What is Coronoid Fractures?
The coronoid process, which is a bony bump, is found at the proximal or closest end of the volar surface of the ulna, or inner forearm. In combination with the olecranon process, it forms the greater sigmoid notch, which connects to the lower part of the humerus bone in the elbow joint. The coronoid process serves a crucial role in preventing the ulna from shifting towards the back. It’s also where the anterior bundle of the ulnar collateral ligament connects. This ligament is attached to the inner part of the coronoid, approximately 1.8 centimeters from its tip.
The ulnar collateral ligament helps limit forces that push the elbow joint outwards. Further up, the elbow joint capsule also connects about 0.6 centimeters from the coronoid tip. Downward, near the base of the coronoid, the brachialis muscle is also attached; this muscle helps bend the elbow without causing the forearm to rotate.
If the coronoid bone breaks, it usually indicates that the elbow is unstable. These fractures often occur with elbow dislocations and other fractures involving the radius and ulna of the forearm and the humerus in the upper arm.
What Causes Coronoid Fractures?
Coronoid fractures, or breaks in a part of the elbow, are thought to be caused by a rough or tearing force when the elbow is put under extreme stress. These types of fractures often happen as a result of an elbow dislocation. In fact, between 2 to 15 percent of elbow dislocations end up causing a coronoid fracture.
Additionally, considerable pressure that skews the elbow sideways can result in fractures of the front inner section of the coronoid.
Risk Factors and Frequency for Coronoid Fractures
Coronoid fractures usually occur because of trauma. This type of injury is more common in individuals who participate in sports, high-speed activities, or other riskier behaviors. Car accidents are the main cause of these fractures in the upper arm bone.
About 10 to 15% of fractures around the elbow are coronoid fractures.
Signs and Symptoms of Coronoid Fractures
Elbow dislocation usually comes with distinct signs and symptoms. Patients may tell you that their elbow joint moved out of place and that they had to put it back themselves. If the elbow is still dislocated, you will be able to see a clear change in its shape. The elbow would probably be bent at about 75 degrees, especially if there’s a lot of fluid build-up (also known as effusion) in the joint. This position gives more room inside the joint.
Take note that the normal angle at which the elbow naturally bends – called the “carrying angle” – is about 11 degrees in men and 13 degrees in women. You might feel tenderness throughout the elbow area when you touch it. You need to inspect the skin near the elbow thoroughly to rule out open fractures. After putting the elbow joint back into place, you need to check the range of motion and see which positions maintain stability. A normal elbow angle is around 140 degrees, and it can rotate approximately 80 degrees in each direction. The blood flow and nerve function should be checked both prior to and after attempting to relocate the dislocations.
- Visual deformity of the elbow
- Elbow bent at an unusual angle
- Tenderness in the elbow
- Possible fluid build-up in the joint
- Normal “carrying angle” differs in men and women
- Inspection of the skin for open fractures
- Judge if movement or rotation is restricted
- Evaluation of blood flow and nerve function before and after dislocation correction
There are a few tests for specific ligaments in the elbow. These tests are designed to detect possible damages or injuries. For example, a general check for elbow joint stability can be done by applying gentle pressure to the joint while moving it in different directions. Other tests, such as the “milking maneuver” and the “lateral pivot shift test,” are performed to detect injuries to smaller structures within the joint. A positive result from these tests usually means there’s pain, discomfort, or instability in the elbow.
If the test results show potential issues, that could mean instability in the elbow. If the tests are negative, that may mean the elbow doesn’t have any serious structural injuries.
- General stability test
- “Milking maneuver”
- “Lateral pivot shift test”
- “Posterolateral rotatory drawer test”
Finally, a simple way to examine the patient is by asking them to push themselves up from the arm of their chair using the affected arm. If they experience pain, instability, or apprehension during the task, this could be an indicator of elbow instability. You can repeat the test with the forearm in different rotational positions to determine the extent of the apprehension.
Testing for Coronoid Fractures
If you have a suspected coronoid fracture, the first step after a physical examination is usually standard radiographs or X-rays. These are taken from the front to back, side to side, and at an angle. The side view is often the most useful in determining the size and shift of the fracture.
Computed tomography (CT) scans can provide a more detailed look at the fractures. These are particularly useful because simple X-rays can sometimes be hard to read due to overlapping lines.
There are classification systems set up to better understand and discuss coronoid fractures. The Regan and Morrey system is commonly used and classifies fractures based on how much of the coronoid process, a projection on the ulna bone in the forearm, is affected. Type one involves only the tip, type two involves 50% or less, and type three involves more than 50%.
The O’Driscoll system offers a more comprehensive way to classify these fractures, especially highlighting those that involve the anteromedial facet, an area on the inner-face of the coronoid process. Type I fractures in this system also involve the tip but are often linked to severe elbow injuries and instability. Type II involves the anteromedial portion and can also include the sublime tubercle, a small protuberance on the coronoid process. These injuries often disrupt the stability of the elbow. Type III fractures affect the base of the coronoid process and are often associated with other fractures in the upper part of the ulna bone.
Treatment Options for Coronoid Fractures
When a person’s elbow gets dislocated, doctors try first to fix it without surgery as soon as possible. However, if there are bone fragments or soft tissue trapped in the joint, surgery might be necessary.
When it comes to a fracture of the small bone at the middle part of the elbow (the coronoid process), a non-surgical treatment could be used. This usually involves short-term immobilization of the elbow, followed by exercises to restore the range of movement and prevent stiffness. This way of treatment can be successful, especially when the fracture is minor and involves less than half of the height of the small bone, the radial head isn’t also fractured, and the joint between the ulna and humerus bones is perfectly concentric.
Whether or not to opt for surgery mainly depends on how stable the elbow is, rather than the size of the fractured fragment. Minor fractures, the so-called Regan and Morrey type I fractures, could result in stable elbows and be compatible with non-surgical treatment. Surgery is usually needed for fractures related to unstable elbows. The particular method for surgical fixation and the approach for the surgery can vary based on the specific characteristics of the fracture and any associated injuries.
There are a couple of ways to approach a surgery: either from the front or from the back of the elbow. The back approach could be advantageous for severe fractures when other significant elbow injuries are also present. The front approach provides good access to the fracture but might put at risk the nerves and blood vessels around it.
Internally fixing these fractures involves either suturing the small bone with a special type of stitch that goes through a hole made in the upper arm bone, or using screws or small plates for fixation. The method used often depends on the specifics of the fracture. For example, the medial buttress plating combined with lateral collateral ligament repair has been proven effective for some types of fractures.
What else can Coronoid Fractures be?
If you dislocate your elbow, it’s sometimes accompanied by a fracture – but not always. This simple kind of dislocation doesn’t have any related bone breaks and isn’t as common.
There’s a particular type of elbow injury called the ‘terrible triad’. This injury is known for causing instability in the elbow and extensive arthritis after the injury. The ‘terrible triad’ comprises three specific damages – a fracture in the coronoid process of the elbow, a fracture in the radial head of the elbow, and a dislocated elbow (commonly associated with a lateral collateral ligament injury which results in the elbow being unstable).
People who suffer this type of injury generally need surgery to stabilize the fractures and repair the damaged ligament. However, if after the elbow has been properly realigned and both fractures are suitable for non-surgical treatment, non-operative treatment may be an option.
What to expect with Coronoid Fractures
Quick and proper treatment of coronoid fractures can result in positive recovery. If these injuries are not correctly identified and treated, it can seriously restrict elbow movement because of pain and instability.
Possible Complications When Diagnosed with Coronoid Fractures
It’s typical to see abnormal bone growth around the elbow after surgical procedures. This can be managed with medications like indomethacin, or with radiation therapy.
People often have trouble moving their elbow (elbow stiffness) after it has been immobilized for a while.
Additional frequent complications include the elbow becoming unstable again following the return of normal activity and the development of arthritis due to injury. To reduce these problems, it’s very important to ensure that the elbow joint is correctly aligned after treatment. Most medical professionals agree that the stability of the elbow can be restored if it’s kept in its correct anatomical position for at least a month. This gives the ligaments around the elbow enough time to heal properly.
Recovery from Coronoid Fractures
Physical therapy plans after a coronoid fracture fixation can vary depending on the surgeon’s approach. Usually, the elbow is kept static and bent at a 90 degree angle at first. If the side of the elbow is unstable, the forearm is commonly positioned in a way that it’s turned downwards to help increase stability and protect any repaired or reconstructed ligaments. On the other hand, if the medial ligaments — those inside the arm — are injured, the forearm is kept in an upwards position.
You should avoid lifting your arm to the side since this can strain repaired ligaments on the outer side of the arm. Around one to two weeks after the surgery, the patient usually starts simple range of motion exercises. These are later upgraded to exercises that build strength around 8 to 12 weeks post-surgery.
Keeping the elbow immobile for a long time has often led to stiffness, resulting in disappointing outcomes. So, to reduce these chances, a hinged elbow brace may be used in the initial stages of recovery to offer extra protection and limit overstretching. Full freedom of movement is often allowed about four to six months after the surgical fixation.
Preventing Coronoid Fractures
Preventing fractures of the coronoid process (a part of your elbow) is challenging because they usually occur due to accidents or injuries. It’s crucial that patients understand the potential risks and complications associated with these fractures. This could include issues like instability and arthritis, which can occur whether you have surgery or not.
Many people with coronoid process fractures need surgery, so it’s important to fully discuss the potential risks and benefits of these procedures. Patients should have all the information they need to make informed decisions about their treatment. Surgery may also come with its own set of expectations and limitations, which should also be discussed so the patient knows what to expect during recovery.