© 2017. This article aims to provide surgeons with a practical, clinical overview of different forms of 'arthritis' - a term encompassing most of the joint pathology causing joint symptoms or dysfunction. Conventionally, arthritis can be non-inflammatory (osteoarthritis) or inflammatory (crystal and autoimmune arthropathies). Septic arthritis is an important differential diagnosis when patients present with tender, swollen joints but is not covered in detail here. Common symptoms and signs in patients with different types of arthritis are reviewed, as well as aetiology and pathogenesis. Non-surgical treatment is described, with particular reference to the inflammatory arthropathies since the new, effective biologic treatments are particularly important where surgery is planned or patients present with suspected sepsis. Diagnosis of inflammatory arthritis (particularly in children) may be delayed and in an era of effective treatment it is important that all clinicians involved in musculoskeletal medicine and surgery are aware of potential differential diagnoses for joint pain and deformity. Good communication between rheumatologists and surgeons in managing different forms of arthritis is especially important.