Terrible Triad Injuries Trauma Case for FRCS (Tr & Orth) Oral Examination
A 29-year-old man fell from a horse, injuring his right dominant elbow. He is seen in the fracture clinic and these are his radiographs from the emergency department.
1. Describe the appearances of these radiographs and what structures you would expect to be injured.
These radiographs show a dislocation of the elbow associated with a displaced and comminuted fracture of the radial head and a fracture of the coronoid. This is often referred to as a terrible triad injury and represents a high-energy injury. Soft tissue stabilizers of the elbow, such as the lateral collateral ligament, the anterior capsule of the elbow joint in association with the coronoid fracture, and possibly the medial collateral ligament, are expected to be injured.
The radiographs presented show a combination of injuries, commonly referred to as a terrible triad injury, such as a dislocation of the elbow, a displaced and comminuted fracture of the radial head, and a fracture of the coronoid. This type of injury is often associated with high-energy events and is inherently unstable. With this type of injury, it is expected that soft tissue stabilizers of the elbow, such as the lateral collateral ligament, the anterior capsule of the elbow joint in association with the coronoid fracture, and possibly the medial collateral ligament, are damaged.
2. What treatment would you advise for this injury?
Since this is an inherently unstable injury, I would advise operative treatment to restore ulnohumeral joint stability by reducing the dislocation and repairing the coronoid fracture. If the coronoid fragment is too small to fix, I would perform a suture repair of the anterior capsule to the proximal ulna. The radial head would need to be replaced, and the lateral collateral ligament would need repair. If residual instability persists following fixation, I would consider a separate repair of the medial collateral ligament, or alternatively, I would consider augmenting the fixation by applying an external fixator across the elbow. A preoperative CT scan would provide useful information regarding the degree of comminution, fracture fragment origin, degree of displacement, and other factors to be considered during the operation.
For a terrible triad injury, an operative treatment is required to restore ulnohumeral joint stability by reducing the dislocation and repairing the coronoid fracture, depending on size. If the coronoid fragment is too small, a suture repair of the anterior capsule to the proximal ulna is recommended. Radial head replacement is necessary, along with repair of the lateral collateral ligament. If residual instability persists following fixation, a separate repair of the medial collateral ligament is an option, or alternatively, augmentation of the fixation by applying an external fixator across the elbow. A preoperative CT scan can further assist in determining the degree of comminution, fracture fragment origin, degree of displacement, and other factors to be considered during the operation.
3. Describe your planned operative sequence for fixation and repair.
I would position the patient in the lateral position with the affected arm over a bolster. Preoperative antibiotics would be administered and a narrow sterile tourniquet would be used. I would use the utility posterior approach to the elbow, raising thick flaps. The ulnar nerve would be identified, decompressed, and protected in situ. I would also identify any traumatic tear in the lateral structures. I would excise the radial head fragments first, which would give me access to the coronoid and anterior capsule. Depending on coronoid fragment size, I would reduce and fix the coronoid fracture with a single screw or I would suture the anterior capsule down to the coronoid footprint using suture anchors. The next step would be to prepare and place a radial head replacement, taking care not to 'overstuff' the joint. The ulnohumeral joint would be reduced and confirmed, and closure in layers including a repair of the lateral collateral ligament using a suture anchor would conclude the operation.
For the operative sequence to fix a terrible triad injury, I would position the patient laterally with the affected arm over a bolster. Preoperative antibiotics would be administered, and a narrow sterile tourniquet would be used. To access the elbow, I would perform the utility posterior approach, raising thick flaps and identifying the ulnar nerve, which I would decompress and protect in situ. Next, I would excise the radial head fragments and repair any trauma tear in the lateral structures. Depending on the size of the coronoid fragment, I would either fix it using a single screw or suture the anterior capsule down to the coronoid footprint using suture anchors. I would then prepare and insert the radial head replacement, careful not to 'overstuff' the joint, and reduce and confirm the ulnohumeral joint. Closure in layers, including a repair of the lateral collateral ligament using a suture anchor, would conclude the operation.
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