Risk Factors Related to Modular Femoral Stem Failures in Revision Hip Arthroplasty / 대한고관절학회지

PURPOSE: The purpose of this study was to analyze failure rates and causes of hip arthroplasty revisions associated with the use of cementless modular femoral stems. MATERIALS AND METHODS: This study comprised 93 patients(100 hips) that were followed up for more than two years after revision involving modular femoral stem arthroplasty. The clinical results were evaluated using the Harris Hip Score and the radiologic results were evaluated using leg length discrepancy, subsidence and bone formation assessments. We analyzed the relationship between the number of hip surgeries performed and the bone deficiencies and failures observed. Preoperative femoral bone deficiencies were described by Paprosky Grade; Grade I or II were identified in 24 hips, IIIa in 4 hips, IIIb in 28 hips and IV in 3 hips. RESULTS: We observed 80 hips with aseptic loosening, 10 hips with infection after previous revision, 8 hips with periprosthetic fractures and 2 hips with dislocations. Clinical results improved from a preoperative score of 42 (HHS) to a postoperative mean score of 81.5. The cause of early failure in 4 hips was identified as femoral stem subsidence, and the cause of late failure in 3 hips was due to infection. According to the comparison analysis, there was no statistical significance between femoral bone deficiency (P=0.727) and application of cement (P=0.087), but hips with previous revision surgery showed a higher rate of failure (P=0.024). CONCLUSION: Cementless modular stems produced satisfactory results. The main cause of failure was subsidence. A significant risk factor for failure was hips which had undergone previous revision surgery.

Structural Allograft for Femoral Deficiency in Revision Total Hip Arthroplasty / 대한정형외과학회잡지

PURPOSE: We investigated the results and the effectiveness of structural allografts, which were obtained from a donated cadaver for femoral deficiency in revision total hip arthroplasty. MATERIALS AND METHODS: We reviewed 27 patients who received a structural allograft for femoral deficiency in revision total hip arthroplasty with a minimum follow-up of 2 years. All allografts were fresh frozen bone obtained from donated cadavers. Whole proximal femur was used in 3 patients and strut or cortical onlay graft in the others. The results were evaluated by using Harris hip scores and by the presence of complications, clinically and stability of stem, osteolysis, radiolucent line, and by the radiographic union of the allograft. RESULTS: The average Harris hip score improved from 40.1 preoperatively to 86.9 postoperatively, and the stem showed bony stability in 18 patients, fibrous stability in 8 patients, and instability in 1 patient due to the recurrence of infection. Radiologically, osteolysis was observed in 4 patients (14.8%), radiolucent line over 2 mm in 1 patient, and union of allografts in 25 patients (92.6%) that showed stable stem. The average union time was 7.5 months. Nonunion of allografts were observed in 2 patients revised with a cancellous bone autograft. Complications were infection in 1 patient, dislocation in 2 patients, and heterotopic ossification in 1 patient. CONCLUSIONS: Structural allografts obtained from cadaveric donor were used for large femoral deficiency in revision total hip arthroplasty. Our results show that satisfactory union and can successfully restore the bone stock for further surgery.