From: Acute flares of knee osteoarthritis in primary care: a feasibility and pilot case-crossover study
Inclusion criteria | Mode of ascertainment |
 Male or female aged ≥ 40 years | GPSS |
 Registered as a permanent resident with participating general practices | GPSS |
 Recorded consultation for knee OA or knee OA-related joint symptoms in the last 2 years†| GPSS |
 Access to an email account and to the Internet | PCRF |
Exclusion criteria | |
 Known diagnosis of inflammatory arthropathy, spondyloarthropathy, or crystal arthropathy (e.g. rheumatoid arthritis, ankylosing spondylitis, reactive arthritis, systemic lupus erythematosus, gout, psoriatic arthritis)†| GPSS |
 Recorded diagnosis of fibromyalgia†| GPSS |
 Red flags: recent significant trauma to knees; acutely hot swollen joint | GPSS, PCRF |
 Previous total knee arthroplasty or on waiting list for total knee arthroplasty | GPSS, PCRF |
 Corticosteroid injection into the knee in the last 3 months | PCRF |
 Surgery to either knee within the past 3 months | GPSS, PCRF |
 Unable to complete questionnaires written in English via the study website | PCRF |
 Vulnerable individuals (e.g. psychiatric illness, learning difficulties, dementia, terminal illness, and severe enduring mental ill health) | GPSS |