title: Articular cartilage calcification of the hip and knee is highly prevalent, independent of age but associated with histological osteoarthritis: evidence for a systemic disorder.
abstract: Based on the concept of a systemic predisposition for articular cartilage calcification (CC), the aim of this study was to determine the prevalence and amount of bilateral CC of hip and knee joints in an unselected sample cohort by high-resolution digital contact radiography (DCR) and to analyze the association of CC with histological OA.
  
  
  
  Both hip and knee joints of 87 donors (48 m and 39 f; mean age 62) were analyzed by DCR in this post-mortem study of an unselected cohort of donors. Histological OA (OARSI) of the main load bearing area of femoral heads and medial femoral condyles was determined.
  
  
  
  The prevalence of CC of the femoral head was 96.6%, of the knee 94.3%. Bilateral calcification was detected in 79.3% of hips and 86.2% of knees. Concomitant CC of all four joints was detected in 69.0% of donors. There was no difference between the amount of CC of hips and knees (P = 0.47). The amount of CC of any given hip or knee correlated with that of the contralateral hip (rs= 0.54, P < 0.001) or knee (rs= 0.50, P < 0.001). There was a correlation between the amount of CC and histological OA (hips rs= 0.48, P < 0.001, knees rs= 0.30, P = 0.004), but not between CC and age (hips rs= -0.09, P = 0.42; knees rs= 0.10, P = 0.34).
  
  
  
  These data support the concept that articular CC occurs as the result of a systemic disorder. CC appears to be an early element of hip and knee OA pathogenesis independent of age.
authors.affiliation: Department of Orthopaedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: t.hawellek@uke.de.
authors.forename: T
authors.initials: T
authors.lastname: Hawellek
authors.affiliation: Department of Orthopaedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: j.hubert@uke.de.
authors.forename: J
authors.initials: J
authors.lastname: Hubert
authors.affiliation: Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: shischke@uke.de.
authors.forename: S
authors.initials: S
authors.lastname: Hischke
authors.affiliation: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: m.krause@uke.de.
authors.forename: M
authors.initials: M
authors.lastname: Krause
authors.affiliation: Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany. Electronic address: Jessica.Bertrand@ukmuenster.de.
authors.forename: J
authors.initials: J
authors.lastname: Bertrand
authors.affiliation: Institute of Experimental Musculoskeletal Medicine, University Hospital Münster, Münster, Germany. Electronic address: thomas.pap@uni-muenster.de.
authors.forename: T
authors.initials: T
authors.lastname: Pap
authors.affiliation: Department of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: pueschel@uke.de.
authors.forename: K
authors.initials: K
authors.lastname: Püschel
authors.affiliation: Department of Orthopaedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: ruether@uke.uni-hamburg.de.
authors.forename: W
authors.initials: W
authors.lastname: Rüther
authors.affiliation: Department of Orthopaedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Electronic address: niemeier@uke.uni-hamburg.de.
authors.forename: A
authors.initials: A
authors.lastname: Niemeier
mesh_terms: D002113:Calcification, Physiologic; D002358:Cartilage, Articular; D005260:Female; D006801:Humans; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis; D011859:Radiography
keywords: Age; Cartilage calcification; Chondrocalcinosis; Hip; Knee; Osteoarthritis