Kinematics of shoulder abduction in the scapular plane. On the influence of abduction velocity and external load.

In this paper the kinematics of arm abduction in the scapular plane of 38 healthy experimental subjects is reported. The ratio of the glenohumoral and the scapulothoracic components of the motion were determined and the influence of the abduction speed and of the external load on it were investigated. The investigation of the effect of abduction speed involved all 38 subjects. Each of them performed one slow and one fast abduction. Statistical analysis showed that there were large differences between individuals, but that for any one individual the abduction process is essentially reproducible. For the one individual there is a strong, linear relationship between glenohumeral and scapulothoracic rotation. The slope of the regression of the glenohumeral component on total arm abduction varied from 0.75 to 0.5 with a sample mean of 0.66. It means that only two-thirds of arm abduction occurs in the glenohumeral joint, the remaining third taking place via scapular rotation. In slowly performed abductions the slope of the regression was significantly greater than in the high-speed movements, but differences were very small. In the investigation of the effect of external load, statistical analysis indicated that the slope of the intraindividual regression is largely independent of the load. The possibility of observer bias was analysed, too. It was found that the standard deviation of the abduction parameters determined by different observers was between 6 and 10% of that between different experimental subjects. RELEVANCE: A knowledge of the kinematics of the shoulder joint is necessary to understand subacromial pathology and in particular impingement problems. The scapulohumeral rhythm depends on the balanced and coordinated function of the muscles involved. The activation pattern of the abductor muscles, as reflected in shoulder kinematics, seems to be individual and stored as an engram.

Correlative histologic and arthroscopic evaluation in rheumatoid knee joints.

The correlation between arthroscopic observations and histologic changes in rheumatoid arthritis is still controversial. Synovial samples of 21 knee joints in rheumatoid arthritis patients were comparatively investigated by endoscopy and histology. Biopsies were scored by an endoscopist and subsequently dissected. Different histochemical and immunocytochemical staining techniques were used to define inflammatory activity. Arthroscopic and histological values were compared by rating scales and variance analysis. Our study indicates that synovial biopsy is of diagnostic value in rheumatoid arthritis. However, its usefulness depends on the histochemical methods used. The results revealed highly significant correlations of endoscopic features with the number of neutrophilic granulocytes, intravascular leukocytes, and peroxidase-positive macrophages. However, no relationship was found between the detection of lymphocytes or resident macrophages and inflammatory scores. The close correlation between endoscopic and histological findings suggests that arthroscopic evaluation allows a valuable classification of the inflammatory activity in rheumatoid synovitis.

[Digital roentgen analysis as a tool for kinematic studies of the shoulder--a study of radiation dosage]. / Die Röntgendigitalanlage als Instrument zur kinematischen Untersuchung der Schulter--Eine Untersuchung zur Strahlenbelastung.

The radiation exposure during biomechanical investigation of the shoulder joint done with a digital radiography system (Polytron 1000 VR - Siemens) was measured experimentally. Total radiation dose and surface dose were determined by phantom measurements. The radiation exposure per image is about 1/6 to 1/7 of that of a conventional study. The digital radiography system used is thus suitable for kinesiologic studies of large joints in healthy volunteers.

Cartilage changes in rats induced by papain and the influence of treatment with N-acetylglucosamine.

Cartilage damage in the knee joints of rats was induced with a single intraarticular injection of 10 mg papain. Such damage was indicated by a decrease in the content of glycosaminoglycans and histologically detectable alterations in the surface of patellar cartilage. Daily treatment of the rats with N-acetylglucosamine by gavage led to an increase of the glycosaminoglycans of the cartilage and of incorporation of the radioactive precursor of glycosaminoglycan synthesis, 3H-glucosamine hydrochloride, in comparison to control animals treated with saline. The incidence of pathological alterations of the cartilage in histological samples was reduced.

Proliferative response of synovial fluid and peripheral blood mononuclear cells to arthritogenic and non-arthritogenic microbial antigens and to the 65-kDa mycobacterial heat-shock protein.

Cellular immune responses to microbial antigens have been implicated in the pathogenesis of some forms of arthritis including reactive arthritis, Reiter's syndrome, ankylosing spondylitis and rheumatoid arthritis. We investigated the proliferative T cell responses of paired peripheral blood (PB) and synovial fluid (SF) mononuclear cells (MC) to so-called arthritogenic bacteria (Yersinia enterocolitica and Salmonella typhimurium), to control antigens, such as Candida albicans, mumps virus and purified protein derivative, to the recombinant mycobacterial 65-kDa heat-shock protein (hsp 65) and the mitogen phytohemagglutinin (PHA) in 16 patients with different inflammatory rheumatic diseases. The [3H]thymidine uptake of unstimulated cells (medium control) as well as the proliferative response to the different antigens tested was markedly increased in SFMC irrespective of the underlying rheumatic disease. In contrast, mitogenic stimulation was decreased in SFMC. The proliferative response to the hsp 65 correlated significantly with the responses to Yersinia, Salmonella and Candida. These results may reflect an enhanced function of SF antigen-presenting cells, different functional properties and subset distributions of PB and SF T cells with a preferential accumulation of helper-inducer/memory T cells or a maintenance of an ongoing immune response by T cells cross-recognizing self epitopes such as epitopes located on the hsp 65. Thus, care should be taken in the interpretation of SF T cell responses to microbial antigens as diagnostic tools in arthritis.