[Quantitative detection of keratan sulfate specific epitopes in synovial fluid in inflammatory and degenerative joint diseases]. / Quantitativer Nachweis Keratansulphat-spezifischer Epitope im Synovialpunktat bei entzündlichen und degenerativen Gelenkerkrankungen.

The release of keratan sulphate (KS) bearing proteoglycan fragments from the extracellular matrix of cartilage into the synovial fluid is believed to be an early event in most joint pathologies. Quantitative analysis of KS in body fluids is therefore regarded as having a certain potential in monitoring articular cartilage catabolism. We describe the application of a non-competitive enzyme linked immunosorbent assay (ELISA) for the quantitation of KS-epitope in synovial fluids, using a monoclonal anti-KS antibody. Synovial fluids from 75 patients were analyzed, comprising the following disease groups: i) rheumatoid arthritis (n = 42), ii) osteoarthritis (n = 20), iii) gouty arthritis (n = 5), and iv) reactive arthritis (Reiter's disease, n = 8). Highest concentrations of synovial KS-epitope were found in reactive arthritis (median = 1410 ng/ml), and in gouty arthritis (median = 2105 ng/ml). However, significantly lower concentrations of KS-epitope (p less than 0.01) were observed in synovial fluids from patients with rheumatoid arthritis (median = 197 ng/ml) and osteoarthritis (median = 337 ng/ml). Although considerable variation of individual values was observed in all groups, a weak and inverse correlation between synovial levels of KS-epitope and inflammatory disease activity was seen only in patients with rheumatoid arthritis. However, KS-epitope levels did not correlate with either the synovial IL-1 activity, nor the number of synovial leucocytes.

[Plasminogen activator activity of the synovial fluid as an indicator of activation phenomena in degenerative joint diseases]. / Die Plasminogenaktivator-Aktivität der Synovialflüssigkeit als Indikator für Aktivierungsphänomene bei degenerativen Gelenkerkrankungen.

Activity of plasminogen activator in synovial fluids of patients with osteoarthritis was determined by a radial diffusion assay. Synovial fluid from human knee joints was obtained by joint lavage with 35 ml physiological saline containing 0.5% hydroxyethyl starch. Synovial fluids from contralateral, healthy knee joints served as controls. The activity of plasminogen activator in synovial fluid from activated (painful) osteoarthritis is significantly higher than in cases of latent osteoarthritis, whereas the activity of controls is significantly lower as in latent osteoarthritis. The findings are helpful for the discovery of patients with enhanced plasminogen activator levels in synovia which should be treated therapeutically.

Leukocyte migration in synovial tissue. Leukocyte distribution, orientation, and migratory pattern after immune complex deposition in rabbit knee joints.

Complement-activating bovine serum albumin (BSA)-anti-BSA immune complexes (ICs) were injected into rabbit knee joint cavities; the contralateral control joint was injected with BSA together with normal rabbit serum. The migration of leukocytes from the synovial venules into the joint cavity was analyzed with light microscopy (LM), scanning (SEM) and transmission (TEM) electron microscopy. EM autoradiography was used to study the endocytosis of ICs by leukocytes. The shape, orientation, and distribution of migrating polymorphonuclear granulocytes (PMNGs) were analyzed by LM morphometry. PMNGs accumulated in the joints injected with ICs. The peak of the number of PMNGs in the synovial tissue was reached after 4 hours, in the joint cavity after 6 hours. PMNGs in the synovial tissue were concentrated in the intimal layer. Migrating PMNGs were polarized, as judged by the ratio between the long (D max) and short (D min) axes of the cells. There was a close association between the migrating PMNGs and the collagen fibers. The morphometric data showed that the nonflattened, cylindrically-shaped PMNGs were oriented along the collagen bundles, running parallel to the synovial surface, and did not migrate in the straight direction of a theoretic leukotactic gradient originating in the joint cavity after IC deposition. SEM and TEM showed that the PMNGs were aligned along the collagen fibers and interacted activity with the collagen by pseudopods and cytoplasmic projections. EM autoradiography showed that the PMNGs in the joint cavity had ingested 125I-labeled ICs and were degranulated. In contrast, the PMNGs within the synovial membrane did not show any signs of IC endocytosis or any apparent degranulation. Synovial type A cells were found to contain ICs. This study indicates that the response of PMNGs in IC-induced synovitis consists of two distinct phases: an initial, mainly migratory phase in the synovial membrane where the PMNGs appear to use the collagen fibres as a climbing framework, and a second phase, in the joint cavity, characterized by PMNG metabolic activation, endocytosis of ICs, and degranulation. The apparent inability of PMNGs in the synovial membrane to ingest ICs and become degranulated might be due to not only concentration differences of ICs and leukotactic factors between the joint cavity and the synovial tissue but also might be related to the apparently active interaction with collagen.

Localization and cytophotometric analysis of cathepsin B activity in unfixed and undecalcified cryostat sections of whole rat knee joints.

Cathepsin B activity is demonstrated histochemically with a post-coupling method using Z-Arg-Arg-4-methoxy-2-naphthylamide as substrate and Fast Blue BB as coupling reagent in unfixed and undecalcified cryostat sections of whole rat knee joints. Sections were attached to transparent tape to keep the integrity of the tissue intact, such attachment being essential for precise precipitation of the final reaction product at sites of enzyme activity. Also essential was inclusion of polyvinyl alcohol in the enzyme incubation medium. High cathepsin B activity was found in osteoclasts, chondrocytes, fibroblasts, synovial cells, and bone marrow cells in knee joints after induction of arthritis. The final reaction product was precipitated as fine cytoplasmic granules probably corresponding to lysosomes. The reaction was specific because addition to the incubation medium of selective inhibitors of cathepsin B-like activity completely blocked the activity. The amount of final reaction product in synovium and in bone marrow cells was analyzed cytophotometrically. Specific formation of final reaction product was linear with incubation time up to 60 min at 37 degrees C and with section thickness up to 12 microns. Variation of the substrate concentration in the incubation medium revealed a KM value of 1.86 +/- 0.36 mM in synovial cells and 2.48 +/- 0.51 mM in bone marrow cells and Vmax values (expressed as mean integrated absorbance) of 1.18 +/- 0.10 in synovial cells and 1.02 +/- 0.11 in bone marrow cells. Both KM and Vmax values were significantly different in synovial cells and bone marrow cells (p less than 0.01) which could be owing to the presence of different isoenzymes in these tissues. We conclude that the described post-coupling method is sufficient to yield precise localization and that the method is valid for quantitative purposes.

Macrophages and dendritic cells during the early stages of antigen-induced arthritis in rats: immunohistochemical analysis of cryostat sections of the whole knee joint.

The appearance of different macrophage subpopulations, Ia-positive antigen-presenting dendritic cells and of T and B lymphocytes was studied in early phases of antigen-induced arthritis in rat knee joints. Cryostat sections of whole knee joints were analysed with immunohistochemical techniques using monoclonal antibodies against rat macrophages, Ia-antigen, and lymphocyte subpopulations. The results showed that in the early phases of the development of arthritis, the synovium was already infiltrated by many monocytes, young macrophages, granulocytes, perivascular Ia-positive non-lymphoid cells, some mature tissue macrophages, and only few T lymphocytes. In later phases not only monocytes, young macrophages and Ia-positive cells became more prominent but also the more mature ED2 positive macrophages and the ED3 positive macrophages that are normally confined to lymphoid organs became increasingly important. The T-cell population increased to some extent in later phases of arthritis induction, possibly induced by clustering with the Ia-positive cells.

Triple crystal disease: monosodium urate monohydrate, calcium pyrophosphate dihydrate, and basic calcium phosphate in a single joint.

A 49 year old man is described with a polyarticular arthritis. Synovial fluid aspirated from the knee joint showed monosodium urate monohydrate and calcium pyrophosphate dihydrate by polarised light microscopy. Additionally, diphosphonate binding and scanning electron microscopy with energy dispersive analysis showed that basic calcium phosphate crystals were also present. This appears to be the first report of three crystals occurring simultaneously in a single joint.

A paramagnetic agent causing ochronotic arthropathy.

Magnetic resonance imaging (MRI) identified a paramagnetic substance in the hyaline cartilage of the hips and knees in a patient with ochronosis. Chemical studies characterized the paramagnetic agent as melanin. The free radicals contained in melanin were shown to initiate cytotoxicity. The loss of cartilage in ochronotic arthropathy now can be explained at the electron level using the superoxide theory of oxygen toxicity. Inappropriate metabolism of oxygen also may explain early cartilage degeneration in hemochromatosis, hemosiderosis, and Wilson's disease.

Ligament length relationships in the moving knee.

This article presents an investigation of potential ligament attachment sites for surgical reconstruction of the anterior and posterior cruciate ligaments as well as for the lateral extraarticular iliotibial band tenodesis. Our methodology was based on quantitative measurements of knee anatomy and motion in fresh cadavers, not on biomechanical modeling. Using computer search techniques, we located all the ligament insertion sites that were nearly isometric for motion of the intact knee.

[Differential diagnostic value of nephelometrically determined protein fractions in the synovial fluid]. / Zur differentialdiagnostischen Wertigkeit von nephelometrisch bestimmten Proteinfraktionen in der Synovialflüssigkeit.

Synovial fluids of patients suffering from rheumatoid arthritis and osteoarthritis with effusions of the knees were examined. Different parameters were evaluated out of the synovial fluid (immunglobulins, Complement-1Q,-3,-4, haptoglobins, alpha-1-anti-trypsin, alpha-2-macroglobulin, transferrin, ceruloplasmin, rheumatoid factors, total count of cells, and ragocytes) and out of the plasma (blood sedimentation rate). The proteins were analysed by a nephelometricturbidimetric automatic centrifugal analyser. All parameters have been tested by valuable statistical methods and correlated to each other. The results worked out proved the reliability of the used test kits and apparative systems. Correlations within groups of parameters according to their formations (intra-and/or extraarticular) could not have been worked out in a way as it may be supposed. In contrast some parameters themselves are statistically different comparing rheumatoid arthritis and osteoarthritis. In general the results are on a higher level in the rheumatoid arthritis group. Using all parameters mentioned above the statistical differential diagnostic level is based on about 94%. If only blood sedimentation rate, total cell count and ragocytes are evaluated the level is based on 68%.

Amyloid deposits in the knee joint at autopsy.

Joint capsule, meniscus, and cartilage from the patella and medial femoral condyle from 30 non-selected autopsies have been investigated for amyloid deposits with light and electron microscopy. Both right and left knee joints from 28 of the 30 autopsy specimens contained amyloid deposits (93%). The amyloid characteristically showed green dichroism in polarised light after staining with alkaline Congo red. The ultrastructural features were also characteristic of amyloid. Amyloid in capsule tissue was found in a subsynovial location, as well as deeper in the capsule tissue, while in the cartilage amyloid was localised along the surface. The meniscus tissue, in particular, contained heavy deposits of amyloid--mainly along the inner margin. Osteoarthritic changes, with fibrillation of the cartilage, were significantly related to amyloid deposition. No pathogenetic correlation between the osteoarthritic changes and amyloid deposition could be shown in the present investigation.

Patterns of radiographic abnormalities associated with basic calcium phosphate and calcium pyrophosphate dihydrate crystal deposition in the knee.

Radiographs and synovial fluids from 66 knees representing 59 patients with symptomatic osteoarthritis were evaluated to determine the pattern of radiographic abnormalities associated with basic calcium phosphate (BCP), calcium pyrophosphate dihydrate (CPPD), or both crystals together. Crystals were found in 71% of fluids. In general, CPPD crystals correlated with patient age, while BCP crystals correlated with joint degeneration. Synovial fluid BCP and CPPD crystals were found together more often than either alone. Joint compartment narrowing and osteophytes in three compartments are often associated with BCP crystals.

[Stabilization of the external condyle of the knee in chronic anterior laxity. Importance of the popliteal muscle]. / Stabilisation du condyle externe du genou dans les laxités antérieures chroniques. Importance du muscle poplité.

The authors have made an anatomical and experimental study in cadavers. They consider that one of the main features of chronic anterior instability of the knee is related to the instability of the lateral femoral condyle. This is due to the loss of its two stabilizers: the anterior cruciate ligament and the popliteal muscle. The signs of a lesion of the postero-lateral structures have to be looked for: antero-posterior drawer sign in extension, hypermobility of the tibia in lateral rotation and varus laxity. Such instability leads to arthrosis in the long-term. The proposed treatment is based on a reconstruction of the anterior cruciate ligament, using semitendinosus associated with a postero-lateral reconstruction using either the biceps or the fascia lata, or a free transplant from the patellar ligament. Corrective osteotomy of an associated varus deformity may be indicated.

Collagen orientations in the meniscus of the knee joint.

X-ray diffraction shows that the collagen fibrils of dog, pig and human meniscus tend to be oriented circumferentially in the bulk tissue and radially in the surface region. Individual fibrils are not all oriented in these directions but are distributed about the preferred orientations with a standard deviation of around 15 degrees in the bulk tissue. Polarised light microscopy yields results which are consistent with X-ray diffraction. This technique also shows that the fibrils are aggregated into crimped fibres, resembling those of tendon, and that some of these fibres pass from the outer region of the meniscus into the bulk tissue. Artificial split lines demonstrate the radial orientation of outer fibres over most of the superior and inferior surfaces of the meniscus. Split lines reorient as they pass into the bulk tissue which is consistent with the interpretation of X-ray diffraction and polarised light microscopy results of this study. The pattern of collagen orientations is also consistent with the meniscus transmitting compressive load in the knee joint.

Lipid composition of the tissues of human knee joints. II. Synovial fluid in trauma.

Synovial fluid was aspirated from the knees of 125 patients and lipid profiles were determined. The patients had knee injuries with or without fracture of bone; these lipid profiles were compared with "controls" (synovial fluid obtained at surgery from patients that did not have a knee injury). Floating lipid droplets were observed in some of the synovial fluid from patients with fractures. These lipid droplets could be separated as a well-defined supernatant layer after a few minutes of centrifugation (100 X g). This layer was found to consist mostly of triglycerides. The synovial fluid from patients with fracture and those with only soft-tissue trauma showed increases in total lipids and triglyceride content but had lower phospholipids when compared with nontraumatized knees. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, sphingomyelin, cholesterol, monoglycerides, diglycerides, triglycerides, and free fatty acids were present in all synovial fluids assayed. The large amount of triglycerides in the synovial fluid in many cases may be a good indicator of marrow leakage. Because the soft tissue surrounding the knee is also rich in triglycerides, a low phospholipid level in some cases may be an even better indicator of marrow leakage.

Chemical changes of human knee joint menisci in various stages of degeneration.

Human knee joint menisci graded according to degenerative alterations were submitted to chemical analysis. Normal menisci contained 72% water, 0.12% DNA, 22% collagen, and 0.8% total glycosaminoglycans with the following glycosaminoglycan distribution pattern: 40% chondroitin 6-sulphate, 10-20% chondroitin 4-sulphate, 20-30% dermatan sulphate, and 15% keratan sulphate. The water content increased with increasing degeneration, whereas the collagen and glycosaminoglycan contents decreased with relative increase of chondroitin 6-sulphate.

[Microdurimetric and biochemical study of human articular cartilage. Comparison of different joints]. / Etude microdurimétrique et biochimique du cartilage articulaire humain. Comparaisons de diverses jointures.

The micro-hardness and the density of fixed negative charges in cartilage of the shoulders, hips and knees of 6 subjects were studied. These two parameters were narrowly correlated. The resistance and proteoglycan concentration of the cartilage of the femoral head were greater than those of the knee and of the shoulder. They did not vary on each side. There is a significant correlation between the hardness of the cartilage of the femoral head and of the external femoral condyle. The histologically normal cartilage of the femoral head in arthrosis is at the lower limit of control values for hardness.

Intra-articular steroids in osteoarthritis.

Intra-articular steroid therapy for osteoarthritis of the knee has been reassessed by two placebo-controlled trials of 20 mg of triamcinalone hexacetonide in 48 joints. Steroid injections caused a significantly greater reduction in pain and tenderness than placebo, and were preferred by patients. However, the benefits were small and transient. Maximum pain reduction occurred one week after injection, and was accompanied by a fall in the thermographic index suggesting an anti-inflammatory mode of action. Synovial fluid was unafffected by injections, and there was no correlation between synovial fluid cell counts or the radiological grading, and the degree of pain reduction.

Radioactivity studies on 2 synovial specimens after radiation synovectomy with yttrium-90 silicate.

Synovial membranes surgically removed from the knees of 2 patients who had received radioactive yttrium-90 silicate have been examined. Autoradiographs showed that in both cases the activity was unevenly distributed over the synovium. One of the specimens, removed 7 weeks after administration of the isotope, was found to contain a slight degree of radioactivity, attributable in part to a long-lived radioactive contaminant.