Bone remodeling after impacted cancellous allograft in revision hip arthroplasty based on 99mTc-MDP bone scintigraphy

Introduction. Impacted cancellous allograft for the femur reported by Gie et al. (1993) has resulted in a good outcome. Revascularization of the graft was proven with plain radiographs or in some cases, biopsy and autopsy. We have attempted to document the change in appearance of impacted cancellous allograft in the femur over time on scintigraphic scans. Materials and methods. Bone scintigraphy was conducted following total hip arthroplasty of 20 hips without complication using impacted cancellous allograft. At 6 weeks, 1, 2 and 4 years postoperatively, uptake at 5 regions of interest around the femoral component sites was measured. Results. At all 5 regions of interest, uptake was significantly decreased at 1 year postoperatively compared with that at 6 weeks postoperatively. At 2 and 4 years postoperatively, uptake was about 2-fold that of the normal femur in the greater trochanter, lesser trochanter, and stem tip and had decreased to almost the normal level at the lateral stem and medial stem. Conclusion. In revision hip arthroplasty using impacted cancellous allograft, remodeling of the grafted bone of the femur was still incomplete, particularly at the greater trochanter, lesser trochanter, and stem tip even after 4 years postoperatively. It is felt that further time is required for remodeling.