What is the Difference Between Cortical and Cancellous Screw?

The main difference between cortical and cancellous screws lies in their intended use, thread design, core diameter, and self-tapping capability. Here are the key differences between the two types of screws:

• Bone structure: Cortical screws are designed for dense cortical bone, while cancellous screws are intended for less dense cancellous bone.
• Thread design: Cortical screws have a lower thread depth and a more aggressive pitch, allowing them to engage well in cortical bone. Cancellous screws, on the other hand, have a deeper thread with a more excellent pitch, providing better purchase in the porous structure of the cancellous bone.
• Core diameter: Cortical screws have a wider core diameter, giving them greater strength and resistance to shear pressures. This makes them suitable for load-bearing applications.
• Length: Cortical screws come in a variety of lengths to fit different bone depths, allowing surgeons to choose the appropriate screw length based on the procedure's requirements.
• Self-tapping capability: Many cortical screws are self-tapping, meaning they can drill their own pilot hole when inserted. Cancellous screws, however, are typically non-self-tapping and should not be tapped all the way, only the first few turns, because they function better when they cut their own way into cancellous bone.

In summary, understanding the differences between cortical and cancellous screws is crucial for Orthopedic surgeons, as each screw type has specific characteristics that make it suitable for different bone densities and surgical procedures.

Comparative Table: Cortical vs Cancellous Screw

Cortical and cancellous screws are two types of orthopedic screws used in bone surgeries to fix fractures and provide stability. They differ in their thread design, core diameter, and application in various bone densities. Here is a table summarizing the differences between cortical and cancellous screws:

Cortical screws are designed to be used in dense cortical bone and feature a fine pitch with a lower thread depth. They are typically self-tapping and are used for fixation of similar diameter non-locking plates. On the other hand, cancellous screws have a coarse pitch with a deeper thread to improve purchase and engagement in the porous structure of cancellous bone. They are non-self-tapping and perform better when they cut their own way into cancellous bone.