Bone and soft tissue tumours of the foot: review of 83 cases.

PURPOSE: To review cases of bone and soft tissue tumours of the feet managed at the Hyogo College of Medicine, Nishinomiya and Takarazuka Municipal Hospital, Takarazuka, Japan. METHODS: Retrospective analysis of 83 patient records treated for bone and soft tissue tumours of the feet between 1974 and 2000. RESULTS: There were 33 benign bone tumours, one primary malignant bone tumour, and 2 metastatic bone cancer. Marginal resection was performed in cases of osteochondroma and curettage in cases of other benign bone tumour. Despite below-knee amputation in the case of chondrosarcoma, the patient died because of pulmonary metastasis. Two patients with metastatic cancer also died, and 2 cases of osteochondroma and one of benign chondroblastoma recurred. There were 47 cases of soft tissue tumour. Treatment for benign soft tissue tumours was marginal resection; no cases recurred. In contrast, all patients with soft tissue sarcoma died after surgery. The majority of bone tumours were located in the toe and hindfoot areas, in the first and second decades of life, whereas soft tissue tumours occurred mainly in the midfoot area and in patients aged between 20 and 50 years. The sex distribution was almost even for bone tumours (male: female ratio, 19:17), whereas about half as many males as females had soft tissue tumours (14:33). CONCLUSION: Bone and soft tissue tumours of the feet are uncommon. Most bone tumours are chondrogenic, but differential diagnosis of malignant from benign disease is difficult and prognosis is poor. Management of benign tumours by marginal resection has good prognosis, whereas prognosis of soft tissue sarcomas is very poor.

Interleukin-18 and interleukin-12 synergistically inhibit osteoclastic bone-resorbing activity.

The effect of interleukin (IL)-18 on osteoclastic bone-resorbing activity was investigated in vitro. Osteoclast-enriched cells, about 70% of which were tartrate-resistant acid phosphatase (TRAP)-positive, were cultured on dentine slices, and then the total volume of resorption pits on each dentine slice was measured as bone-resorbing activity. When the effects of IL-18 alone at 1, 10, 100, and 1000 ng/mL were examined, bone-resorbing activity was significantly reduced only at 1000 ng/mL, by about 50%. However, IL-18 plus IL-12 (10 ng/mL each) reduced bone-resorbing activity by about 70%, whereas IL-12 alone had no significant effect. When the concentration of interferon (IFN)-gamma in the medium was measured, IL-18 or IL-12 was found to increase it slightly, and the combination of these two cytokines synergistically increased it. The inhibitory effect of the combination of the two cytokines was completely abolished by the addition of an anti-IFN-gamma neutralizing antibody to the medium, but IFN-gamma by itself did not inhibit osteoclastic bone resorption. IL-18 alone or in combination with IL-12 did not affect the number of TRAP-positive cells in culture of osteoclast-enriched cells. Osteoclasts prepared from osteoclast-enriched cells expressed mRNAs of IL-18 receptor, MyD88, and cathepsin K. Furthermore, IL-18 receptor protein was detected on the cell surface of osteoclasts. The present results indicate that the combination of IL-18 and IL-12 synergistically inhibits osteoclastic bone-resorbing activity, suggesting that IFN-gamma participates in the mechanism underlying this inhibition.

The role of imaging modalities in the diagnosis of primary dedifferentiated parosteal osteosarcoma.

Dedifferentiated parosteal osteosarcoma (dd-POS) is defined as high-grade sarcomatous components coexisting with low-grade POS components. With regard to the histological diagnosis of dd-POS, the sampling of a small area of dedifferentiation through the densely mineralized POS can be a problem. In this situation, imaging is important to identify the area with the highest possibility of dedifferentiation. We report a patient in whom dedifferentiation was shown by computed tomography (CT) and magnetic resonance imaging (MRI). CT revealed a radiolucency in a highly mineralized area. T2-Weighted MRI showed a relatively high signal intensity, corresponding to the radiolucency, surrounded by a very low signal intensity area. Furthermore, gadolinium-enhanced T1-weighted MRI showed marked enhancement. Based on these imaging techniques, the condition was diagnosed as most likely to be a dd-POS, although a representative sample was not accessible by incisional biopsy. Neoadjuvant chemotherapy was administered, followed by wide resection and adjuvant chemotherapy. Four years after the surgery, partial lobulectomy was required because of a pulmonary metastasis. Three years after the second surgery, the patient remained well without evidence of metastases. Based on the initial diagnosis and, consequently, the optimal treatment of combined chemotherapy and wide resection, our patient showed a good clinical outcome.

Cell, matrix changes and alpha-smooth muscle actin expression in repair of the canine meniscus.

Processes in the repair of a crevice in the knee joint meniscus were investigated in 10 dogs. Two 2-mm cylindrical plugs from each medial meniscus were removed, rendered acellular by freezing and thawing, and then reinserted into the meniscus. Dogs were euthanized at intervals of 3-52 weeks after surgery. The crevice between the plug and meniscus at 3 weeks after surgery was filled with a tissue containing alpha-smooth muscle actin-positive cells. One year after surgery, the plug had remodeled and was populated with spindle-shaped and fibrochondrocyte-like cells. The plug had an appearance intermediate between that of hyaline and fibrocartilage at this time, with a seamless integration in sites between the remodeled plug and the surrounding meniscus. alpha-smooth muscle actin-positive cells were concentrated at the interface of the remodeled plug and adjacent meniscus and at the surface of the plug. Therefore, remodeling of both the plug and meniscal tissue and the participation of alpha-smooth muscle actin-positive cells appear essential for integration of the plug into the adjacent meniscal tissue. Cells in the superficial zone of the meniscus seem to be active in the repair process. A change in both the phenotype of the cells and the quality of the matrix toward a more hyaline state appears to be an integral part of the remodeling process in the meniscus.

Ceramic unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee joint.

Unicompartmental replacement with a ceramic knee prosthesis was performed in 10 patients with spontaneous osteonecrosis. The follow-up period averaged 42 months, with a range of 24 to 68 months. All of the knees received a Kyocera unicompartmental knee arthroplasty and all patients were evaluated using The Knee Society Clinical Rating System. The mean knee score increased from 50.6 to 90.8 at the last follow-up, showing no deterioration with time. All of the patients showed marked improvement of pain and excellent or good results were obtained in all cases. None of the patients had progressive radiolucency wider than 2 mm at the final follow-up. Ceramic unicompartmental knee arthroplasty is an acceptable treatment for spontaneous osteonecrosis of the knee joint; a satisfactory postoperative range of motion can be achieved, there are few complications, and a high initial success rate.

Clinical experience of ceramic cementless total knee arthroplasty in RA and a histological study of the bone-ceramic interface in revision cases.

The Kyoto total knee cementless prosthesis (KC-1) was used in 23 patients with rheumatoid arthritis. Its femoral component is made of alumina ceramics which articulated with a HDP plate supported by a ceramic plate. Although the followup period is short, the postoperative result is not satisfactory, because remarkable sinking of the tibial component was noticed in those patients who have bone atrophy. We had 6 cases of revision so far. Since 1986, we have been using bone cement in all cases of RA in doing TKA.

A long-term follow-up study of unicompartmental replacement with a Marmor knee prosthesis and the introduction of a new ceramic prosthesis.

Unicompartmental replacement with a Marmor knee prosthesis was performed in 53 patients with unicompartmental osteoarthritis (OA). A five year or longer follow-up study of 15 joints in 13 of these patients was possible, three of which are now more than 10 years post-operative. All 13 patients reported absence of pain on weight-bearing and were able to flex the replaced knee more than 105 degrees. However, the postoperative femorotibial angle (FTA) appeared to be worsening with time, especially in those cases with an immediate postoperative FTA of more than 180 degrees. Since the needed size of the Marmor prosthesis is no longer available, we began using a ceramic prosthesis recently which we are introducing in this article.