Panner disease also involves
the capitellum and presents in a similar manner as a capitellar osteochondritis
dissecans, but in a younger patient population and with a better long-term
prognosis. Panner disease typically occurs in the dominant elbow of boys during
the period of active ossification of the capitellar epiphysis at between 7 and
12 years of age, with a peak at age 9 years.
The pathologic process is similar
to that of Legg-Calvé-Perthes disease and is believed to be caused by
interference in the blood supply to the growing epiphysis, which results in
resorption and eventual repair and replacement of the ossification center. The exact
cause of this avascular necrosis, or bone infarct, continues to be debated,
with popular theories including chronic repetitive trauma, congenital and
hereditary factors, embolism (particularly fat), and endocrine disturbances.
Whatever factors are responsible, the end result is avascular necrosis. Signs
and symptoms are similar to those seen with osteochondritis dissecans,
including dull, aching lateral elbow pain that is aggravated by use and may
improve with rest. Tenderness and swelling along the lateral side of the elbow
with loss of terminal elbow extension are also common. Initial radiographic
changes can appear similar to osteochondritis dissecans, with fragmentation of
the capitellar epiphysis, but whereas lesions of osteochondritis dissecans can
often progress to loose fragments, loose bodies are rare in Panner disease.
Typically, the normal radiographic appearance of the capitellum will be
reconstituted over time as growth progresses. Residual deformity of the
capitellum is rare. MRI will demonstrate signal changes in the capitellar
epiphysis but may be less useful than in osteochondritis dissecans owing to the
lack of concern for an unstable lesion or a loose body.
Symptomatic treatment of
Panner disease is sufficient, because the condition is self-limited, with the
epiphysis becoming revascularized and returning to a normal configuration with
time. Rest and activity modification usually relieve the pain and allow gradual
return of elbow motion. Use of a long-arm cast or splint for 3 to 4 weeks may
be necessary until pain, swelling, and local tenderness subside. The longterm
prognosis is excellent, with complete resolution of symptoms in most patients,
althou h a slight loss of elbow extension may persist in some.
