Incidence of osteonecrosis of the femoral head in divers: an epidemiologic analysis in Dalian

Abstract

Objective To investigate the incidence of osteonecrosis of the femoral head (ONFH) in divers of Dalian.Methods From January 2010 to December 2010,all registered 855 divers in Dalian were enrolled in this study.All divers underwent a unified medical examination and a questionnaire including height,weight,blood pressure and hip inspection.Radiological examination (anteroposterior and frog position)was used for all divers.Suspicious persons with hip pain but normal X-ray performance were confirmed by MRI.Results Sixty-eight divers were confirmed as ONFH,and the incidence of ONFH in divers of Dalian was 7.95％.According to the Ficat classification,12 patients (12 hips) were in Phase 1,40 patients (47 hips)in phase Ⅱ,3 patients (3 hips) in phase Ⅲ,13 patients (15 hips) in phase Ⅳ.The mean age of divers was 32.6+5.5 years (range,18-55 years).The onset ages of most patients ranged from 30 years to 50 years,accounted for 83.82％ (57/68).Among all patients,primary school education accounted for 10.58％ (38/359),junior high school education 6.28％ (28/446),high school education 4.26％ (2/47),university education 0 (0/3); seniority less than 5 years accounted for 4.55％ (20/440),6-10 years 9.69％ (28/289),11-15 years 13.04％ (12/92),16-20 years 21.05％ (4/19),more than 20 years 26.67％ (4/15); self-employed accounted for 11.88％ (19/160),private enterprise 8.41％ (38/452),and national enterprise 4.53％ (11/243).Conclusion The incidence of ONFH is high in divers of Dalian,which is different in terms of age,seniority,level of education,enterprise nature. Key words: Femur head necrosis; Diving; Incidence; Epidemiologic studies