***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 
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    Input: 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 Osteoarthritis of the knee is the most common cause of chronic disability among older persons in the United States [ 1 ] . In persons with symptomatic osteoarthritis of the knee , quadriceps muscle weakness is common and is widely believed to result from disuse atrophy secondary to joint pain . Although exercises to strengthen the quadriceps may relieve joint pain in persons with osteoarthritis of the knee [ 2 - 6 ] , the role of periarticular muscle weakness in the pathogenesis of joint pain and disability in these persons is poorly understood . The basis for the beneficial effect of strengthening exercises is unclear , and the duration of the improvement has not been studied . Furthermore , the possibility that muscle weakness is an etiologic factor underlying the pathologic changes of osteoarthritis has seldom been considered . Elucidation of the role of muscle weakness in osteoarthritis is particularly important given our growing underst and ing of safe and effective methods for increasing strength in elderly persons [ 7 , 8 ] . A substantial proportion of persons who have radiographic evidence of osteoarthritis of the knee have no joint pain [ 9 ] . Because asymptomatic persons with radiographic changes seldom seek medical attention for osteoarthritis , muscle weakness has not been studied previously in this group . Thus , it is not known whether quadriceps weakness precedes or follows joint pain or ( if it follows joint pain ) whether it is mediated by disuse atrophy or by physiologic mechanisms that may inhibit muscle contraction [ 10 ] . To address this issue , we studied the relation among lower-extremity muscle strength , lower-extremity lean tissue mass , and osteoarthritis of the knee in men and women 65 years of age and older . Methods Study Group To obtain a sample of elderly persons living in the community , we conducted brief  telephone interviews with residents of households in central Indiana . Potential participants were selected through modified r and om-digit dialing to increase the sample d proportion of persons 65 years of age and older . Persons were eligible if they met the minimal criteria for participation : They were willing and able to provide informed consent and to undergo the necessary strength assessment s and other evaluations . Persons were excluded if they had had amputations of both lower extremities , had undergone total knee arthroplasty , or had recently had a cerebrovascular accident or myocardial infa rct ion . A total of 462 persons ( approximately 55 % of all who were eligible ) agreed to participate and completed the following evaluations . Evaluations Radiography of the Knee St and ing anteroposterior and lateral radiographs of both knees of each study participant were obtained , and the severity of osteoarthritis in the tibiofemoral compartment was grade d by a musculoskeletal radiologist according to the criteria of Kellgren and Lawrence . Similar criteria , based on the presence of osteophytes and joint space narrowing , were used for the patellofemoral compartment [ 11 ] . The radiologist was blinded to the clinical status and characteristics of all patients . A participant had to have a Kellgren and Lawrence grade of 2 or more in either knee to be classified as having osteoarthritis . Knee Pain and Function The Western Ontario and McMaster Universities Arthritis Index was used to evaluate knee pain and function [ 12 ] . This index assesses the severity of knee pain during 5 activities or situations ( walking on a flat surface , going up or down stairs , at night while in bed , sitting or lying , and st and ing upright ) and the severity of impairment of lower-extremity function during 17 activities . Pain and functional impairment were assessed in each knee separately . Responses to each question about the severity of knee pain and level of impairment were recorded on a categorical scale as none , mild , moderate , severe , or extreme . Each category was assigned a corresponding numeric score from 1 to 5 ( 5 = extreme ) . Hence , the range on the pain scale was 5 to 25 and the range on the physical impairment scale was 17 to 85 ( 85 = greatest functional limitation ) . For the purpose s of analysis , participants who rated the severity of their knee pain as moderate or greater ( 3 ) with any of the 5 activities on more than half of the days in the month preceding the evaluation were considered to have knee pain . Thus , pain in the more distant past that had resolved was not included . Participants were also question ed about current and previous regular ( 5 times per week ) or occasional use of over-the-counter and prescription analgesics and nonsteroidal anti-inflammatory drugs ( NSAIDs ) in the past year . Lower-Extremity Muscle Strength The strength of each leg was evaluated by using an isokinetic dynamometer ( KIN-COM 500H , Chattecx Corp. , Hixson , Tennessee ) . Peak torque was recorded in both the concentric ( contractions during muscle shortening ) and eccentric ( contractions during muscle lengthening ) modes . Participants were allowed several submaximal or maximal practice efforts to familiarize themselves with the operation of the dynamometer . Once formal testing began , the best of three maximal efforts was recorded for flexion and extension at both 60 degrees per second and 120 degrees per second . Aborted efforts were repeated in order to obtain the best possible representation of strength for each participant . Concentric and eccentric testing yielded similar results , but because of greater variability in eccentric testing , only the concentric test results are shown . Lower-Extremity Lean Tissue Mass Total-body dual-energy x-ray absorptiometry was done in all participants by using a Lunar-DPX-L instrument ( Lunar Corp. , Madison , Wisconsin ) . Results were analyzed for total and regional body composition , including body fat , mineral , and lean components ( lean components were components other than fat or mineral ) . The right and left lower extremities were analyzed separately . The lower extremity was defined as all tissue below a diagonal line drawn outward and upward from the groin area through the femoral neck . Statistical Analysis Participants were divided into four groups on the basis of presence or absence of radiographic evidence of osteoarthritis of the knee and presence or absence of knee pain , as defined above . Men and women were compared by using the t-test . Comparisons of Arthritis Index pain and functional impairment scores were done by using nonparametric approaches . For analyses of continuous data involving more than two groups of participants ( for example , osteoarthritis with or without knee pain ) , analysis of variance was used to determine whether an overall difference was present . The Fisher protected least-significant-difference procedure was used for pairwise comparisons . Comparisons within participants ( for example , comparison of the two legs in a person with unilateral osteoarthritis of the knee ) were done by using paired t-tests . Regression models were constructed with the generalized estimating equations approach of Zeger and Liang [ 13 ] . This approach inflates the st and ard errors to adjust for correlations in both independent variables ( such as strength ) and dependent variables ( such as radiographic grade ) within participants . Statistically significant differences ( P < 0.05 ) in the above analyses are specifically noted below . Results The characteristics of the 462 men and women in the cohort are shown in Table 1 . As expected , men were taller , were heavier , and had greater lower-extremity strength and lean tissue mass in the lower extremities compared with women ( P < 0.001 for all comparisons ) . Table 1 . Age , Height , Weight , and Lower-Extremity Strength and Lean Tissue Mass * One hundred forty-five participants ( 31 % ; 33 % of the women and 30 % of the men ) had radiographic evidence of osteoarthritis involving the tibiofemoral compartment , the patellofemoral compartment , or both . In 62 participants ( 43 % ) , the radiographic changes were unilateral . Table 2 shows the association between osteoarthritis and obesity [ 14 - 16 ] . Women in the cohort who had osteoarthritis were approximately 15 % heavier than women with normal radiographs and no knee pain .  Men with osteoarthritis were also slightly heavier than men without osteoarthritis . Table 2 . Body Weight and Summed Arthritis Index Scores for Recent Pain and Function in the Left Knee in Participants with and without Radiographic Evidence of Osteoarthritis * Among those with radiographic evidence of tibiofemoral osteoarthritis , women were slightly more likely than men to report knee pain ( P = 0.10 ; Table 3 ) . Table 3 . Radiography and Recent Pain in the Left Knee Table 2 also shows the mean summed and the distribution of scores for left knee pain and functional impairment ( data for the right knee were similar ) . Among men and women with radiographic evidence of osteoarthritis who reported having knee pain , the mean summed pain score for the knee with osteoarthritis was approximately 12 ( median score , 2 of 5 ) . In comparison , the mean pain score of participants who reported knee pain but did not have radiographic evidence of osteoarthritis in the painful knee was approximately 10 ( median score , 2 of 5)-only slightly lower than the mean pain score of participants with radiographic changes . Consistent with their relatively low pain scores , these community-dwelling participants with osteoarthritis reported moderately low use of NSAIDs ( Table 4 ) . Table 4 . Participants Reporting Regular Current or Previous Use of Analgesics and Nonsteroidal Anti-inflammatory Drugs Related to the Presence of Radiographic Evidence of Osteoarthritis of the Knee and Recent Knee Pain * Arthritis Index scores for functional impairment paralleled those for pain ( Table 2 ) . Participants with osteoarthritis had the greatest functional impairment ( P < 0.001 for the comparison with patients who did not have pain or radiographic evidence of osteoarthritis ) . Functional impairment in participants who had pain but no radiographic evidence of OBJECTIVE To determine the relationship between change in body mass and knee-joint moments and forces during walking in overweight and obese older adults with knee osteoarthritis ( OA ) following an 18-month clinical trial of diet and exercise . METHODS Data were obtained from 142 sedentary , overweight , and obese older adults with self-reported disability and radiographic evidence of knee OA who underwent 3-dimensional gait analysis .  Gait kinetic outcome variables included peak knee-joint forces and peak internal knee-joint moments . Mixed regression models were created to predict followup kinetic values , using followup body mass as the primary explanatory variable . Baseline body mass was used as a covariate , and thus followup body mass was a surrogate measure for change in body mass ( i.e. , weight loss ) . RESULTS There was a significant direct association between followup body mass and peak followup values of compressive force ( P = 0.001 ) , result ant force ( P = 0.002 ) , abduction moment ( P = 0.03 ) , and medial rotation moment ( P = 0.02 ) . A weight reduction of 9.8 N ( 1 kg ) was associated with reductions of 40.6 N and 38.7 N in compressive and result ant forces , respectively . Thus , each weight-loss unit was associated with an approximately 4-unit reduction in knee-joint forces . In addition , a reduction in body weight of 9.8 N ( 1 kg ) was associated with a 1.4 % reduction ( 0.496 Nm ) in knee abduction moment . CONCLUSION Our results indicate that each pound of weight lost will result in a 4-fold reduction in the load exerted on the knee per step during daily activities . Accumulated over thous and s of steps per day , a reduction of this magnitude would appear to be clinical ly meaningful OBJECTIVE . To compare the safety and efficacy of a topical diclofenac solution versus oral diclofenac in relieving the symptoms of primary osteoarthritis ( OA ) of the knee , in a r and omized , double-blind , double-dummy equivalence trial . METHODS A total of 622 men and women with radiological evidence of primary knee OA and mild to severe symptoms were r and omly assigned to 
    Output:
    
Other noninvasive or less invasive strategies are available that have varying degrees of effect .
Conclusions : Although the evidence supporting many of the clinical management options might be considered modest , those effects are sufficient to permit an active lifestyle and have , given the prevalence of the disease , a public health impact