***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 Synthesis of multiple r and omized controlled trials ( RCTs ) in a systematic review can summarize the effects of individual outcomes and provide numerical answers about the effectiveness of interventions . Filtering of search es is time consuming , and no single method fulfills the principal requirements of speed with accuracy . Automation of systematic review s is driven by a necessity to expedite the availability of current best evidence for policy and clinical decision-making . We developed Rayyan ( http://rayyan.qcri.org ) , a free web and mobile app , that helps expedite the initial screening of abstract s and titles using a process of semi-automation while incorporating a high level of usability . For the beta testing phase , we used two published Cochrane review s in which included studies had been selected manually . Their search es , with 1030 records and 273 records , were uploaded to Rayyan . Different features of Rayyan were tested using these two review s. We also conducted a survey of Rayyan ’s users and collected feedback through a built-in feature . Results Pilot testing of Rayyan focused on usability , accuracy against manual methods , and the added value of the prediction feature . The “ taster ” review ( 273 records ) allowed a quick overview of Rayyan for early comments on usability . The second review ( 1030 records ) required several iterations to identify the previously identified 11 trials . The “ suggestions ” and “ hints , ” based on the “ prediction model , ” appeared as testing progressed beyond five included studies . Post rollout user experiences and a reflexive response by the developers enabled real-time modifications and improvements . The survey respondents reported 40 % average time savings when using Rayyan compared to others tools , with 34 % of the respondents reporting more than 50 % time savings . In addition , around 75 % of the respondents mentioned that screening and labeling studies as well as collaborating on review s to be the two most important features of Rayyan . As of November 2016 , Rayyan users exceed 2000 from over 60 countries conducting hundreds of review s totaling more than 1.6 M citations . Feedback from users , obtained mostly through the app web site and a recent survey , has highlighted the ease in exploration of search es , the time saved , and simplicity in sharing and comparing include-exclude decisions . The strongest features of the app , identified and reported in user feedback , were its ability to help in screening and collaboration as well as the time savings it affords to users . Conclusions Rayyan is responsive and intuitive in use with significant potential to lighten the load of review ers Background : Optimizing calf muscle performance seems to play an important role in minimizing impairments and symptoms after an Achilles tendon rupture ( ATR ) . The literature lacks long-term follow-up studies after ATR that describe calf muscle performance over time . Purpose : The primary aim was to evaluate calf muscle performance and patient-reported outcomes at a mean of 7 years after ATR in patients included in a prospect i ve , r and omized controlled trial . A secondary aim was to evaluate whether improvement in calf muscle performance continued after the 2-year follow-up . Study Design : Cohort study ; Level of evidence , 2 . Methods : Sixty-six subjects ( 13 women , 53 men ) with a mean age of 50 years ( SD , 8.5 years ) were evaluated at a mean of 7 years ( SD , 1 year ) years after their ATR . Thirty-four subjects had surgical treatment and 32 had nonsurgical treatment . Patient-reported outcomes were evaluated with Achilles tendon Total Rupture Score ( ATRS ) and Physical Activity Scale ( PAS ) . Calf muscle performance was evaluated with single-leg st and ing heel-rise test , concentric strength power heel-rise test , and single-legged hop for distance . Limb Symmetry Index ( LSI = injured side/healthy side × 100 ) was calculated for side-to-side differences . Results : Seven years after ATR , the injured side showed decreased values in all calf muscle performance tests ( P < .001-.012 ) . Significant improvement in calf muscle performance did not continue after the 2-year follow-up . Heel-rise height increased significantly ( P = .002 ) between the 1-year ( 10.8 cm ) and the 7-year ( 11.5 cm ) follow-up assessment s. The median ATRS was 96 ( of a possible score of 100 ) and the median PAS was 4 ( of a possible score of 6 ) , indicating minor patient-reported symptoms and fairly high physical activity . No significant differences were found in calf muscle performance or patient-reported outcomes between the treatment groups except for the LSI for heel-rise repetitions . Conclusion : Continued deficits in calf muscle endurance and strength remained 7 years after ATR . No continued improvement in calf muscle performance occurred after the 2-year follow-up except for heel-rise height Background : In patients with an acute Achilles tendon rupture , it has not been possible to determine the superiority of a single specific treatment modality over other treatments with respect to symptoms and function . When several pertinent treatment protocol s are available for an injury , it is of interest to underst and how other variables , such as age , sex , or physical activity level , affect outcome to better individualize the treatment . Purpose : To investigate predictors of both symptomatic and functional outcomes after an acute Achilles tendon rupture . Study Design : Cohort study ( Prognosis ) ; Level of evidence , 2 . Methods : Ninety-three patients ( 79 men and 14 women ; mean age , 40 years ) were evaluated prospect ively at 3 , 6 , and 12 months . The main outcome measures in this study were the Achilles tendon Total Rupture Score ( ATRS ) for symptoms and maximum heel-rise height for function . The independent variables evaluated as possible predictors of outcome included treatment , sex , age , body mass index ( BMI ) , physical activity level , symptoms , and quality of life . Results : Treatment , age , BMI , physical activity level , heel-rise height at 6 months , and the ATRS at 3 months were eligible for further analysis . Only male sex was included for the prediction models . The 4 different multiple linear regression models ( predicting the ATRS at 6 and 12 months and heel-rise height at 6 and 12 months ) were significant ( P < .001-.002 ) , and the R2 values for the models were 0.222 to 0.409 . Surgical or nonsurgical treatment is a moderate predictor of symptoms and a weak predictor of heel-rise height after an acute Achilles tendon rupture . At the 6-month follow-up , surgical treatment was associated with a larger heel-rise height , but the opposite was seen at 12 months . Surgical treatment result ed in a lower degree of symptoms . Increasing age was a strong predictor of reduced heel-rise height , and an increase in age of 10 years reduced the expected heel-rise height by approximately 8 % . A higher BMI was also a strong predictor of a greater degree of symptoms , and a 5-unit higher BMI predicted a reduction of approximately 10 points in the ATRS . Conclusion : The present study identified important possible predictors of outcome . Despite having a wide range of clinical ly relevant variables , the models had a limited ability to predict the final individual outcome . In general , the models appear to be better at predicting function than symptoms Purpose The purpose of this prospect i ve r and omized controlled study was to evaluate the long-term results after an acute Achilles tendon rupture in patients treated surgically or non-surgically .  The focus was to evaluate whether any improvements occurred between the one and 2-year evaluation . Method Eighty-one patients ( 67 men , 14 women ) with a mean ( SD ) age of 42 ( 9.1 ) were included in this study . Forty-two patients were treated surgically  , and 39 treated non-surgically  otherwise the treatment was identical for the two groups . All patients were evaluated using the  Achilles tendon Total Rupture Score ( ATRS ) , the Physical Activity Scale ( PAS ) and vali date d functional tests one and 2 years after injury . Results There were significant functional deficits on the injured side compared with the contralateral side 2 years after Achilles tendon rupture , regardless of treatment . Only minor improvements , even though statistically significant , occurred between the 1- and 2-year evaluations . The physical activity level remained significantly reduced as compared with prior to injury , but the ATRS mean was relatively high in both groups ( 89 and 90 ) . Conclusion This long-term follow-up indicates that the majority of patients with an Achilles tendon rupture have not fully recovered ( in regards to symptoms , physical activity level and function ) 2 years after injury regardless of surgical or non-surgical treatment . Furthermore , only minor improvements occur between the 1- and 2-year evaluations . This indicates that to enhance the final outcome the focus should be on improvements in treatment within the first year . The patients appear to have adjusted to their impairments since the patient-reported outcome is relatively high in spite of functional deficits and lower activity level compared with pre-injury . Level of evidence Prospect i ve r and omized study , Level Non-operative treatment of Achilles tendon ruptures is associated with an increased risk of rerupture . We hypothesized that this is due to inferior mechanical properties during an early phase of healing , and performed a r and omized trial , using a new method to measure the mechanical properties . Tantalum markers were inserted in the tendon stumps , and tendon strain at different loadings was measured by stereo-radiography ( Roentgen stereophotogrammetric analysis ) at 3 , 7 and 19 weeks and 18 months after injury . Thirty patients were r and omized to operative or non-operative treatment . The primary out-come variable was an estimate for the modulus of elasticity at 7 weeks . Strain per force , cross-sectional area and tendon elongation were also measured . The functional outcome variable was the heel-raise index after 18 months . There was no difference in the mean modulus of elasticity or other mechanical or functional variables between operative and non-operative treatments at any time-point , but strain per force at 7 and 19 weeks had a significantly larger variation in the non-operative group . This group , therefore , might contain more outliers with poor healing . The modulus of elasticity at 7 weeks correlated with the heel-raise index after 18 months in both treatment groups ( r(2 ) = 0.75 ; P=0.0001 ) . This correlation is an intriguing finding Background : The optimal treatment for acute Achilles tendon ruptures is still an ongoing debate . Acute ultrasonography ( US ) investigation to measure the diastasis between the tendon ends has previously been used to classify acute Achilles tendon ruptures ; however , no study has used US to predict reruptures and functional outcomes . Purpose : To investigate whether acute US can be used to predict the risk of reruptures and outcomes after treatment of an acute Achilles tendon rupture . Study Design : Cohort study ; Level of evidence , 2 . Methods : Forty-five patients ( 37 men , 8 women ) with a mean age of 39 ± 9.2 years ( range , 23 - 59 years ) from a cohort of 97 patients participating in a r and omized controlled study comparing surgical and nonsurgical treatment were included . US was performed within 72 hours from the index injury . Diastasis between the tendon ends was documented . Reruptures were documented , and the patients ’ functional outcomes were measured 12 months after injury . Results : Patients with a diastasis of > 10 mm treated nonsurgically had a higher degree of rerupture . In the nonsurgically treated group , 3 of 4 patients with a diastasis of > 10 mm suffered from rerupture ( P < .001 ) . Moreover , in the nonsurgical group , there was significantly worse outcomes in patients with a diastasis of > 5 mm in terms of patient-reported outcomes using the Achilles tendon Total Rupture Score ( ATRS ) ( P = .004 ) and heel-rise height at 12 months ( P = .048 ) compared with the group with a lesser degree of tendon separation . Conclusion : US may be a useful tool to predict the risk of rerupture and greater degree of functional deficit . It may be an important measure in a clinical treatment algorithm for deciding whether a patient will benefit from surgical intervention after an acute Achilles tendon rupture Purpose The purpose of this study was to establish a relationship between the lengthening of the Achilles tendon post-rupture and surgical repair to muscle activation patterns during walking in order to serve as a reference for post-surgical assessment . Method The Achilles tendon lengths were collected from 4 patients with an Achilles tendon rupture 6 and 12 months post-surgery along with 5 healthy controls via ultrasound . EMG was collected from the triceps surae muscles and tibialis anterior during overground walking . Results Achilles lengths at 6 and 12 months post-surgery were significantly longer ( p < 0.05 ) on the involved side compared to the uninvolved side , but there were no side-to-side differences in the healthy controls . The integrated EMG ( iEMG ) of the involved side was significantly higher than the uninvolved side in the lateral gastrocnemius at 6 months and for the medial gastrocnemius at 12 months in the patients with Achilles tendon rupture ; no side-to-side difference was found in the healthy controls . The triceps surae muscles ’ activations were fair to moderately correlated to the Achilles lengths ( 0.38 < r < 0.52 ) . Conclusions The increased Achilles tendon length and iEMG from the triceps surae muscles indicate that loss of function is primarily caused by anatomical changes in the tendon and the appearance of muscle weakness is due to a lack of force transmission capability . This study indicates that when aim ing for full return of function and strength , an important treatment goal appears to be to minimize tendon elongation . Level of evidence Prognostic prospect i ve case series , Level IV Background : Weightbearing in a fixed brace after acute Achilles tendon ruptures does not necessarily lead to mechanical tension 
    Output:
    
Fair evidence of the influence of tendon elongation in biomechanical parameters was found .