2. Characteristics of interventions used in included trials.

Study ID	Description of arthroscopic surgery	Description of post‐surgical exercise (in arthroscopic surgery arm)	Description of control	Co‐interventions
Trials with a placebo control
Moseley 1996	Arthroscopic debridement: diagnostic arthroscopy, joint lavage, shaving of rough articular cartilage, removal of loose debris, trimming of torn/degenerated menisci	Participants were instructed to resume walking and other activities of daily living as soon as their symptoms would allow. No other exercises were given.	Skin incisions without insertion of arthroscope, knee manipulation, saline splashing over the joint. Surgeon asked for all instruments. Simulation of standard arthroscopic debridement as close as possible. Time spent in the operation theatre: 1 hour	Oral analgesia (acetaminophen with codeine), crutches until able to walk comfortably without a limp. NSAIDs taken pre‐operatively could be resumed after the first follow‐up at 10 days. Applied equally in all treatment groups: yes
Moseley 2002	Arthroscopic debridement: diagnostic arthroscopy, joint lavage, shaving of rough articular cartilage, removal of loose debris, trimming of torn or degenerated meniscal fragments, and smoothening of the remaining meniscus to a firm and stable rim. Shaving of spurs from the tibial spine area that blocked full extension.	Participants were given a graduated exercise program after surgery; details of the program were not reported.	Simulated debridement with three 1 cm skin incisions but without insertion of the arthroscope. Knee manipulation, surgeon asked for all instruments, saline splashing. Time spent in the operation theatre: same as debridement group.	Walking aids, graduated exercise program and analgesics. Applied equally in all treatment groups: yes
Roos 2018	Partial meniscectomy with preservation of as much meniscus as possible. Documentation of findings in cartilage, ligaments, synovium and the medial and lateral menisci. Registration of the type and extent of meniscus lesion and ICRS classification of articular cartilage changes.	Post‐operative home‐based exercise program. At 1 week, biking, swimming and fast walking, and at 2 to 3 weeks, more intense biking and jogging were recommended. For the first post‐operative week, 7 different non‐weight‐bearing exercises to improve lower extremity function and knee range of motion were suggested, and an additional 3 weight‐bearing thereafter. All exercises were recommended to be performed 10 to 15 times three times daily.	Skin incisions in same location as in arthroscopic surgery without insertion of arthroscope, knee manipulation, spillage of water, use of all equipment needed for arthroscopic surgery. Surgeon asked for all instruments. Simulation of arthroscopic surgery as close as possible.	Weight‐bearing and non‐weight‐bearing exercises. Applied equally in all treatment groups: yes
Sihvonen 2013	Arthroscopic partial meniscectomy ‐ removal of damaged menisci with arthroscopic instruments (mechanised shaver and meniscal punches) until solid meniscus tissue was reached. Resection of loose, unstable meniscal fragments while preserving as much of the meniscus tissue as possible.	Post‐operative graduated home exercise program for both legs for 10 to 15 minutes at a time, 5 days a week.	The surgeon asked for all instruments, knee manipulation, simulation of a standard arthroscopic partial meniscectomy procedure by using a mechanised shaver (without the blade) outside the knee, suction was also used to drain the joint and saline was splashed. Time spent in the operation theatre: same as the surgery group.	Walking aids, graduated home exercise program, over‐the‐counter analgesics. Applied equally in all treatment groups: yes
Trials with an exercise control
Gauffin 2014	Arthroscopic surgery: inspection of joint, meniscal resection performed if needed (but not performed if not needed)	Post‐operatively all participants were allowed immediate, full weight‐bearing activity. They were advised to resume the exercise programme according to phase 1 for 1 week, and then switch to phase 2.	Unsupervised exercise program lasted 3 months, performed twice a week and comprised two phases. Phase 1 was performed for the first 3 weeks and included 20 to 30 min brisk walk, 10 x 2 sets of the following: squats, pelvic lifts, pelvic lifts with ball between knees, heel raise, wall squats and standing on a pillow on one leg; Phase 2: 20 to 30 min brisk walk, 10 x 3 sets of all exercises done in phase 1. Frequency, intensity and duration: phase 1 ‐ daily, 2 sets; phase 2 ‐ twice per week 3 sets each for 3 months. Supervised: no Setting: home	None specified
Herrlin 2007	Arthroscopic partial meniscectomy: arthroscopic joint inspection, registration of meniscal lesions and Outerbridge classification of changes in the articular cartilage.	Twice a week during a period of 8 weeks each participant followed a standardised exercise program similar to the exercise group. This was followed by a written unsupervised home program twice a week.	A. Supervised exercise.Description: all exercises for 3 x 10 sets. 0 to 8 weeks: stationary bicycling 7 to 15 min, knee extensions concentrically with two legs and eccentrically with one leg, stair walking and balance on wobble boards (3 min), jogging, jumps, landing on a rebounder (5 min), stretching of knee extensors and flexors (1 min/muscle group). 0 to 4 weeks: calf raise on leg press, knee flexions concentrically with two legs and eccentrically with one leg. 1 to 4 weeks: leg press. 5 to 8 weeks: calf raises standing on one leg, lunges with < 80 of knee flexion with or without weight in the hands, knee flexions with one leg, knee extensions with one leg. Frequency, intensity and duration: twice a week for 8 weeks Supervised: yes. Setting: research centre. B. Unsupervised exercise.Description: 3 x 10 sets of one‐leg standing during 1 min and a step down exercise. Frequency, intensity and duration: twice a week for 8 weeks. Supervised: no. Setting: home	None specified
Katz 2013	Arthroscopic partial meniscectomy: trimming of damaged meniscus to a stable rim, removal of loose fragments of cartilage and bone without any penetration of the subchondral bone	Post‐operative standardised physical therapy program, as described in the exercise group.	Supervised exercise.Description:phase I: acute phase (1 to 10 days post‐op) Retrograde Massage, Cryotherapy E‐Stim: NMES or IFC, Joint Mobilisation Soft Tissue Mobilisation Stretching LE Muscles, Quad Sets SAQ/LAQ/HS Curls Hip‐4 way, Bicycle, Elliptical, Treadmill, Leg Press, Balance/Proprioception. Phase II: Subacute Phase (10 days to 4 weeks post‐op) Retrograde Massage Cryotherapy E‐Stim: NMES or IFC, Joint Mobilisation Soft Tissue Mobilisation Stretching LE Muscles, Concentric/Eccentric Hip/Knee progressive resistive exercises, ROM, Resisted terminal knee extension, modified mini squats, step up/down progressions, toe raises, functional and agility training. Phase III: Advanced Activity Phase (4 to 7 weeks post‐op) ‐ continued stretching program, continued PRE therapeutic exercises program, closed chain program with progression to dynamic single leg stance, plyometrics, running, and sport specificity training. Frequency, intensity and duration: 8 exercises, 12 to 15 repetitions, 1 to 2 sets. Supervised: yes for once or twice weekly in the initial sessions in each phase, after which exercises were done at home Setting: clinic for 1/2 sessions then home for the rest of the phase.	Acetaminophen, non‐steroidal anti‐inflammatory agents and intra‐articular injections of glucocorticoids as required. Applied equally in all treatment groups: yes
Kirkley 2008	Arthroscopic surgery: saline irrigation of medial, lateral, and patellofemoral joint compartments, based on joint findings one of the following was done ‐ synovectomy; debridement; or excision of degenerative tears of the menisci, fragments of articular cartilage, or chondral flaps and osteophytes that prevented full extension.	Optimized physical and medical therapy for 12 weeks followed by home exercises and arthritis education similar to the exercise group were given post‐operatively.	A. Physical therapy.Description: not provided. Frequency intensity and duration: 1 hour once a week for 12 consecutive weeks. Supervised: yes Setting: clinic. B. Home exercise along with physical therapy.Description: range‐of‐motion and strengthening exercises. Frequency intensity and duration: twice daily and once on the day of a scheduled physical‐therapy session for 12 weeks along with the physical therapy. Supervised: no Setting: home. C. Unsupervised home exercise.Description: not provided. Frequency intensity and duration: duration of the study. Supervised: no. Setting: home	Step‐wise use of acetaminophen and non‐steroidal anti‐inflammatory drugs, intra‐articular injection of hyaluronic acid and oral glucosamine. Arthritis education ‐ attendance at local Arthritis Society workshops, The Arthritis Helpbook and an educational videotape. Applied equally in all treatment groups: yes
Kise 2016	Arthroscopic partial meniscectomy: joint inspection and lavage, probing of menisci and resection of unstable meniscal tissue	Participants were advised to use crutches until normal weight‐bearing, and were given written and oral instructions for simple home exercises to be performed two to four times daily.	Supervised exercise.Description: stationary cycle (20 min) 3 x 10 sets of the following: squat, single‐leg squat, step‐up, knee stability in pull loop and skating; hamstring on fitball (3 x 8); 2‐4 x 15‐6 sets of: single‐leg leg press, single‐leg knee extension, single‐leg leg curl; limping cross (3 x 3 rounds). Frequency intensity and duration: minimum of two and a maximum of three sessions each week (24 to 36 sessions). Each session lasted approximately 60 to 80 minutes for a total of 12 weeks. Supervised: yes Setting: clinic	None specified
Osteras 2012	Arthroscopic partial meniscectomy	None specified	Supervised exercise.Description: 15 to 20 min of aerobic work on a stationary ergometer cycle. After 4 exercises each of 3 sets of 30 repetitions halfway through the exercise program, the participants cycled for 10 min and again after the last 4 exercises, the participants did another 10 min on a stationary ergometer cycle. Frequency intensity and duration: 3 times per week for 3 months. Supervised: yes. Setting: clinic	None specified
Van de Graaf 2018	Arthroscopic partial meniscectomy: standard anteromedial and anterolateral portals were introduced for inspection of the knee joint. The affected meniscus was partially removed until a stable and solid meniscus remained.	Post‐operatively, participants received instructions for a home exercise program which consisted of one leg standing for 60 seconds and a step‐down exercise comprising 3, 9, 10 repetitions, twice a week.	Physical therapy (PT). Participants were referred to PT clinics which were instructed about the exercise protocol by a knee‐specialised physical therapist or the primary investigator, prior to the first participant’s referral. The PT exercise protocol developed by a knee‐specialised physical therapist consisted of 16 sessions of 30 minutes each conducted over 8 weeks. The PT protocol comprised cardiovascular, coordination/balance, and closed kinetic chain strength exercises (in which the distal part of the extremity is fixed to an object that is stationary). If PT failed, the participant was allowed to attend additional PT sessions or have APM, depending on their preference	Home exercise program. Applied equally in all treatment groups: yes
Yim 2013	Arthroscopic meniscectomy: meniscal resection with limited debridement of the articular surface lesion.	Post‐operatively, all participants were provided with a home exercise program, which was conducted unsupervised, using the same protocol as the non‐operative group for 8 weeks.	A. Supervised exercise.Description: scheduled physical exercise to improve muscle strength, endurance, and flexibility. Frequency intensity and duration: 60 minutes per session, 3 times weekly, for 3 weeks. Supervised: yes Setting: clinic B. Unsupervised exercise.Description: 3 x 10 sets of the following: half squats with < 45 degrees of flexion with weights, squats with full flexion with weights, knee extension in sitting position, knee flexion in sitting position; stretching of knee extensors and flexors 1 min/muscle group, stationary bicycling (gradual increase every 15 min). Frequency intensity and duration: daily for 8 weeks Supervised: no Setting: home	Analgesics, NSAIDs or muscle relaxants for the first 2 weeks. Applied equally in all treatment groups: yes
	Other trials
Chang 1993	Joint inspection followed by either debridement of torn meniscus and removal of meniscal and cruciate ligament fragments, removal of proliferative synovium, excision of loose articular cartilage fragments, based on the joint findings	Participants were routinely instructed in partial weight‐bearing precautions for 10 days post‐operatively, followed by physical therapy, consisting of strengthening and flexibility exercises and gait training.	Non‐arthroscopic (closed‐needle joint) lavage: tidal knee lavage was done under local anaesthesia. A total of 1 litre of saline was injected into and aspirated from the knee in aliquots of 40‐120 cc, depending on the size of the knee capsule.	Non‐narcotic analgesia and physical therapy, consisting of strengthening and flexibility exercises and gait training. Applied equally in all treatment groups: yes
Saeed 2015	Arthroscopic debridement performed using two portals in all cases and under spinal anaesthesia	None reported	Intra‐articular hyaluronic acid injections under intradermal anaesthesia given weekly for 5 weeks with a 24‐gauge needle under strict aseptic conditions in the operation theatre. In case of joint effusion, aspiration was done before the injection to prevent dilution of the injection.	None specified
Vermesan 2013	Arthroscopic debridement	None reported	A single intra‐articular glucocorticoid injection using 1 mL of betamethasone in 4 mL of 1% lidocaine was administered.	None specified
Merchan 1993	Arthroscopic surgery: debridement of synovial tissue; removal of degenerative menisci, osteophytes, and loose bodies; limited debridement of cartilage defects	Post‐operatively, a compression bandage was used with early exercises, motion, and weight‐bearing as tolerated. Physiotherapy consisting of quadriceps exercises and knee flexion exercises was practiced for 4 weeks after surgery.	The non‐operative treatment consisted of non‐steroidal anti‐inflammatory drugs and a decrease in the intensity of the activities of daily living for a pain‐free knee. Physiotherapy was practiced as in the operative group (i.e. quadriceps and knee flexion exercises for 4 weeks).	None specified

APM: arthroscopic partial meniscectomy; ICRS: International Cartilage Repair Society; NSAIDS: non‐steroidal anti‐inflammatory drugs