title: Untreated asymptomatic hips in patients with osteonecrosis of the femoral head.
abstract: Because there is no consensus regarding the factors predicting femoral head collapse in asymptomatic osteonecrosis of the hip, we studied the risk factors for collapse. Between 1990 and 2000, we used MRI to confirm asymptomatic osteonecrosis of the femoral head in 81 patients (81 hips) whose other hip had nontraumatic symptomatic osteonecrosis and we monitored them prospectively. The minimum followup was 5 years (mean, 8.3 years; range, 5-16 years). At the latest followup, 31 hips (38%) were symptomatic and 26 hips (32%) had collapsed. The mean interval between diagnosis and collapse was 4.1 years. We observed no correlation between femoral head collapse and patients' age, gender, weight, presumed cause of osteonecrosis, or length of followup. With combined factors, only extent of large necrotic lesion (hazard ratio, 4.06; 95% confidence interval, 1.29-12.77) and location of Type C2 necrotic lesion (hazard ratio, 6.35; 95% confidence interval, 1.18-34.11) predicted collapse.
authors.affiliation: Department of Orthopaedic Surgery, Keimyung University, School of Medicine, Dongsan Medical Center, 194 Dongsan-dong, Joong-gu, Daegu 700-712, Korea. min@dsmc.or.kr
authors.forename: Byung-Woo
authors.initials: BW
authors.lastname: Min
authors.forename: Kwang-Soon
authors.initials: KS
authors.lastname: Song
authors.forename: Chul-Hyun
authors.initials: CH
authors.lastname: Cho
authors.forename: Sung-Moon
authors.initials: SM
authors.lastname: Lee
authors.forename: Kyung-Jae
authors.initials: KJ
authors.lastname: Lee
mesh_terms: D000328:Adult; D018450:Disease Progression; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005271:Femur Head Necrosis / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000209:etiology / Q000473:pathology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011859:Radiography; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors