Early diagnosis of osteoarthrosis of the temporomandibular joint: correlation between arthroscopic diagnosis and keratan sulfate levels in the synovial fluid

A re-evaluation of the importance of disc position in temporomandibular disorders

During the 1970s there was a resurgence of interest in disc displacement as being central to the pathology of internal derangement. Since then it has been proposed that a displaced disc can result in pain, mandibular dysfunction, degenerative joint disease and mandibular growth disturbances. Two decades later, and with the introduction of sophisticated investigations and treatment modalities, doubts have emerged as to true pathological significance of disc position. Evidence derived from clinical observations, autopsy material, imaging studies and surgical findings has failed to establish strong support for the central role of disc displacement in internal derangement of the temporomandibular joint.

Pathogenesis of degenerative joint disease in the human temporomandibular joint

The wide range of disease prevalences reported in epidemiological studies of temporomandibular degenerative joint disease reflects the fact that diagnoses are frequently guided by the presence or absence of non-specific signs and symptoms. Treatment is aimed at alleviating the disease symptoms rather than being guided by an understanding of the underlying disease processes. Much of our current understanding of disease processes in the temporomandibular joint is based on the study of other articular joints. Although it is likely that the molecular basis of pathogenesis is similar to that of other joints, additional study of the temporomandibular joint is required due to its unique structure and function. This review summarizes the unique structural and molecular features of the temporomandibular joint and the epidemiology of degenerative temporomandibular joint disease. As is discussed in this review, recent research has provided a better understanding of the molecular basis of degenerative joint disease processes, including insights into: the regulation of cytokine expression and activation, arachidonic acid metabolism, neural contributions to inflammation, mechanisms of extracellular matrix degradation, modulation of cell adhesion in inflammatory states, and the roles of free radicals and heat shock proteins in degenerative joint disease. Finally, the multiple cellular and molecular mechanisms involved in disease initiation and progression, along with factors that may modify the adaptive capacity of the joint, are presented as the basis for the rational design of new and more effective therapy.

Differential levels of synovial fluid aggrecan aggregate components in experimental osteoarthritis and joint disuse

The levels of proteoglycan aggregate components (link protein, keratan sulfate epitope, and total sulfated glycosaminoglycan) were determined in the synovial fluid lavages of dogs with experimental osteoarthritis or disuse atrophy. A model of experimental osteoarthritis was created by transection of the anterior cruciate ligament of the right knee; studies were carried out 6 and 12 weeks after surgery. Joint disuse was studied at 4 and 8 weeks after initiation of the disuse. Recovery after disuse also was studied in joints that had 3 weeks of remobilization after 4 or 8 weeks of disuse. Synovial fluid lavages from the right knee joints of untreated animals were used as controls. The concentrations of keratan sulfate epitope, sulfated glycosaminoglycan, and link protein in the synovial fluid lavages at 6 and 12 weeks after transection of the anterior cruciate were elevated compared with the control values. Similar analysis of the fluid after disuse showed that the levels of keratan sulfate epitope and sulfated glycosaminoglycan were increased compared with the control levels and the levels after transection. However, the concentration of link protein in the fluid after disuse was not significantly different from the control level. The levels of keratan sulfate epitope and sulfated glycosaminoglycan in the synovial fluid lavages after disuse with recovery were high, but the levels of link protein remained low. The results indicate that the catabolism of proteoglycan aggregates in articular cartilage during early osteoarthritis and disuse is different. The determination of keratan sulfate epitope in synovial fluid lavages appears to provide a relatively general indication of proteoglycan catabolism, whereas increased levels of link protein may be more indicative of cartilage degeneration.

Diagnostic accuracy of the ultrathin arthroscope for temporomandibular joint osteoarthrosis: comparison of arthroscopic and histologic findings in a sheep model

The diagnostic accuracy of the ultrathin arthroscope was evaluated by examination of the superior joint space of the left temporomandibular joint in 20 sheep. At the time of induction of osteoarthrosis all joints were found to be normal. Six months later the arthroscopic examination was repeated and the results compared with the histologic examination. Similar findings were seen in 11 joints (55%), with arthroscopic overdiagnosis in two (10%) and underdiagnosis in seven (35%). Eight of 16 (50%) disc perforations were found. It was concluded that underdiagnosis occurred because the whole joint space cannot be examined arthroscopically and fibrillated tissue masks bone exposure.

Current concepts in the surgical management of temporomandibular joint disorders

A thorough understanding of the structure and function of diarthrodial joints is necessary for clinicians who treat individuals with temporomandibular disorders. Surgical procedures must be based on principles designed to restore and preserve joint physiology. The surgical management of patients with temporomandibular joint disorders not only requires adherence to surgical principles that make sense from a physiologic basis, but also an understanding of the disease process and continued nonsurgical management that is aimed at reducing or eliminating factors which perpetuate joint overloading.

Diagnosis of intracapsular pathology associated with temporomandibular joint disorders

The clinical diagnosis of a Temporomandibular Disorder (TMD) has traditionally been based on data gathered by means of a medical history and physical examination. The most common signs and symptoms associated with TMD are reduced jaw opening, pain and elevated tenderness in the muscles of mastication, pain and elevated temporomandibular joint (TMJ) tenderness, and TMJ noises upon movement. These signs and symptoms are routinely detectable by a skilled clinician upon examination. Unfortunately, the clinical problem described globally as a TMD has several different and overlapping patho-physiologic disease processes, and a traditional clinical examination does not provide highly tissue-specific pathologic information. Were it readily available, such information would be greatly useful, since logical and accurate treatment planning requires that each disease process be correctly identified. One important challenge for researchers interested in TMD will be the careful definition and subsequent validation of diagnostic methods which identify the relevant ongoing pathological disease process. On such research area, which has great promise, is the establishment of a valid diagnostic technique for intracapsular pathologies unique to TMD patients. This paper provides a critical review and discussion of the diagnostic validity of TMJ arthroscopy and other related methods of identifying intracapsular pathologies associated with TMD.

The quantitation of a native chondroitin sulfate epitope in synovial fluid lavages and articular cartilage from canine experimental osteoarthritis and disuse atrophy

OBJECTIVE

Previous studies have shown the presence of a native chondroitin sulfate epitope in articular cartilage proteoglycans from canine knee joints with experimental early osteoarthritis (OA), but not in normal cartilage. The objective of this study was to quantitate the native epitope recognized by monoclonal antibody 3-B-3 in synovial fluids and articular cartilage of diseased joints.

METHODS

An immunoassay with monoclonal antibody 3-B-3, which recognizes a native chondroitin-6-sulfate structure, was developed and used to analyze synovial fluid lavage material and extracts of articular cartilage from canine knee joints with early experimental OA or with mild disuse atrophy, and from control animals.

RESULTS

The concentration of epitope in the OA fluids was elevated 33-35-fold, and in the OA articular cartilage extracts it was elevated > 200-fold, compared with samples from the control group. No significant difference was detected in the levels of 3-B-3 epitope in the synovial fluid lavage material or cartilage extracts from the joints of the disuse group versus the control group.

CONCLUSION

The native 3-B-3 epitope in articular cartilage and synovial fluids may be a specific marker of ongoing anabolic events in early degenerative joint disease.

Synovial fluid analyses detect and differentiate proteoglycan metabolism in canine experimental models of osteoarthritis and disuse atrophy

Canine experimental models of osteoarthritis (OA) and disuse atrophy were used to study cartilage metabolism. The synovial fluids from the OA joints showed elevated levels of keratan sulfate (KS) epitope and link protein, indicating increased catabolism. Analysis of fluids from joints with disuse atrophy showed high levels of KS epitope, but no increase in link protein. Quantitation of a novel chondroitin sulfate (3B3) epitope showed it to be present only in the synovial fluids and articular cartilage of the OA joints. The results indicate that these may be important indicators, or markers, of degenerative joint disease.

Antigenic properties of keratan sulfate: influence of antigen structure, monoclonal antibodies, and antibody valency

The influence of (a) antigen structure, (b) type of monoclonal antibody, and (c) antibody bivalency on the immunochemical detection and quantification of keratan sulfate (KS) from aggrecan has been studied. Apparent KS epitope levels were determined by immunoglobulin G (IgG)-enzyme-linked immunosorbent assay (ELISA) in preparations of human aggrecan and in a defined series of lower molecular weight proteoglycan preparations generated by proteolytic and alkali treatment of aggrecan. Gel filtration chromatography showed KS epitope to be preferentially detected in the higher molecular weight fragments of the preparations. In single KS chains the epitope was detected in the chains of higher M(r). The ability of the proteoglycan to inhibit in the IgG-ELISA decreased with a reduction in proteoglycan fragment size, ranging between 6- and 260-fold, depending on the antibody used. This was considered to be a cooperative binding effect. With most antibodies, the sensitivity of the IgG-ELISA (represented by the steepness of the inhibition slope) was also reduced with smaller inhibitor sizes. The lowest limit of detectability (the amount of KS required to generate 20% inhibition) varied by up to 60-fold depending on the antibody used. The use of monovalent Fab fragments instead of the whole IgG anti-KS antibody in the ELISA showed that the bivalency of the antibody also affected the quantitation of the assay. In the Fab-ELISA the assay was found to have an increased detectability (by 9.5-fold with aggrecan as the inhibitor), and the proteoglycan fragments and aggrecan all generated parallel inhibition curves. Although the Fab-ELISA was somewhat influenced by the structural presentation of the KS, this was not apparent for small fragments and single chains. Thus the effects of cooperative binding and antibody valency could be overcome and quantitative data could be obtained for all samples, using papain-digested samples and the Fab-ELISA. Application of this assay to analysis of body fluids showed the KS-containing fragments in synovial fluid, serum, and urine were of different sizes and could be quantified.