What is coronoid process fracture?
The coronoid process is a triangular projection on the anterior surface of the third olecranon bone. It acts as a bony buttress to prevent posterior dislocation; additional stability is provided by its three soft insertions, namely the anterior joint capsule of the elbow, the brachialis muscle and the medial ulnar collateral ligament.
Elbow injury, especially one that is associated with a dislocation, can cause elbow disability through damage to both the bony structures and the soft tissues. The coronoid process is one of the bony structures that can get fractured. It plays an important role in the elbow’s stability after dislocation.
Though coronoid fractures of the ulna are uncommon, it is critical to identify if one does occur. There are three types of coronoid fractures as described by Regan and Morrey:
Type I fractures, involving the tip of the coronoid
Type II fractures, involving more than the tip but less than 50 per cent of the coronoid
Type III fractures, which involve more than 50 per cent of the coronoid
Further, each type of coronoid fracture can be designated as A or B (where B signifies an associated dislocation).
What are the causes of the disorder?
Fractures of the coronoid process are fairly uncommon and occur in a small percentage of patients with dislocation. These fractures occur as a result of injury known as the ‘terrible triad of the elbow’ involving a postero-lateral or posterior elbow dislocation, a radial head fracture, and a coronoid process fracture.
Coronoid fractures most commonly occur in association with an elbow dislocation, which results from a high-energy impact along with soft tissue injury, like those experienced in sports, daily routing activities or at work. Trauma from accident can also cause such an injury. An elbow dislocation most commonly occurs when a person falls on the elbow or an outstretched hand from a fair height. The exact mechanism by which coronoid process fracture results could be flexion, twisting or hyperextension.
What one needs to know about symptoms or signs?
- Tenderness, which could be multifocal and felt in areas with maximum injury
- Restricted motion, as the patient is unable to flex, extend or rotate completely
Which specialist should be consulted in case of signs and symptoms?
An olecranon fracture must be shown to an orthopaedic surgeon who treats broken bone injuries.
What are the screening tests and investigations done to confirm or rule out the disorder?
- Physical exam – The doctor takes into account the patient’s medical history and checks for any deformity. Range of motion is determined to understand the extent of damage, followed by neurovascular testing, two-point discrimination, and signs of any diminished or abnormal pulses.
- Imaging tests – X-rays are useful in detecting fractures and dislocation. Small coronoid process fractures can be missed easily and often resemble radial head fractures. For further definitive diagnosis, computed tomography (CT) or magnetic resonance imaging (MRI) may be performed. While a CT scan offers better bony definition, an MRI allows better soft tissue identification.
What treatment modalities are available for management of the disorder?
Non-operative treatment (Reduction) – Type 1 and type II fractures can be treated with closed reduction of the dislocation area followed by placing it in a splint with a moderate degree of flexion for three weeks or less. Stability of reduction is evaluated using a fluoroscopic technique performed under general anaesthesia. A rehabilitation programme for the elbow follows reduction.
Surgery – A midline incision is made posteriorly and the ulnar origin of the extensor carpi ulnaris is lifted to reach the coronoid process. Once the fracture site is accessed, the coronoid process fragment is reduced and fixed with the help of screws along with stabilization through sutures. The elbow is later immobilized in a splint at 90 degrees flexion. In the first 24 hours after surgery, the neurovascular status of the upper arm is closely monitored for any signs of dysfunction.
What are the known complications in management of the disorder?
- Loss of range of motion, which may result from prolonged immobilisation of the elbow
- Loss of terminal extension
- Heterotopic ossification
- Instability, pain and parasthesias
What precautions or steps are necessary to stay healthy and happy during the treatment?
It is advised to mobilise the elbow as soon as it is comfortable for the patient, as prolonged immobilisation of more than 3-4 weeks may lead to poor recovery; persistent stiffness, pain and loss of function may occur. During recovery, the elbow is protected from stress with the help of a brace.
Recovery requires a balance between maintaining stability and regaining motion. Regular imaging tests are conducted to ensure stable reduction, and the elbow is gradually mobilised through therapy. The patient is generally able to perform the most basic activities through an elbow flexion ranging from 30 to 140 degrees.
“Coronoid Fractures of the Elbow,” NCBI, Jason Wells and Robert H. Ablove, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2442031/
“Coronoid Fracture,” Medscape, Nirmal Tejwani et al, http://emedicine.medscape.com/article/1230817-overview
“Coronoid process fracture,” Radiopaedia.org, Dr Maulik S Patel and Dr Alexandra Stanislavsky et al. http://radiopaedia.org/articles/coronoid-process-fracture