title: The prevalence of and factors related to calcium pyrophosphate dihydrate crystal deposition in the knee joint.
abstract: OBJECTIVE
  The purpose of this study was to reveal the accurate prevalence and related factors to the presence of calcium pyrophosphate dihydrate (CPPD) crystal deposition in cadaveric knee joints.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Six hundred and eight knees from 304 cadavers (332 male knees and 276 female knees, formalin fixed, Japanese anatomical specimens) were included in this study. The average age of the cadavers was 78.3 ± 10.7 years. Knees were macroscopically evaluated for the existence of CPPD, and the depth of cartilage degeneration of the femoro-tibial joint following the Outerbridge's classification. CPPD crystal was confirmed under Fourier transform infrared spectroscopy (FTIR) analysis using light microscopy. Statistical analysis was performed to reveal the correlation between the occurrence of CPPD deposition in the knee joint and gender, age, and the depth of cartilage degeneration of the femoro-tibial joint.
  
  
  RESULTS
  The prevalence of grossly visible CPPD crystal was 13% (79 knees). In all of these knees, CPPD crystal was confirmed under FTIR analysis. Statistical analysis showed significant correlation between the occurrence of CPPD deposition and gender (P < 0.001), and depth of cartilage degeneration in the femoro-tibial joint (P < 0.001). In the cartilage degeneration positive knees (Over grade 3 in Outerbridge's classification), average age of CPPD deposition knee was significantly higher than CPPD negative knees.
  
  
  CONCLUSIONS
  In this study, the prevalence of CPPD deposition disease was evaluated in a relatively large sample size of cadaveric knees. The prevalence of CPPD deposition disease was 13%, and was significantly correlated with the subject's age, gender, and severity of cartilage degeneration in the femoro-tibial joint.
authors.affiliation: Department of Orthopaedic Surgery, Surugadai Nihon University Hospital, Tokyo, Japan. Electronic address: keinosukeryu@yahoo.co.jp.
authors.forename: K
authors.initials: K
authors.lastname: Ryu
authors.affiliation: Department of Orthopaedic Surgery, Kamimoku Hot Springs Hospital, Minakami, Japan. Electronic address: sekaiwoseisu@yahoo.co.jp.
authors.forename: T
authors.initials: T
authors.lastname: Iriuchishima
authors.affiliation: Departments of Orthopaedic Surgery, Kasai Shouikai Hospital, Tokyo, Japan. Electronic address: m-oshida@shoikai.com.
authors.forename: M
authors.initials: M
authors.lastname: Oshida
authors.affiliation: Departments of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan. Electronic address: nusportskato@gmail.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Department of Orthopaedic Surgery, Surugadai Nihon University Hospital, Tokyo, Japan. Electronic address: saito.akiyoshi@nihon-u.ac.jp.
authors.forename: A
authors.initials: A
authors.lastname: Saito
authors.affiliation: Departments of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan. Electronic address: imada.masato@nihon-u.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Imada
authors.affiliation: Departments of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan. Electronic address: aizawa.shin@nihon-u.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Aizawa
authors.affiliation: Departments of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan. Electronic address: ytoku@med.nihon-u.ac.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Tokuhashi
authors.affiliation: Departments of Orthopaedic Surgery, Nihon University School of Medicine, Tokyo, Japan. Electronic address: ryu.junnosuke@nihon-u.ac.jp.
authors.forename: J
authors.initials: J
authors.lastname: Ryu
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002131:Calcium Pyrophosphate / Q000378:metabolism*; D002805:Chondrocalcinosis / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D007719:Knee Joint / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008853:Microscopy; D015995:Prevalence; D012737:Sex Factors; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002131:Calcium Pyrophosphate
keywords: Calcium pyrophosphate dihydrate (CPPD); Chondrocalcinosis; Knee; Osteoarthritis; Prevalence