What is Terrible Triad of the Elbow?
The “terrible triad of the elbow” is a medical term first used by a doctor named Hotchkiss in 1996. It refers to a very unstable type of injury that involves a dislocated elbow, along with fractures in either the radial head or neck (the top part of the forearm’s bone), and the coronoid process (a small bony projection in the elbow).
This injury is named “terrible” due to its historically bad outcomes and high chance of complications. The elbow is normally very stable thanks to its many bone and soft tissue structures. This complex anatomy, combined with the high functional demands we put on our elbow, makes treating elbow injuries challenging.
Even a simple elbow dislocation without any bone fractures can cause a lot of soft tissue damage, including tears in the capsule surrounding the joint and the ligaments. More complex dislocations involve fractures in one or more of the major bones that help stabilize the joint. If the radial head, coronoid process, or olecranon (the bony tip of the elbow) fractures, it makes the dislocation more unstable and usually means surgery is needed to restore the joint’s normal anatomy and stability.
While we’ve improved in diagnosing and treating these types of injuries over time, and have a better understanding of how the elbow works, there are still debates about the best way to treat the terrible triad of the elbow. Doctors are using standardized surgical guidelines and new treatment plans to try and improve recovery for these patients. To effectively assess and treat this injury, doctors need a deep understanding of how each bone and soft tissue contributes to the stability of the elbow.
What Causes Terrible Triad of the Elbow?
About 60% of complex dislocations, which are severe joint injuries, are caused by falling from standing. These usually occur when someone falls on an outstretched arm. This puts pressure in specific directions – sideways, downwards, and in a twist – leading to a particular kind of dislocation, known as a posterolateral dislocation.
Complex dislocation often involves damage to three main parts, sometimes called the ‘terrible triad’. First, the elbow dislocates. Secondly, the injury could spread to the area on the inner side of the elbow, possibly damaging the key ligament there (the medial collateral ligament). The injury to the outer part is often a tearing from its original position, along with a rupture of the muscle that extends the forearm from the outside of the upper arm.
At the same time as the elbow dislocation, two structures in the forearm, the radial head and the coronoid process, may also get injured. The damage to these parts can differ in how large and complex they are. The risk of the joint becoming unstable again or developing arthritis later on increases with the complexity of the injury and the number of parts involved.
Risk Factors and Frequency for Terrible Triad of the Elbow
Radial head fractures, which make up between 20 to 30% of all adult elbow fractures, usually occur in individuals between the ages of 30 and 60. The average age at which these fractures most frequently occur is 45.
Coronoid fractures are a less common type of elbow injury, accounting for 10 to 15% of incidents. The elbow, despite being one of the most stable joints in our body, is prone to dislocations – it’s the second most commonly dislocated joint. Interestingly, about 20% of these elbow dislocations happen along with a fracture.
Signs and Symptoms of Terrible Triad of the Elbow
Trauma injuries like high-energy elbow fractures and dislocations should follow the Advanced Trauma Life Support (ATLS) guidelines when being evaluated. These kinds of injuries often come with other damage to the same limb. For instance, a painful distal radioulnar joint (DRUJ) could indicate an issue with the interosseous ligament and hint at a simultaneous Essex-Lopresti injury.
A fracture-dislocation often shows large swelling, pain, and noticeable deformity. Regular elbow movement varies from about 30 to 130 degrees of bend and 50 degrees of twist in each direction. However, patients with these injuries may have limited elbow or forearm movement.
You can observe signs like bruising, swelling, and tenderness over the side of the elbow; you might even see a deformity if there’s a related dislocation. It’s crucial to examine the range of movement, including bending and straightening, turning the arm, and check for any obstacles. Anesthesia can help in identifying any mechanical obstacles.
Before attempting any reduction or manipulation of the limb, a detailed check of the nerve and blood supply should be carried out. The ulnar nerve can easily get damaged due to its location along the inner elbow joint. Rarely, but significantly, the brachial artery could be injured, leading to low blood supply and dangerous compression of the muscles, usually in children.
To evaluate elbow stability, several tests are performed, along with checking how the forearm reacts to forces from either side. For the DRUJ specifically, examination includes checking the wrist for pain and comparing it with its normal state. Also, the interosseous membrane is checked for tenderness, and a radial pull test is performed; if there is noticeable translation, this could alert to an issue with the forearm stability, i.e., an Essex-Lopresti injury. If patients come in with similar symptoms repeatedly or after a delay, it’s crucial to thoroughly assess the elbow movement, rotation of the forearm, pain, and nerve function.
Testing for Terrible Triad of the Elbow
If you have a complex injury, front and side views of X-rays are essential to determine the extent of your injury. Sometimes, the full scale of the injury may not be immediately evident. In such cases, your doctor may order additional imaging of your shoulder, wrist, and hand to exclude potential injuries there. These X-rays can also help to check the health of the joints in your elbow. Specifically, side view X-rays can be useful in identifying certain bone fractures.
While X-rays can diagnose most injuries, in some cases, you might have to undergo a CT scan. This is especially common for significant injuries like the “terrible triad” injury of the elbow, where the CT scan can provide a more detailed view of the fractures, including their size, shape, and displacement. Sometimes, fractures may not be visible on X-rays, but they can be detected using a CT scan. Three-dimensional (3D) images provide an even more detailed view of the fractures and can help your doctor plan your treatment better.
CT imaging is also useful to identify other bone injuries in your elbow that were not spotted on the initial X-rays. Fluoroscopic – live X-ray – images taken under anesthesia can help your doctor make treatment decisions while you’re in an operation. In some cases, it might not be practical to have X-rays taken after particular procedures. In such instances, your doctor might carry out an examination under anesthesia while gently moving your elbow. Remember, it’s crucial to have X-rays taken before and after any procedures.
If you’ve had a procedure done in the past or if you have not immediately sought treatment after an injury, the imaging you need may depend on your specific situation. You may require non-standard views if your injured joint is stiff, or to understand better the interplay and alignment of your joint surfaces. Sometimes, a past fixation procedure or a radial head implant can mask other joint surfaces and misrepresent their alignment. In such cases, you may need a CT scan or an MRI.
There are different classification systems, such as the Mason, Regan and Morrey, and O’Driscoll classifications to help diagnose certain types of fractures. For radial head fractures (the bone in your forearm that meets your elbow), the Mason Classification system is followed:
Type I: The fracture is either not displaced at all or is slightly displaced (less than 2 mm) with no hindrance to the rotation of the arm
Type II: The fracture is displaced (more than 2 mm) or angled with possible interference with the rotation of the forearm
Type III: The fracture is not only displaced, but it’s also splintered, causing definite issues with movement
Type IV: The fracture is associated with a dislocation of the elbow
The Regan and Morrey Classification system categorizes three types of coronoid fractures (fractures of a part of the ulna in your elbow):
Type I: The fracture involves the top part of the coronoid
Type II: The fracture involves half or less of the coronoid’s height
Type III: The fracture involves more than half the height of the coronoid
The O’Driscoll Classification system gives us more information about coronoid injuries based on their location and number, focusing on fractures caused by particular forces.
Treatment Options for Terrible Triad of the Elbow
All treatments for elbow injuries aim to restore the stability needed to let the elbow move. To do this, the bone structure needs to be realigned, the radial head and contact needs to be restored, and the ligaments need to be repaired. The usual methods are applied for injuries seen within two weeks of happening.
If the elbow is stable enough to move, treatment can be non-surgical with the arm kept in a bent position for a week to 10 days. This approach is used when the fracture is small, doesn’t need surgery, and, following treatment, your elbow can move like normal. Gradually, the range of your elbow’s movement is increased. The process starts with moving your arm inside a splint at a 90 degrees angle. The important thing is to avoid straining the elbow. Strengthening exercises can start after six weeks.
If the elbow injury is severe that it includes an unstable radial head fracture, a type III coronoid fracture and elbow dislocation, surgical treatment may be required. The surgical options are open reduction internal fixation (ORIF), radial head replacement, Ligament Complex reconstruction, and possible Medial Collateral Ligament reconstruction. If the elbow remains unstable after surgical treatment, the next step would be MCL reconstruction.
Elbow dislocation should be managed by immediate closed reduction, which is a procedure to set the bone back into place. After this procedure, movement exercises for the elbow should be started. The arm will be placed in a splint, in a bent position. Practice moving the elbow should be encouraged and the splint should not be left on for more than three weeks because it could cause the elbow to stay in a permanently bent position.
When surgical treatment is necessary for fractures in the radial head of the elbow, the typical choice is open reduction internal fixation (ORIF), a type of surgery used to stabilize and heal a broken bone. If the fracture is more severe and involves more than three fragments, the radial head may need to be replaced. Both approaches show good results. Patients that underwent replacement surgery usually meets less complications and has better elbow movement compared to those who underwent repair.
Elbow injuries does take some time to heal. Whether you had surgery followed by a rest period, or not, expect to start physiotherapy after about 10 to 14 days. This involves active movement exercises that will help with reducing pain and swelling and start the healing process, that’s very important for recovery.
The speed of recovery also depends on the severity of the injury and how quickly you received treatment. A published study suggests that there’s higher chance of elbow stiffness after surgery when the surgery is delayed. It is found that the optimal time for surgical treatment would be 24 hours up to 14 days after injury. Another study found that patients who had surgery within two weeks of injury had better arm movement after their recovery.
What else can Terrible Triad of the Elbow be?
Humeroulnar dislocations, which are caused by strong impacts and result in severe instability, are different from simple dislocations.
The classification of these fracture-dislocations can be explained using the Modified Mason Classification system, where:
- Type I fractures don’t need surgery
- Type II fractures require surgical fixation
- Type III fractures necessitate joint replacement(arthroplasty)
Additional injuries such as fractures in connecting areas of the elbow (radial head and coronoid), known as the “terrible triad,” can increase the risk of ongoing instability and further complications like arthritis.
These fractures can be classified further based on size and location. For instance, coronoid fractures (in the elbow) can be:
- Tip fractures
- Front (anteromedial) fractures
- Base (basal) fractures
These types can be broken down further depending on their characteristics. For example, basal fractures can be associated with fractures in the tip of the elbow bone (olecranon).
Another type of injury in this category results in disruption of multiple structures in the elbow, including the joint notch, dislocation of the forearm, and fractures. These are serious injuries that affect all bone stabilizers of the elbow and can cause instability.
Severe cases also include fractures (transolecranon fracture-dislocations) that involve a complex fracture in the elbow’s main bone (olecranon) or dislocation of the forearm while the adjoint bones remain in connection. These injuries result from high-impact forces and are often accompanied by other serious elbow injuries.
The direction of forearm dislocation – whether front (anterior) or back (posterior), depends on the injury mechanism. The elbow can regain stability once the upper bone of the forearm is restored. However, operations involving wire tension bands are known to have complications such as degeneration of the joint (arthritis) in around 70% of cases or ulnar nerve dysfunction in about 25% of patients.
Sometimes, people suffer from Monteggia fracture-dislocations, which are usually observed in older, frail women with low bone density after a low-impact fall. This type of injury often leads to persistent instability despite attempts to fix all the bone stabilizers.
Another rare type of injury is seen after a fall on an outstretched arm, resulting in fractures in the front part of the elbow (coronoid), often not associated with a radial head fracture. These fractures can cause subtle instability changes that might not be easily detected but can rapidly lead to joint degeneration.
What to expect with Terrible Triad of the Elbow
Although it’s uncommon, ‘terrible triad injuries’, historically, have poor results due to continuous instability, stiffness, and joint conditions. Essentially, these conditions, though individually manageable, together they form a difficult combination to treat.
Physicians should be alert in identifying these patterns quickly, by performing detailed examinations of the affected area. This is crucial to providing treatment in a timely manner. Once a potential injury pattern is identified, medical imaging like X-rays, MRI’s, etc, would be used to confirm the diagnosis and to decide on the best possible treatment approach.
Possible Complications When Diagnosed with Terrible Triad of the Elbow
Elbow fracture-dislocation can lead to various issues, including unusual bone growth called heterotopic ossification, infections, abnormal fusion of bones, joint stiffness, repetitive instability, arthritis as a result of trauma, inflexibility, bone non-joining, nerve damage in the forearm, complications involving surgical implants that require further surgeries and discomfort due to the surgical hardware. Surgical treatments, especially for severe injuries called “terrible triad” injuries, have a high risk of complications and even the need for further surgery in up to 54.5% of cases.
Properly setting a bone fracture within a joint is important in preventing arthritis, but some loss of arm extension ability might be expected. Post-surgery stiffness can occur in 5 to 15% of elbow fracture patients. Arthritis is also common following high-energy trauma and will largely depend on the amount of recurring elbow instability. Joint replacement surgery can be considered for younger patients, while a total elbow replacement may be better for older, less active patients.
A slight loss of motion after an elbow fracture is to be expected. Patients will generally experience more loss in extension than in flexion. The severity of stiffness will increase depending on the initial impact of the injury, the amount of heterotopic bone formed, and the delay in movement after repair. Treatments for insufficient motion range or severe stiffness include splinting, removing the heterotopic bone, and releasing the joint capsule.
Formation of calcium deposits in the ligaments and joint capsule after trauma occurs relatively frequently, with a 20% occurrence rate reported in previous studies. However, in cases of operatively treated fracture dislocations, heterotopic ossification has occurred in up to 43% of cases.
An x-ray taken 3 to 4 weeks post-injury may show near-complete fusion of the elbow due to heterotopic ossification. The severity of this condition will increase depending on several factors, including the magnitude of the injury, the extent of damage to soft tissues, how long the arm was immobilized, whether there was a neurological injury or infection, how long it took to perform surgery, and the presence of associated burns. This abnormal bone growth usually occurs in the tissues surrounding the joint and the muscles of the arm. The best time to remove the heterotopic bone is typically when the bone structure can be seen on imaging.
Non-joining of fractures can occur due to the forces at play during flexion or active extension. Bony non-joining is most commonly seen after radial neck fracture repairs due to decreased blood supply, which can precede bone death and non-joining. Recurring instability is relatively rare but more common in specific types of fractures. This most often happens when fractures or ligament injuries are not properly identified or treated.
Common Complications:
- An unusual bone growth, commonly known as heterotopic ossification
- Infections
- Abnormal fusion of bones, known as synostosis
- Joint stiffness, also known as arthrofibrosis
- Recurring instability
- Arthritis due to trauma
- Inability to move elbow freely
- Non-joining of bones
- Forearm nerve damage
- Issues with surgical implants, requiring further surgeries
- Discomfort due to surgical hardware
Recovery from Terrible Triad of the Elbow
After surgery, splints are usually kept in place for up to 10 days, depending on the stability achieved during surgery and if there are other injuries to contend with. If both the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) were fixed during surgery, the splint is typically positioned to keep the elbow slightly bent and in a neutral position. If these ligaments were not involved, the splint is positioned to keep the elbow bent with the forearm facing downwards. This position helps to stabilize the elbow against shifting backwardly.
Interestingly, some patients can begin range of motion (ROM) exercises – that is, exercises to improve joint flexibility – as early as the first day after surgery. Most patients, however, start these exercises within two days to improve the elbow’s functionality. Exercises that actively involve the patient or those assisted by a therapist help to engage the muscles that stabilize the elbow. The forearm is allowed to rotate during these exercises, and exercises involving the shoulder and wrist are also recommended without any restrictions.
However, patients are usually advised to avoid fully straightening the elbow within the last 30 degrees of movement for four weeks since this is the most unstable position.
Managing elbow injuries, especially a condition known as the “terrible triad” – characterized by dislocation of the elbow, fracture of the radial head, and fracture of the coronoid process of the ulna, can be challenging. Despite the best treatment and adherence to post-surgery rehabilitation, it is rarely possible to restore the elbow’s normal movement range. According to several studies, these patients on average have about 113 degrees to 115 degrees of elbow bending and straightening movement with a persistent elbow bend of about 19 to 24 degrees. These limitations in elbow movements are a common outcome when treating the “terrible triad.”
Preventing Terrible Triad of the Elbow
The main aim of treating a severe elbow injury, often referred to as a ‘terrible triad’ injury, is to regain stability in the elbow and prevent further complications. Surgery is generally accepted as the best treatment option for obtaining positive, functional results.
Studies have shown that most patients with this type of injury achieve good to excellent scores on two commonly used assessments, the Disabilities of Arm, Shoulder, and Hand (DASH) and the Mayo Elbow Performance Score (MEPS). The MEPS assessment measures pain, mobility, stability, and function. In this scoring system, a score of 90 to 100 is considered excellent, 75 to 89 is good, 60 to 74 is fair, and anything under 60 is seen as a poor outcome.
The scores from these assessments can be useful in educating patients about what they can realistically expect after surgery. They help compare different surgical techniques and therapies that don’t involve surgery, and can also motivate patients to follow through with rehabilitation exercises after surgery to achieve optimal results.
Research has consistently shown that surgical treatment of this type of elbow injury yields good to excellent results. The same was observed in earlier studies done before 2009, implying that current surgical approaches continue to be effective in achieving positive results for patients.
However, it’s important to note that despite most patients achieving good to excellent outcomes after surgery, there is still a risk of complications after the operation. Health professionals are continually striving to improve treatment approaches to further reduce the number of patients who experience less favorable outcomes or face complications after surgery.
