title: The prevalence of predisposing deformity in osteoarthritic hip joints.
abstract: It is becoming increasingly evident that hip joint deformities may be major contributors to the development of osteoarthritis, and the term 'idiopathic osteoarthritis' may be inappropriate in many cases. Our study cohort was derived from the Copenhagen Osteoarthritis Sub-study, a cross sectional population-based database of 4151 individuals, all of whom had a standard anteroposterior weight-bearing pelvic radiograph taken. Hip joints were classified according to type and degree of deformity. We defined hip osteoarthritis by a minimum joint space width of < or = 2 mm. This cut-off has a significant relationship in both sexes with the clinical presentation. The study cohort which fulfilled these inclusion criteria consisted of 322 females (149 right hips and 173 left hips) and 162 males (77 right hips and 85 left hips) with osteoarthritis. We found an overall prevalence of predisposing hip deformities in females of 62.4% and in males of 78.9%. Minor and major deformities showed the same prevalence. Both sexes had a comparable prevalence of minor and major hip joint deformity, except for pistol grip deformity, which was more prevalent in men. We concluded that 'idiopathic osteoarthritis' is uncommon, and that even minor predisposing deformities are associated with hip osteoarthritis.
authors.affiliation: The Orthopaedic Department, University Hospital Hvidovre, Copenhagen, Denmark. J.klit1@gmail.com
authors.forename: Jakob
authors.initials: J
authors.lastname: Klit
authors.forename: Kasper
authors.initials: K
authors.lastname: Gosvig
authors.forename: Steffen
authors.initials: S
authors.lastname: Jacobsen
authors.forename: Stig
authors.initials: S
authors.lastname: Sonne-Holm
authors.forename: Anders
authors.initials: A
authors.lastname: Troelsen
mesh_terms: D000077:Acetabulum / Q000002:abnormalities* / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005270:Femur Head / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006618:Hip Dislocation, Congenital / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006621:Hip Joint / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D011859:Radiography; D012737:Sex Factors; D055815:Young Adult