Mid-term Results of Revision Total Hip Arthroplasty Using Modular Cementless Femoral Stems / 대한고관절학회지

PURPOSE: The purpose of this study was to evaluate the clinical and radiological results of revision total hip arthroplasty using modular distal fixation stems for proximal femoral deficiency. MATERIALS AND METHODS: Forty-five patients (47 hips) were analyzed more than 24 months after revision total hip arthroplasty that used modular distal fixation stems and was performed between 2006 and 2012. There were proximal femoral defects in all cases. Preoperative femoral defect classification revealed Paprosky type II in 31 cases, type IIIA in 7, and type IIIB in 9. The mean duration of follow-up was 53.4 (25-100) months. We evaluated the Harris hip score (HHS), walking ability according to Koval as clinical parameters, stem stability, and stem position change as radiographic parameters. Kaplan-Meier survival analysis was performed. RESULTS: The average HHS improved form 39.5 points to 91.3 points and walking ability also improved in most cases; all patients had stable fixation of the femoral stem. Postoperative complications included 5 cases of infection and 2 cases of dislocation. The survival rate with the end point of re-revision surgery due to infection or dislocation was 86% after 8-year follow-up. CONCLUSION: Cementless revision total hip arthroplasty using modular femoral stems is useful because the stems can be stably fixed on the diaphyseal portion of the femur, which has relatively good bone quality at mid-term follow-up.

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.

Cementless Total Hip Arthroplasty Using a Modular Femoral Component in Patients with Femoral Head Osteonecrosis: Comparison of Metal-on-Metal and Ceramic-on-Ceramic Articulation

PURPOSE: The purpose of this study was to evaluate the clinical and radiological outcomes after total hip arthroplasty using the S-ROM modular system for osteonecrosis of the femoral head, and to compare the results between the groups using metal-on-metal articulation and ceramic-on-ceramic articulation. MATERIALS AND METHODS: Sixty-six patients (78 hips) with osteonecrosis of the femoral head were evaluated after primary total hip arthroplasty between January 2001 and December 2004, using an S-ROM proximal modular femoral stem. The average follow-up was 77 months (range, 60 to 122 months) and all patients were followed for more than five years. RESULTS: The average Harris hip score improved from 53 points to 88.5 points at the final follow-up. At the latest radiologic evaluation, sixty-seven stems had bony ingrowth stability, and 10 stems had stable fibrous ingrowth. However, one stem had diffuse extensive osteolysis and loosening, which was revised at 9 years. Postoperative complications included 4 cases of heterotrophic ossificiation, 1 case of linear fracture after insertion of the femoral stem, 1 case of dislocation, 2 cases of infection, and 1 case of extensive osteolysis and loosening. There were 3 cases of revision and Kaplan-Meier survivorship analysis with revision estimated at a 95.7% chance of survival for the femoral component during 122 months. CONCLUSION: Our study showed that total hip arthroplasty using the S-ROM modular system with metal-on-metal articulation or ceramic-on-ceramic articulation had favorable clinical and radiological mid- to long-term results.

Hip Arthroplasty Using Cementless Modular Femoral Stem for Displaced Femoral Neck Fracture in Patients More than 70 Years Old

Purpose: To evaluate the clinical and radiological results of hip arthroplasty using a cementless modular femoral stem in patients older than 70 years with a femoral neck fracture. Materials and Methods: From January 2002 to May 2005, 67 hip arthroplasty procedures (66 patients) using a cementless modular femoral stem for displaced femoral neck fractures in patients older than 70 years of age were evaluated. All the patients were followed up for more than 2 years. The mean age at surgery was 77 (70~92) years. There were 22 men and 44 women. The mean follow up period was 31 months (24~41). The clinical evaluation was performed by examining the perioperative Activities of Daily Living (ADL) and postoperative complications. The radiological evaluation for femoral stem loosening and osteolysis was performed using the serial postoperative radiographs. The radiological evaluation for leg length discrepancies was performed using the immediate postoperative radiograph. Results: In preoperative ADL, 31 cases (46%) were in grade 1, 21 (31.5%) in grade 2, 14 (21%) in grade 3, 1 (1.5%) in grade 4 and none in grade 5. A review of the postoperative ADL revealed 25 cases (37.5%) in grade 1, 18 (27%) in grade 2, 21 (31%) in grade 3, 3(4.5%) in grade 4 and none in grade 5. Postoperative restoration of the ADL was observed in 48 cases (71.5%). There were no significant complications. Radiographically, all cases showed stable bony fixation of the femoral stem with the exception of 1 case, who showed subsidence and a pedestal reaction. Postoperative leg length discrepancy was observed in 5 cases (7.5%) but was <1 cm in all cases. Conclusion: In elderly patients older than 70 years of age with a displaced femoral neck fracture, cementless hip arthroplasty using a modular femoral stem provides good initial stability and subsequent secure bony fixation with minimal complications.

Total Hip Arthroplasty with Use of Proximal Modular Femoral Stem in Secondary Coxarthrosis of Hip Associated with Deformed Femur

Purpose: The purpose of this study was to evaluate the clinical and radiological results of total hip arthroplasty using a proximal modular femoral stem in patients who had secondary coxarthrosis associated with a deformed femur. Materials and Methods: Forty-two patients (45 hips) with secondary coxarthrosis were evaluated after primary total hip arthroplasty using an S-ROM proximal modular femoral stem, between January 2001 and March 2004. The average follow-up was 44 months (range, 24 to 60 months). The mean age of the patients was 48.5 years old and there was a predominance of female patients (65.5%). The preoperative diagnoses included 26 cases of developmental dysplasia of the hip, 13 cases of sequalae of LCP, 2 cases of epiphyseal dysplasia, 3 cases of sequalae of pyogenic arthritis, and 1 case of congenital coxa vara. Results: The average Harris hip score improved from 52.2 points to 85.5 points. All the femoral stems demosntrated stable fixation, which included 37 cases by bony ingrowth and 8 cases by stable fibrous ingrowth. Neither osteolysis nor progressive radiolucent lines around the femoral stems were found at the latest follow-up. Postoperative complications included: 2 cases of hip dislocations, 1 case of periprosthetic fracture, 1 case of infected cup loosening, and 1 case of sciatic nerve palsy. Overall, forty-one hips (91.9%) exhibited excellent or good clinical results at the most recent follow-up. Conclusion: For advanced secondary coxarthrosis, total hip arthroplasty with use of a proximal modular femoral stem yielded good mid-term results based on clinical and radiological criteria.

Comparison of Monoblock and Modular Femoral Stem on Isolated Acetabular Revision with Use of Uncemented Cup

Purpose: The purpose of our study was to assess the clinical and radiological results of isolated acetabular revision and the differences in the results between monoblock and modular femoral stems. Materials and Methods: Between October 1991 and June 2002, 39 patients (39 hips) underwent isolated acetabular revisions with use of uncemented cups and bone grafts. The mean period of follow-up was 5 years 3 months (range, 2 years 1 month to 9 years 8 months). The mean age of the patients at the time of the surgery was 51 years old (range, 26 to 75 years old). The monoblock femoral stems were used in 19 hips and the modular femoral stems were used in 20 hips. The monoblock stems were retained without exchange provided that there was no gross scratch on the femoral head and the femoral stem was confirmed to be stable and fixed intraoperatively. In the modular stems, the femoral heads were always exchanged with new ones. Results: The mean Harris hip score improved from 57 to 87 points. Radiologically, all the stems retained at surgery remained well osseointegrated without osteolysis. Re-revisions of the acetabular components were performed in 5 hips using monoblock stems due to periacetabular osteolysis caused by excessive wear of polyethylene and subsequent loosening of the cups in 3 hips and mechanically unstable acetabular cups without osteolysis in 2 hips. The mean wear rate of polyethylene coupled with the monoblock stem was 0.27 mm/year which was greater than the 0.11 mm/year in the cases with modular stems. Conclusion: To prevent failure of acetabular cups that may occur later by excessive wear of polyethylene, we recommend revision of the well-fixed monoblock femoral stems even though there is no gross scratch on the femoral heads of the monoblock stems.