You are in: eMedicine Specialties > Orthopedic Surgery > ELBOW Coronoid FractureArticle Last Updated: Jul 8, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Nirmal Tejwani, MD, MPA, Associate Professor of Orthopedic Surgery, New York University Hospital for Joint Diseases; Chief of Orthopedic Trauma, Bellevue Hospital Nirmal Tejwani is a member of the following medical societies: AO Foundation and Orthopaedic Trauma Association Coauthor(s): Mihir M Thacker, MBBS, MS(Orth), DNB(Orth), FCPS(Orth), D'Ortho, Assistant Professor of Orthopedic Surgery and Pediatrics, Thomas Jefferson University; Consulting Staff, Department of Pediatric Orthopedic Surgery, Alfred I duPont Hospital for Children; Orthopedic Oncologist, Helen F Graham Cancer Center and Christiana Care Health Services Editors: Steven I Rabin, MD, Clinical Associate Professor, Loyola University Medical Center; Chair, Department of Orthopedic Surgery, Dreyer Medical Clinic; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Robert J Nowinski, DO, Clinical Assistant Professor of Orthopaedic Surgery, Ohio State University College of Medicine and Public Health, Ohio University College of Osteopathic Medicine; Private Practice, Orthopedic and Neurological Consultants, Inc, Columbus, Ohio; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Harris Gellman, MD, Consulting Surgeon, Broward Hand Center, Voluntary Clinical Professor of Orthopedic Surgery and Plastic Surgery, Departments of Orthopedic Surgery and Surgery, University of Miami School of Medicine Author and Editor Disclosure Synonyms and related keywords: coronoid fracture, fracture dislocation of the elbow, elbow fracture, broken arm, broken elbow, Monteggia fracture, elbow fracture dislocation, radial head fracture, terrible triad of the elbow, olecranon fracture, medial humeral condyle fracture, lateral humeral condyle fracture INTRODUCTIONSection 2 of 11
  Coronoid fractures are often seen as a part of complex elbow fracture dislocations or high Monteggia fractures (rare). ProblemFractures of the coronoid rarely occur in isolation. They usually occur in combination with a radial head fracture, a dislocation of the elbow, or both (terrible triad of the elbow).1 Large coronoid fractures often are associated with persistent elbow instability even after reduction of the dislocation. Recently, the trend has been toward fixation of these injuries to restore stability and initiate an early range-of-motion program.2, 3, 4 FrequencyCoronoid fractures account for less than 1-2% of all elbow fractures. Coronoid fractures have been identified in 10-15% of elbow dislocations.5, 6 Radial head fractures are seen in about 5-10% of elbow dislocations.7 Coronoid fractures, especially with large fragments, are associated with more instability and an increased incidence of complications. EtiologyCoronoid fractures were believed to result from avulsion of a bony fragment of the coronoid by the brachialis, which inserts onto the coronoid process. This, however, does not explain the mechanism of type 1 and some type 2 fractures, as the brachialis attaches to the base of the coronoid process of the ulna. (See Workup, Imaging Studies, below, for a discussion of fracture types.) These fractures probably occur from shear forces at the time of the dislocation when the trochlea pushes off a piece of the coronoid. PathophysiologyMorrey and coworkers, in their biomechanical study of the elbow, concluded that approximately 50% of the elbow stability comes from the congruent articulation between the trochlea and the ulna.8 Closkey et al studied the stabilizing function of the coronoid process under axial load to the elbow.9 They found no significant difference, at any flexion position, in posterior axial displacement between intact elbows and elbows in which 50% or less of the coronoid process was fractured (types 1 and 2) (P = .43). Differences in posterior axial displacement were significant, across all flexion positions, between intact elbows and elbows in which more than 50% of the coronoid process was fractured (type 3) (P = .006). They concluded that in response to axial load, elbows with a fracture involving more than 50% of the coronoid process displace more readily than elbows with a fracture involving 50% or less of the coronoid process, especially when the elbow is flexed 60º and beyond. ClinicalCoronoid fractures are usually seen in patients with elbow dislocations. The patient usually presents with a history of a fall on the outstretched hand and a deformity of the elbow. The presence of an unstable reduction is suggestive of an associated coronoid or radial head fracture. An irreducible dislocation, on the other hand, should arouse suspicion of soft tissue (brachialis, median nerve) or bony (medial epicondyle) interposition in the joint. Distal vascularity and neurologic status should always be tested in these cases. In children, coronoid fractures have a bimodal age distribution, with peaks at age 8-9 years and at age 12-14 years.10 Coronoid fractures in children are often associated with elbow dislocations, olecranon fractures, medial epicondyle fractures, or lateral condyle fractures. In children younger than 6 years, Blasier has described an unusual flap injury of the unossified coronoid in which the elbow is dislocated and a small flap of the articular surface gets flipped back into the joint.11 This usually appears on the lateral radiograph as a small flake of bone in the anterior portion of the joint. This flake is a clue to the underlying pathoanatomy and the extent of injury. INDICATIONSSection 3 of 11
A displaced coronoid fracture that presents with a block to elbow motion is a definite indication for surgical stabilization. Type 3 fractures need to be fixed.12 If the fragment is too comminuted for internal fixation, then a hinged external fixator should be applied across the elbow and a protected range-of-motion program should be started.13 Type 2 fractures with elbow instability are also best treated with a hinged external fixator. Type 1 and most type 2 fractures are usually managed nonoperatively. RELEVANT ANATOMYSection 4 of 11
The coronoid acts as the anterior buttress of the greater sigmoid notch of the ulna. It provides attachment to the anterior band of the medial collateral ligament (MCL) and the middle portion of the anterior capsule. The anterior colliculus of the MCL is the primary stabilizer of the elbow against valgus strain in the functional arc of 20-120° of flexion. This ligament is most likely to become injured with a low coronoid fracture with the elbow in full extension.14 A fracture of the coronoid, therefore, results in the loss of all of these supports. The brachialis muscle is attached to the base of the coronoid process.15 Dissection of the brachialis during fixation of these fractures contributes to the risk of heterotopic ossification in these cases. CONTRAINDICATIONSSection 5 of 11
Type 1 and type 2 fractures usually do not require operative stabilization. Highly comminuted type 3 fractures pose a significant problem during open reduction and internal fixation (ORIF) and may be better treated with a hinged external fixator. WORKUPSection 6 of 11
Imaging Studies
TREATMENTSection 7 of 11
Medical therapyNonoperative treatment is indicated for type 1 and type 2 injuries. This includes closed reduction of the dislocation and splinting it in a moderate degree of flexion for a short period (<3 wk) before starting a program of protected mobilization of the elbow. Surgical therapySee Indications, above. Preoperative detailsAdequate preoperative imaging studies should be carried out to ascertain the exact fracture anatomy. Skin condition must be evaluated because severe soft-tissue injury and swelling may be present. Intraoperative detailsThe coronoid can be approached posteromedially through a posterior midline incision after lifting the ulnar origin of the extensor carpi ulnaris (ECU) subperiosteally. In cases of a Monteggia fracture-dislocation, the coronoid may be approached through the interval between the ECU and the anconeus laterally and the flexor carpi ulnaris (FCU) medially. The radial head may be approached between the anconeus medially and the ECU laterally. This will help prevent formation of a synostosis between the radius and the ulna. After exposing the fracture site and cleaning the edges, the fragment is anatomically reduced and fixed by means of an interfragmentary screw (from posterior to anterior, or from anterior to posterior if the fragment is small or osteoporotic). The fracture may also be stabilized using heavy nonabsorbable sutures. In patients with highly comminuted coronoid fractures, reconstruction using a piece of the radial head (Esser technique) or a piece of the olecranon (Moritomo technique) has been described.18 Postoperative detailsThe elbow is immobilized at 90° of flexion in a well-padded posterior splint. The neurovascular status of the upper limb is monitored closely for the fist 24 hours. At the earliest sign of neurovascular dysfunction, encircling dressing and bandages should be loosened and compartment pressures should be measured. Follow-upThe elbow is immobilized for about a week, and then a protected mobilization program in a hinged orthosis is initiated, which prevents varus-valgus stresses on the elbow. Brace use is continued for approximately 4-6 weeks to allow the ligaments to heal. Prophylaxis against heterotopic ossification is initiated the day after surgery. The authors prefer to use indomethacin (75 mg PO) for 3 weeks following the surgery. COMPLICATIONSSection 8 of 11
Complications include the following:
OUTCOME AND PROGNOSISSection 9 of 11
The prognosis for a complex fracture dislocation of the elbow is definitely poorer than that for a simple elbow dislocation, which has been shown to have good long-term results.19, 20 Prognostic factors include the following:
FUTURE AND CONTROVERSIESSection 10 of 11
In the past, coronoid fractures were treated with a longer period of immobilization (3-4 wk) in greater degrees of flexion, and this was believed to be a better alternative than operative treatment. However, with increasing understanding of the contribution of the coronoid to stability of the elbow, the trend increasingly is toward operative stabilization of these injuries and initiation of an early, protected range-of-motion program to avoid the most dreaded complication of these injuries, which is stiffness. REFERENCESSection 11 of 11
Article Last Updated: Jul 8, 2008 |
