Analysis Of The Perceived Leg Length Before And After Total Hip Arthroplasty

Background: Total hip arthroplasty is a effective and mature surgery for severe hip disease, the optimal choice for fearful avascular necrosis of femoral head. In our country, because of the different level of the economy and education, A majority of patients with avascular necrosis of femoral head choose operative treatment in severe cases, so leg length discrepancy is common in patients with avascular necrosis of femoral head. At present, under the circumstances of no leg length discrepancy by reason of THA, different levels of preoperative perceived leg length discrepancy affect the perceived leg length after THA and the sequential change of the perceived LLD with time is less common.Objective: Leg length discrepancy(LLD) after total hip arthroplasty(THA) is a significant factor of patient dissatisfaction. We are analyze the follow-up results of preoperative and postoperative perceived LLD of patients, which contralateral femoral head is normal and unilateral avascular necrosis of femoral head for the primary THA. Under the circumstances of no leg length discrepancy by reason of THA, to assess different levels of preoperative perceived leg length discrepancy affect the perceivedleg length after THA and the sequential change of the perceived LLD with time.Method: Between January 2013 and December 2015, 53 patients with unilateral avascular necrosis of femoral head were performed by the same team in The First Hospital of Jilin University. Between them, 5 patients lost follow-up due to no clinic reexamination, 3 patients had radiographic LLD after THA, then 45 patients(36 cases for men, 9 cases for women) were selected for a retrospective study, the average age is 54.8 years(28 to 72 years), 29 patients with right avascular necrosis of femoral head,16 patients with left avascular necrosis of femoral head. Lumbar and other leg diseases were excluded in all patients, we measured the length of perceived LLD before THA and divided them into group A,group B and group C.30 cases in group A(0-10mm),9 cases in group B(10-20mm), 6 cases in group C(>20mm).All patients were measured radiographic LLD after THA with standard AP radiographs of pelvic, we believe leg length equal if the radiographic LLD under 5mm.We measure the length of perceived LLD in one week after THA, The post-operative clinics follow-up was at one month, three months, six months, twelve months and every half year. At the same time, the length of perceived LLD were measured. All date were analyzed statistically using SPSS 20.0 software.Results: All the 45 patients were followed up 6 to 24 months(mean15.3 months).6 patients had no LLD before and after THA, 6 patients felt LLD preoperatively and no perceived LLD postoperatively,33 patients(73%) felt the perceived LLD in one week after THA. In 9 cases(20%)of the 40 patients with followed-up, the perceived LLD persisted at one year after the surgery. The length of the perceived LLD were corrected in all patients and there were significant difference for all patients( P ﹤0.001).There were no significant difference of the perceived LLD after THA in different stages among the three groups(P >0.05).The perceived LLD decreased with time(P﹤0.05). The patients in group A can recover 57% in 3 months postoperatively and 86% in 6 months postoperatively.90% of patients in group A felt no perceived LLD in one year after THA. 67% of patients in group B felt no perceived LLD in one year after THA, there were still one(12.5%) patient felt LLD in 8 patients who were follow-up in 18 months after THA and the length of perceived LLD was 2.5mm,but the length of the perceived LLD in all patients was1.67mm±3.31 mm postoperatively. 33% of patients in group C felt no perceived LLD in one year after THA, 80% of the patients in group C can recover in 2 years. The length of LLD in patients still with perceived LLD was all 2.5mm, but the average length of LLD after THA in one weeks was 5mm..Conclusion: The THA can significantly improve LLD in patients with unilateral avascular necrosis of femoral head. The different lever of perceived LLD preoperatively had no significant relation with the perceived LLD postoperatively, and no significant relation in different stages among the three groups after THA.90% of the patients that the perceived LLD within 10 mm preoperatively felt no LLD in one year postoperatively. 67% of the patients that the perceived LLD between 10 mm and 20 mm preoperatively felt no LLD in one year postoperatively,87.5% of this patients felt no LLD in 18 months postoperatively.33% of the patients that the perceived LLD beyond 20 mm preoperatively felt no LLD in one year postoperatively, 80% of this patients felt no LLD in two years postoperatively.