title: Idiopathic and secondary osteonecrosis of the femoral head show different thrombophilic changes and normal or higher levels of platelet growth factors.
abstract: OBJECTIVE
  Thrombophilia represents a risk factor both for idiopathic and secondary osteonecrosis (ON). We evaluated whether clotting changes in idiopathic ON were different from corticosteroid-associated ON. As platelet-rich plasma has been proposed as an adjuvant in surgery, we also assessed whether platelet and serum growth factors were similar to those in healthy subjects.
  
  
  METHODS
  18 patients with idiopathic ON and 18 with corticosteroid-associated ON were compared with 44 controls for acquired and inherited thrombophilia. Platelet factor 4 (PF4), transforming growth factor-β1, platelet-derived growth factor-BB (PDGF-BB), and vascular endothelial growth factor were assayed in the supernatants of thrombin-activated platelets, in platelet lysates, and in serum from 14 ON patients and 10 controls.
  
  
  RESULTS
  Idiopathic ON patients had higher plasminogen levels (median 118%) than controls (101%) (p = 0.02). Those with corticosteroid-associated ON had significantly higher D-dimer (333 ng/mL) and lower protein C levels (129%) than controls (164 ng/mL, p = 0.004; 160%, p = 0.02). The frequency of inherited thrombophilia was not different from the controls. No statistically significant differences were found between idiopathic and corticosteroid-associated ON. 20 of the 36 ON patients were smokers. (The controls were selected from smokers because nicotine favors hypercoagulability). ON patients had significantly higher serum PF4 levels (7,383 IU/mL) and PDGF-BB levels (3.1 ng/mL) than controls (4,697 IU/mL, p = 0.005; 2.2 ng/mL, p = 0.02).
  
  
  CONCLUSIONS
  Acquired hypercoagulability was common in both ON types, but the specific changes varied. The release of GF from platelets was not affected, providing a biological basis for platelet-rich plasma being used as an adjuvant in surgical treatment.
authors.affiliation: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopaedic Institute, Bologna, Italy. ecenni70@gmail.com
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Cenni
authors.forename: Caterina
authors.initials: C
authors.lastname: Fotia
authors.forename: Enis
authors.initials: E
authors.lastname: Rustemi
authors.forename: Kimitachi
authors.initials: K
authors.lastname: Yuasa
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Caltavuturo
authors.forename: Armando
authors.initials: A
authors.lastname: Giunti
authors.forename: Nicola
authors.initials: N
authors.lastname: Baldini
mesh_terms: D000305:Adrenal Cortex Hormones / Q000009:adverse effects; D000328:Adult; D000368:Aged; D001780:Blood Coagulation Tests; D001798:Blood Proteins / Q000032:analysis; D005260:Female; D005271:Femur Head Necrosis / Q000097:blood* / Q000209:etiology / Q000601:surgery; D005342:Fibrinolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010982:Platelet-Derived Growth Factor / Q000032:analysis*; D019851:Thrombophilia / Q000097:blood* / Q000209:etiology / Q000235:genetics; D042442:Vascular Endothelial Growth Factors / Q000097:blood
chemical_list: D000305:Adrenal Cortex Hormones; D001798:Blood Proteins; D010982:Platelet-Derived Growth Factor; D042442:Vascular Endothelial Growth Factors