Episode 2

Listen to Episode:

Objectives:

After listening to this episode, we hope that you can:

1. Perform a comprehensive history and physical examination for wrist injuries.
2. Determine appropriate imaging for distal radius fractures and the essential measurements to be performed.
3. Classify the different types of distal radius fractures.
4. Differentiate between indications for surgical fixation versus non-operative management of distal radius fractures, including an overview of surgical techniques and fixation constructs.
   

What are locking plates?

There are two primary types of locking plates:

1. Fixed Angle (Monoaxial): These plates allow the screw to be locked in a single, predetermined direction. This feature is crucial for ensuring the correct alignment and trajectory of the screw during insertion, akin to using a guided pathway for drilling.
2. Variable Angle (Polyaxial): These plates offer a range of motion, allowing screws to be locked within a 10°-15° cone. This flexibility is particularly beneficial for periarticular fractures, where precision in screw trajectory across the joint line is paramount.

Advantages of locked plating:

• Ideal for conditions with high failure risk in non-locked plating due to factors such as poor bone quality, limited contact area, presence of bone defects, or when bicortical fixation is not feasible.
• Relies on a fixed-angle construct rather than friction between the plate and bone, promoting a more stable fixation.
• Offers biological fixation by preserving blood supply to the bone and fracture site, especially when applied solely with locking screws, since the periosteum under the plate is not compressed. This principle can be compromised if the locking plate is first secured with a non-locking screw.

Disadvantages of locked plating:

• Lack of tactile feedback regarding screw engagement and bone quality.
• Generally thicker than non-locking plates, which may lead to discomfort or symptomatic issues.
• Potential challenges with removal due to cold welding, particularly with certain titanium alloys.
• Higher cost.

Another important distinction between locking and non-locking plates is their mechanism of failure. Non-locked plating relies on friction between the plate and bone, secured by screws. Its failure mechanism involves the individual loosening and pullout of screws, whereas locked plating typically fails under a larger force with all screws cutting out in unison.

Additional Resources