PREDICTION OF OSTEONECROSIS BY BONE SPECT AFTER SURGICAL FIXATION OF FEMORAL NECK FRACTURES

Introduction We have evaluated the circulation of the femoral head after multiple pinning for femoral neck fractures by bone SPECT. Methods Forty-four patients (33 women, 11 men, who had a mean age of 67 years) were enrolled prospectively. Early and late bone SPECT images were obtained on 2 to 13 days and 3 months after surgery and follow-up periods were over 12 months (average, 29 months). Results Seventeen cases showed normal uptake on early bone SPECT and healed successfully. Twenty-seven cases showed decreased uptake on early bone SPECT. Among these 27 cases, reperfusion was confirmed in 18 cases (66.7%) by late bone SPECT. The remaining 9 cases showed no recovery and the femoral heads were collapsed eventually. According to the Garden classification, osteonecrosis was found in 4 of 28 cases (14.3%) in Type I, 2 of, 15 cases (13.3%) in Type II, 3 of 6 cases (50%) in Type III and osteonecrosis was not detected in the one Type IV case. Conclusion In summary, bone SPECT is very sensitive and vascular insufficiency could be found even in the early post-operative period. Cases with normal uptake showed successful union. But, bone SPECT in early post-operative periods cannot be used to predict final outcome, as 66.7% of cases were recovered from ischemia. Although osteonecrosis was higher in cases with displacement, we should be careful for impacted fractures (Type I) as the incidence of osteonecrosis was not low.