Difference Between Cortical and Cancellous Screw

Definition of Cortical and Cancellous Screw

Cortical Screws

Cortical screws are a type of bone screw that is designed for use in cortical bone, which is the hard outer layer of bone found in the shafts of long bones such as the femur or humerus.

Characteristics:

• Cortical screws have a smooth, unthreaded shank that allows for easy insertion into the dense cortical bone.
• They have a threaded head that provides good fixation in the bone.
• They are typically made of stainless steel or titanium.
• They are available in a range of lengths and diameters to accommodate different bone sizes.

Indications for use:

• Cortical screws are often used in orthopedic surgery to fix fractures in cortical bone, such as in the femur, tibia, or humerus.
• They can also be used for other procedures, such as spinal fusion or joint arthroplasty.

Advantages:

• The smooth shank of cortical screws reduces the risk of bone damage during insertion.
• They provide excellent fixation in the hard cortical bone, which can help to prevent implant failure.
• They can be easily removed if necessary.

Disadvantages:

• Cortical screws are not suitable for use in cancellous bone, which is the softer, spongy inner layer of bone.
• They may be more difficult to insert in bones with a thick cortex or in bones with a small diameter.
• They may cause stress risers in the bone, which can increase the risk of fracture or implant failure over time.

Cancellous Screws

Cancellous screws are a type of bone screw that is designed for use in cancellous bone, which is the spongy, porous inner layer of bone found at the ends of long bones and in the vertebrae.

Characteristics:

• Cancellous screws have a threaded shank that allows for good fixation in the softer cancellous bone.
• They typically have a partially threaded head, which can provide additional stability in the bone.
• They are often made of stainless steel or titanium.
• They are available in a range of lengths and diameters to accommodate different bone sizes.

Indications for use:

• Cancellous screws are often used in orthopedic surgery to fix fractures in cancellous bone, such as in the distal radius or ankle.
• They can also be used for other procedures, such as spinal fusion or joint arthroplasty.

Advantages:

• Cancellous screws provide excellent fixation in the softer cancellous bone, which can help to prevent implant failure.
• They are easier to insert in cancellous bone compared to cortical screws.
• They are less likely to cause stress risers in the bone compared to cortical screws.

Disadvantages:

• Cancellous screws may not provide sufficient fixation in cortical bone.
• They may be more difficult to remove compared to cortical screws.
• They may cause bone damage during insertion if not placed correctly.

Importance of knowing the difference between cortical and cancellous screws

Knowing the difference between cortical and cancellous screws is important because it allows for the appropriate selection of screws based on the specific indications and characteristics of the bone being operated on.

Using the wrong type of screw can result in poor fixation, implant failure, or damage to the bone. For example, using a cancellous screw in cortical bone may not provide sufficient fixation, while using a cortical screw in cancellous bone may cause bone damage or implant failure.

Understanding the differences between cortical and cancellous screws also allows surgeons to optimize patient outcomes by selecting the most appropriate screw for the specific patient and procedure. This can help to reduce the risk of complications and improve postoperative recovery.

Knowing the difference between cortical and cancellous screws is essential for safe and effective orthopedic surgery.

Comparison between Cortical and Cancellous Screws

Here are some of the key differences between cortical and cancellous screws:

1. Tread Design: Cortical screws typically have a smooth, unthreaded shank that allows for easy insertion into hard cortical bone, while cancellous screws have a threaded shank that provides good fixation in softer cancellous bone. Cancellous screws often have a partially threaded head that can provide additional stability in the bone.
2. Length and Diameter: Cortical screws are generally longer and have a smaller diameter than cancellous screws to accommodate the denser cortical bone. Cancellous screws are shorter and have a larger diameter to accommodate the softer cancellous bone.
3. Insertion Technique: Cortical screws are usually inserted with a tap to create a thread path in the bone, while cancellous screws can often be inserted directly into the bone without the need for tapping.
4. Indications for Use: Cortical screws are typically used in the shafts of long bones, while cancellous screws are commonly used in the ends of long bones and in the vertebrae.
5. Biomechanical Properties: Cortical screws provide better resistance to bending forces, while cancellous screws provide better resistance to compression forces.
6. Complications: Cortical screws may cause stress risers in the bone, which can increase the risk of fracture or implant failure over time. Cancellous screws may cause bone damage during insertion if not placed correctly.

Understanding these differences is critical for selecting the appropriate screw for a specific procedure and bone type.

Conclusion

Cortical and cancellous screws are two different types of bone screws with distinct characteristics that make them suitable for different indications and bone types. Cortical screws are designed for use in hard, dense cortical bone, while cancellous screws are designed for use in softer, spongy cancellous bone. Understanding the differences between these screws is essential for selecting the appropriate screw for a specific patient and procedure, as using the wrong type of screw can result in poor fixation, implant failure, or bone damage. By selecting the most appropriate screw, surgeons can optimize patient outcomes and reduce the risk of complications, leading to better postoperative recovery.

References Website

Here are some references you can use to learn more about cortical and cancellous screws:

1. “Cortical and cancellous screws” – OrthopaedicsOne (https://www.orthopaedicsone.com/display/Main/Cortical+and+cancellous+screws) This website provides a comprehensive overview of cortical and cancellous screws, including their different, indications for use, and surgical techniques.
2. “Bone Screws: A Comprehensive Guide” – Bone and Spine (https://boneandspine.com/bone-screws/) This article provides an in-depth discussion of bone screws, including cortical and cancellous screws, as well as other types of screws used in orthopedic surgery.
3. “Cortical and Cancellous Bone Screws” – Wheeless’ Textbook of Orthopaedics (https://www.wheelessonline.com/bones/cortical_and_cancellous_bone_screws) This website provides a detailed overview of cortical and cancellous screws, including their design, indications for use, and potential complications.
4. “Cortical vs Cancellous Screws: Which is Right for Your Surgery?” – The Bone & Joint Center (https://www.albanyboneandjoint.com/cortical-vs-cancellous-screws/) This article provides a patient-focused explanation of the differences between cortical and cancellous screws, including their benefits and risks.
5. “Cortical and Cancellous Screws” – Zimmer Biomet (https://www.zimmerbiomet.com/medical-professionals/surgical-products/spine/thoracolumbar-solutions/screw-systems/cortical-and-cancellous-screws.html) This website provides information on the cortical and cancellous screws available through Zimmer Biomet, including their design features and indications for use.