The Relations Of Leg Length Discrepancy And Clinical Outcomes After Total Hip Arthroplasty

Objective A group of total hip arthroplasty were followed up to investigate the relationship of the leg length discrepancy with the extent of wearing and the function of the hip operated.Methods A series of 42 hip joints(42 patients) were followed up routinely. The average follow-up period was 76.6 months. The leg length and linear polyethylene was measured, while the Harris Hip Score(HHS) was assessed. The results were statistically analyzed, with a P value less than 0.05 indicating significant difference.Results 4 hips were excluded for some reasons and 38 hips were left with no evidences of component loosening and clinical failure at the latest follow-up. The absolute LLD was (9.8±7.1) mm, the Harris hip score was 82.1± 14.6 at the latest follow-up, the average linear wear rate 0.25 per year. There was significantly correlation between LLD andHHS(r=0.3482, P=0.032), but the rectilinear relation was not exactly. In the variability analysis, the patients were divided into two groups, LLD≤10mm and LLD> 10mm. There was still significantly difference of HHS between the two(P=0.0066). However, no correlation of linear wear rate with LLD was found in linear regression analysis, and no significantly difference between the wear rate of two groups either. Conclusion Leg length discrepancy after THA will influence the long-term function of hip joints, meanwhile it may result in lesion of the contralateral hip. Excessive LLD will be more likely to cause sciatica , low back pain, even instability. It is essential to balance the leg length for better outcomes and satisfaction, depending on careful preoperative templating and intraoperative judgement.