PAS inclusions, immunoreactive tenascin and proliferative activity in low-grade chondrosarcomas.

To distinguish between chondrosarcoma (grade 1--borderline histology) and enchondroma, we examined six chondrosarcomas (grade 1--borderline histology) which looked like benign lesions. Their diagnosis, albeit based on clinical, radiologic and pathologic examinations, was not easily reached. Moreover, we examined six enchondromas and 11 chondrosarcomas, the diagnoses of which were straightforward. All cartilaginous tumors were studied, placing emphasis on PAS-positive intracytoplasmic globules. Anti-Ki67 proliferation-associated nuclear antigen antibody and tenascin antibody were applied. The following features were observed in low-grade chondrosarcomas: (1) masses of hyalin and/or myxoid cartilage invading spaces around the tumor, (2) host lamellar bone trabeculae surrounded by cartilage on all sides, (3) tumoral resorption of bone trabeculae. Intracytopasmic hyalin globules (ICG) were more frequently found in malignant than in benign neoplasm (p = 0.042). Moreover, tenascin matrix immunoreactivity was more likely to be observed in benign than in malignant neoplasm (p = 0.029). Ki67 immunoreactivity was more frequent in characterized than in low-grade chondrosarcomas or in enchondromas, where it was null (p = 0.0044).

Experimental study of the sacroiliac joint micromotion in pelvic disruption.

OBJECTIVE: To measure the sacroiliac (SI) joint micromotion when different ligamentous lesions are created to simulate various degrees of pelvic anteroposterior compression injury. DESIGN: Cadaveric study. MATERIALS AND METHOD: Six SI joints were studied using a special device that made it possible to vary up to 310 N the loads applied on the ischial tuberosity and to measure simultaneously the SI micromotion. RESULTS: SI micromotion increases when the sacrospinous and sacrotuberous ligaments, and even more when the interosseous ligaments, have been sectioned off. In these cases, the stability of the SI joint is not restored by an isolated pubic fixation. CONCLUSION: This microinstability of the SI joint could contribute to the pain and arthritic changes sometimes observed in patients after anteroposterior compression injury. These experimental results could justify a larger spectrum of indications of SI joint fixation, but this should be confirmed by clinical study.