Herrlin 2007.

Study characteristics
Methods	Study design: single centre, parallel‐group, two‐arm, randomised, controlled trial Setting: Capio Artro Clinic, Stockholm Sports Trauma Research Center, Sweden Trial time period: participants were enrolled between June 2003 and April 2005 Interventions: arthroscopic surgery plus supervised exercise versus supervised exercise Sample size calculations: sample size calculations reported that 40 participants per group were needed to detect an average difference of 10 points in the KOOS with 80% power. P = 0.05 was considered to be statistically significant. Analysis: intention‐to‐treat
Participants	Number of participants Number screened: 180 (80 declined participation, 3 ineligible) Number of participants at enrolment: 97 Number randomised: 96 (1 left the study after randomisation as his knee returned to normal function), 47 in the arthroscopy group and 49 in the exercise group Number included in analyses: 92 at 24 months (46 in the arthroscopy group and 46 in the exercise group); 92 at 60 months (45 in the arthroscopy group and 47 in the exercise group) Inclusion criteria Age 45 to 64 years Knee pain without a trauma, daily or almost daily pain experienced during the last 2 to 6 months Knee osteoarthritis grade 0 or 1 on weight‐bearing knee radiographs according to Ahlbacks classification Medial meniscal tear on MRI Understanding of the Swedish language. Exclusion criteria Traumatic meniscal injury Neurological and rheumatic inflammatory diseases Loose bodies, ligament injuries, osteochondral defects and tumours (MRI) Earlier knee surgery, prosthetic replacements of the hip or knee and fractures to the lower extremities less than 1 year old Contraindication to physical training Baseline characteristics Arthroscopy (N = 47) Mean (SD) age (men): 54 (4.6) years Mean (SD) age (women): 54 (5.6) years Number of men and women: M/F = 28/19 Mean (SD) body‐mass index (men): 27 (3.9) Mean (SD) body‐mass index (women): 25 (3.9) Pain medication (no.) men ‐ 5 Pain medication (no.) women ‐ 5 Median (IQR 25‐75) Tegner activity scale: 3 (0‐6) Mean (SD) KOOS 5 subscales (data supplied by authors): pain 55.9 (18.7); symptoms 63.1 (17.4); ADL 66.4 (20.1); sports 26.1 (23.1); QoL 36.3 (18.8) Mean (SD) Lysholm total score: 60.9 (14.6) Mean (SD) VAS, movement: 5.8 (2.6) Mean (SD) VAS, rest: 2.4 (2.4) Exercise (N = 49) Mean (SD) age (men): 55 (5.5) years Mean (SD) age (women): 59 (3.8) years Number of men and women: M/F = 27/16 Mean (SD) body‐mass index (men): 26 (3.3) Mean (SD) body‐mass index (women): 25 (6.5) Pain medication (no.) men ‐ 3 Pain medication (no.) women ‐ 3 Median (IQR 25‐75) Tegner activity scale: 3 (0‐7) Mean (SD) KOOS 5 subscales (data supplied by authors): pain 62.6 (19.1); symptoms 67.0 (17.9); ADL 69.7 (21.2); sports 36.5 (27.3); QoL 37.3 (17.4) Mean (SD) Lysholm total score: 68.2 (15.7) Mean (SD) VAS, movement: 4.6 (2.7) Mean (SD) VAS, rest: 2.4 (2.58) Pre‐treatment group differences: there were no differences in baseline characteristics between the two groups
Interventions	Arthroscopic surgery Arthroscopic partial meniscectomy plus supervised exercise. Arthroscopy was performed on an outpatient basis by two experienced surgeons, majority under local anaesthesia. A 5.5 mm, 30, arthroscope was used with a pressure‐controlled irrigation system. A standard operation protocol was used to document possible findings in cartilage, ligaments, synovium and the medial and lateral meniscus. Meniscal lesions were registered and changes in the articular cartilage were classified according to the Outerbridge classification: grade 0 = intact articular surfaces, grade I = softening of the surfaces, grade II = partial‐thickness defects less than 1.5 cm, grade III = partial‐thickness tears greater than 1.5 cm/fragmentation, grade IV = exposed bone. Twice a week during a period of 8 weeks, each participant followed a standardised exercise programme which consisted of exercises for improving muscle strength and endurance, muscle flexibility, balance and proprioception. The goal of the exercise programme was to reduce pain, restore full ROM and improve knee function. The participants were informed to exert the exercises with some strain but perform them almost pain‐free and without having any negative influence in the affected knee at the following day. If the participant could tolerate the exercises without any problems, he/she performed the exercises with increasing weights and higher resistance. Exercise Supervised exercise programme. Each participant followed a standardised exercise programme with the possibility for individual adaptation twice a week for a period of 8 weeks, as described above.
Outcomes	Outcomes were measured at baseline and at 2, 6, 12, 24 and 60 months' follow‐up (the published papers reported at 2, 6, 24 and 60 months; author supplied 12‐month data upon request). Outcomes Knee injury and Osteoarthritis Outcome Scale (KOOS) comprising 5 subscales ‐ pain, symptoms, ADL, sports/rec, QoL, where scores range from 0 to 100 where 100 indicates good knee function Lysholm Knee Scoring Scale, where scores range from 0 to 100 with higher scores indicating better knee function without symptoms Tegner Activity Scale, which covers activities in daily life and sports. Scores range from 0 to 100 with higher scores indicating better activity/ function Knee pain during rest and during weight bearing measured on 10‐point Visual Analogue Scales (VAS). Scores range from 0 = no pain to 10 = maximal pain Degree of osteoarthritis based on radiographic assessment at 60 months' follow‐up and classified according to Ahlback classification (grade 1: joint space narrowing (less than 3 mm); grade 2: joint space obliteration; grade 3: minor bone attrition (0‐5 mm); grade 4: moderate bone attrition (5‐10 mm); grade 5: severe bone attrition (more than 10 mm)). Radiographs taken in weight‐bearing in antero‐posterior projection, in lateral projection with the knee joint in semi flexion and skyline view of patella with knee flexed at 30 degrees. Progression of knee OA appeared to be defined post hoc of at least one grade progression on the Ahlback classification Outcomes used in this review at 2 and 6 months, 2 and 5 years Pain measured on KOOS Pain subscale (0 to 100; higher score = less pain) (we multiplied the mean values by –1 so that lower scores = less pain, as per Cochrane Handbook guidance) Function measured on KOOS ADL subscale (0 to 100, higher score = better function) Knee‐specific health‐related quality of life measured on KOOS QoL subscale (0 to 100, higher score = better QoL) Progression of knee osteoarthritis Adverse events
Notes	Funding: not reported Trial registration: not done Adverse events: Arthroscopic surgery Serious adverse events: No. (%): 3/47 (6.4%) Three participants had an additional arthroscopy between 13 and 40 months after the initial operation. Re‐arthroscopy showed degenerative articular changes. Other adverse events: 0/47 (0%) Total adverse events: 3/47 (6.4%) 3 participants from the arthroscopy group had an additional arthroscopic procedure between 13 and 40 months following the original surgery. Exercise Serious adverse events: 13/49 (26.5%) 13 participants presented with medial meniscal tears on arthroscopic examination and were treated with partial meniscectomy. Other adverse events: 0/49 (0%) Total adverse events: 13/49 (26.5%) Cross‐overs: 13 participants from the exercise group had an arthroscopy at an average of 6.5 months after the intervention. Knee surgery (replacement or osteotomy): not reported Progression of knee OA: 2/43 participants from the arthroscopy group and 2/45 participants from the exercise group who had radiographic examination at 60 months after the intervention had progression of knee osteoarthritis in the medial compartment. In three cases, progression was from grade 1 to grade 2 and in one case from grade 1 to grade 3 (the authors did not specify which treatment group the latter participant was from) Withdrawals: none Data analysis: KOOS Pain, KOOS ADL and KOOS QoL were extracted at 2, 6, 12 and 24 months based on data supplied by the author upon request; progression of knee osteoarthritis was extracted from published paper.
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 reporting of allocation concealment in this study
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants and study personnel was not done
Blinding of outcome assessor Self‐reported outcomes	High risk	As blinding of participants was not done, there is a risk of bias in the measurement of knee pain and function
Blinding of outcome assessor Assessor‐reported outcome (knee replacement)	Low risk	No blinding of study personnel but the assessor‐reported outcomes, adverse events and progression of knee OA based on radiographic examination, are unlikely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants who completed baseline measurements completed follow‐up assessments at 8 weeks and 6 months. 4 participants were lost to follow‐up at 24 months (1 from arthroscopy group and 3 from exercise group) and 4 participants were lost to follow‐up at 60 months (2 from arthroscopy group and 2 from exercise group)
Selective reporting (reporting bias)	High risk	Trial registration not done. 12‐month outcomes were not reported in the trial publications
Other bias	Low risk	No other bias apparent