Effects of extensive circumferential periosteal stripping on the microstructure and mechanical properties of the murine femoral cortex.

Extensive periosteal stripping (PS) is a risk factor for post-radiation pathologic fracture following surgery for extremity soft tissue tumors. The purpose of this study was to determine the effects of PS on bone structure and mechanical properties. Thirty-one skeletally mature mice underwent PS, with circumferential removal of periosteum from an 8-mm segment of the mid-diaphysis of the left femur. Thirty-one control mice underwent sham surgery in which the femur was isolated without manipulation of the periosteum. At 2, 6, 12, or 26 weeks following surgery, the left femora were examined by micro-CT to quantify cortical thickness (CtTh), cross-sectional area (CSA), bone volume (BV), and polar moment of inertia (PMI). Three-point mechanical bend testing was performed and peak load, stiffness, and energy to failure were determined. PS resulted in significantly decreased CtTh, CSA, BV, and PMI at all time points. Peak load, stiffness, and energy to failure were significantly reduced at 2, 6, and 12 weeks. There were no significant differences in mechanical properties at 26 weeks. In this mouse model, extensive circumferential PS resulted in sustained changes in bone structure that were still evident after 6 months, accompanied by reductions in bone strength that persisted for at least 3 months.