title: Osteophytes: relevance and biology.
abstract: OBJECTIVE
  Osteophytes are common features of osteoarthritis. This review summarizes the current understanding of the clinical relevance and biology of osteophytes.
  
  
  METHODS
  This review summarizes peer-reviewed articles published in the PubMed database before May 2006. In addition this review is supplemented with own data and theoretical considerations with regard to osteophyte formation.
  
  
  RESULTS
  Osteophytes can contribute both to the functional properties of affected joints and to clinical relevant symptoms. Osteophyte formation is highly associated with cartilage damage but osteophytes can develop without explicit cartilage damage. Osteophytes are mainly derived from precursor cells in the periosteum and growth factors of the TGFbeta superfamily appear to play a crucial role in their induction.
  
  
  CONCLUSIONS
  Osteophyte formation is an integral component of OA pathogenesis and understanding the biology of osteophyte formation can give insights in the disturbed homeostasis in OA joints.
authors.affiliation: Experimental Rheumatology & Advanced Therapeutics, NCMLS, Radboud University, Medical Center Nijmegen, The Netherlands. p.vanderkraan@reuma.umcn.nl
authors.forename: Peter M
authors.initials: PM
authors.lastname: van der Kraan
authors.forename: Wim B
authors.initials: WB
authors.lastname: van den Berg
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology*; D051379:Mice; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology*; D010521:Periosteum / Q000166:cytology; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D016212:Transforming Growth Factor beta