Treatment of standardized femoral osteotomies using extracorporeal shockwave therapy (ESWT)

Abstract

ESWT is used in treatment of pseudoarthrosis and may also be considered for distraction osteogenesis (callus lengthening) operations. In this study, effects of ESWT on the callus were studied. On 20 male, ten-week-old white Wistar rats transverse femoral osteotomies were performed at mid-diaphysis, and internally fixated with Kirschner wires. At the end of the third week, animals, randomly divided into two groups, underwent ESWT with 1500 (Group I) and 500 (Group II) shockwaves/treatment at a generating voltage of 10 kV on their right femurs; left femurs were used as controls. At the end of the ninth week, animals were sacrificed. Both femurs were examined using X-Ray, computerized tomography (CT), Dual Energy X-Ray Absorptiometry (DEXA), and histological methods. X-Ray data showed that Group I femurs displayed a higher percentage of nonunions and secondary axial displacements than Group II. Group II had a higher percentage of unions and fewer secondary axial displacements than Group I. CT data showed that ESW treated right legs in both groups had a greater callus area, and lower average density of image pixel than controls. In the DEXA analysis of Group II, although there were not any significant differences in neither the bone mineral content (BMC) nor the bone mineral density (BMD) between the treated and untreated bones; the treated femurs had a slightly lower mineral content and mineral density than the untreated femurs. The histological score of Group II was considerably higher than that of Group I. In agreement with other studies done on bone healing, the exuberant amount of callus observed after ESWT did not correlate with the level of bone healing.