Michael R. Mickelson

We evaluated 121 patients who had had slipped capital femoral epiphysis (149 involved hips) twenty-one to forty-seven years after the diagnosis was made. The results were very good in most of the eighty-three hips with the slip left unreduced. Fifty-four hips that were treated by procedures designed to improve the alignment of the slipped femoral head had more complications and less favorable results, but in general, these were the more severe slips. However, there were enough slips of comparable severity that were treated unreduced to suggest that the long-term results, even in moderate and severe slips, were better after in situ fixation than after operative and manipulative treatment (as performed between 1915 and 1952). Twelve of the thirteen hips with acute slips were reduced (the thirteenth was one of the eighty-three unreduced hips) and aseptic necrosis developed in three, while nine had good results.

This clinical, radiographic, and histologic study clarifies the evolution of the distinct clinical and radiographic disorder known as adolescent tibia vara (Blount's disease). Although previous reports have suggested that the disorder occurs in a limb that has been normally aligned until adolescence, we have found that most children with adolescent tibia vara maintain a mild degree of infantile physiologic genu varum. Then, concurrent with the adolescent growth spurt, certain children with predisposing factors, such as obesity, extreme activity, or rapid growth, injure the posteromedial physis as a result of repetitive trauma due to normal use of a limb already in mild varus. The result is growth suppression, further varus, and a classic radiographic presentation. Histologic examination in two cases suggests injury to the growth plate as demonstrated by fissuring and clefts in the physis as well as fibrovascular and cartilaginous repair tissue at the physeal-metaphyseal junction. Transverse trabeculae, resembling growth arrest lines, were noted in the adjacent metaphysis; however, true bony bridging of the growth plate was not seen. Recommended treatment is corrective osteotomy below the growth plate.

The technique of fine-needle aspiration biopsy seems to be ideally suited for the diagnosis of lytic bone lesions at practically any location in the skeleton. The technique is simple, carries minimum risks, and can often be performed on an outpatient basis. Advances in cytological techniques have made it possible to reach an accurate diagnosis for most patients within twenty-four hours. The accuracy rate in the present study of seventy patients was 87.5 per cent, but the lesions studied included few primary bone tumors. One limitation of the technique is the difficulty in sampling a lesion that is covered by compact bone.

UNLABELLED: Core biopsies of the proximal femoral growth plate from three patients with slipped capital femoral epiphysis were compared with three normal growth plates from patients of similar ages. The growth plates of patients with slipped capital femoral epiphysis had a normal resting zone, a loose and fibrillated proliferative zone, and a very disarranged and thickened hypertrophic zone. The proliferative zone stained strongly with alcian blue, suggesting the presence of abundant proteoglycans in the cartilage matrix. The thickened hypertrophic zone was strongly positive to periodic acid-Schiff stain, indicating the presence of abundant structural glycoproteins. Enchondral ossification was scanty and irregular, and there were large clusters of cartilage in the metaphysis. Slippage occurred through the thickened proliferative and hypertrophic zones. CLINICAL RELEVANCE: The proximal femoral growth plate in slipped capital femoral epiphysis is histochemically abnormal and histologically disarranged. These features contribute to abnormal widening of the growth plate and to further slippage.

Seven cases of synovial sarcoma were studied by electron microscopy. The 4 cases of the monophasic spindle type contained elongated cells arranged in sheets and cords; ultrastructurally the cells contained many cytoplasmic processes and were scattered in an amorphous matrix. The monophasic spindle type demonstrates ultrastructural characteristics that are unique and serve to differentiate it from the biphasic pattern and from fibrosarcoma. Three cases of the biphasic variety demonstrated cytologic characteristics of a true glandular epithelium and a malignant spindle cell stroma. The epithelial nature of the biphasic variety is a feature that raises doubt whether synovium is the stem cell.