title: Mid-term prognosis of non-traumatic osteonecrosis of the femoral head.
abstract: We followed, prospectively, 77 patients (90 hips) with early-stage, non-traumatic osteonecrosis of the femoral head for a mean period of nine years. At the time of final review, 56 (62%) were symptomatic. Using the Cox model, the initial radiological stage, the progression of staging, the reduction in size of the lesions and the percentage of necrotic volume on MRI were identified as risk factors. Using the Harris score of < 70 or surgery as the endpoint, the cumulative rates of survival were 60.0% at one year, 43.3% at two years, 38.9% at five years and 37.2% at ten years. Survival curves demonstrated that clinical deterioration could occur 90 months after the initial diagnosis, suggesting that asymptomatic patients should be followed carefully for several years. Radiological time-dependent reduction in size without progressive collapse may represent repair even when the collapse is minimal.
authors.affiliation: Department of Orthopaedic Surgery, Asahikawa Medical College, Midorigaoka Higashi, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ito
authors.forename: T
authors.initials: T
authors.lastname: Matsuno
authors.forename: N
authors.initials: N
authors.lastname: Omizu
authors.forename: Y
authors.initials: Y
authors.lastname: Aoki
authors.forename: A
authors.initials: A
authors.lastname: Minami
mesh_terms: D000328:Adult; D018450:Disease Progression; D005260:Female; D005271:Femur Head Necrosis / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome