The exact prevalence of radiocapitellar joint injuries in adolescents is unknown. The most common elbow disorders in young athletes include overuse injuries, such as osteochondritis dissecans and Panner disease. Fractures of the capitellum and radial neck can also occur in this age group as a result of direct trauma. Marion and Faysse reported only one capitellar fracture in a series of 2,000 elbow fractures in children1. Two fracture patterns of the capitellum have traditionally been described. The first type, a coronal shear fracture often referred to as the Hahn-Steinthal fracture, usually contains a large portion of cancellous bone from the lateral humeral condyle and may include the lateral crista of the trochlea as well2,3. The second type, a pure articular fracture called the Kocher-Lorenz fracture, has little or no subchondral bone attached to the fragment4,5 and is rarely seen in children6.
Since the publication of the study by Marion and Faysse1, several cases of capitellar fractures have been described in older adolescents, whose bone more closely resembles that of an adult7-9; however, a pure articular fracture of the capitellum has rarely, if ever, been reported in children who were less than twelve years of age6. There have been two reports describing anterior or articular sleeve fractures of the lateral condyle10,11, and both of these injuries occurred in patients who were less than twelve years of age. Each of these injuries involved a substantial portion of the articular surface of the capitellum, although neither was a pure capitellar injury. The fracture fragment in these patients was composed mainly of the articular surface from the capitellum, in addition to nonarticular epicondylar and metaphyseal portions of the lateral condyle. The authors noted that diagnosing these injuries can be difficult because there is often little bone attached to the articular cartilage fragment, thereby resulting in poor visualization on standard radiographs and requiring further imaging with arthrography or magnetic resonance imaging.
We present the case of a twelve-year-old boy who sustained a pure Kocher-Lorenz fracture of the capitellum as a result of a direct impact to the elbow during a youth-league football game. The patient's elbow was hyperflexed at the time of impact; thus, it appears that the radial head caused the osteochondral shear fracture through acute eccentric axial loading. The patient and his parents were informed that data concerning this case would be submitted for publication, and they consented.
A twelve-year-old, right-hand dominant, otherwise healthy boy was referred to our center for consultation after having pain in the left elbow for approximately five weeks. The patient had no history of elbow problems and had experienced no musculoskeletal problems prior to the onset of pain. The birth history was normal and all developmental milestones had been achieved within the normal age ranges. Five weeks prior to our evaluation, the patient had sustained a direct impact injury to the hyperflexed left elbow during a football game. His elbow struck the helmet of an opponent, after which the patient immediately experienced pain in the elbow. He sat out for several plays and then returned to the game without appreciable discomfort, although he lacked full motion in the elbow. The patient continued to compete and continued to have elbow problems for the remainder of the football season. Occasionally, he would describe a sensation of locking to his parents, who noticed that he intermittently favored his left elbow in daily activities. These problems prompted a visit to a local orthopaedic surgeon, who obtained radiographs and a magnetic resonance imaging scan, after which the patient was referred to our center for definitive treatment.
On physical examination and comparison of both elbows at our center, the left elbow was noted to have minimal soft-tissue swelling and a small, palpable joint effusion. There was full pronation and supination of the forearm bilaterally, but the left elbow lacked 5° of extension and had 135° of flexion in comparison with the right elbow, which exhibited 5° of hyperextension and 150° of flexion. There was tenderness to palpation over the posterolateral gutter of the left elbow. During both active and passive elbow motion, a catching and grinding sensation was appreciated through the flexion-extension arc.
Radiographs revealed a congruent elbow joint that had open growth plates and appropriate ossification for the age of the patient and had no obvious loose bodies. The magnetic resonance imaging scan showed a small effusion as well as a coronal shear fracture of the capitellum, with the fracture fragment lying in the posterolateral gutter of the elbow (Figs. 1-A and 1-B). The capitellar defect measured 8 mm by 9 mm and was concave in shape.
Surgical Technique
The patient underwent arthroscopy of the left elbow, which revealed diffuse synovitis and a large osteochondral defect in the articular surface of the capitellum. The cartilaginous capitellar fragment was visible in the posterolateral gutter, and it was determined that an anatomic repair could only be accomplished through an open arthrotomy. A posterolateral approach was made through the Kocher interval12, with care taken to remain anterior to the lateral ulnar collateral ligament and to preserve the posterolateral soft-tissue sleeve. The osteochondral fragment was removed from the joint, and a thin rim of subchondral bone and calcified cartilage was seen on its deep surface. The fracture fragment was then reshaped to match the capitellar defect, and the capitellar bed was débrided of fibrous tissue back to bleeding subchondral bone.
The loose fragment was attached to the capitellum with chondral darts (Arthrex, Naples, Florida), resulting in only partial stability of the fragment with rotation and flexion-extension across the radiocapitellar articulation. This fixation was deemed unsatisfactory, and the darts were removed. Two horizontal mattress sutures (1-0 Vicryl; Ethicon, Somerville, New Jersey) were then placed across the fracture fragment in an "x" configuration with use of a smooth Keith needle (Figs. 2-A and 2-B). This suture technique achieved both stable fixation and compression of the fracture fragment. The wound was closed in the usual fashion and the elbow was placed in a soft dressing with a sling for comfort, and the patient was allowed to begin immediate elbow motion.
At the time of the three-month follow-up, the patient had no symptoms of mechanical problems in the left elbow. There was no pain and no tenderness to palpation over the capitellum or the posterolateral gutter. Range of motion of the left elbow had improved to 0° of extension and 145° of flexion, with full forearm pronation and supination. The patient had returned to sports and had no elbow discomfort or limitations. A repeat magnetic resonance imaging scan revealed restoration of the contour of the capitellar articular surface with healing of the Kocher-Lorenz fragment (Fig. 3). At the time of the fourteen-month follow-up, the patient was continuing to do well and had no pain, swelling, or mechanical symptoms. The anatomic carrying angle of the left elbow was maintained, and there was full pronation and supination of the elbow with a flexion-extension arc of 0° to 150°. The patient continued to participate in sports, including football and wrestling, without symptoms, and he stated that the elbow felt normal.