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A long term study of Charnley total hip replacements
Insights
This study evaluated 100 Charnley low friction arthroplasties over 15 years. Results show high survival rates for hip implants, with 91% overall survival and good clinical outcomes, despite some component wear and loosening.
Area of Science:
- Orthopedic Surgery
- Biomaterials Science
Background:
- The Charnley low friction arthroplasty is a common hip replacement procedure.
- Long-term outcomes and failure modes require continued investigation.
Purpose of the Study:
- To assess the long-term survival and clinical outcomes of the first 100 Charnley low friction arthroplasties.
- To identify factors associated with implant failure and wear.
Main Methods:
- Survival analysis of 100 hip arthroplasties with a minimum 14.4-year follow-up.
- Clinical evaluation of surviving implants.
- Radiographic assessment for component loosening and wear.
Main Results:
- Fifteen-year survival rates: 91% for total arthroplasty, 91% for femoral component, 96% for acetabular component.
- 87.5% of surviving hips had good or excellent clinical results.
- Polyethylene wear averaged 1.85 mm, associated with male sex and calcar resorption.
Conclusions:
- Charnley low friction arthroplasty demonstrates durable long-term performance.
- Femoral component loosening correlates with femoral shaft diameter.
- Polyethylene wear is a significant factor in long-term implant integrity.
Abstract:
This study concerns our first 100 Charnley low friction arthroplasties. The follow-up of the surviving forty hips ranged from 14.4 to 16.2 years (average 15.3 years). Thirty-nine of the original 100 hips were lost to follow-up due to death. Twenty-one could not be traced. There had been six known failures (defined as removal or revision of the prosthesis), two of which occurred in the surviving forty hips. Femoral component failure had occurred twice as often as acetabular failure. Survival analysis was performed using the last follow-up from all 100 hips. This depicted 91% survival of the arthroplasty (both components), 91% survival of the femoral component, and 96% survival of the acetabular component at fifteen years. Clinical evaluation of the surviving forty hips revealed 87.5% good and excellent results. This represented a small decline from 95% good and excellent results in the same hips at the ten year follow-up. Radiographic evaluation of thirty-two of forty hips demonstrated 6% migration of acetabular components, and 7% loose femoral components, while 31% of the acetabular components and 50% of the femoral components showed no sign of loosening. Femoral loosening was positively correlated with femoral shaft diameter. Measurable polyethylene wear was present in twenty-seven of thirty-two hips. The wear ranged from 0.2 to 8.5 millimeters (average 1.85 millimeters). Wear was associated with male sex and with calcar resorption.