A case of duplication of the patella in the coronal plane is reported. Previously reported cases of double patella have shown sagittal or vertical duplication, and some have been associated with multiple epiphyseal dysplasia. In our case, excision of one patella and realignment of the extensor mechanism relieved symptoms of giving-way.

The effects of gamma irradiation on the growth plate have been studied in nineteen rabbits with a 1,000 rads/skin dose. The rabbits were killed after one to ninety days. The growth plates were studied by microscopic examination, thymidine-H3 autoradiography, and fluorescence with radiographic measurement. Changes were already detected after twenty-four hours at the cell mitosis level, which showed the sensitiveness of the chondrocyte itself. The lesions were clearly seen with the optical microscope after seven days, and they were most advanced between the fourteenth and twenty-first day after irradiation. Regeneration of the cartilage began in the fourth week and the histological appearance became normal after seventy days. Fluorescence with tetracycline showed a temporary retardation of growth, with consequent shortening of the affected limb.