Introduction:
The triad injury of the elbow is a traumatic condition occurring to the elbow joint that includes three bones. The bones forming the elbow joint are the humerus, the radius, and the ulna. The triad injury of the elbow is also called "the terrible triad of the elbow" because of its poor prognosis. It is a condition that doctors and patients do not appreciate well. This concept was introduced by a person called Hotchkiss in 1996. But recent advances in medicine and standardization of treatment for this condition have given it a better prognosis and not so "terrible injury."
What Is the Anatomy of Elbow?
The elbow joint is a ball and socket joint made by the fusion of three bony joints, namely the humeroradial joint, humeroulnar, and superior radioulnar joints bound together by the synovial capsule. The bones forming these are the radius, ulna, and humerus. These three bony joints are separated by a cartilaginous membrane called the hyaline cartilage covered within the synovial capsule.
The synovial capsule consists of the synovial fluid providing lubrication for the easy movement of the joint. The elbow joint works on the principle of the hinge axis, working in a single planar motion. Four ligaments connect the elbow joint's bones: the ulnar collateral ligament, radial collateral ligament, annular ligament, and quadrate ligaments, which help stabilize the elbow joint. The ulnar collateral artery, radial collateral artery, middle collateral artery, recurrent radial artery, and ulnar artery provide the blood supply to the elbow.
What Are the Causes of Triad Injury?
Triad injury occurs due to traumatic injuries and accidents where the arm is outstretched and flexed and when the blow directly falls on the elbow. The triad injury is most likely to occur when these three factors co-occur:
a) When the elbow is extended and abducted.
b) When the arm is rotated.
c) When there is more impact along the axis.
It is seen in sports personnel, road accidents, vehicle crashes, or high-intensity fall with arms stretched.
What Are the Symptoms of Triad Injury?
Triad injury is characterized by the fracture of three bony structures: the head of the humerus, the radial bone, and the coronoid process of the ulna. The clinical symptoms are:
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Fracture of the radial head.
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Fracture of the coronoid process.
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Dislocation of the elbow.
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Injuries involving the associated ligaments.
1. Fracture of the Radial Head: Radial head fractures commonly occur in elbow dislocations, seen in almost 30 % of the cases.
Mason-Johnson classified radial head fractures as:
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Type 1: Non-displacement radial head fracture.
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Type 2: Partial articular fracture with displacement.
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Type 3: Comminuted fractures involving the entire radial head.
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Type 4: Fractures of the radial head with dislocation of the elbow joint.
Hotchkiss modified this classification as:
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Type 1: Non-displaced or minimally displaced fractures of the head and neck.
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Type 2: Displaced fractures of the head and neck.
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Type 3: Severely comminuted fracture of radial head and neck.
Radial fractures are the most common injury in an elbow fracture, occurring in almost 20 % of the cases, and it is more commonly seen in female patients than in male patients between the age group of 30 to 40 years. Patients complain of the following manifestations:
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Pain.
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Clicking.
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Stiffness of the elbow.
2. Fracture of Coronoid Process: The fracture of the coronoid process is very commonly associated with other elbow joint injuries.
Regan-Morrey classified fracture of the coronoid process as:
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Type 1: Avulsion of the tip of the coronoid process.
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Type 2: The fractured fragment involves more than 50 % of the coronoid process.
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Type 3: The fractured fragment involves less than 50 % of the coronoid process.
This classification is further subdivided into type A and type B, depending on whether the elbow dislocation is present.
O'Driscoll classified fracture of the coronoid process as:
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Type 1: Transverse fracture with fracture line confined to the coronoid tip.
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Type 2: Fracture of anteromedial facet with fracture line running past the coronoid tip and anteromedial facet.
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Type 3: Larger fractures involve more than 50 % of coronoid height running across the basal plate and body of the coronoid process.
The clinical symptoms of the triad of elbow dislocation are:
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Excruciating pain.
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Clicking and locking of the elbow joint during extension.
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Instability during outward and medial deviation.
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Stiffness of the elbow joint.
How Is Triad Injury of Elbow Investigated?
There are two investigation methods used for identifying the triad of elbow injury; they are:
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Radiographs (X-rays): They are used to evaluate the roundness of bony joints, assess the fracture line and dislocation degree, and help differentiate pre and post-reduction films.
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Computed Tomography (CT) Scan: Computed tomography is used in triad injury of the elbow for better evaluation of the coronoid process and to understand the fracture line through 3D imaging (three-dimensional imaging).
How To Treat Triad Injury of the Elbow?
The triad injury of the elbow can be treated by two methods, operative and non-operative methods:
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Non-Operative Management: The non-operative management of elbow injury includes:
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Management of pain.
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Reduction of the dislocation.
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Stabilization of dislocated joints.
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Static inelastic splinting is done at night after four to six weeks, followed by strengthening exercises after six weeks.
Surgical Management:
The surgical management of treating the fracture with surgical procedures includes:
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Radial head arthroplasty with open reduction and internal fixation.
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Reconstruction and repair of the medial and lateral collateral ligaments.
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Fixation and reduction of the coronoid process.
Postoperative Management:
The postoperative management of this condition is done by:
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Using external agents to fix the elbow with hinged or static braces.
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Achieving immobilization by using splints.
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Rehabilitation of the elbow by physiotherapy.
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Healing of the elbow starts from around six to 12 weeks.
What Are the Postoperative Complications?
The postoperative complications of the triad of elbow fractures include:
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Instability of the elbow.
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Failure of internal fixtures.
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Poor blood supply to the bones leads to osteonecrosis (it is the decay of bone due to lack of oxygen, blood supply, or infection).
Conclusion:
The triad of the elbow, also called the "terrible triad of the elbow," is a very scandalous combination of elbow dislocation, fracture of the coronoid process, and radial head, which has always been a difficult task to fix. It also compromised the prognosis of the condition making the patient endure prolonged postoperative pain and elbow instability. But with the development in technology and medicine, the diagnosis, screening, and the quality of surgical and non-surgical procedures provided for the patients have increased the standard of treatment outcome, giving the patient a better postoperative life.
