Capitellum and Capitellar-Trochlear Shear Fractures

What Are Capitellum Fractures?

Capitellum fractures are rare, making up less than 1% of all elbow fractures. These fractures often occur along with radial head fractures and elbow dislocations. The capitellum is the rounded part of the elbow joint where the'humerus (upper arm bone) meets the radius (forearm bone).  

Types of Capitellum Fractures

There are different types of capitellum fractures based on their severity and pattern:

1. Type 1: Complete fractures of the capitellum.
2. Type 2: Superficial fractures on the surface of the capitellum.
3. Type 3: Comminuted fractures (broken into several pieces).
4. Type 4: Coronal shear fractures involving both the capitellum and a portion of the trochlea (another part of the elbow joint).

Understanding the Anatomy

The elbow joint includes two bony projections called condyles that support the trochlea. The capitellum is part of these structures and plays a crucial role in elbow movement. It is the first part of the elbow to develop in children and is critical for the joint's flexibility and strength.

Causes and Symptoms

Capitellum fractures usually occur in adults due to:

• High-impact injuries such as falls or accidents.
• Direct blows to the elbow.

Symptoms include:

• Pain and swelling on the outer side of the elbow.
• Difficulty moving the elbow, especially in bending and extending it.
• Sometimes, a grinding or popping sensation (crepitus) during movement.

Diagnosis

To diagnose a capitellum fracture, doctors use:

• X-rays: To view the bone structure and identify the fracture.
• CT Scans: For detailed images and better understanding of complex fractures. These scans can also create 3D reconstructions of the bone.
• Special Views: Such as the radial head-capitellum view, which helps eliminate shadows from other parts of the elbow for a clearer picture.

Treatment Options

Nonoperative Management

• Suitable only for truly nondisplaced (bones not moved out of place) and isolated capitellum fractures.
• Treatment includes splinting the arm for about three weeks, followed by protected movement.
• Close monitoring is necessary as these fractures can easily become unstable.

Surgical Management

Surgery is often recommended to ensure the best outcome:

• Open Reduction and Internal Fixation (ORIF): This surgery aligns the bone fragments and fixes them in place using screws and plates.
• Advantages: Restores natural anatomy and function.
• Disadvantages: Possible stiffness and risk of fixation failure.
• Total Elbow Arthroplasty: Considered for elderly patients with complex fractures.
• Advantages: Allows early return to function and movement.
• Disadvantages: Limits some functions of the elbow.

Preparing for Surgery

Before surgery, a detailed CT scan (and possibly a 3D reconstruction) will help the surgeon understand the fracture's specifics. This ensures accurate planning and increases the chances of a successful outcome.

Goals of Surgery

The goals of surgery are:

• Short-Term: Achieve proper alignment and stable fixation to allow early movement.
• Long-Term: Aim for a pain-free elbow with maximum range of motion and minimal stiffness, while avoiding arthritis caused by the injury.

Conclusion

Capitellum fractures require careful diagnosis and treatment. While nonoperative management is an option for minor, stable fractures, surgery is often necessary to restore full function and prevent long-term complications. Always follow your doctor's advice and attend all follow-up appointments to ensure the best recovery.