DUAL-ENERGY X-RAY ABSORPTIOMETRY (DEXA) IN EVALUATION OF THE PROXIMALFEMUR AFTER REPAIR OF PROXIMAL FEMORAL PHYSEAL FRACTURES IN IMMATURE DOGS

Thin slices of the proximal femora of twelve immature dogs were examin ed with dual energy x-ray absorptiometry, after surgical creation and repair of proximal femoral physeal fractures. A protocol for the subtr action of microvascular barium sulphate was used to eliminate interfer ence from the barium with the determination of bone mineral content (B MC), bone mineral density (BMD) and volumetric bone mineral density (V BMD). The results showed there was a significant decrease in the BMC ( four and eight weeks) and BMD (eight weeks) for the entire proximal fe mora of the operated side when compared to the non-operated side. Sign ificant decreases were also seen for the BMC of the physeal region at week eight and the VBMD of the metaphyseal area in the two week femora . The findings with DEXA support the clinical findings of femoral neck thinning in proximal femoral physeal fractures that are surgically re paired. The DEXA findings suggest that the quality of the bone of the femoral neck is less as shown by the decreased BMC, BMD and VBMD. Post operative complications may occur at a higher frequency when such qual ity changes occur.