Histological analysis and histomorphometry

To evaluate the bone response around the implants, histological and histomorphometric analyses were conducted. The sections were prepared as described in the “Micro-CT evaluation” section and then stained by Van–Greson staining. Histological evaluation was carried out using a light microscope (DM6000B, Leica Microsystems, Wetzlar, Germany). For the histomorphometric analysis, a computer-based image analysis system (Leica LAS AF, Leica Microsystems) was used. The bone-to-implant contact ratio (BIC, %) was calculated at 10× magnification for three different sections per implant. Each ROI was defined in the area of the metaphysis along one side of the implant to exclude the growth plate area and inferior cortical bone of the femoral condyle.