The importance of marginal sclerosis in the recovery of mechanical strength after curettage of bone lesions.

Objectives: This study investigated the role of marginal sclerosis in the recovery of mechanical strength following curettage and grafting of osseous lesions. To date, it remains unclear as to whether marginal sclerosis fully or partially restores the mechanical resistance of the affected bone to compressive, flexural, and torsional loads.

Methodology: Adult male Rattus norvegicus rats (WISTAR albino strain) aged approximately 90-days were used. Bone defects were created in the tibiae, and the animals were subsequently euthanized at different time points for outcome analysis. Various assessment methods were employed, including radiography, histology, immunohistochemistry, microcomputed tomography (micro-CT), mechanical bending and torsion tests.

Results: This study revealed a progressive thickening of the osseous window borders before complete closure and a significant correlation between the intensity of marginal sclerosis that was radiographically observed, the rate of bone formation on histology, and the newly formed bone volume on micro-CT. Radiographs revealed thin marginal sclerosis at seven days post surgery, with a significant increase in sclerosis thickness being observed at ten days, whereas micro-CT revealed proportions of new bone formation of 44.80% at seven days and 105.70% at ten days. Additionally, at seven days, the mechanical resistance of the operated bones to torsion and bending was comparable to that of the non-operated bones, thereby indicating a complete recovery of mechanical strength.

Conclusion: This study revealed that the appearance of marginal sclerosis around bone defects (as identified by radiography) is associated with the complete recovery of mechanical strength in rat tibiae under both bending and torsion.