Approach Considerations
Type 1 and most type 2 fractures (see Workup) usually are managed nonoperatively [32] and do not require operative stabilization. [33, 34] 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. [35] A displaced coronoid fracture that presents with a block to elbow motion is a definite indication for surgical stabilization. [36]
In the past, coronoid fractures were treated with a longer period of immobilization (3-4 weeks) 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 the stability of the elbow, there has been a trend toward operative stabilization of these injuries and initiation of an early protected range-of-motion (ROM) program to avoid the most dreaded complication of these injuries, which is stiffness.
However, after studying 58 patients over an 8-year period, Kiene et al concluded that surgical therapy could not be statistically justified, particularly if the patient underwent therapy with an external fixator, immobilization for more than 3 weeks, and complications and unstable osteosyntheses. [37]
Medical Therapy
Nonoperative treatment is generally indicated for type 1 and most type 2 injuries. This includes closed reduction of the dislocation and splinting in a moderate degree of flexion for a short period (< 3 weeks) before initiation of a program of protected mobilization of the elbow.
Surgical Therapy
For type 3 fractures or those occurring in conjunction with other injuries about the elbow resulting in instability, operative management is typically required. [38, 39] There are several approaches to management, including the following:
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ORIF
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Suture lasso fixation
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Closed reduction with percutaneous pinning
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External fixation
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Arthroscopically assisted closed reduction and internal fixation
The authors’ preferred operative method, when feasible, is ORIF, as described below. If the fragment is too comminuted for internal fixation, then a hinged external fixator should be applied across the elbow, and a protected ROM program should be started. [40]
The ultimate goal of surgery for these fractures should be restoration of a stable arc of elbow motion within the functional range (30-130º).
Preparation for surgery
Adequate preoperative imaging studies should be carried out to ascertain the exact fracture anatomy. This typically includes complete radiographs and computed tomography (CT) of the elbow. Magnetic resonance imaging (MRI) may be useful for evaluating soft-tissue structures but typically is not required.
Skin condition must be evaluated because severe soft-tissue injury and swelling may be present.
Operative details
There are several surgical approaches that allow visualization of the coronoid. If an associated radial head fracture has occurred, the coronoid can be approached through the radial head fracture site via a laterally based incision.
If the radial head is intact, the coronoid can be approached via a medial incision, through the floor of the cubital tunnel. This is accomplished by identifying and protecting the ulnar nerve and then elevating the flexor carpi ulnaris (FCU) and the flexor pronator group from distal to proximal until the sublime tubercle is visualized. Once the MCL (medial collateral ligament) has been protected, the coronoid fracture can be addressed.
Finally, if both medial and lateral work is being performed on the elbow, a posterior incision can be used, and the coronoid can be accessed through either of the aforementioned approaches by raising full-thickness flaps.
In the case of a Monteggia type fracture-dislocation, the coronoid may be approached through the interval between the extensor carpi ulnaris (ECU) and the anconeus laterally and the FCU medially. The radial head may be approached between the anconeus medially and the ECU laterally. Using this dual-interval approach reduces the risk of synostosis formation between the radius and the ulna.
In transolecranon fracture-dislocations, the coronoid may be approached through the olecranon fracture by displacing the proximal piece proximally; fixation may then be achieved with headless compression screws and subsequent operative fixation of the olecranon.
After exposure of the fracture site, the hematoma should be evacuated, and the edges of the fracture should be cleaned to facilitate anatomic reduction. Fixation may be achieved by means of several methods, including the following:
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Use of an interfragmentary screw (from posterior to anterior or, if the fragment is small or osteoporotic, from anterior to posterior)
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Plate-and-screw fixation (see the first and second images below)
Status post open reduction and internal fixation of coronoid with plate-and-screw construct. Courtesy of Kenneth Egol, MD.
Second example of plate-and-screw constructs for fixation of type 3 coronoid fracture. Courtesy of Kenneth Egol, MD.
Status post open reduction and suture fixation of coronoid, as evidenced by drill holes in proximal ulna. Sutures are used as a lasso to capture coronoid fragment, passed through ulnar drill holes, and tied over posterior ulna bony bridge. Patient is also status post radial head replacement for comminuted radial head fracture. This is an example of typical operative management of "terrible triad" elbow injuries.
As noted above, the goal of any fixation should be a stable construct that allows early ROM. (See the image below.)
Chronic elbow fracture dislocation presentation films with type II coronoid fracture (left) and fixation films (right). Fixation consisted of radial head replacement and suture lasso fixation of coronoid fracture. Since the elbow remained unstable throughout the range of motion, a hinged external fixator was placed.
The results from one study noted that suture lasso fixation of coronoid fractures for terrible triad injuries results in fewer complications and greater stability compared with screw or suture anchor fixation techniques. [43] A higher rate of implant failure was noted with internal screw fixation, whereas the suture anchor technique resulted in a higher rate of malunion and nonunion.
Giannicola et al studied 18 patients in whom coronoid fractures were repaired with fine-threaded Kirschner wires (K-wires). [44] After 26 months, results were excellent in 10 patients, good in seven, and fair in one, according to the Mayo Elbow Performance Index. The authors concluded that this technique was an easy, minimally invasive, stable, and successful procedure for obtaining osteosynthesis in patients with coronoid fractures and complex elbow instability.
A study by Ouyang et al described the use of a novel arthroscopic portal for coronoid visualization, followed by placement of an anterior-to-posterior screw for fracture fixation. [45] In this series, all fractures healed without displacement and there were no cases or neurovascular injury.
In patients with highly comminuted coronoid fractures or chronic lesions resulting in unstable elbows, reconstruction using a piece of the radial head (Esser technique) or a piece of the olecranon (Moritomo technique) has been described. [46] Gray et al studied the effect of a prosthesis on restoring stability to the coronoid-deficient elbow by analyzing eight cadaveric arms. [47] They concluded that the use of an anatomic implant restored stability and was deserving of further study.
In a 2021 narrative review of the literature on reconstruction of the coronoid process of the ulna, Zhao et al suggested that for elbow joint instability caused by a fresh comminuted fracture of the coronoid or an old fracture with coronoid absorption, coronoid reconstruction should be performed to restore elbow joint stability if the instability was induced by coronoid process defects. [48] They noted that multiple methods of coronoid reconstruction are being evaluated but no unified standard has yet been established.
Postoperative Care
Immediately after the operation, the elbow is immobilized at 90° of flexion in a well-padded posterior splint for comfort. 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 monitored for signs of compartment syndrome.
The goal of fixation is a stable and preserved functional arc of motion. Accordingly, splints are typically removed 1-2 weeks after the procedure, depending on the strength of the chosen construct, and protected ROM exercises are begun.
Complications
Complications include the following:
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Neurovascular injury
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Stiffness
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Instability and recurrent dislocation
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Posttraumatic arthritis of the elbow
Long-Term Monitoring
The elbow is immobilized for about 1 week, and a protected mobilization program in a hinged orthosis is then 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 may also be initiated on postoperative day 1. The authors prefer to use indomethacin (75 mg PO) for 3 weeks after the procedure.
Patients should be followed to ensure that they achieve a functional arc of motion.
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Elbow joint, anterior view.
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Elbow joint, posterior view.
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Type 2 coronoid fracture: unstable elbow fracture dislocation with fracture involving <50% of coronoid height and associated radial head fracture.
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Type 3 coronoid fracture: fracture involving >50% of coronoid height.
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Type 1 coronoid fracture: avulsion fracture at tip of coronoid.
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Status post open reduction and internal fixation of coronoid with plate-and-screw construct. Courtesy of Kenneth Egol, MD.
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Status post open reduction and suture fixation of coronoid, as evidenced by drill holes in proximal ulna. Sutures are used as a lasso to capture coronoid fragment, passed through ulnar drill holes, and tied over posterior ulna bony bridge. Patient is also status post radial head replacement for comminuted radial head fracture. This is an example of typical operative management of "terrible triad" elbow injuries.
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Second example of plate-and-screw constructs for fixation of type 3 coronoid fracture. Courtesy of Kenneth Egol, MD.
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Chronic elbow fracture dislocation presentation films with type II coronoid fracture (left) and fixation films (right). Fixation consisted of radial head replacement and suture lasso fixation of coronoid fracture. Since the elbow remained unstable throughout the range of motion, a hinged external fixator was placed.
