8: Terrible Triad Injuries of the Elbow

PROCEDURE 8 Terrible Triad Injuries of the Elbow



Paul K. Mathew, Graham J.W. King, George S. Athwal



image


Indications



image An elbow dislocation associated with radial head and coronoid fractures that renders the articulation incongruous and/or unstable


Examination/Imaging




Treatment Options



• Nonoperative treatment can be implemented only if all of the following criteria are met:
image The ulnohumeral and radiocapitellar joints are concentrically reduced following closed reduction of the elbow dislocation.

image The elbow can be extended to 30–45° before becoming unstable, suggesting there is sufficient stability to allow early range of motion.

image The radial head or neck fracture is undisplaced or minimally displaced and is not causing a mechanical block to forearm rotation or elbow flexion/extension.

image The coronoid fracture is small, typically a type I fracture.


image The elbow is inspected for obvious dislocation or open injury necessitating immediate reduction and/or surgical treatment.

image The joint is palpated for bony alignment and areas of tenderness to locate pathology.

image The elbow is moved actively and passively to evaluate for stability or a block to motion.

image The arm is examined above and below the joint for tenderness and mobility. Specifically, examination must ensure that no distal radioulnar joint tenderness is present as this may suggest a concomitant interosseous membrane injury (Essex-Lopresti lesion).

image A detailed neurologic examination is performed to evaluate the function of the axillary, musculo-cutaneous, median, ulnar, and radial nerves.

image The vascular status is assessed by evaluation of capillary refill and distal pulses.

image Radiographs
• Prereduction and postreduction (Fig. 1A and 1B) anteroposterior and lateral radiographs are obtained to examine fracture characteristics and concentricity of the elbow joint.

• Regardless of the radiographic projection, a line drawn through the center of the radial neck should intersect with the center of the capitellum.

• Lateral radiographs can be used to determine the height of a coronoid fracture.

image Computed tomography (CT)
• CT is obtained following joint reduction to better evaluate fracture patterns, comminution and displacement.

• Three-dimensional images can improve visualization and understanding of the fracture pattern and fracture line propagation.
♦ The three-dimensional CT image in Figure 2A demonstrates a radial head and neck fracture.

♦ A three-dimensional anterior CT image shows an anterolateral coronoid fracture (Fig. 2B).

image

FIGURE 1


image

FIGURE 2



Surgical Anatomy



BONES



image The proximal ulna
• The greater sigmoid notch, with its central guiding ridge, articulates with the trochlea and is made up of the coronoid and olecranon (Fig. 3A).
♦ The coronoid process provides an important anterior and varus buttress to the elbow joint and consists of the tip, body, anterolateral facet, anteromedial facet, and sublime tubercle (insertion for the anterior bundle of the medial collateral ligament).

• The lesser sigmoid notch articulates with radial head, forming the proximal radioulnar joint.

• The crista supinatoris, located just distal to the radial notch on the lateral aspect of the proximal ulna, provides the insertion for the lateral ulnar collateral ligament (Fig. 3B).

image The proximal radius
• The radial head (Fig. 3C), which is elliptical in shape and offset from the neck, articulates with the capitellum and lesser sigmoid notch.
♦ Hyaline cartilage covers the majority of articular margins and all of the articular dish.

♦ The anterolateral portion of the articular margin does not articulate with the proximal ulna and is devoid of hyaline cartilage (so-called “safe zone”).

• The bicipital or radial tuberosity is distal to the radial neck and serves as the attachment site for the biceps tendon (see Fig. 3C).

image

FIGURE 3



LIGAMENTS



image Lateral collateral ligament (LCL)
• The LCL consists of the lateral ulnar collateral, radial collateral, and annular ligaments (Fig. 4A).

• It is an important varus and posterolateral rotational stabilizer of the elbow.

• Its origin on the lateral epicondyle is isometric.

• The lateral ulnar collateral ligament originates on the lateral epicondyle and attaches to the crista supinatoris.

• The radial collateral ligament originates on the lateral epicondyle and fans out to attach to the annular ligament.

• The annular ligament attaches to the anterior and posterior margins of the lesser sigmoid (radial) notch.

image Medial collateral ligament (MCL)
• The MCL consists of the anterior bundle, posterior bundle, and transverse ligament (Fig. 4B).

• It is an important valgus and posteromedial rotational stabilizer of the elbow.

• Its origin on the anteroinferior aspect of the medial epicondyle is distal to the axis of rotation and therefore tension increases in flexion.

• The anterior bundle originates from the medial epicondyle and inserts on the sublime tubercle of the coronoid.

• The posterior bundle originates from the medial epicondyle and inserts on the ulnar aspect of the greater sigmoid notch.

• The transverse ligament has no known function.

image

FIGURE 4




PEARLS



• With the arm across the chest, use a 3-L intravenous fluid bag placed under the ipsilateral scapula to protract the shoulder. A second assistant may be needed on the opposite side of the operating table.

• When using an arm table, make sure the torso is shifted close to edge of the operating table to move the elbow into the center of the table. A rolled drape placed underneath the medial or lateral aspect of the elbow with the shoulder in internal or external rotation, respectively, facilitates positioning.

• When using the lateral decubitus position, ensure the armholder is well padded and is situated over the biceps muscle to avoid pressure points. If using a bean bag for positioning leave the suction attached to maintain deflation during surgery. Tilt the operating table 10 degrees towards the operative side after the patient is secured to prevent the arm from slipping back off the arm support.

• Positioning supine with the arm across the chest and lateral decubitus positioning have an advantage over the arm table for unstable injuries as gravity tends to reduce the elbow in the former two positions, while rotation of the shoulder to gain access to the medial and lateral sides of the elbow when using an arm table tends to subluxate the elbow and stress collateral ligament repairs and fracture fixation.


MUSCLES



image Several muscles act as dynamic stabilizers of the elbow joint (Fig. 5).

image The biceps, brachialis, and triceps compress the joint and stabilize the articulation; however, a posterior vector of forces contributes to posterior subluxation of the elbow when the coronoid and/or radial head are deficient.

image The flexor pronator muscles arise from the medial epicondyle and provide dynamic valgus stability.

image The common extensor muscles arise from the lateral epicondyle and provide dynamic varus stability.

image

FIGURE 5



Positioning



image For lateral surgery, patients can be placed in the supine position with the arm over the chest supported by a rolled drape to allow the elbow to flex to 90° (Fig. 6A).
• Alternatively, an articulated arm positioner can be used to stabilize the arm.

image For medial surgery, patients can be placed in the lateral decubitus position with the aid of an elbow positioner (Fig. 6B).

image

FIGURE 6



Exposures




PITFALLS



• Lack of a second assistant when using the supine position.

• Failure to protract the scapula.

• Armholder placed in the antecubital fossa when the patient is in the lateral position.

• A stiff shoulder limits medial and lateral exposure with an arm table or with the patient in the lateral decubitus position.



Equipment



• A sterile tourniquet will allow more proximal incision length and can be removed if more exposure is required.

• A padded armholder placed under the anterior surface of the humerus in the lateral decubitus position is needed to stabilize the arm during surgery.

• A beanbag or alternative positioning braces are needed when performing surgery in the lateral decubitus position.


SKIN INCISION



image Choice of skin incision(s) location is controversial; it depends on the fracture/instability pattern, soft tissue injury, and surgeon preference.

image Options are medial, lateral, and posterior skin incisions.

image A posterior skin incision minimizes injury to the cutaneous nerves and allows both lateral and medial deep exposures if needed; however, larger skin flaps are required.

image A medial skin incision has highest risk of cutaneous nerve injury.


DEEP EXPOSURE



image Lateral surgical approach to the elbow: access to the radial head and neck, lateral collateral ligament, and most coronoid fractures can be achieved by one of two approaches.
• Kocher’s interval
♦ Kocher’s interval between the extensor carpi ulnaris and anconeus is identified (Fig. 7A) and incised (Fig. 7B).

♦ The interval is bluntly developed and the collateral ligament complex is identified deep to the anconeus muscle (Fig. 7C).

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Jun 7, 2016 | Posted by in ORTHOPEDIC | Comments Off on 8: Terrible Triad Injuries of the Elbow

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