Moseley 2002.

Study characteristics
Methods	Study design: single centre, three‐arm, randomised, placebo‐controlled trial Setting: Houston Veterans Affairs Medical Center, Houston, Texas, USA Trial time period: participants were enrolled from October 1995 through September 1998 Interventions: arthroscopic debridement versus arthroscopic lavage versus placebo surgery Sample size calculations: a total sample of 180 participants (60 participants in each arm) would provide 90% statistical power and a two‐sided type I error of 0.04 to detect a moderate effect size (0.55) between the placebo group and the combined arthroscopic‐treatment groups Analysis: no information on intention‐to‐treat analysis or analysis on data from those who did not complete the 24‐month follow‐up
Participants	Number of participants Number of consecutive participants who were eligible: 324 Number of participants who declined to participate: 144 Number of participants at enrolment: 180 Number randomised: 180: 59 in the arthroscopic debridement group, 61 in the lavage group and 60 in the placebo group Number completing trial: 165: 53 in the arthroscopic debridement group, 56 in the lavage group and 55 in the placebo group Number included in analysis of primary outcome (KSPS at 24 months): 163: 53 in the debridement group, 55 in the lavage group and 55 in the placebo group Criteria for defining knee osteoarthritis: the definition was according to the American College of Rheumatology. The severity of osteoarthritis in the study knee (that with the greatest pain‐induced limitation of function) was assessed radiographically and graded on a scale of zero to four. The scores for the three compartments were added together to generate a severity grade of 0 to 12. Inclusion criteria 75 years of age or younger Had knee OA as defined by the American College of Rheumatology Reported moderate knee pain on average (> 4 on a visual‐analogue scale ranging from 0 to 10) despite maximal medical treatment for at least six months Not undergone arthroscopy of the knee during the previous two years Exclusion criteria Severity of osteoarthritis at grade 9 or higher Severe deformity Serious medical problems Baseline characteristics Arthroscopic debridement Mean (SD) age: 53.6 (12.2) years Proportion (%) of men and women: M/F = 96.6/3.4 Severity of osteoarthritis in knee (%): mild (30.5), moderate (45.8), severe (23.7) Analgesic use (%): non‐prescription (64.4), prescription (15.3) Mean score on Knee Society Clinical Rating Scale: knee symptoms (51.4), function (57.6) Mean (SD) AIMS score: pain 59.3 (22.2) Mean (SD) Psychological attributes: anxiety 28.4 (22.4), depression 22.0 (35.3), expectations for benefit 3.6 (1.1), optimism 73.7 (17.1), satisfaction with general health 46.5 (24.8), social functioning 67.6 (25.2), somatisation 10.0 (10.7), stress 27.9 (18.8), vitality 57.7 (19.3) Arthroscopic Lavage Mean (SD) age: 51.2 (10.5) years Proportion (%) of men and women: M/F = 88.5/11.5 Severity of osteoarthritis in knee (%): mild (27.9), moderate (45.9), severe (26.2) Analgesic use (%): non‐prescription (67.2), prescription (21.3) Mean score on Knee Society Clinical Rating Scale: knee symptoms (50.2), function (62.4) Mean (SD) AIMS score: pain 59.3 (16.7) Mean (SD) Psychological attributes: anxiety 30.2 (19.9), depression 28.1 (37.2), expectations for benefit 3.5 (0.9), optimism 74.5 (19.4), satisfaction with general health 43.7 (22.4), social functioning 60.3 (23.9), somatisation 9.6 (12.4), stress 26.1 (18.2), vitality 52.7 (19.7) Placebo Surgery Mean (SD) age: 52 (11.1) years Proportion (%) of men and women: M/F = 93.3/6.7 Severity of osteoarthritis in knee (%): mild (28.3), moderate (46.7), severe (25.0) Analgesic use (%): non‐prescription (70.0), prescription (21.7) Mean score on Knee Society Clinical Rating Scale: knee symptoms (49.4), function (62.2) Mean (SD) AIMS score: Pain 59.5 (18.5) Mean (SD) Psychological attributes: anxiety 27.0 (21.0), depression 20.0 (32.0), expectations for benefit 3.5 (1.0), optimism 72.6 (21.0), satisfaction with general health 39.3 (25.1), social functioning 65.5 (25.6), somatisation 11.3 (12.7), stress 28.4 (19.7), vitality 54.8 (21.0) Pre‐treatment group differences: although baseline characteristics appeared to be similar across all three groups, the lavage group showed higher scores for depression compared to the other two groups and the use of prescription analgesics was lower in the debridement group.
Interventions	One orthopedic surgeon (board‐certified, fellowship‐trained in arthroscopy and sports medicine, in practice for 10 years in academic medical centre) performed all the operations. Post‐operative care was delivered according to a protocol specifying that all participants should receive the same walking aids, graduated exercise program and analgesics. The protocol was not provided in the publication or supplementary appendix. Arthroscopic debridement After diagnostic arthroscopy, the joint was lavaged with at least 10 litres of fluid, rough articular cartilage was shaved (chrondroplasty was performed), loose debris was removed, all torn or degenerated meniscal fragments were trimmed, and the remaining meniscus was smoothed to a firm and stable rim. No abrasion arthroplasty or microfracture was performed. Typically, bone spurs were not removed, but any spurs from the tibial spine area that blocked full extension were shaved smooth. Participants received standard general anaesthesia with endotracheal intubation. Arthroscopic lavage After diagnostic arthroscopy, the joint was lavaged with at least 10 litres of fluid. Anything that could be flushed out through arthroscopic cannulas was removed. Normally, no instruments were used to mechanically debride or remove tissue. However, if a mechanically important, unstable tear in the meniscus (e.g. a displaced “bucket‐handle” tear) was encountered, the torn portion was removed and the remaining meniscus was smoothed to a firm, stable rim. No other debridement was performed. Participants received standard general anaesthesia with endotracheal intubation. Placebo surgery Simulated debridement with three 1‐cm skin incisions but without insertion of the arthroscope. The surgeon asked for all instruments and manipulated the knee as if arthroscopy were being performed. Saline was splashed to simulate the sounds of lavage. No instrument entered the portals for arthroscopy. The participant was kept in the operating room for the amount of time required for a debridement. Participants received a short‐acting intravenous tranquilliser and an opioid and spontaneously breathed oxygen‐enriched air. Participants spent the night after the procedure in the hospital and were cared for by nurses who were unaware of the treatment‐group assignment.
Outcomes	Outcomes were measured at baseline and at 2 and 6 weeks, and at 3, 6, 12, 18 and 24 months after the procedure. Primary outcome Pain in the study knee assessed by a 12‐item self‐reported Knee‐Specific Pain Scale (KSPS) at 24 months' follow‐up. Scores range from 0 to 100 with higher scores indicating more severe pain. Secondary outcomes (measured at all time points) A 4‐item pain subscale of the Arthritis Impact Measurement Scales (AIMS2‐P) with higher scores indicating more severe pain. Scores were transformed into scores on a scale from 0 to 100. A 2‐item pain subscale of the Medical Outcomes Study 36‐item Short‐Form General Health Survey (SF‐36‐P), where higher scores indicate less severe pain. Scores were transformed into scores on a scale from 0 to 100. A 5‐item walking–bending subscale from the AIMS2 (AIMS2‐WB), transformed into scores on a scale from 0 to 100, with higher scores indicating more limited physical function. A 10‐item physical‐function subscale from the SF‐36 (SF‐36‐PF), transformed into scores on a scale from 0 to 100, with higher scores indicating better function. The Physical Functioning Scale (PFS) which records the amount of time in seconds required to walk 30 metres and to climb up and down a flight of stairs as quickly as possible. Longer time (in seconds) indicates poorer functioning. Outcomes included in this review at 3 and 6 months and 2 years Pain ‐ SF‐36 pain subscale (0 to 100, lower score = less pain) Function ‐ SF‐36 physical function subscale (0 to 100, higher score = better function) NB. Adverse events could not be included as the details of the group to which the adverse events belonged were not reported. Quality of life outcome data could not be included as SF‐36 Mental Component Summary (MCS) scores were not reported.
Notes	Funding: supported by a grant from the Department of Veterans Affairs Trial registration: not reported Serious adverse events: none reported Other adverse events Incisional erythema ‐ 1 participant Calf swelling in the leg that had undergone surgery; venography was negative for thrombosis ‐ 1 participant Details of the group to which these participants belonged were not reported. Knee surgery (replacement or osteotomy): not reported Progression of knee OA: not reported Withdrawals: 6/59 in the arthroscopic debridement group, 5/61 in the lavage group and 5/60 in the placebo group Data analysis: we included arthroscopic debridement versus placebo in Analysis 1.1 and Analysis 1.2 and we excluded the lavage treatment arm from this review. We included the SF‐36‐P and SF‐36‐PF scores for pain and function, respectively, but other measures for these outcome domains were available.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomly assigned using a stratified randomisation process in blocks of six based on the severity of osteoarthritis (grade 1, 2 or 3; grade 4, 5 or 6; and grade 7 or 8) using sealed, sequentially‐numbered, stratum‐specific envelopes. Probably low risk
Allocation concealment (selection bias)	Low risk	Sealed, sequentially‐numbered, stratum‐specific envelopes containing treatment assignments were prepared by research staff and handed to the surgeon in the operating suite.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding of participants was done ("the treatment assignment was not revealed to the patient"). Study personnel who were unaware of the treatment‐group assignments performed all post‐operative outcome assessments; the operating surgeon did not participate in outcome assessment. To assess whether participants remained unaware of their treatment‐group assignment, they were asked at each follow‐up visit to guess which procedure they had undergone. Participants in the placebo group were no more likely than participants in the other two groups to guess that they had undergone a placebo procedure. For example, at 2 weeks, 13.8% of participants in the placebo group guessed that they had undergone a placebo procedure, and 13.2% of participants in the lavage and debridement groups guessed that they had undergone a placebo procedure.
Blinding of outcome assessor Self‐reported outcomes	Low risk	Blinding of participants was done and there is low risk of bias in the measurement of pain and function.
Blinding of outcome assessor Assessor‐reported outcome (knee replacement)	Low risk	Knee replacement not measured.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	6/59 (10%) in the debridement group, 5/61 (8%) in the lavage group and 5/60 (8%) in the placebo group did not complete the study. No data were given on the reasons for loss to follow‐up or withdrawals.
Selective reporting (reporting bias)	Low risk	Trial registration not done and protocol not available. The published article included results on all study outcomes as described in methods
Other bias	Low risk	No other bias apparent