***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: Introduction Correct placement of both tibial and femoral tunnels is one of the main factors for a favorable clinical outcome after anterior cruciate ligament ( ACL ) reconstruction . We used an original system of computer assisted surgery ( CAS ) . The system , based on fluoroscopic guidance combined with special graphical software of image analyzing , showed to the surgeon , before drilling , the recommended placement of tibial and femoral tunnel centers . We compared the first anatomical and clinical results of this procedure to the usual one single incision technique . Material s and methods We conducted a prospect i ve study on 73 patients ; 37 patients were operated on with CAS and 36 without CAS , by the same senior surgeon . The mean age was 27 years for both groups . Every patient was review ed at an average of 2.2 years ( range 1–4.5 ) by an independent observer , using IKDC scoring system , KT-1000 , and passive stress radiographs . Results Time between ACL rupture and reconstruction averaged 30 months for both groups . CAS needed 9.3 min extra surgery time . Clinical evaluation was grade d from A to C as per the IKDC scoring system : 67.6 % A , 29.7 % B , 2.7 % C with CAS ; and 60 % A , 37.1 % B , 2.9 % C without CAS . IKDC subjective knee evaluation score averaged 89.7 with CAS and 89.5 without CAS . Pre operative KT-1000 maxi manual differential laxity averaged 7 . At revision time , all the patients after CAS had a differential laxity less than 2 and 97.7 % without CAS . Stress X-rays differential laxity averaged 2.4 mm with CAS and 3 mm without CAS . The area of dispersion of the tunnels ’ center was smaller on the femoral side using the CAS method . There was no statistically significant difference between both groups using IKDC score , KT-1000 and passive stress radiographs . Conclusions The CAS method provided a more accurate and reproducible tunnels placement without clinical significant effect BACKGROUND Accurate and precise tunnel placement is critical to the success of anterior cruciate ligament ( ACL ) reconstruction . A new development , computer-assisted surgery , aids in placement of the ACL bone tunnels during surgery . Our hypothesis was that computer-assisted ACL reconstruction would allow more accurate and precise tunnel placement compared with conventional surgery . METHODS In a prospect i ve , double-blind , r and omized clinical study , 100 patients eligible for ACL reconstruction with a transtibial technique were stratified by surgeon and r and omized to either conventional or computer-assisted surgery . Measurement of femoral and tibial tunnel placement with use of three-dimensional computed tomography ( CT ) was used as the primary outcome to compare conventional ACL surgery with computer-assisted surgery . RESULTS The placement of the femoral tunnel did not differ between groups ( mean , 39.7 % of the proximal-distal distance on the intracondylar axis [ Blumensaat line ] in the conventional group compared with 39.0 % in the computer-assisted surgery group ; p = 0.70 ) . The anterior-posterior positioning of the tibial tunnel on the tibial plateau also did not differ significantly ( 38.9 % in the conventional group compared with 38.2 % in the computer-assisted surgery group ; p = 0.58 ) . There was no significant difference in the precision of either the femoral or the tibial tunnel placement between the two groups . CONCLUSIONS There was no significant difference in either the accuracy or the precision of tunnel placement between conventional and computer-assisted ACL reconstruction Existing published knee rating systems that assess sports participation , knee function , and subjective symptomatology following ligamentous surgical procedures were analyzed . Major errors in question naire design and data reduction have led to invalid conclusions . A question naire containing a minimum set of rating criteria was formulated to validly assess athletic participation before and after treatment or surgery . Select questions and a data reduction format were established to assess the intensity of sports participation , changes in sports participation , the variables that produced the changes , self-assessed functional limitations , and the ability to participate in different types of sports . A clinical trial of the question naire was performed on 59 patients . An interview conducted upon completion of the question naire enabled the authors to detect difficulties or inconsistencies in the responses to the questions . The design format described in this report forms the basis for a subjective evaluation of ligamentous surgery . A st and ard format for analysis of sports participation and knee function is proposed to aid investigators in comparing variations in clinical results PURPOSE The purpose of this prospect i ve r and omized study was to assess biomechanical , radiographic , and functional results after single-bundle anterior cruciate ligament ( ACL ) reconstruction by use of a navigation system . METHODS ACL reconstruction was performed by use of the OrthoPilot navigation system ( B. Braun-Aesculap , Tuttlingen , Germany ) in 40 patients ( group 1 ) ; and in another 40 patients ,  surgery was done by the st and ard manual targeting technique  ( group 2 ) . The anterior laxity was measured with a KT-1000 arthrometer ( MEDmetric , San Diego , CA ) . Femoral and tibial tunnel position was evaluated radiologically according to the method described by Bernard and Hertel and by Harner et al. , respectively . The question naire-based Lysholm and International Knee Documentation Committee scales were included to compare the functional state in both groups . RESULTS The knees in group 1 were as stable as those in group 2 during the arthrometer testing , with a lower value of dispersion . The postoperative Lysholm and International Knee Documentation Committee scores had the same value in both groups . Statistical differences existed with regard to anterior-posterior femoral tunnel placement when the navigated and st and ard techniques were compared ; in the navigated group , more exact results were found . No significant complications were observed . CONCLUSIONS The only difference that we found between the navigated and st and ard groups was in radiographic tunnel position measurement . The computer-assisted navigation technique in our study result ed in more accurate tunnel placement in the femur ( but not the tibia ) than the traditional arthroscopic technique . However , the performed st and ard radiographic measurements are of limited precision in principle . Functional scales and stability tests gave similar results in both groups . LEVEL OF EVIDENCE Level I , therapeutic study PURPOSE The purpose of this study was to evaluate the benefits of computer navigation on tunnel placement during anterior cruciate ligament reconstruction . METHODS A prospect i ve , r and omized , controlled study comparing computer navigation with manual operation was performed between December 2003 and April 2004 . We assigned 20 patients to the computer navigation group and 20 patients to the manual navigation group .  Surgery was performed by use of a patellar tendon autograft with press-fit fixation . A lateral radiograph of the knee at maximum extension was used to determine the exact position of the tibial tunnel at 4 days postoperatively . Outcomes were evaluated with International Knee Documentation Committee 2000 , Tegner , and Lysholm scoring . There was an additional magnetic resonance imaging ( MRI ) evaluation of tunnel placement and graft quality at the most recent follow-up , approximately 24 months after surgery . RESULTS The postoperative radiographs and 2-year postoperative MRI scans showed no differences between groups for tibial or femoral tunnel placement . In both groups the mean tibial tunnel placement was 46 % of the maximal diameter of the tibia . There were no significant differences between groups for objective and subjective outcomes scoring . Although some qualitative differences existed between groups with respect to MRI graft appearance at 2 years , this had no correlation with overall results . CONCLUSIONS No significant differences were found between computer-assisted and manually navigated anterior cruciate ligament reconstruction with regard to tunnel placement and clinical results at a mean of 2 years postoperatively . LEVEL OF EVIDENCE Level I , r and omized , single-blinded , controlled trial Background Poor outcome in anterior cruciate ligament reconstruction is often related to tunnel position . Hypothesis Improving accuracy of the tunnel position will lead to improved outcome . Study Design R and omized controlled trial ; Level of evidence , 1 . Methods Sixty patients were r and omized to either st and ard instrumentation or computer-assisted guides to position the tibial and femoral tunnels . The results were evaluated on clinical outcome based on International Knee Documentation Committee form ( laxity ) and radiologic assessment : radiologic Lachman ( Telos at 150 and 200 N ) and analysis of the tunnel positions . Results International Knee Documentation Committee laxity was level A in 22 knees in the conventional group ( mean , 1.5 mm at 200 N ) compared with 26 navigated knees ( mean laxity , 1.3 mm ; P= .49 ) . Laxity was less than 2 mm in 96.7 % of the navigated group and 83 % of the conventional group ( P= .292 ) . The variability of laxity in the navigated group was significantly less than in the conventional group , with the st and ard deviation of the navigated group being smaller than that in the conventional group ( P= .0003 at 150 N and .0005 at 200 N Telos ) . A significant difference ( P= .03 ) was found between the groups in the ATB value ( distance between the projection of the Blumensaat line on the tibial plateau and the anterior edge of the tibial tunnel ) , characterizing the sagittal position of the tibial tunnel ( negative ATB values imply graft impingement in extension ) . In the conventional group , mean ATB was –0.2 ( –5 to + 4 ) , whereas it was 0.4 ( 0 to 3 ) in the navigated patients . There were no negative ATB values in the navigated group . Conclusion This study confirms that the accuracy and consistency of tibial tunnel position can be improved by the use of computer-assisted navigation and that the clinical result in terms of laxity is more reliable Background Next to graft fixation , correct positioning of the tibial and femoral tunnel is a deciding factor for the clinical result of anterior cruciate ligament reconstruction surgery .  Computer-assisted navigation has been proposed as a method to improve tunnel positioning . Purpose To examine the differences in tibial tunnel placement between cruciate ligament operations using manual and computer-assisted navigation . Study Design R and omized controlled trial ; Level of evidence , 1 . Methods Between December 2003 and April 2004 , 53 athletes underwent anterior cruciate ligament reconstruction surgery with arthroscopic press-fit technique .  The first group ( group N ; 24 athletes ) were operated on with the aid of a navigation system ( OrthoPilot , Aesculap AG & Co. KG , Braun ) , and the second group ( group M ; 29 athletes ) were “ manually ” operated on . A lateral radiograph of the knee at maximum extension was used to determine the exact position of the tibial tunnel four days postoperatively . In the measurements , the anterior and posterior boundaries of the tibial tunnel , as well as the center of the tibial tunnel in relation to the maximum tibia anteroposterior diameter were evaluated ( indicated in percent ) . An analysis of the tibial tunnel position proportional to the slope of the intercondylar roof was done to determine intercondylar impingement ( method according to Howell ) . The centers of the tibial tunnels were compared with the “ optimal ” position noted in previous studies . The st and ard deviation was determined for both groups to determine the variance of placement . Results The anterior tibial tunnel border was 19.4 mm in group M ( 29.7 % ) and 21.2 mm in group N ( 32.2 % ) ( P=.18 ) . The center of the tibial tunnel was located at 24.6 mm in group M ( 35.6 % ) and at 26.6 mm in group N ( 40.3 % ) ( P=.19 ) . In group M , the posterior tibial tunnel position was located at 30.2 mm ( 46.2 % ) , and in group N at 32.2 mm ( 49.1 % ) ( P=.21 ) . When comparing the centers of the tibial tunnels with the optimal 44 % found in previous studies , the value for group M ( 37.6 % ) varied significantly , while group N ( 40.5 % ) did not . However , there was no significant difference in the range variance for either group ; the st and ard deviation was 6.9 % ( 4.3 mm ) for group M and 5.9 % ( 3.5 mm ) for group N. One athlete showed moderate impingement in group N , and two athletes in group M. Conclusion Assisted navigation offers good support for correct placement of the tibial tunnel , although experienced surgeons can achieve essentially the same positioning as surgeons using computer-assisted navigation . Whether it is advisable to implement this procedure in daily surgical routine should be decided based on clinical results Overwhelming evidence shows the quality of reporting of r and omised controlled trials ( RCTs ) is not optimal . Without transparent reporting , readers can not judge the reliability and validity of trial findings nor extract information for systematic review s. Recent method ological analyses indicate that inadequate reporting and design are associated with biased estimates of treatment effects . Such systematic error is seriously damaging to RCTs , which are considered the gold st and ard for evaluating interventions because of their ability to minimise or avoid bias . A group of scientists and editors developed the CONSORT ( Consoli date d St and ards of Reporting Trials ) statement to improve the quality of reporting of RCTs . It was first published in 1996 and up date d in 2001 . The statement consists of a checklist and flow diagram that authors can use for reporting an RCT . Many leading medical journals and major international editorial groups have endorsed the CONSORT statement . The statement facilitates critical appraisal and interpretation of RCTs . During the 2001 CONSORT revision , it became clear that explanation and elaboration of the principles underlying the CONSORT statement would help investigators and others to write or appraise trial reports . A CONSORT explanation and elaboration 
    Output:
    
From the available evidence , we are unable to demonstrate or refute a favourable effect of CAS for cruciate ligament reconstructions of the knee compared with conventional reconstructions .
However , the currently available evidence does not indicate that CAS in knee ligament reconstruction improves outcome .