The strength between the cortical screw and bone following an orthopaedic implant surgery is an important determinant for the success of osteosynthesis. An excessive axial cutting force during drilling produces microcracks in the bone surface, resulting in reduced strength between the screw and bone, resulting in loosening of implant. The present work, investigates the influence of drilling parameters on microcracks generated in the drilled surface and pull-out strength of screw fixed in cortical bone of human tibia. The holes were drilled by two different techniques: conventional surgical bone drilling (CSBD) and rotary ultrasonic bone drilling (RUBD), by a recently developed operation theatre (OT) compatible machine. Cutting force generated in drilling of human tibia using RUBD was 30–40% lesser than that of CSBD. Scanning electron microscopy (SEM) also revealed that RUBD produced significantly lesser and thinner microcracks than that of CSBD in human bones. Biomechanical pull-out test results showed that, the pull-out strength of screws inserted into drilled holes by RUBD was much higher (100–150%) than that of CSBD. A significant difference in pull-out strength (p < 0.05) between RUBD and CSBD was revealed by statistical analysis at 95% confidence interval.

骨科植入手术后皮质螺钉和骨之间的强度是骨缝合术成功的重要决定因素。钻孔过程中过大的轴向切削力会在骨表面产生微裂纹，导致螺钉与骨之间的强度降低，导致种植体松动。目前的工作，研究钻孔参数对钻孔表面产生的微裂纹和固定在人胫骨皮质骨中的螺钉拔出强度的影响。这些孔是通过两种不同的技术钻孔的：传统的外科骨钻孔 (CSBD) 和旋转超声骨钻孔 (RUBD)，由最近开发的手术室 (OT) 兼容机器。使用 RUBD 在人类胫骨钻孔中产生的切削力比 CSBD 小 30-40%。扫描电子显微镜 (SEM) 还显示 RUBD 在人体骨骼中产生的微裂纹明显少于 CSBD。生物力学拔出试验结果表明，RUBD 插入钻孔的螺钉的拔出强度远高于 CSBD（100-150%）。拉拔强度有显着差异（p < 0.05) 在 RUBD 和 CSBD 之间通过 95% 置信区间的统计分析显示。