title: Potential role of tartrate-resistant acid phosphatase 5b (TRACP 5b) as a surrogate marker of late loosening in patients with total hip arthroplasty: a cohort study.
abstract: In a cohort study, the role of the active tartrate-resistant acid phosphatase (TRACP 5b), a marker of bone-resorbing osteoclasts, for the assessment of loosening after total hip arthroplasty (THA), was analyzed, as well as its correlation with osteolysis and multinucleated cell appearance in the retrievals. Eighty THA patients, who went consecutively to the orthopedic department, were asked to participate, and 54 accepted and were enrolled in the study. Finally, 46 subjects were analyzed, clinical-radiographic evaluation was considered the gold standard, serum TRACP 5b was blindly measured, and a cut-off was obtained, by performing a ROC Curve. Based on the gold standard, patients were split by 19 stable and 27 loosened subjects, and results were matched. TRACP 5b was significantly higher in loosened patients than in stable ones (p < 0.001). A good specificity (89.5%), positive predictive value (90.0%), and likelihood ratio (6.33) were calculated, that provided strong evidence of loosening with TRACP 5b levels higher than the cut-off. Moreover, TRACP 5b and osteolysis (Fisher's exact test, p = 0.03) were found significantly correlated. TRACP 5b has been proven a reliable marker, specifically related to resorbing-multinucleated cells, to ascertain late loosening in THA, and could support standard procedures, if confirmed by performing prospective studies.
authors.affiliation: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopaedic Institute, Via di Barbiano 1/10, 40136 Bologna, Italy. lucia.savarino@ior.it
authors.forename: Lucia
authors.initials: L
authors.lastname: Savarino
authors.forename: Sofia
authors.initials: S
authors.lastname: Avnet
authors.forename: Michelina
authors.initials: M
authors.lastname: Greco
authors.forename: Armando
authors.initials: A
authors.lastname: Giunti
authors.forename: Nicola
authors.initials: N
authors.lastname: Baldini
mesh_terms: D000135:Acid Phosphatase / Q000097:blood*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D015415:Biomarkers / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D015726:Giant Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D008264:Macrophages / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010010:Osteoclasts / Q000473:pathology; D010014:Osteolysis / Q000097:blood* / Q000000981:diagnostic imaging* / Q000473:pathology; D011237:Predictive Value of Tests; D011475:Prosthesis Failure; D011859:Radiography; D012680:Sensitivity and Specificity; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; C000605510:ACP5 protein, human; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase