| Classification | Description | Notes |
| Regan-Morrey Type 1 | Transverse tip fracture | Stability depends on fragment size |
| Regan-Morrey Type 2 | Anteromediaal facet | Provides stability during varus stress. Surgical treatment |
| Regan-Morrey Type 3 | >50% articular surface | Surgical treatment |
| O’Driscoll Type 1 | Tip avulsion | Conservative treatment |
| O’Driscoll Type 2 | <50% articular surface | Conservative treatment |
| O’Driscoll Type 3 | >50% articular surface | Surgical treatment |
References:
Sheehan, S. E., et al. (2013). “Traumatic Elbow Injuries: What the Orthopedic Surgeon Wants to Know.” Radiographics 33(3): 869-888.
Regan W, Morrey B. (1989) “Fractures of the coronoid process of the ulna.” J Bone Joint Surg Am. 71(9):1348-54.
O’Driscoll SW, Jupiter JB, Cohen MS, Ring D, McKee MD. (2003) :Difficult elbow fractures: pearls and pitfalls.” Instr Course Lect 52:113–134.
Ring D. (2006) “Fractures of the coronoid process of the ulna.” J Hand Surg Am 31(10):1679–1689.