The clinical assessment study of the foot (CASF): study protocol for a prospective observational study of foot pain and foot osteoarthritis in the general population

Abstract

BackgroundSymptomatic osteoarthritis (OA) affects approximately 10% of adults aged over 60 years. The foot joint complex is commonly affected by OA, yet there is relatively little research into OA of the foot, compared with other frequently affected sites such as the knee and hand. Existing epidemiological studies of foot OA have focussed predominantly on the first metatarsophalangeal joint at the expense of other joints. This three-year prospective population-based observational cohort study will describe the prevalence of symptomatic radiographic foot OA, relate its occurrence to symptoms, examination findings and life-style-factors, describe the natural history of foot OA, and examine how it presents to, and is diagnosed and managed in primary care.MethodsAll adults aged 50 years and over registered with four general practices in North Staffordshire, UK, will be invited to participate in a postal Health Survey questionnaire. Respondents to the questionnaire who indicate that they have experienced foot pain in the preceding twelve months will be invited to attend a research clinic for a detailed clinical assessment. This assessment will consist of: clinical interview; physical examination; digital photography of both feet and ankles; plain x-rays of both feet, ankles and hands; ultrasound examination of the plantar fascia; anthropometric measurement; and a further self-complete questionnaire. Follow-up will be undertaken in consenting participants by postal questionnaire at 18 months (clinic attenders only) and three years (clinic attenders and survey participants), and also by review of medical records.DiscussionThis three-year prospective epidemiological study will combine survey data, comprehensive clinical, x-ray and ultrasound assessment, and review of primary care records to identify radiographic phenotypes of foot OA in a population of community-dwelling older adults, and describe their impact on symptoms, function and clinical examination findings, and their presentation, diagnosis and management in primary care.

Epidemiology of Shoe Wearing Patterns Over Time in Older Women: Associations With Foot Pain and Hallux Valgus

“…The design was an unmatched population-based case-control study using prevalent cases, derived from baseline data from the Clinical Assessment Study of the Foot (19). Adults aged 50 years and older registered with four general practices were invited to take part in the study, irrespective of consultation for foot pain or problems.…”

Investigations of Potential Phenotypes of Foot Osteoarthritis: Cross‐Sectional Analysis From the Clinical Assessment Study of the Foot

“…All adults ages ≥50 years registered with 4 general practices in North Staffordshire, UK, were mailed a health survey questionnaire, irrespective of any foot‐related health care consultation. Responders to the health survey reporting pain in or around the foot within the last year and who consented to further contact were invited to attend a research clinic 12. A flowchart showing the recruitment of participants to the CASF study has been published previously 7.…”

“…Further details on the data collection methods and outcome measures can be found in the published study protocol 12.…”

“…In addition, metabolic factors (hypertension, type 2 diabetes mellitus, impaired fasting glucose [IFG], dyslipidemia, and lipid‐lowering drugs) and nodal OA, which have been implicated in OA etiology at other joints, were investigated 19, 20, 21, 22. Demographic data (age, sex, occupation), along with the presence of hip pain and knee pain in the last year, wearing of high‐heeled and narrow‐toed footwear between the ages of 20 and 49 years, 12, and intermittent claudication determined from the Edinburgh Claudication Questionnaire 23, were collected in the health survey questionnaire. Self‐reported hallux valgus was determined using a validated line‐drawing instrument consisting of 5 drawings for each foot, with each one illustrating a sequential increase in hallux valgus angle of 15° 24.…”

“…At the research clinics, the presence of finger nodes were determined by observation and palpation, and height and weight were measured to calculate body mass index (BMI). Previous foot and ankle injuries were recorded during a standardized clinical interview 12. Posteroanterior radiographs were also taken of each hand and interphalangeal joints were scored (by MM) for the presence of OA (Kellgren/Lawrence grade ≥2).…”