Coronoid Fracture
Key to Elbow Stability
Understanding the critical role of the coronoid in elbow function
Understanding Coronoid Fractures
The coronoid process is essential for elbow stability. It forms the anterior buttress of the ulnohumeral joint and prevents posterior subluxation. Coronoid fractures rarely occur in isolation - they are usually part of complex injury patterns.
Stability Function
- • Anterior buttress against posterior dislocation
- • Anteromedial facet resists varus stress
- • Attachment for anterior band of MCL
- • Attachment for anterior capsule
- • At least 50% height needed for stability
Regan-Morrey Classification
Small fragment from the coronoid tip
If isolated and stable: non-operative possible
Fragment involves less than 50% of coronoid height
Usually requires fixation if unstable
Fragment involves more than 50% of coronoid height
Always requires surgical fixation
Treatment Options
For small tip fragments (Type I) where capsule is key:
- • Suture passed through anterior capsule attached to fragment
- • Pulled through drill holes in ulna
- • Captures the capsule and stabilizes the joint
For larger fragments (Type II, III):
- • Headless compression screws from posterior
- • Anterior-to-posterior direction also possible
- • Provides rigid fixation for larger fragments
For anteromedial facet fractures (O'Brien Type 2):
- • Medial approach with FCU split
- • Small buttress plate on anteromedial facet
- • Critical for varus stability
Evidence & References
• Regan W, Morrey B. Fractures of the coronoid process of the ulna. JBJS Am 1989
• O'Brien MJ, et al. The anatomy of the anteromedial facet of the coronoid process. J Bone Joint Surg Am 2003
• Ring D, et al. Coronoid fractures. Hand Clin 2007
Last Updated: January 2025 | Content reviewed by Dr. Deepthi Nandan Reddy, FRCS (Ortho)