Coronoid Process Fracture
Key fracture for elbow stability, often associated with dislocation or the terrible triad. The coronoid process forms the anterior buttress of the ulna, essential for preventing posterior subluxation. Regan-Morrey classification with 3 types.
Characteristics
Fracture of the coronoid process of the ulna is an essential lesion in elbow stability biomechanics [1]. The coronoid forms the anterior buttress of the greater sigmoid cavity, acting as a primary stabilizer by opposing posterior displacement of the ulna beneath the humeral trochlea. Isolated fractures are rare (2-15% of elbow fractures); they are most often associated with elbow dislocation, radial head fracture, or as part of the terrible triad [2].
True incidence is difficult to assess as tip fractures may be missed on standard radiographs. CT scan has become the reference examination for fracture characterization. O'Driscoll supplemented the Regan-Morrey classification with subtypes of the anteromedial facet, involved in posteromedial rotatory instability (PMRI), a distinct instability pattern from classic posterolateral instability [3].
Treatment depends on fracture type and associated injuries: stable isolated Type I fractures may be treated functionally, while Types II and III require surgical reconstruction (anterior screw fixation, plate, suture anchors) to restore the anterior buttress. The overall management of elbow instability takes precedence over the isolated fracture.
- The coronoid process is a triangular bony projection on the anterior surface of the proximal ulna. It receives the insertion of the brachialis muscle (anterior surface), the anterior bundle of the medial collateral ligament (sublime tubercle on the anteromedial facet), and the anterior capsule (tip). It forms the anterior buttress of the humeroulnar joint.
- The mechanism is most often indirect: posterior elbow dislocation with shearing of the coronoid tip, or avulsion by the brachialis during forced hyperextension. Anteromedial facet fractures result from a posteromedial varus mechanism different from classic posterolateral dislocation.
- Risk factors: high-energy elbow trauma, elbow dislocation (30-40% of dislocations have an associated coronoid fracture), terrible triad of the elbow, chronic elbow instability, posteromedial fracture-dislocation.
- Complications: residual elbow instability (main complication if fracture untreated), recurrent posterior subluxation, post-traumatic arthritis, joint stiffness, medial collateral ligament insufficiency if sublime tubercle involved, posteromedial rotatory instability (PMRI).
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- Type I – Tip fracture
Avulsion fracture of the coronoid process tip involving less than 10% of total height. Often small fragment carrying the anterior capsular insertion. Conservative treatment possible if elbow is stable and concentric. Close radiographic monitoring required.
- Type II – Fragment ≤ 50% of height
Fracture involving a fragment up to 50% of the coronoid process height. Significantly compromises the anterior buttress and elbow stability. Surgical treatment recommended by screw fixation or plate, especially with associated instability. May involve the sublime tubercle (MCL insertion).
- Type III – Fragment > 50% of height
Fracture involving more than 50% of the coronoid process height, causing major loss of the anterior buttress and severe elbow instability. Systematic surgical treatment by buttress plate or reconstruction. Almost always associated with dislocation and/or ligamentous injuries. More guarded prognosis.
Medical and Surgical Management
- Stable isolated Type I fractures: functional treatment with early mobilization under hinged brace protection. Stability check under fluoroscopy. Most heal without sequelae if the elbow remains concentric.
- Type II-III fractures: surgical reconstruction by anterior screw fixation (anteroposterior screw), buttress plate, or suture anchor reinsertion (lasso technique). The goal is to restore the anterior buttress to maintain humeroulnar congruence. Anterior or medial surgical approach depending on type.
- Anteromedial facet fractures (O'Driscoll subtypes): reconstruction by buttress plate or bone graft. Frequent association with LUCL injury requiring concomitant repair. Articulated external fixator if residual intraoperative instability.
Physiotherapy treatment
- Early mobilization under hinged brace protection with adjustable stops. Initial protected range of 30-90° flexion (avoid full extension which stresses the anterior buttress). Progression of 10-15° per week based on clinical and radiographic stability.
- Strengthening of anterior dynamic stabilizers: brachialis and biceps, which contribute to anterior joint coaptation. Early isometric exercises in flexion, then progressive resistance from week 6.
- Closed-chain elbow proprioceptive work: weight-bearing on table, then wall, then floor. Dynamic stabilization is essential to compensate for the frequent residual ligamentous insufficiency in injuries combining coronoid fracture and instability.
- Progressive functional recovery with particular attention to stability: regular clinical and radiographic monitoring. Return to weight-bearing activities at week 8-12. Return to sports at 4-6 months depending on fracture type and associated injuries.
After the session
You may feel slight fatigue or tightness: this is normal. Continue the exercises taught at home to maintain session benefits.
Questions About Elbow Rehabilitation
When should I start physiotherapy after elbow surgery?
Rehabilitation generally begins between 3 and 21 days after the operation, depending on the type of procedure and the stability of the surgical fixation. For fractures treated with stable internal fixation (screw plate), early mobilization is often authorized from D+3 to D+5 to prevent joint stiffness. In cases of elbow replacement or complex ligament repair, the delay may be extended to 2-3 weeks with initial immobilization in a splint. A systematic review published in the Journal of Shoulder and Elbow Surgery confirms that early mobilization after elbow surgery significantly improves final range of motion without increasing the risk of complications [Hackl et al., 2023] . Your surgeon will advise the optimal timing based on your specific procedure.
What are the goals of elbow rehabilitation?
Elbow rehabilitation pursues several complementary goals, adapted to each phase of recovery. In the initial phase (0-6 weeks), the priority is to restore range of motion in flexion-extension (goal: 30°-130° minimum for daily activities) and in pronation-supination (50° in each direction minimum). In the intermediate phase (6-12 weeks), the focus is on progressive muscle strengthening of the flexors, extensors and rotators of the forearm, as well as restoring joint stability through proprioceptive exercises. In the advanced phase (3-6 months), the emphasis is on functional reintegration: daily activities, work tasks and return to sports. Scientific literature highlights that the minimum functional arc of the elbow (30°-130° of flexion-extension, 50° of pronation and 50° of supination) is necessary to perform 90% of daily activities [Mofidi et al., 2020] . Scar treatment and adhesion prevention complete this comprehensive care approach.
Is elbow rehabilitation painful?
The techniques used are progressive and adapted to your tolerance. The elbow is a joint particularly prone to stiffness and inflammatory reactions: overly aggressive rehabilitation can paradoxically worsen the situation by causing heterotopic ossifications (abnormal bone formations in soft tissues). Exercises must be regular but never forced . The physiotherapist always adapts the intensity to stay below the pain threshold, following the "no pain, more gain" rule specific to the elbow. Gentle, regular active mobilization spread across the day in short sequences is generally preferred to prevent stiffness, with early active mobilization recommended after an elbow injury [Akhtar et al., 2021] . Complementary techniques such as cryotherapy , microcurrents and Novafon vibration therapy also help control pain during sessions.
Scientific sources
Average duration
8 to 16 weeks for isolated fracture, 4 to 6 months for complex associated injuries