Of 118 patients with 151 knees treated for Osgood-Schlatter disease,
fourteen patients (fifteen knees) had a distinct and separate ossicle at
the proximal aspect of the tibial tubercle. This ossicle appeared after the
child was first seen in all but three of the fifteen knees. When the
ossicle failed to unite with the tubercle, the non-union was associated
with local discomfort during activity and when direct pressure was applied
on the tubercle. The symptoms did not respond to conservative treatment for
an average of 3.8 years. Resection of the ossicle along with the adjacent
bursa was followed by prompt relief of symptoms. Histological studies
showed no evidence of avascularity. All ossicles were attached to the
distal part of the undersurface of the ligamentum patellae and were
separated from the tubercle by a bursa or scar tissue. The findings
strongly support the concept that avulsion of the proximal cartilaginous
part of the tibial tubercle is the cause of Osgood-Schlatter disease and
they also suggest that once a separate ossicle is formed and becomes
symptomatic, surgical excision is necessary to relieve the symptoms.