Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases.

The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.

The majority of patients with osteoarthritis present to orthopaedic surgeons seeking relief of pain and associated restoration of function. Although our understanding of the physiology of pain has improved greatly over the last 25 years there remain a number of unexplained pain-related observations in patients with osteoarthritis. The understanding of pain in osteoarthritis, its modulation and treatment is central to orthopaedic clinical practice and in this annotation we explore some of the current concepts applicable. We also introduce the concept of the ‘phantom joint’ as a cause for persistent pain after joint replacement.