Effects of Glucosamine on Joint Fluid in Osteoarthritis Patients

Overview

Osteoarthritis (OA) is the most common joint disease associated with aging. Although many patients take glucosamine supplements as a non-traditional treatment for osteoarthritis, the effectiveness of these supplements is questionable. This study will evaluate glucosamine therapy by directly analyzing two functions of joint fluid that are impaired by osteoarthritis - namely, the abilities to lubricate the joint and absorb shocks during activity. Joint fluid samples will be collected from subjects with knee osteoarthritis and analyzed on a device that simulates typical joint movements. After 3 months of glucosamine supplementation, samples will be collected again to detect potential improvements in joint fluid function.

Background: The effectiveness of glucosamine sulphate as a treatment for OA is still under debate. Most clinical trials evaluate the effectiveness of OA treatments by self-administered questionnaires about joint pain, stiffness and function (Lequesne Algofunctional Index, Western Ontario and McMaster Universities Osteoarthritis Index - WOMAC). Although OA has been shown to reduce the viscosity and viscoelasticity of synovial fluid, few studies have used these properties as objective outcome measures in the assessment of glucosamine therapy. The purpose of this study is to investigate whether glucosamine sulphate oral supplements improve the viscous and viscoelastic properties of synovial fluid in osteoarthritis patients and to explore potential correlations between these properties and subjective assessments of joint pain and function. Research Method: Patients will be invited to participate in the study if they have been recommended for synovial fluid aspiration to relieve joint discomfort caused by effusion. Subjects will be randomly assigned to receive either 1500mg of glucosamine sulphate or a placebo daily for 3 months. To relieve pain, subjects will be allowed to take up to 4000 mg of acetaminophen per day. If this is insufficient, NSAIDS will be permitted up to a maximum period of 5 consecutive days. Subjects will be asked to keep a log of their analgesics consumption. At the baseline visit, patient demographics will be recorded and subjects will be asked to complete the WOMAC index questionnaire, which includes 24 questions to evaluate joint pain, stiffness and physical function. After noting the degree of joint effusion (minor, moderate, severe), an experienced physician will aspirate synovial fluid from the study knee to relieve joint pressure. A sample will be collected for analysis of viscosity and viscoelasticity. Followup visits will be scheduled after every 4 weeks over the 3-month study period. Each visit will include the completion of a WOMAC questionnaire, clinical assessment of the degree of joint effusion and aspiration of synovial fluid (as necessary) for characterization. Any adverse events (such as headaches, abdominal pain, allergic episodes) will also be reported to the physician. Changes in synovial fluid viscosity and viscoelasticity will be determined after 3 months of glucosamine supplementation and compared to the placebo group. Correlations between synovial fluid properties and WOMAC scores will also be described.