Cartilage changes of femoral head osteonecrosis in stage Ⅱ and Ⅲ as detected by dGEMRIC

Objective To detect the cartilage changes of hip joint with osteonecrosis of femoral head (ONFH) in stages Ⅱ and Ⅲ and provide evidence for understanding cartilage changes of femoral head of osteonecrosis before collapse. Methods The cartilage changes of ONFH were determined by delayed gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC). According to ARCO classification of ONFH, the samples were divided into three groups: Group A, 11 hips, stageⅡ; Group B,13 hips, stage Ⅲ; Group C, 10 hips, normal. All participates underwent the tests by dGEMRIC. And the data of T1Gd were collected and analyzed. Results The values of T1Gd were 420 ±60 (Group A) ,361 ±54(Group B) and 538 ±26 (Group C) respectively. There was a significant difference among three groups.The values of T1Gd in the ONFH patients were lower than their healthy counterparts. The values of T1Gd of Group B was 14% lower than those of Group A. And the difference was significant statistically. Conclusion Cartilage of the femoral head undergoes abnormal metabolic changes before collapse. There is a loss of GAG in the cartilage and it aggravates with the worsening of ONFH.