Prediction of collapse and selection of preserving femoral head for the osteonec rosis of the femoral head / 中华骨科杂志

ABSTRACT

Objective To explore the risk factors of collapse of osteonecro si s of the femoral head (ONFH) with a retrospective study, and put forward a treat ment protocol according to this study results. Methods From October 1993 to Apri l 2000, 40 cases (56 hips) were followed-up. The term of follow-up ranged from 1 2 to 68 months (average 29.2 months). The age of patients was from 16 to 60 year s old (average 36.8 years old). Preoperatively, the AP and frog view X-ray film, coronal and sagittal MRI were taken. The staging of ONFH proposed by ARCO was a dopted. Clinically the Harris score was used to assess the clinical outcome. The patients were divided into three groups 1) Non-operative 10 cases (14 hips), stage Ⅰin 7 hips(ⅠA 4,ⅠC 3),stageⅡin 7 hips (ⅡA 1,ⅡB 3,ⅡC 3); 2) Core dec ompression with vascularized iliac bone graft (VICBG) 18 cases (24 hips ), stag eⅠin 6 hips (ⅠB 4,ⅠC 2), stageⅡin 16 hips (ⅡA 4,ⅡB 8,ⅡC 4), stageⅢ in 2 hips (ⅢA); 3) Transtrochanteric rotational osteotomy(TRO) 12 cases (18 hips), stageⅡin 1 hip (ⅡC), stageⅢ in 17 hips (ⅢA 8, ⅢB 7,ⅢC 2). Harris score was 46 to 82 (mean 62.9). Results Collapse of the femoral head occurred in 9 hips a mong the 14 hips in the nonoperative group, in 10 hips among the 24 hips in the VICBG group. In TRO group, further deterioration was prevented in all but one hi p. Whether theres surgical intervention or not, no collapse occurred in both s tageⅠA and ⅡA, collapse occurred in both stage ⅠB and ⅡB was 7 hips among 15 hips (46.7%), 13 hips progressed into collapse of the femoral head with ⅠC and ⅡC (100%). The Harris score was 47 to 93(mean 77.4) postoperatively. Conclusio n With MR imaging, it is possible to predict the possibility of collapse of ONFH . The lower risk is below 30 percent of necrotic area, the higher risk is 30 to 60 percent of necrotic area, and the higherest risk is beyond 60 percent of necr otic area. The best results can be obtained if selection of treatment individual ly according to ARCO stage, patient age and necrotic extent.