title: Creatinine and nonprotein nitrogen plasma levels: possible etiopathogenetic factors in rotator cuff tears.
abstract: OBJECTIVE
  To determine the plasma levels of nonprotein nitrogen (NPN) and creatinine in healthy patients with rotator cuff tears.
  
  
  METHODS
  The study included 400 subjects. The study group included 200 patients (93 men and 107 women; mean age, 56.8 years; range, 23-81 years) who underwent arthroscopic repair of a rotator cuff tear from 2004 to 2007. The control group included 200 patients (93 men and 107 women; mean age, 53.9 years; range, 20-81 years) who underwent arthroscopy for management of a meniscal tear, with or without articular cartilage damage, in the same period. The 2 groups were frequency-matched by age and sex. Measurement of plasma levels of NPN and creatinine were performed in all patients.
  
  
  RESULTS
  Patients with rotator cuff tears showed higher plasma NPN levels within the normal range (P = 0.035) than patients with knee disorders (control group). Creatinine levels were comparable (P = 0.66) in both groups.
  
  
  CONCLUSIONS
  There appears to be an association between plasma NPN levels and rotator cuff tears. On the basis of our findings, plasma NPN could be involved in the pathogenesis of rotator cuff tears, although we advocate further research to draw more definitive conclusions.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Rome, Rome, Italy.
authors.forename: Rocco
authors.initials: R
authors.lastname: Papalia
authors.forename: Angelo
authors.initials: A
authors.lastname: Del Buono
authors.forename: Francesco
authors.initials: F
authors.lastname: Leonardi
authors.forename: Leonardo
authors.initials: L
authors.lastname: Osti
authors.forename: Nicola
authors.initials: N
authors.lastname: Maffulli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Denaro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000097:blood*; D011379:Prognosis; D012189:Retrospective Studies; D017006:Rotator Cuff / Q000378:metabolism; D000070636:Rotator Cuff Injuries; D012421:Rupture; D014947:Wounds and Injuries / Q000097:blood / Q000209:etiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D003404:Creatinine; D009584:Nitrogen