***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Glucosamine and chondroitin sulfate are used to treat osteoarthritis . The multicenter , double-blind , placebo- and celecoxib-controlled Glucosamine/chondroitin Arthritis Intervention Trial ( GAIT ) evaluated their efficacy and safety as a treatment for knee pain from osteoarthritis . METHODS We r and omly assigned 1583 patients with symptomatic knee osteoarthritis to receive 1500 mg of glucosamine daily , 1200 mg of chondroitin sulfate daily , both glucosamine and chondroitin sulfate , 200 mg of celecoxib daily , or placebo for 24 weeks . Up to 4000 mg of acetaminophen daily was allowed as rescue analgesia . Assignment was stratified according to the severity of knee pain ( mild [ N=1229 ] vs. moderate to severe [ N=354 ] ) . The primary outcome measure was a 20 percent decrease in knee pain from baseline to week 24 . RESULTS The mean age of the patients was 59 years , and 64 percent were women . Overall , glucosamine and chondroitin sulfate were not significantly better than placebo in reducing knee pain by 20 percent . As compared with the rate of response to placebo ( 60.1 percent ) , the rate of response to glucosamine was 3.9 percentage points higher ( P=0.30 ) , the rate of response to chondroitin sulfate was 5.3 percentage points higher ( P=0.17 ) , and the rate of response to combined treatment was 6.5 percentage points higher ( P=0.09 ) . The rate of response in the celecoxib control group was 10.0 percentage points higher than that in the placebo control group ( P=0.008 ) . For patients with moderate-to-severe pain at baseline , the rate of response was significantly higher with combined therapy than with placebo ( 79.2 percent vs. 54.3 percent , P=0.002 ) . Adverse events were mild , infrequent , and evenly distributed among the groups . CONCLUSIONS Glucosamine and chondroitin sulfate alone or in combination did not reduce pain effectively in the overall group of patients with osteoarthritis of the knee . Exploratory analyses suggest that the combination of glucosamine and chondroitin sulfate may be effective in the subgroup of patients with moderate-to-severe knee pain . ( Clinical Trials.gov number , NCT00032890 . ) Background The heterogeneity statistic I2 , interpreted as the percentage of variability due to heterogeneity between studies rather than sampling error , depends on precision , that is , the size of the studies included . Methods Based on a real meta- analysis , we simulate artificially ' inflating ' the sample size under the r and om effects model . For a given inflation factor M = 1 , 2 , 3 , ... and for each trial i , we create a M-inflated trial by drawing a treatment effect estimate from the r and om effects model , using si2MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi = xH8viVGI8Gi = hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY = rqGqVepae9pg0db9vqaiVgFr0xfr = xfr = xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGaem4Cam3aa0baaSqaaiabdMgaPbqaaiabikdaYaaaaaa@2FBE@/M as within-trial sampling variance . Results As precision increases , while estimates of the heterogeneity variance τ2 remain unchanged on average , estimates of I2 increase rapidly to nearly 100 % . A similar phenomenon is apparent in a sample of 157 meta-analyses . Conclusion When deciding whether or not to pool treatment estimates in a meta- analysis , the yard-stick should be the clinical relevance of any heterogeneity present . τ2 , rather than I2 , is the appropriate measure for this purpose Summary Twenty patients with persistent symptoms due to osteoarthritis of the knee were r and omly allocated to a saline washout or control group . Both groups showed improvement . Knee washout conferred no more benefit than intra-articular saline injection OBJECTIVE To determine if visually-guided arthroscopic irrigation is an effective therapeutic intervention in patients with early knee osteoarthritis . DESIGN Ninety patients with knee osteoarthritis were r and omized in a double-blind fashion to receive either arthroscopic irrigation with 3000 ml of saline ( treatment group ) or the minimal amount of irrigation ( 250 ml ) required to perform arthroscopy ( placebo group ) . The primary outcome variable was aggregate WOMAC score . RESULTS The study did not demonstrate an effect of irrigation on arthritis severity as measured by aggregate WOMAC scores , the primary outcome variable ; the mean change in aggregate WOMAC score at 12 months was 15.5 ( 95 % CI 7.7 , 23.4 ) for the full irrigation group compared to 8.9 ( 95 % CI 4.9 , 13.0 ) for the minimal irrigation group ( P=0.10 ) . Full irrigation did have a statistically significant effect on patients ' self-reported pain as measured by the WOMAC pain subscale and by a visual analog scale ( VAS ) ( the secondary outcome variables ) . Mean change in WOMAC pain scores decreased by 4.2 ( 95 % CI -0.9 , 9.4 ) for the full irrigation group compared with a mean decrease of 2.3 ( 95 % CI -0.1 , 4.7 ) in the minimal irrigation group ( P=0.04 ) . Mean VAS pain scores decreased by 1.47 ( 95 % CI -1.2 , 4.1 ) in the full irrigation group compared to a mean decrease of 0.12 ( 95 % CI 0.0 , 0.3 ) in the minimal irrigation group ( P=0.02 ) . A hypothesis-generating post-hoc analysis of the effect of positively birefrigent intraarticular crystals showed that patients with and without intraarticular crystals had statistically significant improvements in pain assessment s and aggregate WOMAC scores at 12 months ; patients with crystals had statistically greater improvements in pain . CONCLUSIONS Visually-guided arthroscopic irrigation may be a useful therapeutic option for relief of pain in a subset of patients with knee OA , particularly in those who have occult intraarticular crystals OBJECTIVES Patients with knee osteoarthritis ( OA ) often suffer pain that is not fully controlled by analgesics and often require intra-articular therapies . The aim of this study was to compare the benefits of intra-articular corticosteroid injections ( CSIs ) and tidal irrigation ( TI ) in patients with OA of the knee . METHODS We performed a dual-centre , single blind , r and omised , parallel group trial comparing TI and CSI .  Patients with knee OA were r and omised to either irrigation using a 3.2 mm arthroscope under local anaesthesia or an intra-articular injection of 40 mg triamcinolone acetonide and 1 % lidocaine . Patients were followed for 6 months . The primary outcome measure was the Western Ontario and McMaster Universities OA Index total pain score ( visual analogue scale , VAS ) . RESULTS One hundred and fifty patients were recruited of whom 71 received TI and 79 CSI . In both treatment groups , over 80 % of patients reported improvement at 2 and 4 weeks . After this time , the benefit of CSI decreased whereas that of TI was maintained : at 26 weeks the pain relief afforded by TI was significantly greater than that of CSI . At 26 weeks 29 % of the CSI group reported improvement vs 64 % of the TI group ( P<0.001 ) . Patients with a knee effusion responded better to both treatments , however , this was most apparent for CSI . Patients with less severe radiographic OA also obtained the greatest improvement from both treatments . CONCLUSION Both procedures lead to significant short-term pain relief of at least 4 weeks , however , TI displayed a significantly greater duration of benefit .  Patients with effusions and milder radiographic change obtained the best response to treatment A strong clinical impression exists that joint lavage often provides symptomatic relief for painful osteoarthritis of the knee . A controlled trial was conducted to test this hypothesis . A group of 37 painful osteoarthritic knees were treated by arthroscopic lavage and physiotherapy , and a control group of 24 knees were treated by  physiotherapy alone .  There was better relief of pain in the lavage group , and the effect was still present at one year . An improvement in the signs of inflammation lasted for about three months . Pain was relieved more effectively in patients with slight radiographic changes than in those with advanced changes . Our results confirm the effectiveness of joint lavage in the management of painful osteoarthritis of the knee OBJECTIVE To evaluate the effectiveness of tidal irrigation ( TI ) in comparison with a well-matched sham irrigation ( SI ) procedure as a treatment for knee osteoarthritis ( OA ) . METHODS One hundred eighty subjects with knee OA were r and omized to receive TI or SI , with clinical followup over the ensuing 12 months . The primary outcomes of interest were change in pain and function , as measured by the Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC ) . Subjects and the nurse assessor were blinded , and success of blinding was assessed . RESULTS Although the study groups were otherwise comparable , the baseline WOMAC pain and physical functioning scores were higher ( worse ) in the SI group . After adjustment for baseline , there were no differences between the effects Thirty-five patients with limited extent of degenerative osteoarthritis of the femorotibial joint treated by arthroscope-guided surgery were compared after 1 - 3 years with 38 patients with a similar condition treated conservatively . In selecting a patient for arthroscope-guided surgery , the most important considerations were a normal mechanical axis , a limited extent of the degenerative process , and a femorotibial pain of sudden onset or that had been present for < 6 months . Clinical evaluation was undertaken using a modification of the Hospital for Special Surgery Knee Rating Score . The surgical procedure included partial meniscectomy , limited debridement of loose articular cartilage and removal of loose bodies . In the operated group , 26 patients ( 75 % ) showed improvement , five ( 14 % ) remained unchanged , and four ( 11 % ) were worse than before surgery . The average age of patients was 57 years . In the nonoperated group , six patients ( 16 % ) were improved , 12 ( 31 % ) unchanged , and 20 ( 53 % ) worse than before treatment . The average age of patients was 56 years .  Arthroscope-guided surgery for limited degenerative osteoarthritis of the femorotibial joint with normal limb alignment or for degenerative meniscal tears has proven to be a useful technique OBJECTIVE To assess the efficacy of intra-articular steroid injections following arthroscopy and joint lavage in symptomatic OA of the knee . METHODS Seventy-seven patients with OA of the knee were r and omized to receive either 120 mg methylprednisolone acetate ( MPA ) or placebo following arthroscopy . Clinical assessment s included severity of pain on movement and at rest , stiffness , the presence of joint effusions , range of movement , WOMAC ( Western Ontario and McMaster Universities Osteoarthritis Index ) score and Lequesne functional assessment . The outcome measures were evaluated at baseline and 2 , 4 , 8 , 12 and 24 weeks . Further arthroscopies and synovial biopsies were performed at the time of clinical response and at relapse . RESULTS An intention-to-treat analysis was performed on 71 patients ( 38 MPA , 33 placebo ) . Using the OARSI ( Osteoarthritis Research Society International ) response criteria , 58 % of the steroid group vs 33 % of the placebo group ( adjusted relative risk = 2.38 ) ( P = 0.004 ) responded at 4 weeks . At other time points , there were no significant differences between the treatment groups . There were no significant differences between the two treatment groups for pain , stiffness or WOMAC or Lequesne assessment s at any time point . CONCLUSIONS The response to intra-articular corticosteroids following joint lavage is short-lived ( 2 - 4 weeks ) , achievement of an OARSI response criterion being the only difference between the two groups OBJECTIVE To evaluate the efficacy of joint lavage and intraarticular steroid injection , alone and in combination , in the treatment of patients with symptomatic knee osteoarthritis ( OA ) . METHODS Ninety-eight patients with painful tibiofemoral OA were enrolled in a prospect i ve , r and omized , controlled , 2 x 2 factorial- design trial of 6 months ' duration . The 4 treatment groups consisted of 1 ) intraarticular placebo ( 1.5 ml of 0.9 % normal saline ) , 2 ) intraarticular corticosteroids ( 3.75 mg of cort 
    Output:
    
Joint lavage does not result in a relevant benefit for patients with knee osteoarthritis in terms of pain relief or improvement of function