Reciprocal relationship of synovial fluid volume and Oxygen tension

Abstract

To investigate the impact of synovial fluid volume on oxygen tension (Po,) and other metabolic correlates, 24 specimens of synovial fluid from the knees of 22 patients were analyzed for volume, number of leukocytes (WBC), pH, PO,, Pco,, glucose, protein, and complement (CH50) levels. Concurrent arterial blood samples were obtained in 21 instances. Synovial fluid Po, values varied inversely with volumes of synovial fluid (r = -0.54, P < 0.01), but when patients with rheumatoid arthritis were excluded, the correlation was more significant (r = -0.76, P c 0.001). When synovial fluid Po, dropped below 45 mm Hg, intraarticular acidosis resulted. The decrease in pH (r = 0.93, P < 0.001), the lowering of glucose values (r = 0.89, P < 0.001), and the rise in PCO, (r = -0.79, P < 0.01) can be explained by a shift toward anaerobic metabolism coupled with the impaired elimination of its products. Systemic acidosis and hypoxia were not found. Intraarticular hypoxia most likely represents circulatory imbalance at the level of the synovial membrane, although an inverse relationship of synovial fluid PO, and WBC was also noted. Complement and protein levels had no correlation with volume, pH, or respiratory gas tensions of synovial fluids. Our data support the importance of the effective blood Address reprint requests to George Ho, Jr., MD, Veterans Administration Medical Center, Davis Park, Providence, Rhode Island 02908.Submitted for publication July 8, 1980; accepted in revised form November 25, 1980 flow to the joint in maintaining homeostasis. The volume of synovial effusion and the compliance of the joint c a p sule appear to be important determinants of the articular blood supply.The study of synovial fluid respiratory gases began when easily reproducible measurements of pH, Po,, Pco2, and HCO, by blood gas analyzers became available. Several studies examined the diagnostic specificity of synovial fluid respiratory gases and their metabolic and histologic correlates (1-3). Most have shown that progressive hypoxia was associated with increased glucose consumption leading to lactate accumulation, bicarbonate consumption, acidosis, and hypercapnia. The lowest PO, and pH levels with the highest Pco2 and lactate levels were usually found in synovial fluids from adults with rheumatoid arthritis who had the most advanced histopathologic changes (2). The precise mechanism of intraarticular hypoxia is unknown, but a "circulatory-metabolic" imbalance was proposed and investigated by Goetzl et a1 in 1971 (4). The present study was undertaken to confirm the profound metabolic consequences of intraarticular hypoxia and to examine the influence of synovial fluid volume on respiratory gases in joint effusions of various causes. MATERIALS AND METHODSTwenty-four specimens of synovial fluid from 23 knee joints of 22 patients were obtained during diagnostic or therapeutic arthrocentesis. All patients were supine with the knee in maximal extension. The initial 2-3 ml were aspirated into a heparinized syringe and the remainder was remove...

Fluorapatite-coated implants in experimental arthritis: the response of rabbit trabecular bone

“…A low pH may increase the solubility of the FA coating. Previous obserx/ations indicate that an acidosis can prevail in arthritic joints due to synovial effusion and circulatory imbalance [27][28][29][30]. For that reason it might be expected that the FA coating should be more extensively resorbed in arthritic joints.…”

Comparison of synovial PO2 and sympathetic vasoconstrictor responses in normal and acutely inflamed rabbit knee joints

“…and volume in the diseased human knee joint (Richman et al 1981 (Richman et al 1981). Another possibility is the release of more substance P or calcitonin gene-related peptide (CGRP), which have been shown to be potent vasodilators of joint blood vessels (Lam & Ferrell, 1992), by unmyelinated sensory C fibres of the inflamed joints.…”

“…P8°02 and synovial blood flow showed a highly significant positive correlation, confirming the highly dependent nature of this relationship. In many patients with rheumatoid arthritis, synovial fluid aspirated from affected joints has been found to have low P02 values (Falchuk, Goetzl & Kulka, 1970;Lund-Olesen, 1970; Treuhaft & McCarty, 1971;Harilainen, Ahlqvist, Lalla, Myllynen & Rokkanen, 1989), with anoxia occurring in some cases (Lund-Olesen, 1970;Richman, Su & Ho, 1981). At first sight this appears paradoxical, since these joints were inflamed and would therefore be expected to be hyperaemic, but it has been proposed that a circulatory-metabolic imbalance may exist in diseased joints, in that the increase in blood flow to the joint may not keep pace with its metabolic activity (Falchuk et al 1970;Goetzl, Falchuk, Zeiger, Sullivan, Hebert, Adams & Decker, 1971).…”

Changes in synovial PO2 and blood flow in the rabbit knee joint due to stimulation of the posterior articular nerve.

“…Actual Po2 values varied widely, but in many patients with rheumatoid arthritis it was observed that intra-articular Po2 values were significantly lower than venous Po2 values (Falchuk, Goetzl & Kulka, 1970;Lund-Olesen, 1970; Treuhaft & McCarty, 1971), with anoxia occurring in some cases (Lund-Olesen, 1970;Richman, Su & Ho, 1981) even though the affected joints were inflamed and therefore hyperaemic. To explain this paradox it has been suggested that intra-articular hypoxia occurs due to a circulatory-metabolic imbalance (Falchuk, Goetzl & Kulka, 1970;Goetzl, Falchuk, Zeiger, Sullivan, Hebert, Adams & Decker, 1971).…”