American Board of Surgical Assistants (ABSA) Orthopedic Test 2025 – 400 Free Practice Questions to Pass the Exam

The assertion that cancellous bone gives the best fixation is misleading. Generally, cortical bone provides superior fixation for screws compared to cancellous bone. This is because cortical bone is denser and offers a stronger surface for screw threads to grip, leading to greater stability. Cancellous bone, while valuable for certain applications such as securing implants in less load-bearing areas, does not provide the same level of fixation stability. It is often used in conjunction with constructs designed to optimize fixation, but it is not the optimal choice for achieving maximal stability alone.

In contrast, the other statements correctly depict various aspects of screw fixation in orthopedic applications—indicating the versatility and requirements associated with using screws for fracture fixation, particularly in the context of oblique or spiral fractures, the necessity for proper screw length to ensure adequate fixation through both cortices, and the specific role of cortical lag screws in the context of compression plate stabilization.