Capitellum Fractures

Modern Study Review (AI-Generated)

High-Yield Summary

Capitellum fractures are rare, intra-articular distal humerus injuries involving the anterior aspect of the capitellum, often caused by a fall on an outstretched hand. Accurate diagnosis and anatomic reduction are critical to restore elbow function and prevent long-term stiffness or arthritis. Modern management emphasizes stable fixation with early mobilization to optimize outcomes. Understanding fracture patterns and using advanced imaging improves surgical planning.

Key Diagnostic Findings

Anatomy

• Capitellum: The rounded, anterior-lateral articular surface of the distal humerus articulating with the radial head.
• Adjacent structures: Lateral trochlear ridge, radial head, lateral collateral ligament complex.

Clinical Presentation

• Lateral elbow pain and swelling after trauma (usually a fall on an outstretched hand).
• Limited elbow range of motion, especially extension and flexion.
• Tenderness localized over the radiocapitellar joint.

Imaging

• X-rays:
• AP and lateral views may show a fragment anterior to the distal humerus.
• Oblique views can better delineate fracture pattern.
• CT scan:
• Recommended for detailed assessment of fracture morphology and comminution.
• Essential for surgical planning, especially in complex or type 4 fractures.

Classification Systems

Current Gold Standard Treatment

Non-operative

• Reserved for nondisplaced fractures or patients with low functional demands.
• Immobilization in a posterior splint for a short period (1-2 weeks), followed by early motion.
• Close radiographic follow-up to detect displacement.

Operative

• Indications: Displaced fractures, comminution, involvement of lateral trochlear ridge, or mechanical block to motion.
• Approach: Lateral approach between anconeus and extensor carpi ulnaris (ECU) to minimize soft tissue disruption.
• Fixation:
• Anatomic reduction under direct visualization.
• Headless compression screws (e.g., Herbert screws) preferred for stable fixation and minimal hardware prominence.
• Avoid excessive posterior dissection to preserve blood supply.
• Small, non-fixable fragments may be excised.
• Postoperative care: Early range of motion to prevent stiffness.

Modern Complications & Outcomes

Complications

Outcomes

• Anatomic reduction and stable fixation correlate with excellent functional outcomes.
• Early motion protocols improve range of motion and reduce stiffness.
• Long-term prognosis depends on fracture complexity and cartilage involvement.

Classic Clinical Notes

Capitellum Fractures

(Jupiter Classification)

• Type 1 – complete fracture (Hahn-Steinthal)
• Type 2 – superficial fracture of cartilage (Kocher-Lorenz) – excision
• Type 3 – comminuted fracture

(McKee Classification)

• Type 4 – ‘coronal shear’ of capitellum ± lateral trochlear ridge

Treatment:

• Anatomic reduction and early motion.
• Lateral approach between anconeus and ECU.
• Reduce under direct vision using Herbert or standard (sunken) screws.
• Avoid excessive posterior dissection.
• Tiny fragments can be excised.
• Avascular necrosis surprisingly rare.

Last Updated on January 25, 2026 by orthonet