Analysis Of Influencing Factors Of Leg Length Discrepancy After Primary Total Hip Arthroplasty

Objective: To study the influencing factors of Leg length(LLD)after total hip arthroplasty(THA).Methods: this study selected in December2018-December 2020 the 2 years in our spine bone disease surgery patients with unilateral total hip replacement for the first time at 174 as the research object,in which the length of lower limbs after total hip replacement sent 5 mm or less 129cases(group reconstruction),double lower limbs length difference > 5 mm of 45cases(not reconstruction group),compared the clinical data of two groups of patients,the first of two groups of data to the single factor continuous variables analysis and single factor classification analysis,finally will have statistical significance of the related factors affecting the binary logistic regression analysis.Results: The average length difference between lower limbs was-7.15±5.88 mm before operation,and 1.49±4.75 mm after operation,with statistical significance(P< 0.05).The average Harris score of the affected side was 35.99±11.55(3.7～55.4),and the average Harris score of the postoperative side was 88.93±4.59(73.0～98.0),the difference was statistically significant(P < 0.05).The univariate analysis of continuous variables showed that the difference of bilateral hip eccentricity,bilateral hip rotation center height difference,retained femoral talus length,neck length of femoral prosthesis,implant depth of femoral prosthesis were related to the difference of lower extremity length,and the difference was statistically significant(P < 0.05).Univariate analysis of classification variables showed that whether patients had osteoporosis or not and whether the reconstruction of eccentricity was related to the length of lower limbs after total hip arthroplasty,and the difference was statistically significant(P < 0.05).The results of binary logistic regression analysis showed that the height difference of rotation center of both hips(P < 0.05),the length of femoral calar retained(P < 0.05),the length of neck of femoral prosthesis(P < 0.05),and the depth of implant of femoral prosthesis(P < 0.05)were the independent influencing factors of whether the length of lower extremity was reconstructed after total hip arthroplasty(THA).Conclusion: In conclusion,neck length of femoral prosthesis,implant depth of femoral prosthesis,height difference of rotation center of both hips,and length of preserved femoral talus are the main influencing factors of unequal length of lower extremity after primary total hip arthroplasty.Among them,the neck length of femoral prosthesis had the highest influence index,followed by the height difference between the rotation centers of the two hips,and the last was the length of the femoral talus retained and the depth of the femoral prosthesis implanted.