title: Tartrate-resistant acid phosphatase 5b (TRAP 5b) as a marker of osteoclast activity in the early phase after cementless total hip replacement.
abstract: BACKGROUND
  After total hip replacement, increased bone metabolism is seen. A local periprosthetic osteopenia can be measured by dual-energy X-ray absorptiometry (DXA), but it is still unkown whether biochemical markers can be used to monitor the local remodeling at an earlier stage.
  
  
  METHODS
  In this prospective study we compared the biochemical markers tartrate-resistant acid phosphatase 5b (TRAP 5b), bone ALP, osteocalcin and CrossLaps with periprosthetic DXA in 17 consecutive patients after uncemented total hip replacement.
  
  
  RESULTS
  We found a highly significant early increase in TRAP 5b after 2 weeks and 6 weeks, which was followed by a densitometrically detectable decrease in bone mineral density after 26 weeks, especially in periprosthetic section Gruen zone 7. Bone ALP and osteocalcin levels as markers of osteoblast activity, and also Cross-Laps as a further marker of osteoclast activity, did not appear to allow any significant prediction of local bone remodeling.
  
  
  CONCLUSIONS
  Our findings show that TRAP 5b is a sensitive parameter for monitoring of osteoclast activity after cementless total hip replacement, and may predict local osteopenia.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital, Frankfurt/Main, Germany. B.Habermann@Friedrichsheim.de
authors.forename: Bjoern
authors.initials: B
authors.lastname: Habermann
authors.forename: Christian
authors.initials: C
authors.lastname: Eberhardt
authors.forename: Matthias
authors.initials: M
authors.lastname: Feld
authors.forename: Ludwig
authors.initials: L
authors.lastname: Zichner
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Kurth
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis*; D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000032:analysis; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D015415:Biomarkers / Q000032:analysis*; D015519:Bone Density; D016723:Bone Remodeling; D001862:Bone Resorption; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000032:analysis; D010010:Osteoclasts / Q000201:enzymology*; D011446:Prospective Studies; D011475:Prosthesis Failure; D013644:Tartrates
chemical_list: D015415:Biomarkers; D013644:Tartrates; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase