NCT00562822.

Methods	Study design: prospective single‐blind, single‐centre, parallel, two‐arm randomised controlled trial Setting: London Health Sciences Centre ‐ University Hospital, London, Ontario, Canada Trial time period: January 1999 to August 2007 Interventions: arthroscopic surgery plus optimised physical and medical therapy versus optimised physical and medical therapy Sample size calculations: estimated enrolment of 188 participants, no sample size calculations reported Analysis: not reported
Participants	Inclusion Criteria Idiopathic or secondary osteoarthritis of the knee with Grade 2 to 4 radiographic severity as defined by the modified Kellgren‐Lawrence classification Exclusion Criteria Participants with inflammatory or post‐infectious arthritis Those who had undergone previous arthroscopic treatment for knee osteoarthritis Those with isolate Grade III to IV medical compartment osteoarthritis with greater than 5 degrees of varus deformity
Interventions	Arthroscopic surgery plus optimised physical and medical therapy: arthroscopic surgery to treat unresolved symptoms of osteoarthritis of the knee Optimised physical and medical therapy: treatment with physical and medical therapy alone
Outcomes	Primary outcome measures: Function, pain and quality of life based on the WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) scores (time frame: 2 years) Secondary outcome measures: Health utility using the standard‐gamble technique (time frame: 24 months)
Notes	Clinical trial registration:NCT00562822 Trial status: recruitment completed Estimated study completion date: recruitment completed in August 2007; however, results not available yet