high tibial osteotomy,and the degree of correction is 53.67% At time,the Tinetti Gait Balance Analysis Scale scored the highest,the β value and 95% confidence interval on the left and right sides of the inflection point were 0.49(0.20,0.78,P=0.0009)and-0.26(-0.30,-0.22),P<0.0001);when the degree of correction is55.19%,the Kujala score is the highest,the β value and 95% confidence interval on the left and right sides of the inflection point are 2.48(1.40,3.56,P=0.0009)and-0.88(-1.12,-0.64,P<0.0001));KSS score is highest when the degree of correction is 55.45%,the β value and 95%confidence interval on the left and right sides of the inflection point are2.77(1.64,3.90,P<0.0001)and-1.18(-1.46,-0.91,P<0.0001),respectively The VAS score is the lowest when the degree of correction is55.00%,and the β value and 95% confidence interval on the left and right sides of the inflection point are-0.16(-0.29,-0.03,P=0.0146)and 0.08(0.05,0.10,P<0.0001),respectively.Conclusion: The lower-limb mechanical axis position had a non-linear correlation with the functional status of the knee joint after OWHTO.When the ratio of the medial tibial plateau width(the distance between the medial edge of the tibial plateau and the intersection point of the tibial plateau tangent line and the lower-limb mechanical axis)to the total tibial plateau width was approximately 53%～56%(instead of62.5%),the postoperative outcomes of OWHTO were optimized,and the patients had the highest satisfaction.In addition,high BMI was not conducive to the postoperative recovery of knee joint function.