Fracture Radial Head

B Extension Varus Ulnar metaphysis fracture +/- radial head subluxation... 

The elbow and wrist differ from most other joints in that certain movements (pronation/supination) are inextricably linked. This is accomplished by the mobile radius rotating around the static ulna. Proxi-mally, the radial head articulates with the radial notch on the lateral aspect of the coronoid process of the ulna. Distally, the ulnar notch of the radius rotates around the head of the ulna. In addition, the shafts of the bones are linked by the interosseous membrane. Damage to any of these structures may restrict pronation or supination. In adults, angulation or malrotation of more than 10 can result in restricted rotation of the forearm. For this reason, adult fractures are usually managed by open reduction and internal fixation. In children, the potential for remodelling is good around the wrist and more deformity can be accepted. 

Fig. 9.13. Both the forearm bones are malunited following fracturing in a 3-year-old child initially treated by osteotomy of the ulna. Arthrogram shows that the radial head is still subluxed and radial osteotomy is required...

The Monteggia lesion is dislocation of the radial head associated with a forearm injury. This should not he confused with the Galeazzi injury which is fracture of the radius and dislocation of the distal radioulnar joint. 

The dislocated radial head is an easily missed lesion, not infrequently resulting in litigation. The forearm fracture is readily identified and attention is drawn away from the co-existing elbow injury. It is vital that for long bone fractures, the adjacent joints are both imaged and properly reviewed. 

Monteggia injuries occur most frequently between the ages of 5 and 7. Patients will generally complain of forearm and elbow pain. If the ulna is fractured, pain will be maximal in the arm and there may be swelling and deformity. The elbow will also be swollen. In 10%-20% of cases, a neuropraxia of the radial nerve will be present, particularly if the radial head is dislocated laterally or anteriorly. Most of these nerve injuries will recover within 6-9 weeks and intervention is not indicated unless there is no sign of clinical or electromyographic recovery at 6 months. 

A number of equivalent lesions have also been described. Commonest of these is the Type 1 variant Where the radial head is dislocated anteriorly but the ulna has plastic deformation rather than a fracture. Other variants include dislocations with associated radial neck fractures, olecranon fractures and dislocations of the ulnar-humeral joint. In some respects, the pulled elbow , commonly seen in infants, can also be considered a Bado I equivalent. The injury occurs when the elbow has traction applied, usually resulting in hyperextension and pronation. The radial head subluxes through the annular ligament but does not truly dislocate and radiographs are either normal or will show an effusion with elevation of the fat pads. 

Fig. 18.13a,b. Type I Monteggia fracture with plastic deformation of the ulna, a AP radiograph shows minimal displacement and dislocation could easily he missed, b Lateral radiograph clearly demonstrates the dislocated radial head... 

Fracture which is complete, displaced and rotated with loss of relationship of the radial head against the capitellum. 

Rarely, the radial head is completely displaced, often lying adjacent to the capitellum. This fracture can occur during the reduction of a dislocated elbow if there is an undisplaced radial neck fracture (Fig. 18.18). The radial head may be reduced by closed manipulation aided by manipulation with percutaneous K-wire. One should be careful to make sure that the reduced radial head is not rotated 180° (Wood 1969). 

These include fractures of the radial neck, lateral condyle, distal radius and subluxation of the radial head (Evans 1999a). Physeal fractures are rare and the majority of injuries are metaphyseal fractures. As with any other intra-articular fracture, it is important to restore the articular surface if the fracture is displaced. 

Fig. 18.18. a,b AP and lateral radiographs of radial neck fracture displaced by reduction of the dislocated elbow. Radial head lies adjacent to the capitellum. c Intraoperative radiographs showing intramedullary nancy nail and percutaneous wire used to manipulate the femoral head, d Post reduction film... 

Metaphyseal fractures can be classified according to mechanism of injury. The majority of injuries occur with the elbow in extension, the olecranon locked in the olecranon fossa and the maximum stress developed in the proximal metaphyseal region leading to fracture. When a valgus stress is applied, there may be asso ciated compression fractures of the radial neck and avulsion of the medial epicondyle. Varus stress is associated with radial head subluxation. 

Extension inj uries are reduced by placing the arm into full extension, correcting the varus or valgus, treating the associated injury such as radial head or medial condyle fracture, before immobilising in a cast for 3 weeks in slight flexion. 

Wilkins KE, Morrey BE, Jobe FW, Kvitne RS, Coonrad RW, Figgie HE, Jupiter JB, Inglis AE, Wright PE, Burns EB (1991) The elbow. Instr Course Lect 40 1-87 Wood SK (1969) Reversal of the radial head during reduction of fractures of the neck of the radius in children. J Bone Joint Surg Br 51 707-710... 

Fig. 8.46a,b. Posterior interosseous nerve syndrome, a Transverse 12-5 MHz US image obtained over the supinator area in patient with a previous radial head fracture and radial nerve deficit demonstrates the posterior interosseous nerve (arrowheads) entrapped within a hypoechoic scar (arrows) in the area of the supinator muscle (s). b Gross operative view shows the main trunk of the radial nerve (asterisks) as it splits into the superficial cutaneous sensory branch (arrowheads) and the deep posterior interosseous nerve (narrow arrows). This latter nerve is irregularly swollen as it passes over the bone (large arrows) as a result of the scar encasement visible in a... 

---