RADIAL HEAD FRACTURES: APPROACHES AND FIXATION

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Radial Head Fractures


Approaches and Fixation


Frank J. Raia and Melvin P. Rosenwasser


Historically, radial head fractures were treated with excision of the head and its fragments. Excision has significant sequelae, however, including instability, loss of strength, and proximal radial migration with disruption of the distal radioulnar joint (DRUJ) causing pain at the wrist. In Essex-Lo-presti lesions, the damage to the DRUJ and the interosseous membrane may not be discovered on initial presentation, especially if wrist films are normal and the patient does not have wrist pain. These factors have led to a change in treatment of radial head fractures whereby the primary goal is fixation. If primary fixation cannot be adequately achieved, alternate treatments are either late excision or radial head replacement. In this section, we will address primary fixation.


Indications (Fig. 42–1)


The most commonly used classification system was developed by Mason in 1954 and is as follows:



Type I = undisplaced


Type II = displaced


Type III = comminuted


An additional class has been added to this classification, type IV, which is radial head fracture associated with elbow dislocation.


It is important to stratify these injuries into isolated radial head fractures (types I, II, and III) or those in association with fracture dislocations such as the Monteggia fracture and its variants.


If the radial head fracture is isolated and the patient has no mechanical block to motion, then the head may be left in place even with a slight tilt or diastasis. If forearm rotation is limited, then proceed to open reduction and internal fixation (ORIF) with headless screws. Only in rare instances would a displaced radial head fracture be left in place.


For a radial head fracture associated with an elbow fracture dislocation, it is imperative to perform an ORIF or to place a metallic load-tolerant prosthesis (i.e., no silicone) if radial head fixation cannot be adequately accomplished.


If the radial neck is involved, it may be difficult or impossible to obtain stable internal fixation of the radial head, without using a small T-plate in the “safe zone” defined by Smith and Hotchkiss (Fig. 42–2).


Contraindications



1.    Type I fractures are treated nonoperatively with early motion. Joint aspiration may be performed as needed.


2.    Radial head fractures with fragments that displace too far into the anterior or posterior pouch should not be fixed, as their chance of viability is low. Rather, the fragments should be excised and radial head replacement considered.


Mechanisms of Injury



1.    A fall on an outstretched hand with axial compression of the radius and ulna, the elbow partially flexed, and the forearm in pronation causes most isolated radial head fractures.


2.    When a valgus force is additionally applied at the time of fall, concomitant injuries can occur as the elbow subluxes or dislocates. The soft tissues most at risk for injury include the lateral collateral ligament complex (Fig. 42–3A), the medial collateral ligament complex (Fig. 42–3B), and the anterior capsule.


Physical Examination



1.    The patient often presents with an effusion (which can be tense), ecchymosis, and pain (especially with rotation of the forearm).


2.    The exam may reveal tenderness over the radial head, and decreased range of motion (ROM) with a block to extension, flexion, and/or rotation depending on the displacement. The exam can be enhanced by aspiration of the hemarthrosis and injection of marcaine/lidocaine.


3.    If associated with soft tissue disruption due to elbow subluxation or dislocation, the elbow may be unstable to varus and/or valgus stress. Stability may be difficult to determine at presentation secondary to guarding. A full exam may not be possible until the patient is under anesthesia.


4.    The distal radioulnar joint must also be completely evaluated for tenderness and instability.


Diagnostic Tests



1.    Elbow anteroposterior (AP), lateral, and oblique X-rays. Ensure neutral rotation of the lateral view. Also, if the elbow is flexed secondary to pain or effusion, the AP view of the radial head fracture may under- or overestimate the deformity.


2.    Radiocapitellar or capitocondylar view (lateral view with the X-ray tube angulated 45 degrees toward the shoulder).


3.    Wrist X-rays to rule out DRUJ injury.


4.    Magnetic resonance imaging may be performed when one suspects an occult Essex-Lopresti lesion to assess the interosseous membrane (IOM) as IOM lesions may be difficult to diagnose based on initial exam and X-rays.


Differential Diagnoses and Concomitant Injuries


Soft Tissue Injuries



1.    Lateral or medial collateral ligament injuries. The ligaments usually avulse proximally at their origin on the humeral epicondyle, but may present as intrasubstance tears or distal avulsions.


2.    Brachialis muscle and anterior capsule rupture. These may occur secondary to radial head fragment intrusion.


3.    Interosseous membrane injury.


4.    Distal radioulnar joint injury (dorsal/palmar radioulnar ligaments and TFCC).


Fractures



1.    Coronoid: type I coronoid fractures occur due to a shear force, while types II and III may be avulsion fractures associated with the anterior bundle of the medial collateral ligament.


2.    Ulna: proximal to midshaft, even segmental (Monteggia variants).


3.    Capitellum (impaction chondral injury).

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Aug 8, 2016 | Posted by in ORTHOPEDIC | Comments Off on RADIAL HEAD FRACTURES: APPROACHES AND FIXATION

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