Fractures of the capitellum

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Anatomy

Background:

• The capitellum is a key component of the distal humerus.
• Its role in elbow stability, particularly valgus stability, requires further elucidation.
• Understanding its contribution is crucial for managing elbow fractures and injuries.

Purpose of the Study:

• To investigate the contribution of the capitellum to elbow stability.
• To evaluate the effect of capitellum excision on valgus motion in cadaveric elbows.
• To correlate clinical findings of capitellum fractures with elbow instability.

Main Methods:

• Cadaveric elbow specimens (n=40) were used to assess valgus motion after sequential excision of the capitellum and other stabilizing structures.
• A retrospective review of 17 patients with capitellum fractures treated over 15 years was conducted.
• Clinical outcomes were analyzed based on treatment modalities and associated injuries.

Main Results:

• Excision of the capitellum alone resulted in minimal increase in valgus motion.
• Severe valgus deformity was observed only after release of the ulnar collateral ligament or medial collateral ligament.
• Clinical cases showed valgus instability primarily when capitellum fractures were associated with medial ligament injuries.

Conclusions:

• The capitellum contributes minimally to the inherent valgus stability of an intact elbow.
• Medial stabilizing structures, particularly the medial collateral ligament, are critical for preventing valgus instability.
• Treatment of capitellum fractures should consider associated ligamentous injuries for optimal outcomes.