Clinical outcomes of femoral revision using restoration modular stem / 中华骨科杂志

ABSTRACT

Objective To investigate the early outcomes of revision hip arthroplasty using restoration modular (RM) stem.Methods Fifty-nine patients underwent revision hip arthroplasty with RM stem from April 2012 to June 2015 in our center with a minimal of two years follow-up.The patients including 24 male and 35 female had a median age of 61.0 (56,66) years.The median BMI was 24.0 (22.5,26.0) kg/m2,while the median interval from the primary surgery was 10.5 (6.0,14.5) years.The rea sons for revision inculded infection in 8 patients,aseptic loosening in 45,recurrent dislocation in 1,and periprosthetic fracture in 5.There were 3 cases of type B2 and 2 cases of B3 periprosthetic fracture according to Vancouver classification.The bone defects severity was conducted according to Paprosky classification that 14 patients in type Ⅱ,31 in type ⅢA,8 in type ⅢB,and 1 in type Ⅳ.Acetabular component were revised in 56 cases.Patients were followed up at 3 months,6 months,1 year and annually thereafter for clinical and radiological evaluation.Results All the patients were followed up with a median duration of 30.4 (27.3,37.9)months,the median Harris score significantly improved from 37 (31,53) points preoperatively to 84 (80,95) points at the last follow up (Z=-6.681,P=0.000).There were 3 patients had perforation or fracture intra-operatively,two of them were fixed by strut allograft.The other one who did not compromise the implant stability was not fixed.Extended trochanteric osteotomy was applied in 14 cases and they healed well at 3-6 months during follow-up.There was one case of early dislocation at 6 days postoperatively,which was treated with close reduction and immobilization without recurrence.No infection,stem fracture,hematoma formation and sciatic nerve injury were reported.No femoral component loosening was identified at the latest follow-up.Median subsidence was 1.0 (0,2.0) mm with the maximum case 6.0 mm and 3 cases 3.5 mm.All of subsidence developed within the first year postoperatively but without further aggravation.The affected leg lengthened 17.5± 10.1 mm (range 2-40 mm) after operation.The affected leg was shorter 17.5± 12.6 mm (shorter 44.4 mm to longer 3.0 mm) than that in the normal side pre-operatively.However,the distinction decreased to 0.1±9.6 mm postoperatively (shorter 24.8 mm to longer 22.4 mm,t=-10.538,P=0.000).Conclusion Early satisfactory results are achieved in hip revision using RM modular stem at the femoral side.The modular design could simplify the surgical procedure with better control of leg length and joint stability.Long-term follow-up is still required for further evaluation.