Clinical Results of a Constrained liner for Prevention and Treatment of Recurrent Dislocation after Total Hip Replacement

초록

BACKGROUND The purpose of this paper was to evaluate the failure rate and the risk factors leading to instability after THRA with CAL as well as treatment strategies. METHODS From 1999 to 2017, using two institution’s THRA registry, we identified 46 THRA cases using a constrained liner and minimum 2 years more followed up (a mean follow-up of 3.8 years). Of the 46, 12 patients were used CAL for prevention of dislocation in primary THRA, 34 patients were used CAL for treatment of recurrent dislocation after primary THRA. Clinical and radiological evaluation were performed. We evaluated failure rate of CAL and risk factors. RESULTS Twelve of the 46 hips (26%) had a dislocation after use of CAL in primary and revision THRA. Patients who had abductor muscle deficiency had a significantly higher rate of dislocation even use of CAL when compared to patients who had intact abductor muscle (hazard ratio 4.4, 95% confidence interval, 0.26 to 0.65; P=0.016). Component malposition was not a statistically significant risk factor. (hazard ratio 0.299, 95% confidence interval, 0.15 to 0.59; P=0.299). Also, neuromuscular disorder was not a statistically significant risk factor. (hazard ratio 0.548, 95% confidence interval, -0.17 to 0.43; P=0.531). And younger patients under 75 years of age had a statistically higher dislocation rate even use of CAL than patients over 75 years of age. (hazard ratio 7.642, 95% confidence interval, 65.2 to 72.2; P=0.011). CONCLUSION Use of CAL in primary and revision THRA show relatively high failure rate (26%) for prevention and treatment of dislocation. Abductor muscle deficiency and relatively young age were a risk factor for failure of CAL for hip dislocation. We recommend the recurrent dislocation with the presence of abductor muscle deficiency patients were treated not only THRA using CAL, but also additional abductor muscle reconstruction for reducing the risk of dislocation.