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Open Access Highly Accessed Study protocol

Efficacy of strength and aerobic exercise on patient-reported outcomes and structural changes in patients with knee osteoarthritis: study protocol for a randomized controlled trial

Britt Elin Øiestad1*, Nina Østerås2, Richard Frobell3, Margreth Grotle4, Helga Brøgger5 and May Arna Risberg16

Author Affiliations

1 Norwegian Research Center for Active Rehabilitation (NAR), Department of Orthopedics, Oslo University Hospital, Kirkeveien 166, 0407 Oslo, Norway

2 National Resource Center for Rehabilitation in Rheumatology, Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway

3 Department of Orthopaedics, Lund University Hospital, Lund, Sweden

4 Oslo University College, Oslo, Norway

5 Department of Radiology, Oslo University Hospital Ullevaal, Oslo, Norway

6 Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway

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BMC Musculoskeletal Disorders 2013, 14:266  doi:10.1186/1471-2474-14-266

Published: 12 September 2013

Abstract

Background

Despite an extensive literature on treatment interventions for patients with knee osteoarthritis, studies comparing the efficacy of different exercise interventions and living the life as usual on quality of life, cartilage quality and cost-effectiveness are lacking. The aim of the present study is to compare the efficacy of two different exercise programs compared to a control group in individuals with established radiographic and symptomatic knee osteoarthritis on self-reported knee-related quality of life, knee pain, physical function, and cartilage quality.

Methods/Design

A three-armed randomized controlled trial involving two exercise interventions and a control group of individuals doing as they usually do is described. The patients will have mild to moderate radiographic osteoarthritis according to the Kellgren and Lawrence classification (grade 2–3), and fulfill the American College of Rheumatology clinical criteria, be aged between 45 and 65 years, and have no other serious physical or mental illnesses. The patients will be randomly allocated to a strength exercise group; a cycling group, or a control group. The primary outcome is the Knee injury and Osteoarthritis Outcome Score knee-related quality of life subscale. Secondary outcomes include all five Knee Injury and Osteoarthritis Outcome Score subscales, morphological evaluation of cartilage including focal thickness, subchondral bone marrow edema, proteoglycan content and collagen degradation (measured using magnetic resonance imaging clinical sequences, T2 mapping and T1ρ), specific serum biomarkers, isokinetic muscle strength, maximal oxygen uptake, quality of life (EuroQol 5D), and self-efficacy (Arthritis Self-Efficacy Scale). A sample size calculation on the primary outcome showed that 207 individuals, 69 in each group, is needed to detect a clinically relevant difference of 10 points with 80% power and a significance level of 5%. Assessments will be conducted at baseline, 14 weeks, 1 year and 2 years post-randomization. The interventions will be a 14 weeks exercise program.

Discussion

Although exercise therapy has been found to be effective in knee osteoarthritis, the knowledge of the underlying mechanisms for why exercise works is lacking. This study will contribute with knowledge on the efficacy of strength exercise versus cycling on patient-reported outcomes, cartilage quality and cost-effectiveness.

Trial registration

Clinicaltrial.gov Identifier: NCT01682980.

Keywords:
Knee; Osteoarthritis; Exercise therapy; Articular cartilage; Cost-effectiveness