***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: In a prospect i ve , r and omised , multicentre study , 112 patients with Achilles tendon rupture ( ATR ) were allocated to surgical treatment  ( n=59 ) , followed by early functional rehabilitation using a brace , and non-surgical treatment ( n=53 ) , i.e. eight weeks of plaster treatment . In this study , the results of the isokinetic muscle strength evaluation are presented for contractions in both the concentric and the eccentric mode , plantar flexion and dorsiflexion , two angular velocities and three different positions of the subject . The heel-raise test for endurance , maximum calf circumference and tendon width were also evaluated . The re-rupture rate was 20.8 % in the non-surgically-treated group and 1.7 % in the surgically-treated group . No significant differences were found between the treatment groups in terms of the isokinetic strength measurements and the endurance test among the patients who did not sustain a re-rupture . If a re-rupture is avoided , both surgical and non-surgical treatment for ATR produce good functional outcome ; however , the muscle function was not restored after two years in either group BACKGROUND For many years it has been cl aim ed that observational studies find stronger treatment effects than r and omized , controlled trials . We compared the results of observational studies with those of r and omized , controlled trials . METHODS We search ed the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition . We then search ed the Medline and Cochrane data bases to identify all the r and omized , controlled trials and observational studies comparing the same treatments for these conditions . For each treatment , the magnitudes of the effects in the various observational studies were combined by the Mantel-Haenszel or weighted analysis -of-variance procedure and then compared with the combined magnitude of the effects in the r and omized , controlled trials that evaluated the same treatment . RESULTS There were 136 reports about 19 diverse treatments , such as calcium-channel-blocker therapy for coronary artery disease , appendectomy , and interventions for subfertility .  In most cases , the estimates of the treatment effects from observational studies and r and omized , controlled trials were similar . In only 2 of the 19 analyses of treatment effects did the combined magnitude of the effect in observational studies lie outside the 95 percent confidence interval for the combined magnitude in the r and omized , controlled trials . CONCLUSIONS We found little evidence that estimates of treatment effects in observational studies reported after 1984 are either consistently larger than or qualitatively different from those obtained in r and omized , controlled trials Background : The purpose of this study was to compare the functional results of operative and nonoperative treatment of acute Achilles tendon rupture using an identical rehabilitation program of functional bracing . Methods : Over a 10-year period , 200 patients ( 99 operative , 101 nonoperative ) aged between 18 and 65 years were treated at our institution ’s physiotherapy department after acute Achilles tendon rupture . There were 132 patients ( 62 operative , 70 nonoperative ) available for a minimum 2-year follow-up ( average 6.5 years ; range , 2 - 13 years ) . Functional outcome was assessed using the  Achilles tendon total rupture score ( ATRS ) . Results : With the numbers available , no significant difference could be detected in ATRS between operative ( mean 84.8 , median 90 ) and nonoperative groups ( mean 85.3 , median 91 ; P = 0.55 ) . No significant difference could be detected in ATRS between male and female patients however treated ( P = 0.30 ) or between patients younger and older than 40 years at time of injury ( P = 0.68 ) . There was no correlation between ATRS score and age at injury in all patients ( ρ = −0.0168 , P = 0.85 ) . In male patients , there was a weak trend with older patients at follow-up having better scores ( ρ = 0.21 , P = 0.069 ) . However , among female patients , there was a significant negative correlation between ATRS scores and increasing age ( ρ = −0.29 , P = 0.03 ) . Logistic regression analysis failed to show any significant effect of age at rupture , gender , or mode of treatment on ATRS . Conclusions : This study showed no significant difference detectable in ATRS between operative and nonoperative patients in the treatment of acute Achilles tendon ruptures using an identical rehabilitation program with functional bracing . Level of Evidence : Level II , prospect i ve comparative study 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 In a prospect i ve , r and omised , multicentre study , 112 patients ( 99 men and 13 women , aged between 21 and 63 years ) with acute , complete rupture of tendo Achillis were allocated either to surgical treatment followed by early functional rehabilitation , using a brace , or to non-surgical treatment , with plaster splintage for eight weeks . The period of follow-up was for two years . Evaluation was undertaken by independent observers and comprised interviews , clinical measurements , isokinetic muscle performance tests , heel-raise tests and an overall outcome score . The rate of rerupture was 20.8 % after non-surgical and 1.7 % after surgical treatment ( p < 0.001 ) . Surgical and non-surgical treatment produced equally good functional results if complications were avoided . However , the rate of rerupture after non-surgical treatment was unacceptably high 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 A total of 80 patients with an acute rupture of tendo Achillis were r and omised to operative repair using an open technique ( 39 patients ) or non-operative treatment in a cast ( 41 patients ) . Patients were followed up for one year . Outcome measures included clinical complications , range of movement of the ankle , the Short Musculoskeletal Function Assessment ( SMFA ) , and muscle function dynamometry evaluating dorsiflexion and plantar flexion of the ankle . The primary outcome measure was muscle dynamometry . Re-rupture occurred in two of 37 patients ( 5 % ) in the operative group and four of 39 ( 10 % ) in the non-operative group , which was not statistically significant ( p = 0.68 ) . There was a slightly greater range of plantar flexion and dorsiflexion of the ankle in the operative group at three months which was not statistically significant , but at four and six months the range of dorsiflexion was better in the non-operative group , although this did not reach statistically significance either . After 12 weeks the peak torque difference of plantar flexion compared with the normal side was less in the operative than the non-operative group ( 47 % vs 61 % , respectively , p < 0.005 ) . The difference declined to 26 % and 30 % at 26 weeks and 20 % and 25 % at 52 weeks , respectively . The difference in dorsiflexion peak torque from the normal side was less than 10 % by 26 weeks in both groups , with no significant differences . The mean SMFA scores were significantly better in the operative group than the non-operative group at three months ( 15 vs 20 , respectively , p < 0.03 ) . No significant differences were observed after this , and at one year the scores were similar in both groups . We were unable to show a convincing functional benefit from surgery for patients with an acute rupture of the tendo Achillis compared with conservative treatment in plaster We performed two independent , r and omised , controlled trials in order to assess the potential benefits of immediate weight-bearing mobilisation after rupture of the tendo Achillis . The first trial , on operatively-treated patients showed an improved functional outcome for patients mobilised fully weight-bearing after surgical repair . Two cases of re-rupture in the treatment group suggested that careful patient selection is required as patients need to follow a structured rehabilitation regimen . The second trial , on conservatively-treated patients , provided no evidence of a functional benefit from immediate weight-bearing mobilisation . However , the practical advantages of immediate weight-bearing did not predispose the patients to a higher complication rate . In particular , there was no evidence of tendon lengthening or a higher re-rupture rate . We would advocate immediate weight-bearing mobilisation for the rehabilitation of all patients with rupture of the tendo Achillis Fifteen operatively and eight  non-operatively  treated subcutaneous achilles tendon ruptures were r and omly selected from 120 surgically and 35 non-surgically treated patients . Their calf muscle function was studied three to five years after treatment . Non-operatively treated patients were found to have a significantly impaired dynamic muscle function of the calf muscles when tested in a specially constructed heel-raise test device . Operatively treated patients did not show any significant impairment of their muscle function . Measurement of muscle area with CT-scanning showed a significant reduction of the calf muscle in the non-operatively treated patient while no such difference could be found in the operatively treated patients . Isokinetic muscle torque did not differ in the two groups of patients , thus Cybex- measurements do not seem to be a discriminating method in study ing muscle function after achilles ruptures . On the basis of our findings we recommend that all athletes with achilles tendon ruptures be treated surgically . In non-athletes and older patients non-operative treatment might be considered The object of this study was to compare treatment of ruptured Achilles tendon by operative " end to end " surgery , percutaneous repair , or conservative therapy clinical ly ; a subject of considerable controversy in the literature . These three methods were compared in 73 patients in a r and omized trial between 1994 and 1996 . After 2.5 years ( 11 - 41 months ) , the actual activities were assigned to the Hannover Achilles tendon score and the ability of doing work or sport activities was assessed . After this period , 59.3 % of the patients showed good and excellent results on the Achilles tendon score , with over 79 points ( open surgery 59.1 % , percutaneous 60 % , conservative treatment 58.3 % ) . None of the patients reached the maximum score of 100 points . During the isometric strength tests , the patients with percutaneous repair had a lower 
    Output:
    
This meta‐ analysis shows that operative treatment of Achilles tendon ruptures reduces the risk of re‐rupture compared with nonoperative treatment .