Femoral component loosening after hip resurfacing arthroplasty

Objective: Before the re-introduction of the current generation of total hip resurfacing arthroplasty, component loosening and osteolysis were of great concern to the orthopaedic community. Early, mid- and long-term clinical results are encouraging, but component loosening still exists. Materials and Methods: Macroscopic, contact radiographic and histopathological analyses after undecalcified preparation of bone tissue specimens were performed. To investigate the frequency and morphological patterns of the loosening of the femoral component, we analysed a series of 190 retrieved femoral remnants that were revised for aseptic failures. Results: Thirty-five (18.4%) hips were revised for clinical and/or radiographic loosening of the femoral component. Pseudoarthrosis (n=17; median in situ time: 16 weeks, interquartile range [IQR]: 9 to 34), collapsed osteonecrosis (n=5; median in situ time: 79 weeks, IQR: 63 to 97), cement-socket debonding (n=3; median in situ time: 89 weeks, IQR: 54 to 97) and at later follow-up bone-cement loosening (n=10; median in situ time: 175 weeks; IQR 112 to 198; p=0.005) were distinct patterns of the femoral remnant-implant loosening. Fibrocartilaginous metaplasia of interface bone trabeculae (n=38; median in situ time: 61 weeks, IQR: 32 to 138) was strongly associated with femoral component loosening (p=0.009). Both the trabecular hyperosteoidosis (n=32; median in situ time: 71 weeks, IQR 50 to 129) and excessive intraosseous lymphocyte infiltration (n=12; median in situ time: 75 weeks, IQR 51 to 98) at the bone-cement interface correlated strongly with fibrocartilaginous metaplasia (p=0.001 and p=0.016 respectively) and all three lesions were associated with the female gender (p=0.021, p=0.009, and p=0.051). Conclusion: Femoral component loosening at early follow-up was mostly caused by pathological changes of the femoral remnant bone tissue: pseudoarthrosis and collapsed osteonecrosis. Fibrocartilaginous metaplasia was frequently observed in hips with femoral component loosening. The potential role of interface hyperosteoidosis as a precursor lesion of bone-cement loosening and its possible association with delayed type hypersensitivity reaction are discussed. © 2010 ISS.

Subjects

Arthroplasty failure

Hip resurfacing

Hyperosteoidosis

Loosening

Metal hypersensitivity

DDC Class

610: Medicine, Health

620: Engineering

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Femoral component loosening after hip resurfacing arthroplasty