title: Incidence and risk of chondrolysis in Denmark: A nationwide population-based study.
abstract: BACKGROUND
  Chondrolysis is a rare disease with destruction of cartilage of joints. Incidence and risk factors have not been studied in a formal epidemiologic population-based setting.
  
  
  METHODS
  We used the Danish National Registry of Patients (NRP) covering all Danish hospitals to identify all cases of chondrolysis from 1994 to 2008. Incidence rates were estimated using the general population as the denominator. For each chondrolysis patient, 10 age-matched population controls were sampled for a case-control analysis. For cases and controls, we ascertained in the NRP history of diabetes, rheumatoid arthritis, orthopedic surgery, including surgery of shoulder and upper arm, injury to shoulder girdle or upper arm, and treatment with pain pump. We determined the prevalence of these risk factors in cases and controls, and computed odds ratios (OR).
  
  
  RESULTS
  We identified 43 patients with chondrolysis in the 15-year study period. The incidence rate was 5.5 per 10,000,000 person-years. Diabetes was more prevalent in chondrolysis cases, compared with the 430 controls (OR = 6.7; 95% confidence intervals [CI]: 1.1-39.9). Orthopedic surgery was also associated with an increased risk of chondrolysis (OR = 28.8, 95% CI: 11.0-75.6), while previous injury was not (OR = 0.8; 95% CI: 0.1-5.9).
  
  
  CONCLUSIONS
  Chondrolysis was rarely diagnosed in Denmark. Diabetes and orthopedic surgery may be risk factors.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Christian F
authors.initials: CF
authors.lastname: Christiansen
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Thygesen
authors.forename: Lars
authors.initials: L
authors.lastname: Pedersen