What type of screw is described as having a sharp end?

The choice of a cancellous screw is appropriate because cancellous screws are specifically designed with a sharp end to facilitate their insertion into softer bone, such as the spongy bone found in the metaphysis of long bones. This design helps the screw to penetrate the bone easily, allowing for secure anchorage in areas where the bone density is less than that found in the cortical bone.

The sharp end of the cancellous screw also allows it to engage with the trabecular structure of the bone effectively, providing better grip compared to screws that may not have a sharp tip. This is particularly important in orthopedic procedures where the stability of an implant relies heavily on its ability to integrate well with the soft bone.

In contrast, cortical screws typically have a blunt or tapered end to facilitate their insertion into the dense cortical bone. Steinmann pins, which are essentially smooth, unthreaded rods, are not designed with a sharp end for bone anchorage. A Hohmann retractor, used to hold back soft tissue, does not involve screw design, thus making the selection of cancellous screw the clear and correct choice in this context.