Properties of tissue from around cemented joint implants with erosive and/or linear osteolysis.

Levels of bone remodeling agents were measured in conditioned media from cultures of periprosthetic pseudosynovial membranes and related to the radiographic features of the failed joint implants. Radiographs of both cemented hip (n = 28) and cemented knee (n = 11) implants were examined and the pattern of radiolucency was classified as erosive linear, or mixed. Similar levels of interleukin-1-beta (IL-1 beta), interleukin-6, tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta-1, and prostaglandin E2 (PGE2) were found in pseudosynovial membrane conditioned media from all 3 groups of hips and the knee group (all linear).

Osteolytic properties of the synovial-like tissue from aseptically failed joint prostheses.

Relationships were found between the bone-resorbing ability of conditioned media (CMs) from culture of peri-prosthetic tissues and their levels of bone-remodelling agents. Bone-resorbing activity was measured by 45Ca release from pre-labelled mouse calvaria and 23 of 40 CMs exhibited bone-resorbing activity. Cytokine and prostanoid levels in the CMs were measured by immunoassay, and the levels of interleukin (IL)-1 beta, IL-6, tumour necrosis factor alpha (TNF alpha) and prostaglandin E2 (PGE2) correlated with each other, except for the latter two.

Analysis of cell types and mediator production from tissues around loosening joint implants.

Quantitative immunophenotypic analysis of cell types present in peri-prosthetic tissue [pseudosynovial membrane (PSM)] from aseptically loose joint implants revealed considerable heterogeneity between tissues from different individuals. The monocyte/macrophage was the commonest leucocyte type; however, its proportion varied widely. T cells normally accounted for approximately 5% of cells, but in a few cases formed > 20% of cells.

Chondro-osseous metaplasia, bone density and patellar cartilage proteoglycan content in the osteoarthritis of STR/ORT mice.

The evolution of osteoarthritis (OA) was compared in male and female STR/ORT mice and in male CBA mice with particular emphasis on the changes in para-articular structures which occur before the classical degenerative phenomena in the articular cartilage of the knee. In male STR but not female STR mice or male CBA mice, chondro-osseous metaplasia was found in the tendinous structures which surround the joint and in the major ligamentous entheses such as the patellar ligament. This change was detectable from the age of three months.

Radiological scoring of osteoarthritis progression in STR/ORT mice.

The progressive changes observed in the knee and ankle joints of male STR/ORT mice, which spontaneously develop osteoarthritis (OA), were quantified by a radiological scoring system. The knee scores for males increased with age whereas those for females plateaued from 5 months. Comparison of scores for the knee and ankle joints showed that the male knee scores increased directly with age but were not significantly different from female scores until 7 months whereas the male ankle scores increased dramatically at 5-6 months and plateaued thereafter.