Evaluation of Risk Factors Influencing Instability after Total Hip Replacement

Abstract

Introduction: Total hip arthroplasty has been successful in relieving pain arising from hip joint diseases and maintains functional stability of hip joint. Instability can be rephrased as subluxation or dislocation of femoral head from the acetabulum. The study has been undertaken to find out causes related to instability after Total Hip Replacement (THR). Aim: To evaluate preoperative, intraoperative and postoperative risk factors influencing instability after THR. Materials and Methods: This retrospective study was carried out from June 2013 to June 2019. Preoperative, postoperative and six months follow-up data was recorded in the questionnaire. A total of eight patients were included in the group having postoperative dislocation and 122 patients were in normal THR group. Clinical outcome was measured using Harris Hip score. Data analysis was done by using Statistical Package for the Social Sciences (SPSS) software version 17.0 and parametric tests like paired t-test, Analysis of Variance (ANOVA) were used. Results: Majority of the patients in the study were in the age group of 31-40 years and 41-50 years (27.69% each) with total mean age of 41.14±12.40 years. About 77.69% were male and 22.31% were female. Mean Harris hip score of the total population was 74.73±5.35. Dislocation post THR was observed in 8 (6.15%) and all these patients were males. Six (75%) patients in hip dislocation group were chronic alcoholics while 41 (33.61%) in non-dislocation group were alcoholics and incidence of dislocation and alcoholism was statistically significant. Capsulectomy was done in 50% patients of hip dislocation group and 16.39% of non-dislocation group thus capsulectomy appears as a significant risk factor for postoperative hip dislocation. Conclusion: The incidence of hip instability after THR was 6.15%. Alcohol addiction was identified as a statistically significant independent preoperative risk factor. It was observed that capsulectomy was a significant risk factor for hip dislocation.