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World J Orthop. Nov 18, 2014; 5(5): 566-573
Published online Nov 18, 2014. doi: 10.5312/wjo.v5.i5.566
Utility of arthroscopic guided synovial biopsy in understanding synovial tissue pathology in health and disease states
Mihir D Wechalekar, Malcolm D Smith
Mihir D Wechalekar, Malcolm D Smith, Rheumatology Research Unit, Repatriation General Hospital, Daw Park SA 5041, Australia
Author contributions: Both authors contributed equally to this work.
Supported by National Health and Medical Research Council Medical and Dental Postgraduate Research Scholarship to Dr. Wechalekar, MD, No. APP1018009
Correspondence to: Malcolm D Smith, BSc (Hons), MBBS, FRACP, PhD, Professor of Medicine, Director of Rheumatology, Southern Adelaide Local Health Network, Rheumatology Research Unit, Repatriation General Hospital, Daws Road, Daw Park SA 5041, South Australia,Australia. malcolm.smith@health.sa.gov.au
Telephone: +61-8-82751819 Fax: +61-8-83744276
Received: February 23, 2014
Revised: April 30, 2014
Accepted: July 12, 2014
Published online: November 18, 2014
Abstract

The synovium is the soft tissue lining diarthrodial joints, tendon sheaths and bursae and is composed of intimal and subintimal layers. The intimal layer is composed of type A cells (macrophages) and type B cells (fibroblasts); in health, the subintima has few inflammatory cells. The synovium performs several homeostatic functions and is the primary target in several inflammatory arthritides. Inflammatory states are characterised by thickening of the synovial lining, macrophage recruitment and fibroblast proliferation, and an influx of inflammatory cells including lymphocytes, monocytes and plasma cells. Of the various methods employed to perform synovial biopsies arthroscopic techniques are considered the “gold standard”, and have an established safety record. Synovial biopsy has been of critical importance in understanding disease pathogenesis and has provided insight into mechanisms of action of targeted therapies by way of direct evidence about events in the synovial tissue in various arthritides. It has been very useful as a research tool for proof of concept studies to assess efficacy and mechanisms of new therapies, provide tissue for in vitro studies, proteomics and microarrays and allow evaluation for biomarkers that may help predict response to therapy and identify new targets for drug development. It also has diagnostic value in the evaluation of neoplastic or granulomatous disease or infection when synovial fluid analysis is non-contributory.

Keywords: Synovium, Synovial biopsy, Arthroscopy, Inflammatory arthritis, Synovial pathology

Core tip: The synovium is the soft tissue lining diarthodial joints, tendon sheaths and bursae. Arthroscopic synovial biopsy techniques have an established safety record. Synovial biopsy has been of critical importance in understanding disease pathogenesis and mechanisms of action of targeted therapies; it has been invaluable as a research tool in proof of concept studies to assess mechanisms and efficacy of new therapies. It also has diagnostic value when synovial fluid analysis is non-contributory.