Abstract
The purpose of this study was to investigate the use of early post-operative bone scintigraphy to predict surgical outcome following vascularized fibular grafting (VFG) for osteonecrosis of the hip. Bone scans from one hundred and four hips (Steinberg stage I–IV) treated with VFG between 1994 and 2000 were retrospectively reviewed. Bone scan scores were significantly lower in the failed group (n=31) compared to the successful group (n=73), p=0.03. Logistic regression demonstrated that a higher bone scan score was associated with success, p=0.028, with an odds ratio of 3.08 (1.13–8.40).
The purpose of this study was to investigate the use of bone scintigraphy to predict surgical outcome following vascularized fibular grafting (VFG) for osteonecrosis of the hip.
Subjects with a higher bone scan score post-operatively had a three-fold higher chance of success than subjects with the lowest score.
These results suggest that having a well perfused and viable graft in the early post-operative period improves the chances of a successful result.
Single Photon Emission Computed Tomography images from one hundred and four hips (Steinberg I–IV) treated with VFG between 1994 and 2000 were retrospectively reviewed. Each scan was divided into three regions, the greater trochanter, neck, and head. The intensity at the graft in each region (axially and coronally) was compared to the intensity at the ipsilateral proximal femoral diaph-ysis and assigned a score: less than diaphysis (one), equal to (two), and greater than (three). Cumulative scores were obtained for each subject. Intraobserver variability was 0.93. Surgical failure was defined as conversion to or on the waiting list for total hip arthroplasty.
Thirty percent of hips failed treatment (n=31, mean survival 34.9 months, range 5–98), while 70% were successful (n=73, mean follow-up 56.6 months, range 22–100). Bone scan scores were significantly lower in the failed group (mean 7.1, range 6–12) compared to the successful group (mean 8.5, range 6–18), p=0.03. Positive skewness (+1.7) was demonstrated as 64% of hips had a score of six while 36% had a score > 6 (range 8–18). Logistic regression demonstrated that a bone scan score > 6 was associated with success, p=0.028, with an odds ratio of 3.08 (1.13–8.40).
Correspondence should be addressed to Cynthia Vezina, Communications Manager, COA, 4150-360 Ste. Catherine St. West, Westmount, QC H3Z 2Y5, Canada
