Osteoarthrosis as the cause of craniomandibular pain and dysfunction: a unifying concept

It has been demonstrated that osteoarthrotic changes in the temporomandibular joint (TMJ) and in other synovial joints show a similar course, both clinically and (ultra)microscopically. Initially, cartilage changes and possibly also changes in the synovial membrane set up a vicious cycle of cartilage breakdown accompanied by attempts at repair. When the degradative process exceeds the response of repair, the osteoarthrotic disorder progresses into clinically detectable stages. Frequently, the gliding capacity of the articular disc is also impaired, giving rise to an internal derangement. In this article, a concept is presented in which it is suggested that in many cases of craniomandibular pain and dysfunction TMJ osteoarthrosis is the basic disorder.

Rheumatoid factors and physiology of synovial joints

Analysis of rheumatoid factor (RF) effects according to physiological principles suggests that RF activity may decrease joint swelling by (i) decreasing synovial fluid (SF) colloid osmotic pressure, by increasing plasma viscosity and thereby decreasing (ii) fluid escape from the plasma and (iii) convective flux of proteins into joints, and by decreasing (iv) diffusion of proteins from capillaries (et cetera?). RF complexes raising whole blood viscosity might (v) decrease blood flow. A more significant cause of SF hypoxia and lactic acidosis may be tamponade of synovial circulation created by swelling-induced high SF hydrostatic pressures. Increase of non-RF IgG or monomeric IgM and possibly agammaglobulinaemia could contribute to swelling more strongly than RF's.

Superoxide generation by synovial fluid neutrophils enhanced by immune complexes and suppressed by rheumatoid factor in synovial fluid

Synovial fluid (SF) from patients with rheumatoid arthritis (RA) enhanced superoxide generation by neutrophils isolated from RA SF, in contrast to SF from patients with osteoarthritis. These superoxide generation-enhancing substances may be intermediate-sized immune complexes and a complement C5-derived fragment. Rheumatoid factor (RF) isolated from RA SF suppressed superoxide generation-enhancing activity of aggregated IgG. Therefore, biologically active RF may block the interaction of the immune complexes with neutrophils accumulating in RA SF, and protect the joint tissue from the effects of oxygen radicals or proteases.

Studies of eicosanoid production in the air pouch model of synovial inflammation

The time course of the inflammatory reaction in the rat air pouch model of synovial inflammation has been investigated at different stages of development of the lining structure using immune (pertussis vaccine) and non-immune (carrageenan) irritants. Exudate volumes and leucocyte numbers were greater with carrageenan than with pertussis vaccine but with both irritants much greater reactions were obtained when the irritant was injected at a time when the air pouch architecture most closely resembled synovium (i.e. 6 days). The time course of fluid accumulation following carrageenan in 6 day pouches was not interrupted when exudate was aspirated from the pouch six days after carrageenan injection. In the 6 day old air pouch PGE2 and 6-oxo-PGF1 alpha concentration peaked at 6 hours and 24 hours respectively. With carrageenan and pertussis vaccine stimulation, LTB4 concentrations were maximal at 3-6 hours with both irritants and low concentrations were still present at 13 days. The presence of a lining structure was found to influence concentrations of PGE2 in the air pouch. Pre-treatment with colchicine or 5-fluorouracil to reduce cell accumulation was not found to effect the modified PGE2 response. Our findings suggest that the presence of a synovial like lining structure may induce changes in composition in respect to cellular content and in putative mediator concentrations. We conclude that it is important in elucidating the mechanisms involved in arthritic inflammation to study injury in a cavity lined by macrophages and fibroblasts.

Significance of the hydrogen ion concentration in synovial fluid in rheumatoid arthritis

The hydrogen ion (H+) concentration and pCO2 were measured in the synovial fluid (SF) from the knee joints of 130 patients with arthritis by an acid-base analyser (ABL2 Acid-Base Laboratory), using a simple technique which prevented contact with air. H+ concentration was significantly higher in SF from 60 RA patients (mean 64.4 n mol/l; range 38-142 n mol/l) compared with patients with OA (mean 44 n mol/l; range 29-56 n mol/l), and 40 with other arthritides (mean 52 n mol/l). The H+ concentration in the SF showed a significant association with other variables of local inflammation-platelet, total leucocyte and polymorph counts, 5-nucleotidase, acid phosphatase and IgA levels in the SF and the clinical knee score, but not with the volume of the effusion. A similar relationship between these variables of inflammatory activity and SF pCO2 was also established. A higher SF H+ concentration was also found in systemically active disease, but no difference in SF pH between seropositive and seronegative patients. Whilst the pH of SF approximated to that of the blood in OA, it was significantly lower in the SF in RA. SF pH is a useful marker of local inflammatory activity, and its measurement is simple, reliable and rapid. It is relevant because changes in pH influence many of the processes involved in inflammation and the pH difference between SF and blood influences the transfer of drugs into the joint.

Transudative knee effusions in Milroy's disease

Two patients, mother and son, with Milroy's disease (chronic hereditary lymphedema) presented with chronic asymptomatic knee effusions. Synovial fluids proved to be transudative in nature. The pathogenesis of knee effusions in Milroy's disease is discussed.

Experimental joint trauma: synovial response to blunt trauma and inflammatory reaction to intraarticular injection of fat

Blunt trauma to knee joints of dogs produces clear usually non-bloody synovial effusions with prominent fat globules. Increased vascular permeability of synovial membrane in areas not directly traumatized can be shown by leakage of intravenously-injected carbon black. To see whether fat released from synovium into the joint might contribute to a low grade inflammation and altered vascular permeability we also injected intraarticular autologous fat and demonstrated its phagocytosis by exudate cells and induction of definite inflammation. These effects of trauma in dogs which closely resemble some human injuries might be a model for evaluating conservative treatment of joint trauma.

Septic arthritis due to Kingella (Moraxella) kingii: case report and review of the literature

Kingella (Moraxella) kingii, a gram-negative bacillus, was isolated as the cause of septic knee arthritis in an adult. Three previous cases (1 adult and 2 children) of septic arthritis due to Moraxella species have been reported. All cases have been characterized by difficulty in identifying the organism, indolent clinical course and slow response to antibiotic treatment.

Synovial fluid total hemolytic complement activity in rheumatic diseases - a reappraisal

The varied and contradictory claims made of the clinical value of measuring total hemolytic complement activity in rheumatic diseases prompted a reappraisal of its role, and a review of the literature, taking into account the anomalies of assay and the semi-quantitative nature of the procedure. We found that measurements of synovial fluid (SF) total hemolytic complement activity were of limited value in determining the diagnosis or prognosis of joint diseases. Also there was no significant relationship between SF total hemolytic complement activity and either clinical activity or other laboratory findings. We believe that measurements of SF complement activity will prove of little use as a guide to the effectiveness of drug therapy.

Descriptions of therapeutic arthrocenthesis and of synovial fluid in a Nahuatl text from prehispanic Mexico

Paracelsus is considered to have been the first to record the viscid quality of the synovial fluid. However, his contemporary Bernardino de Sahagún, a Franciscan friar who came to Mexico shortly after the Spanish conquest, obtained from elderly Aztec Indians who spoke only Nahuatl the descriptions of therapeutic arthrocentesis and of the viscid nature of the synovial fluid. They compared the fluid from the knee joint to the viscid fluid from the leaves of the nopal cactus (Opuntia sp.). We here record their description and confirm the accuracy of their comparison.

Clinical and arthrographic studies on the valve mechanism in communicating popliteal cysts

Forty-one knee joints presenting with significant popliteal cysts were examined clinically and arthrographically. The fluid was aspirated from the cysts and replaced by contrast medium of low viscosity. On knee flexion the contrast fluid spontaneously passed over into the joint in 16 cases (no valve mechanism), in 7 small amounts of fluid were forced into the joint when the cysts were manually compressed, and in 18 no fluid passage to the joint was observed on manipulation (valve mechanism). When a valvular action was established, effusion in the joint was rare and the fluid from the cyst was usually viscous. The cysts with a valvular connection were significantly larger than those without a valve mechanism.

The clinical significance of the valve mechanism in communicating popliteal cysts

In a previous investigation of 41 patients presenting with distended popliteal cysts, a valvular mechanism was demonstrated in 25 cases by means of a specific arthrographic procedure. In the present study the clinical symptoms and signs from the popliteal space and from the joint were assessed and related to the presence or absence of a valvular mechanism. By arthroscopy or arthrotomy seventeen associated knee disorders were diagnosed, e.g., synovitis, osteoarthritis, and tears of a semilunar cartilage. Intraarticular symptoms and intrinsic joint diseases were significantly correlated to the absence of a valve mechanism. The presence of a valve mechanism was indicative of the absence of pathological findings in the joint.

[Biorheologic study of pathological synovial fluids]

Rheometric studies of 34 synovial fluids done using a rheometer with a cone and stage (Shirley-Ferranti type) showed that arthrotic synovial fluids had pseudoplastic characteristics (non-Newtonian) but in inflammatory rheumatisms, the characteristics index rises, the consistency decreases and the fluid tends to loose its pseudoplastic properties and to become Newtonian. Radioisotope synoviorthosis seems capable of restoring to a certain extent and in certain cases the rheometric characteristics of the pseudoplastic properties.