Background and purpose In the QUADX-1 trial, we randomized 140 patients with severe knee osteoarthritis (OA) eligible for a knee arthroplasty to home-based exercise for 12 weeks. Seventy-nine (68%) of the 117 patients, who completed the exercise intervention, postponed surgery. Here, we report how many patients, who completed the 12-week exercise intervention, had received a knee arthroplasty at 2 years and describe their initial exercise response.

Methods From the QUADX-1 trial, we had the following: isometric knee-extensor strength, Oxford Knee Score (OKS), Knee Osteoarthritis Outcome Score (KOOS), average knee pain last week (0-10 numeric rating scale [NRS]), 6-minute walk test, stair climbing test, and self-reported exercise behaviour.

Results At the 2-year follow-up, 50 (43%) of the 117 patients had received a knee arthroplasty (KA group) and 67 (57%) had not (NO-KA group). Compared with the KA group, the NO-KA group had less severe radiographic OA at baseline (KL grade 4: 38% vs 55%) and showed greater— and often clinically relevant—improvements after the 12-week exercise intervention, including knee pain (-2.1 vs -0.1 NRS points), OKS (+6.9 vs +0.5 points), and KOOS ADL (+13.9 vs +1.3 points).

Conclusion Two years after completing the initial 12-week QUADX-1 exercise intervention, more than half the cohort had not received a knee arthroplasty despite initially being considered eligible. Those who had not received a knee arthroplasty at two years had less severe radiographic OA at baseline and generally responded better to 12-week exercise two years earlier, compared to those who had.

Thomas Bandholm reports: Funding for the present manuscript to include The QUADX-1 trial was supported by grants from The Capital Region's strategic funds (R142-A5363), The Capital Region's foundation for cross-continuum research (P-2015-1-01, P-2018-1-02, P-2019-1-03), The Danish Rheumatism Association (R156-A4923), and Copenhagen University Hospital Amager-Hvidovre's strategic funds (2019-800). He also declares that he is an exercise physiologist and physical therapist and may have a cognitive exercise bias. Anders Troelsen reports: Research support, travel/accommodations/meeting expenses unrelated to activities listed from Zimmer Biomet, research support from Pfizer Denmark, consulting fees from Zimmer Biomet and Pfizer Denmark, payment for lectures including on speakers bureau from Zimmer Biomet, advisory board membership with Pfizer Denmark. Kristian Thorborg declares Deputy editorship with Br J Sports Med. Emma Stenholm Koch, Helle Gybel Juhl-Larsen, Birk Mygind Groenfeldt, and Rasmus Skov Husted declare no competing interests.

NCT02931058

https://pmc.ncbi.nlm.nih.gov/articles/PMC5774158/pdf/13063_2017_Article_2366.pdf

The QUADX-1 trial was supported by grants from The Capital Regions strategic funds (R142-A5363), The Capital Regions foundation for cross-continuum research (P-2015-1-01, P-2018-1-02, P-2019-1-03), The Danish Rheumatism Association (R156-A4923), and Copenhagen University Hospital Amager-Hvidovres strategic funds (2019-800). The funding sources had no role in this work.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The QUADX-1 trial was pre-registered (NCT02931058) and approved by the Ethics Committee of the Capital Region, Denmark (H-16025136) as well as the Danish Data Protection Agency (2012-58-0004), including the 2-year follow-up.

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Public deposition of raw data points is not possible due to Denmarks national legislation (Data Protection Act Section 10 and Data Disclosure Proclamation Act) which outline that we can only transfer pseudonymized data to a publishing Journal or preprint server after the Data Protection Authorities approval (Data Protection Act Section 10, subsection 3, nr. 3.). Reviewers and others may obtain access to the data by request, and after the Danish Data Protection Agency has approved of the data transfer from the Capital Region to the Journal or repository entity. If others are to gain access to the pseudonymized data, the Journal or repository entity shall ensure that is an adequate legal basis to share the Capital Regions data and ensure that the data is only being processed for scientific research purposes.