Panner Disease

Anatomy

Panner disease is an osteochondrosis of the capitellum involving the entire ossific nucleus (the growth center). Osteochondrosis refers to the necrosis or breakdown of growth centers in the pediatric or skeletally immature patient followed by regeneration or healing. The growth centers are important because they are responsible for growth of the bones, in this case the growth of the humerus, or long bone of the upper arm. The growth centers at the end of the humerus are responsible for 20% of the final limb length of the upper arm. Thus, injury can result in abnormal growth and decreased length of the arm. The capitellum is the lateral humeral condyle, which is the rounded portion at the end of the humerus. The capitellum articulates with the radial head (one of the forearm bones). The articulation of the capitellum and the radius contributes to movement at the elbow. Simply stated, Panner disease involves the breakdown and then healing of the growth center at the end of the humerus on the lateral (outside) portion. It is the most common cause of chronic lateral elbow pain in athletes under age 10.

Panner disease should be differentiated from osteochondritis dissecans (OCD) of the capitellum, which occurs in an older pediatric population, usually ages 11 to 16, and only involves a portion of the growth center. It is also not characterized by the classic regeneration and recalcification seen in Panner disease. It has the potential for more long-term complications, unlike Panner disease, which is generally a self-limiting condition.

Causes

With increasing participation and an emphasis on excellence at a young age, injuries are becoming more prevalent in the younger population. Often, kids are now participating year-round in only one sport. This does not allow for any rest time and results in an increased incidence of injuries, especially the overuse-type injuries. As described above, the presence of open growth plates represents a unique situation and opportunity for different injuries to occur compared with those seen in the adult or skeletally mature population.

Panner disease is one example of an overuse-type injury. It occurs due to repetitive axial loading or lateral compression of the elbow during activities such as gymnastics and baseball throwing, respectively. During pitching, especially the early-and late-cocking as well as early-acceleration phases, the lateral portion of the elbow experiences large compressive forces. With repetition, these forces can lead to abnormalities in the radiocapitellar articulation, such as Panner disease, in the young athlete. Gymnasts spend a lot of time using their upper extremities as weight-bearing joints. It is thought that this repetitive axial loading is responsible for injury to the lateral elbow growth center in these athletes.

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