title: Bone mineral density and biochemical markers of bone turnover in aseptic loosening after total hip arthroplasty.
abstract: The aims of this study were to determine whether subjects with aseptic loosening after total hip arthroplasty (THA) have regional differences in periprosthetic bone mineral density (BMD) and systemic biochemical markers of bone turnover compared to subjects with successful implants.Proximal femoral and pelvic BMD were measured by dual energy X-ray absorptiometry and bone turnover markers were assayed in 49 subjects 12.6+/-4.3 (mean+/-SD) years after cemented THA. Femoral BMD was lower in Gruen zones 2, 5, 6, and 7 in subjects with a loose femoral implant (n=17) compared to those (n=32) with fixed femoral implants (P<0.05 all comparisons). This BMD difference was greatest (-31%, P=0.02) in the proximal and medial region of the femur. Subjects with femoral loosening had higher levels of the bone resorption marker N-telopeptides of type-I collagen (P=0.02) than those with a fixed femoral implant. No differences in pelvic BMD or bone turnover markers were found between subjects with loose (n=18) versus fixed (n=31) pelvic implants. This study suggests that failure of femoral components after cemented THA is associated with region-specific decreases in BMD and an increase in urinary excretion of N-telopeptide cross-links of type-I collagen. These surrogate outcome markers may be of value in monitoring response to antiresorptive therapies used to treat periprosthetic osteolysis, although the diagnosis of aseptic loosening remains clinical and radiological.
authors.affiliation: Bone Metabolism Group, Division of Clinical Sciences (North), University of Sheffield, Northern General Hospital, Sheffield, UK. wilkomark@aol.com
authors.forename: J Mark
authors.initials: JM
authors.lastname: Wilkinson
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hamer
authors.forename: Angela
authors.initials: A
authors.lastname: Rogers
authors.forename: Ian
authors.initials: I
authors.lastname: Stockley
authors.forename: Richard
authors.initials: R
authors.lastname: Eastell
mesh_terms: D015502:Absorptiometry, Photon; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D015415:Biomarkers; D015519:Bone Density; D003094:Collagen / Q000652:urine; D024042:Collagen Type I; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000601:surgery*; D010388:Pelvis / Q000000981:diagnostic imaging; D010455:Peptides / Q000652:urine; D011237:Predictive Value of Tests; D011475:Prosthesis Failure; D017678:Sex Distribution
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D003094:Collagen