Metallosis is a combined chemical and toxic reaction which, if the wear of a metal implant is large, may cause extensive reaction of synovial membrane and thus triggering the loosening.

We present a case of a 72 year-old man, who underwent to a cemented unicompartimental porous metal coated knee implant because affected by rheumatoid arthritis complicated by osteonecrosis of medial femoral condyle of the knee. Four years after replacement, the patient presented symptoms included moderate swelling, pain, synovitis inability to bear full weight as well as grinding; plain radiographs shows well fixed implant and not finding of loosening of prosthesis; arthroscopy revealed the diagnosis of metallosis. The specimens of synovial tissue were prepared to observation to light and electron microscopy. Total synovialectomy and revison with total knee replacement were successful in relieving the symptoms.

Arthroscopy examination revealed a posterior break of tibial component, source of the release of multiple metal beads; we observe alsogray black discoloration of hypertofic and hyperplastic synovium pannus like; metal beads were detected in the joint space soft tissue and were also embedded in the articulating surface of the tibia component. Microscopic examination shows metal debris as black aggregates and a diffuse sheet like proliferation inside histiocytes of villous membrane. Ultrastructural study demonstrate that the presence of metallic fragments, measuring less than 0.3 micron in diameter is predominantly concentrated inside the macrophage’s phagolisosomes.

Delivery of large number of metal beads from implant and the release of smallest size metal debris play a pivotal role in the development of a foreign body granulomatous reaction. The failure of unicompartimental prosthesis has been accellerated by unperformed sinoviectomy during the first implant; the cells of synovial membrane are continuosly activated, by wear of implant material, to phagocitate and to secrete inflammatory response.

The different spatial sideway of geodes in the same femoral head, their number, dimensions, origin, suggested to us the present document. Before now, it has already been analysed cystic hollows in primary arthrosis. Actually on our study, we relate the outcomes regarding the same phenomenon in rheumatoid arthritis.

Materials and methods. We choose femoral head previously scheduled, considering the same pre-operatory radiographic weightiness diagrams. These were undergone to a parallel and vertical planes cut among them. On three millimetres thickness slices, thanks to constant radiographic enlargement by semiautomatic images analyzator, we detected the number, site and dimensions of geodes. The data obtained, formed into a groups for quadrant (limited by two orthogonal planes crossing the centre of rotation), has been treated by statistical analysis (Anova and t-test).

Results and conclusions. According to preliminary results, it would turn out just one difference between the geodes observed in primary arthrosis and in hip arthrosis secondary to rheumatoid arthritis. This difference it consists in the dimension of cystic hollows that are bigger in rheumatoid arthritis according to the phisiopathology and anatomopathologic particularities.

With the plasma–spray technique of applying a hydrox-ylapatite (HA) coating bone ingrowth can be enhanced and early migration of hip prostheses reduced. The significance of coating resorption is controversial. In this study the bone growth and the degradation of the HA coatings were evaluated and compared by SEM.

Premature loosening was identified in four cups with an Ha coating over a porous-coated surface 3 years post-operatively.The Ha coating has a thickness of up to 50 μm. The cup specimens were soaked in 6% sodium hypochlorite to render them anorganic, dehydrated, and sputter-coated with gold-palladium. Secondary electron images of all specimens were obtained by field emission SEM (Zeiss:DSM.962).

Ultrastructural analysis showed that all porous-coated Ha-coated cups had bridges of lamellar bone in direct contact with the implant surface (30% bone in-on growth). Different types of coating degradation were observed. Delamination between the coating and implant surface releases numerous particles or fragments; the resorption by osteoclasts of the amorphous phase was shown to expose the crystalline phase of the coating grains.

This study suggests that resorption disintegrates the Ha coating and reduces the bonding strength between implant and bone and the strength of the coating-implant interface, which might lead to implant loosening,coating delamination and acceleration of third-body wear processes.

Arthoscopic biopsy provides adequate tissue for most diagnostic requirements. Examination of endoarticular tissue can assist in the diagnosis of some joint infections; sometimes cultures of synovial tissue may be positive even when blood and synovial fluid cultures have been negative. In chronic infections such as tuberculosis and fungal disease, and characteristic synovial lesions, such as granuloma, it may be advised. Both gout and pseudo-gout can demonstrate tophus-like deposits in synovial tissue. Synovial biopsy can have a major role in the diagnosis of synthetic arthritis after ACL reconstruction with synthetic ligaments to identify a foreign body granulomatous reaction to particulate material implant or to verify the arthroplasty effect after loosening of a knee prosthesis.

There is a lack of association between arthroscopic findings and clinical laboratory and radiological features of arthritis. The general diagnosis of rheumatoid arthritis (RA) is usually based on characteristic clinical, radiological and serological manifestations. Synovial biopsy in RA is not normally required for diagnosis because the appearance is not specific, but it may provide important prognostic information. Synovial chondromatosis and pigmented villonodular synovitis are tumours of the synovial membrane that require biopsy for diagnosis. The biopsy of articular cartilage is useful to evaluate the capacity of chondrocytes to proliferate and to test the regeneration of cartilage after resurfacing by autologous chondrocytes implantation or other techniques. Histological confirmation could improve the prognosis of the knee during arthrofibrosis (percentage of elastic fibres), fibrosis of Hoffa disease and cyclop lesion. Another application is study of ligamentisation phenomena after anterior cruciate reconstruction and the presence in osteoarthritic knees with degenerative changes in posterior cruciate ligament.