A four-year-old boy fell from a height of about ten feet (three meters) and sustained an injury of the right forearm. He had a severe posterolateral angular deformity in the proximal part of the forearm without any neurovascular deficit. Motion of the elbow and wrist was very painful and restricted.
Roentgenograms showed a fracture of the proximal third of the ulna, with 55 degrees of lateral angulation on the anteroposterior roentgenogram and 30 degrees of posterior angulation on the lateral roentgenogram. The radial head was displaced posterolaterally, and there was a fracture through the middle third of the radial shaft (Fig. 1). In addition, at the site of the fracture, there was plastic deformation of the ulna in an anteromedial direction.
Two attempts at closed reduction with the patient under general anesthesia were unsuccessful. The angular deformity of the ulna could be corrected only in the anteroposterior plane, and the radial head could not be reduced (Fig. 2). Through a four-centimeter-long incision over the site of the fracture and with minimum periosteal stripping, the fracture of the ulna was exposed and found to be incomplete. The intact medial cortex was broken; however, it was still difficult to obtain end-to-end apposition because the distal end of the proximal fragment was slightly curved as a result of the plastic deformation. The fracture was unstable, and internal fixation was necessary to stabilize the fragments. The distal end of the proximal fragment was brought into view and a square nail, two millimeters in diameter, was inserted into the medullary canal of the proximal fragment and driven through the olecranon until the distal end was visible at the site of the fracture. The fracture was then reduced, and the nail was threaded into the medullary canal of the distal fragment. The radial head was reduced with manual pressure, with the elbow in 90 degrees of flexion and the forearm in supination.
After relocation of the radial head, flexion, extension, supination, and pronation were considered adequate. The roentgenograms showed excellent reduction of both the fractures and the dislocation of the radial head. Internal fixation of the radius was not necessary, as the fragments were well aligned and the reduction was stable (Fig. 3). The extremity was immobilized in an above-the-elbow plaster cast with the elbow in 90 degrees of flexion and the forearm fully supinated.
The postoperative course was uneventful, and the nail was removed six weeks after the operation. Two and one-half years after the injury, the patient had a full range of flexion, extension, supination, and pronation. No additional roentgenograms were made, at the request of the father.
The Monteggia lesion has been classically described as an injury resulting in dislocation of the radial head and fracture of the ulna. Bado found the fracture and dislocation to be displaced in various directions in forty patients2. He modified the description of Monteggia and identified four types of lesions. In type I, there is anterior dislocation of the radial head and fracture of the diaphysis of the ulna at any level, with anterior angulation of the fracture fragments. In type II, there is posterior or posterolateral dislocation of the radial head and fracture of the diaphysis of the ulna, with posterior angulation of the fracture fragments. Type III refers to lateral or anterolateral dislocation of the radial head and fracture of the metaphysis of the ulna. Type IV is characterized by anterior dislocation of the radial head and fracture of the proximal third of the radius and ulna at the same level. Type IV has been recognized as a separate entity, yet few such fractures have been reported. Type-IV lesions have usually been treated with closed reduction3,13; open reduction and internal fixation has been performed only if the closed reduction has been unsuccessful. A satisfactory result after open reduction and internal fixation was reported by Bado2, Thompson and Hamilton, and Gibson and Timperlake.
It is typically very difficult to determine the exact mechanism of injury in a very young child, who is usually unable to provide precise details of the accident. However, the position of the forearm when the patient is first seen, the position of the distal end of the radius on the roentgenograms, and the direction of dislocation all provide indirect clues about the mechanism of injury.
With anterior dislocation of the radial head, the forearm is in a position of hyperpronation4 and hyperextension11; with posterior dislocation, it is in slight flexion. Bado stated that "the attitude of the distal segment of a dislocated articulation represents the movement which led to the dislocation."2
We suggest that, at the time of the impact, the forearm was in supination and the elbow was in flexion, as was seen in our patient at the initial examination, and the weight of the body might have contributed a force, from the medial side of the forearm, to produce a lateral varus stress. All factors worked in combination or in sequence to produce the injury. Roentgenograms, made with the extremity in the same position, showed the distal end of the radius to be more distal to the distal end of the ulna, indicating that the forearm was in supination. Because the child was in severe pain, we did not manipulate the forearm until he was under anesthesia. The postoperative roentgenogram showed the distal end of the radius and the ulna to be at the same position, confirming the previous position of supination.
We used a nail to stabilize the ulna5; this is an easy procedure that can be performed quickly, with minimum periosteal stripping, and the nail can be removed without difficulty at a later date. A round nail was not used because it backs out more easily and provides less rotational stability. Over the years, we have found intramedullary nails to be superior to plates for internal fixation in young children because the rigidity provided by a plate is not needed in these patients. Other authors have also used intramedullary nails to stabilize fractures of the radius and ulna in children7,12. Furthermore, we supplemented the fixation with a cast. On the basis of the current report, we believe that, if proper alignment of the ulna with good fixation is obtained and the radial fracture is in a good position, internal fixation of the radial fracture is not necessary.
A review of the English-language literature revealed the cases of only eight patients, including ours, in whom a type-IV lesion was treated with internal fixation2,6,8-10. Two patients were four years old, and the remaining patients were adults. Both bones were fixed in three patients, one bone was fixed in three, and no details of the fixation were available for two patients. A plate was used for fixation of three bones, and an intramedullary nail was used in six. A plaster cast was used to treat the second fracture in the patients who had fixation of only one bone. The result was poor in two patients: one who had an associated nerve injury and one who had osteoarthrotic changes in the radial head. The result was very good in the patients who had been managed immediately; they regained full motion of the elbow and forearm. It is evident that internal fixation of both bones is not necessary. It is very important that residual angulation or shortening of the ulna be avoided, as this could lead to persistent subluxation or dislocation of the radial head.
All of the previous reports2,6,8-10 of the type-IV injury have described a combination of anterior dislocation of the radial head and anterior angulation of the fracture of the ulna. In our patient, the ulnar fracture was angulated posterolaterally with dislocation of the radial head in the same direction. The mechanism of this injury appears to be different from that in the previous reports. We therefore propose subgroups in Bado's classification of Monteggia fracture-dislocations. Type IV-A should be used to characterize anterior angulation of the ulnar fracture, with anterior dislocation of the radial head and fracture of the radial diaphysis (Fig. 4, A); type IV-B, posterior angulation of the ulnar fracture, with posterior dislocation of the radial head and fracture of the radial diaphysis (Fig. 4, B); type IV-C, lateral angulation of the ulnar fracture, with lateral dislocation of the radial head and fracture of the radial diaphysis (Fig. 4, C); and type IV-D, a combination of types IV-A and IV-C or types IV-B and IV-C. (The lesion in our patient was type IV-D.)