Excessive mechanical stress on synovial joints causes osteoarthritis
(OA) and results in the production of prostaglandin E2 (PGE2), a
key molecule in arthritis, by synovial fibroblasts. However, the
relationship between arthritis-related molecules and mechanical
stress is still unclear. The purpose of this study was to examine
the synovial fibroblast response to cyclic mechanical stress using
an Human synovial fibroblasts were cultured on collagen scaffolds
to produce three-dimensional constructs. A cyclic compressive loading
of 40 kPa at 0.5 Hz was applied to the constructs, with or without
the administration of a cyclooxygenase-2 (COX-2) selective inhibitor
or dexamethasone, and then the concentrations of PGE2, interleukin-1β (IL-1β),
tumour necrosis factor-α (TNF-α), IL-6, IL-8 and COX-2 were measured.Objective
Method
Lesion location and volume are critical factors to select patients with osteonecrosis for whom resurfacing arthroplasty is appropriate. However, no reliable surgical planning system which can assess relationship between necrotic lesions and the femoral component has been established. We have developed a 3D-MRI-based planning system for resurfacing arthroplasty. The purpose of the present study was to evaluate its feasibility. The subjects included five patients with osteonecrosis of ARCO stage 3 or 4 who had undergone resurfacing THA at our institute. All patients had an MRI before surgery using 3D-SPGR sequences and fat suppression 3D-SPGR sequencea. In cases where it was difficult to distinguish bone marrow edema and reparative zone on 3D-SPGR images, fat suppression 3D-SPGR sequences were used. Simulation of resurfacing arthroplasty was performed on image analysis software where multidirectional oblique views could be reconstructed. The femoral neck axis was determined by drawing line through centers of two spheres which were fitted to the normal portion of the femoral head and the mid-portion of femoral neck. A femoral component was virtually implanted to align the femoral neck axis and match the implant center and femoral head center.Introduction
Methods
Femoral neck fracture (FNF) is a common trauma in the elderly individuals. When the blood supply to the femoral head is impaired with a fracture event, the reduction or disruption of blood supply to the bone, hypoxia, leads to death of the bone marrow and trabecular bone, and eventual late segmental collapse. In the reparative process, osteoblasts and osteoclasts perform the important function of repairing the fracture site at the femoral neck. However, the reparative reaction including angiogenesis and osteogenesis remains unknown. In order to investigate the reparative reaction in patients with FNF, the distribution of tartrate resistant acid phosphatase (TRAP)-positive cells and expression of HIF-1 alpha, VEGF, and FGF-2 were observed in 36 hips in 35 patients. There were 6 men and 30 women who had a mean age of 79 years (range, 58 to 94 years). There were 10 hips with Garden stage 3, and 26 hips with Garden stage 4. The mean duration from onset to the surgery was 12 days (range: 1 to 82 days). Hematoxylin eosin staining, TRAP staining, immunohistochemistry using anti HIF-1 alpha, anti VEGF, and anti FGF-2 antibodies were performed for retrieved whole femoral heads. As a control, one femoral head in a patient who underwent wide resection for metastatic acetabular tumor was used.Introduction
Methods
We examined solvent-dried, gamma-irradiated (SD-R) allografts and fresh-frozen (FF) allografts mechanically and morphologically. Before transplantation, FF grafts were more than six times stronger than SD-R grafts. After four weeks, the tensile strength was about the same in both groups. At 24 weeks only collagen fibrils of small diameter were observed in the SD-R grafts while in FF grafts fibrils of small and intermediate diameter were seen. Clinically, we suggest that SD-R grafts could be used as a favourable alternative to FF grafts if care was taken regarding their initial mechanical weakness.
