***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: Conflict between clinical importance and statistical significance is an important problem in medical research . Although clinical importance is best described by asking for the effect size or how much , statistical significance can only suggest whether there is any difference . One way to combine statistical significance and effect sizes is to report confidence intervals . We therefore assessed the reporting of confidence intervals in the orthopaedic literature and factors influencing this frequency . In parallel , we tested the predictive value of statistical significance for effect size . In a r and om sample of predetermined size , we found one in five orthopaedic articles reported confidence intervals . Participation of an individual trained in research methods increased the odds of doing so fivefold . The use of confidence intervals was independent of impact factor , year of publication , and significance of outcomes . The probability of statistically significant results to predict at least a 10 % between-group difference was only 69 % ( 95 % confidence interval , 55%–83 % ) , suggesting that a high proportion of statistically significant results do not reflect large treatment effects . Confidence intervals could help avoid such erroneous interpretation by showing the effect size explicitly Delayed rather than early reconstruction of the anterior cruciate ligament is the current recommended treatment for injury to this ligament since it is thought to give a better functional outcome . We r and omised 105 consecutive patients with injury associated with chondral lesions no more severe than grade s 1 and 2 and /or meniscal tears which only required trimming , to early ( < two weeks ) or delayed ( > four to six weeks ) reconstruction of the anterior cruciate ligament using a quadrupled hamstring graft .  All operations were performed by a single surgeon and a st and ard rehabilitation regime was followed in both groups . The outcomes were assessed using the Lysholm score , the Tegner score and measurement of the range of movement . Stability was assessed by clinical tests and measurements taken with the KT-1000 arthrometer , with all testing performed by a blinded uninvolved experienced observer . A total of six patients were lost to follow-up , with 48 patients assigned to the delayed group and 51 to the early group . None was a competitive athlete . The mean interval between injury and the surgery was seven days ( 2 to 14 ) in the early group and 32 days ( 29 to 42 ) in the delayed group . The mean follow-up was 32 months ( 26 to 36 ) . The results did not show a statistically significant difference for the Lysholm score ( p = 0.86 ) , Tegner activity score ( p = 0.913 ) or the range of movement ( p = 1 ) . Similarly , no distinction could be made for stability testing by clinical examination ( p = 0.56 ) and measurements with the KT-1000 arthrometer ( p = 0.93 ) . Reconstruction of the anterior cruciate ligament gave a similar clinical and functional outcome whether performed early ( < two weeks ) or late at four to six weeks after injury 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 OBJECTIVES : To compare the accuracy of  tunnel placement  and graft isometry for anterior cruciate ligament reconstruction performed using a computer-assisted navigation system ( Orthopilot ) and using traditional instruments . METHODS : The anterior cruciate ligament was removed intact from 36 pairs of human cadaver knees . From each pair , one knee was r and omized to Group 1 ( conventional ) and the other to Group 2 ( Orthopilot ) . An inelastic suture was then passed through the central points of the tibial and femoral tunnels . Neither of the tunnels was drilled . All knees were then dissected , and six parameters were obtained : distances from the tibial tunnel center to the 1 ) posterior cruciate ligament , 2 ) anterior horn of the lateral meniscus and 3 ) medial tibial spine ; 4 ) distance from the femoral tunnel center to the posterior femoral cortex ; 5 ) femoral tunnel coronal angle ; and 6 ) variation of the distance from the femoral to the tibial tunnel with the knee extended and at 90 degrees of flexion . RESULTS : The variation of the distance from the femoral to the tibial tunnel during flexion and extension was smaller in the Orthopilot group ( better isometry ) compared to the conventional group . There were no statistical differences in any other parameters between the groups , and all tunnels were considered to be in satisfactory positions . DISCUSSION : The results obtained for anterior cruciate ligament reconstruction depend on precise isometric point positioning , and a navigation system is a precision tool that can assist surgeons in tunnel positioning . CONCLUSION : No differences in tunnel position were observed between the groups . Nonetheless , better isometry was achieved in the Orthopilot group than with conventional instruments Evidence -based medicine integrates clinical expertise , patients ' values and preferences , and the best available evidence from the medical literature . Evidence -based orthopedics is a model to assist surgeons to improve the process of asking questions , obtaining relevant information efficiently , and making informed decisions with patients . With an increasing appreciation for higher levels of evidence , orthopedic surgeons should move away from lower forms of evidence . The adoption of r and omized trials and high- quality prospect i ve studies to guide patient care requires 2 prerequisites : ( 1 ) greater appreciation for the conduct of r and omized trials in orthopedics and ( 2 ) improved education and training in evidence -based method ologies in surgery To correlate clinical results after  anterior cruciate liga ment reconstruction  with tunnel placement measured radiographically , we prospect ively studied 128 patients who had arthroscopically assisted bone-patellar ten don-bone reconstructions . Patients with bilateral ante rior cruciate ligament reconstructions , other significant knee ligament injuries , or those undergoing chondro plasty or meniscal repairs were excluded , leaving 42 patients . The relationship between radiographic tunnel position and clinical results was determined using the Lysholm score , KT-1000 arthrometer testing , the Teg ner activity level , and the pivot shift and Lachman tests . Clinical results correlated positively with posterior fem oral tunnel placement on lateral radiographs and neg atively with excessive anterior tibial tunnel placement . Specifically , when femoral tunnels were placed at least 60 % posterior along Blumensaat 's line and tibial tun nels were at least 20 % posterior along the tibial pla teau , 69 % of patients had good or excellent Lysholm scores and 79 % had KT-1000 arthrometer maximum manual side-to-side differences of 3 mm or less . When the above criteria were not met , 50 % of patients had good or excellent Lysholm scores and 22 % had KT- 1000 arthrometer maximum manual side-to-side differ ences of 3 mm or less . This close correlation indicates that satisfactory radiographic tunnel position influences outcome after anterior cruciate ligament reconstruc tion 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 
    Output:
    
No significant differences between computer-navigated and conventional groups were found in terms of knee stability and functional assessment during short-term follow-up .