Vermesan 2013.

Study characteristics
Methods	Study design: single centre, parallel‐group, two‐arm, randomised controlled trial Setting: hospital in Italy Trial time period: not reported Interventions: arthroscopic surgery versus a single intra‐articular glucocorticoid injection Sample size calculations: not reported Analysis: not reported
Participants	Number of participants Number of participants screened: 120 Number of participants at enrolment: 120 Number randomised: 120 participants: 60 to the arthroscopic debridement group and 60 to the glucocorticoid injection group Number included in analyses: 120 participants: 60 in the arthroscopic debridement group and 60 in the glucocorticoid injection group (at 1 month); 98 participants: 50 in the arthroscopic debridement group and 48 in the glucocorticoid injection group (at 12 months) Inclusion criteria Non‐traumatic symptomatic knees which had degenerative lesions of the medial compartment (cartilage and meniscus) on MRI Exclusion criteria: not reported Baseline characteristics Arthroscopic surgery Mean (SD) age: 59.2 (7.5) years No. women: 49 Mean (SD) body‐mass index: 32.7 (6.4) Mean (SD) onset of symptoms: 3 (1.5) months Mean (SD) Oxford Knee scores: 29.1 (3.7) Glucocorticoid injection Mean (SD) age: 57.6 (7.8) years No. women: 46 Mean (SD) body‐mass index: 31.9 (6.2) Mean (SD) onset of symptoms: 3 (1.7) months Mean (SD) Oxford Knee scores: 30.3 (3.5) Pre‐treatment group differences: there were no differences in the baseline characteristics between the two groups.
Interventions	Arthroscopic surgery Arthroscopic debridement. No description of this procedure was provided. Intra‐articular glucocorticoid injection A single intra‐articular glucocorticoid injection (1 mL of betamethasone in 4 mL of 1% lidocaine) was administered.
Outcomes	Outcome was measured at 1 month and 1 year of follow‐up. Oxford Knee Scores which range from: 0 to 19 = severe knee arthritis; 20 to 29 = moderate to severe arthritis; 30 to 39 = mild to moderate arthritis; 40 to 48 = satisfactory joint function (Dawson 1998) Outcomes used in this review at 1 month and 1 year Function measured using the Oxford Knee Score (0 to 48, higher score = better function) Knee surgery Knee‐related adverse events
Notes	Funding: no information on the funding source was provided Trial registration: not done Adverse events: only knee‐related adverse events reports (total of 5 participants had knee replacement); unclear if trial measured other adverse events Knee surgery (replacement or osteotomy): a total of 5 participants (4.2%) in both groups had a knee replacement. Per‐group data not given. Progression of knee OA: not reported Withdrawals: 12/60 in the glucocorticoid injection group and 10/60 in the arthroscopic group
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No description of sequence generation process provided
Allocation concealment (selection bias)	Unclear risk	There was no information on allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants and study personnel was not reported. Probably not done
Blinding of outcome assessor Self‐reported outcomes	High risk	As blinding of participants was not reported and probably was not done, there is likely to be a risk of bias in the measurement of knee pain and function using the Oxford Knee Score.
Blinding of outcome assessor Assessor‐reported outcome (knee replacement)	Low risk	No assessor‐reported outcomes were measured in this trial.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	There was no loss to follow‐up for the 1 month follow‐up. 12/60 (20%) participants in the glucocorticoid injection group and 10/60 (16%) participants in the arthroscopic group did not have outcome data at the 12 month follow‐up. The reasons for loss to follow‐up were not reported.
Selective reporting (reporting bias)	High risk	Trial registration not done and protocol not available. The published article had results for one study outcome ‐ the Oxford Knee Scores. Correlation analysis was reported in the methods but this was not reported in the results
Other bias	Low risk	No other bias apparent