PHILADELPHIA – The Osteoarthritis Research Society International is recommending a set of user-friendly physical performance measures for patients with established hip and knee osteoarthritis.
The minimal core set of tests includes the 30-second chair stand test, 40-m fast-paced-walk, and stair negotiation.
Two further tests, the timed up-and-go and 6-minute walk, also are highly recommended, depending on the research setting, to measure ambulatory transitions and aerobic capacity.
The tests had to cover multiple physical activities, use minimal equipment, and be user friendly and inexpensive, steering committee member Kim L. Bennell, Ph.D., said at the World Congress on Osteoarthritis.
Dr. Kim Bennell
For example, the 30-second chair stand test requires only a stop watch and a chair to count how many times a patient can rise from a chair with hips and knees fully extended and sit back down in 30 seconds. The tests are best suited for adults older than 40 years but are relevant for patients with mild to end-stage hip and/or knee osteoarthritis (OA) and following joint replacement.
Currently, there are no international recommendations on which performance-based measures of physical function should be used to measure outcomes in patients with hip and/or knee OA. The hope is that the new recommendations will facilitate a more consistent use of performance-based outcome measures across clinical trials and the clinical setting, said Dr. Bennell, a research physiotherapist and director of the multidisciplinary Centre for Health, Exercise and Sports Medicine, University of Melbourne (Australia).
An international advisory committee of 10 rheumatologists, physical therapists, and an orthopedic surgeon identified the main activity themes of walking, stair negotiation, and sit-to-stand from a systematic review of the literature and by consensus opinion. Another 138 clinicians and researchers also were surveyed and asked to rank the difficulty and feasibility of 23 functional tests for OA patients.
"We wanted to identify the most feasible tests considering practical issues such as time, cost, equipment, space, and administration burden," she said at the meeting, which was sponsored by OARSI.
In the end, none of the tests satisfied all desirable clinimetric criteria of reliability, measurement error, validity, responsiveness, and interpretability. The experts felt stair negotiation was an important measure of mobility, lower-body strength, and balance but balked at recommending a specific test because of insufficient clinimetric evidence and the simple, practical fact that not all facilities have enough stairs to conduct a 9- or 12-step test.
"What we really found in our discussions and our work is that there really wasn’t a lot of good clinimetric evidence across the board on these tests," Dr. Bennell said.
To boost the evidence base, OARSI has put out a call on its website to collect future prospective data and to pool existing data so researchers can calculate minimal clinically important difference (MCID) estimates for different OA subgroups, longitudinal responsiveness estimates for interventions, and normative data for various OA subgroups.
Further details on the tests, including an instructional manual, clinimetric measurement properties, and normative values, are available on the OARSI website. Videos will also be available shortly.
The project was sponsored by OARSI, the Australian National Health and Medical Research Council, Arthritis Australia, and the University of Otago. Dr. Bennell reported having no financial disclosures.