Effects Of Prosthesis Position And Length Of Lower Extremity On Prosthesis Dislocation After Total Hip Arthroplasty Through Posterolateral Approach

Objective: To analyze the relationship between prosthesis position,leg-length discrepancy and prosthesis dislocation after posterolateral approach total hip arthroplasty,to provide some reference for clinical work.Materials and methods: A total of 416 patients(416 hips)who underwent unilateral total hip arthroplasty performed by the same senior surgeon at No.1Orthopedics Hospital of Chengdu from February 2014 to June 2021 were retrospectively analyzed.The basic information of the patients was obtained through the management information system of Zhonglian hospital information system,and the patients were followed up regularly after surgery.The parameters of the prosthesis position and leg-length discrepancy were collected by measuring the imaging system,and the patients were grouped according to whether there was dislocation,and the obtained data were analyzed using SPSS 25.0 software.Results: A total of 416 patients(416 hips)were included in this study,9 in the dislocation group and 407 in the non-dislocation group,with an overall dislocation rate of 2.16%.There was no statistically difference between the dislocation group and the non-dislocation group in terms of prosthesis position(ie: abduction angle,anteversion angle,percentage of vertical distance from the center of rotation,percentage of horizontal distance from the center of rotation,and eccentricity);There was a statistically difference in leg-length discrepancy(z=-2.037,P<0.05),the median percentage of lower extremity length in the dislocation group was 109(98.93,141.52)%,and the median percentage of lower extremity length in the non-dislocation group was 102(101.48),104.68)%.Conclusions:The difference in lower limb length after total hip arthroplasty is a risk factor for prosthesis dislocation,and the surgeon should try to reconstruct an isometric limb for the patient to avoid this risk.