COmmunity-based Rehabilitation after Knee Arthroplasty (CORKA): study protocol for a randomised controlled trial

Background: The number of knee arthroplasties performed each year is steadily increasing. Although the outcome is generally favourable, up to 15 % fail to achieve a satisfactory clinical outcome which may indicate that the existing model of rehabilitation after surgery may not be the most efficacious. Given the increasing number of knee arthroplasties, the relative limited physiotherapy resources available and the increasing age and frailty of patients receiving arthroplasty surgery, it is important that we concentrate our rehabilitation resources on those patients who most need help to achieve a good outcome. This pragmatic randomised controlled trial will investigate the clinical and cost-effectiveness of a community-based multidisciplinary rehabilitation intervention in comparison to usual care. Methods/design: The trial is designed as a prospective, single-blind, two-arm randomised controlled trial (RCT). A bespoke algorithm to predict which patients are at risk of poor outcome will be developed to screen patients for inclusion into a RCT using existing datasets. Six hundred and twenty patients undergoing knee arthroplasty, and assessed as being at risk of poor outcome using this algorithm, will be recruited and randomly allocated to one of two rehabilitation strategies: usual care or an individually tailored community-based rehabilitation package. The primary outcome is the Late Life Function and Disability Instrument measured at 1 year after surgery. Secondary outcomes include the Oxford Knee Score, the Knee injury and Osteoarthritis Outcome Score quality of life subscale, the Physical Activity Scale for the Elderly, the EQ-5D-5L and physical function measured by three performance-based tests: figure of eight, sit to stand and single-leg stand. A nested qualitative study will explore patient experience and perceptions and a health economic analysis will assess whether a home-based multidisciplinary individually tailored rehabilitation package represents good value for money when compared to usual care. Discussion: There is lack of consensus about what constitutes the optimum package of rehabilitation after knee arthroplasty surgery. There is also a need to tailor rehabilitation to the needs of those predicted to do least well by focussing on interventions that target the elderly and frailer population receiving arthroplasty surgery.