Certified Instrument Specialist (CIS) Practice Exam 2025 - Free CIS Practice Questions and Study Guide

Malleolar screws are primarily characterized by being partially threaded with a trocar tip. This design allows for effective fixation of bone fragments in the malleolus area, which is particularly important in orthopedic procedures. The trocar tip aids in the screw's ability to penetrate the bone efficiently, promoting stability during the healing process. The partial threading ensures that the screw can provide the necessary compression at the fracture site while allowing some movement to encourage natural healing.

The other characteristics mentioned in the other choices do not accurately represent malleolar screws' typical design or purpose. For instance, while some screws may have fully threaded designs or wide heads, this is not a hallmark of malleolar screws specifically. Additionally, malleolar screws are not exclusively used for joint replacement, nor are they predominantly made from biodegradable materials, as their primary function is in providing solid mechanical fixation during the healing of fractures.