Effect of leg-length discrepancy after total hip arthroplasty on collapse of the contralateral hip in bilateral steroid-induced avascular necrosis of the femoral head / 中国医师杂志

ABSTRACT

Objective:To study the collapse of the contralateral femoral head after the total hip arthroplasty (THA) in patients with bilateral steroid-induced femoral head necrosis leg-length discrepancy (LLD) influences.Methods:A total of 108 patients with bilateral steroid-induced femoral head necrosis who were treated in Honghui Hospital Affiliated to Xi′an Jiaotong University from June 2014 to June 2016 underwent THA surgery on the hip joints that had symptoms and developed to Association Research Circulation Osseous (ARCO) Ⅲ. At the same time, the non-surgical hip-preserving treatment of the non-collapsed femoral head developed to the ARCO Ⅱ stage was performed. The follow-up period was 2 years, and 98 cases were finally included. According to the size of the leg-length discrepancy [LLD<3 mm group ( n=50), LLD≥3 mm group ( n=48)] and the type of leg-length discrepancy[non collapse side longer group ( n=58) and shorter group ( n=58)], the collapse of the femoral head and the THA were observed. Results:Finally, a total of 56 cases of femoral head collapse occurred in the non collapse side of the hip, of which 50 cases underwent THA within 24 months. There were significant statistical differences in THA and femoral head collapse between LLD<3 mm group and LLD≥3 mm group, non collapse side longer group and non collapse side shorter group ( P<0.05). The 2-year survival rate without collapse in the LLD<3 mm group and LLD≥3 mm group were 52.1% and 34.0%, respectively, and the 2-year survival rates in the longer and shorter non-collapsed limb groups were 56.9% and 22.5%, respectively. Compared with patients with moderate lesions, the survival rate of femoral heads in patients with larger lesions was lower ( OR 4.25, 95% CI 1.55-11.26; P=0.003). LLD<3 mm group ( OR 0.24, 95% CI 0.06-0.50; P<0.01) or non collapse side longer group ( OR 0.13, 95% CI 0.04-0.29; P<0.01) had lower risk of contralateral femoral head collapse after THA. Conclusions:For patients with bilateral steroid-induced femoral head necrosis who have collapsed lateral THA, postoperative leg-length discrepancy extremities is a potential risk factor for collapse of non-collapsed femoral head. LLD<3 mm and avoiding shortening of the uncollapsed limb may reduce the risk of collapse of the uncollapsed femoral head.