Introduction: Although joint aspiration with synovial fluid analysis is useful in the diagnosis of crystal or septic arthritis, the frequency with which it provides a diagnosis or aids subsequent management of patients with arthritis has not been well quantified. We therefore evaluated the usefulness of joint aspiration in the diagnosis and management of patients with arthritis in a hospital-based rheumatology service. Materials and Methods: We reviewed records of all patients with joint aspiration performed by an inpatient rheumatology service in a tertiary referral hospital from November 2003 to December 2004. Data were extracted on the frequency with which joint aspiration provided a diagnosis or aided management. Results: Among 76 patients [mean ± standard deviation (SD), 60.9 ± 15.9 years; 41 males, 35 females, Chinese (50), Malay (20), Indian (4) and others (2)] with 86 joint aspirations, a definitive diagnosis was obtained in 44% of procedures which showed gout (n = 28), septic arthritis (n = 8) or pseudogout (n = 2). In another 47% of procedures, joint aspiration aided diagnosis by allowing categorisation of synovial fluid as inflammatory (n = 25), non-inflammatory (n = 16) or blood-stained (n = 2). Joint(s) aspirated were knees (71%), ankles (15%), elbows (8%), shoulders (2%) and wrists, metacarpo-phalangeal and metatarso-phalageal (approximately 1% each). Conclusion: Joint aspiration provides a definitive diagnosis or information that aids diagnosis in a significant number of patients in a hospital-based rheumatology service.
Joint aspiration with synovial fluid analysis can provide information which complements that which is available from the history and physical examination of the patient, and can help to differentiate various causes of arthritis. It is most useful in monoarthritis, where septic arthritis as a medical emergency needs to be established and treated urgently.1 It is also important in establishing a definitive diagnosis of crystal arthropathy.2 However, the usefulness of joint aspiration has been called into question because of limitations in quality control and poor inter-laboratory reliability of synovial fluid analysis.3 In a 2001 survey of rheumatologists and orthopaedic surgeons in the United Kingdom, synovial fluid cytology was used regularly by only 10% of survey respondents.4 Despite recommendations by textbooks that joint aspiration is an important diagnostic tool, there has been a trend towards performing less arthrocentesis.5-7 The postulated reasons for this decline are the availability of newer diagnostic techniques such as magnetic resonance imaging (MRI), the risks of joint aspiration as an invasive procedure and the lack of quality control for synovial fluid analysis.3
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