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.