***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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    ***EXAMPLES*** 
    Input: Purpose To determine if anatomic double-bundle anterior cruciate ligament ( ACL ) reconstruction  is superior to anatomic single-bundle reconstruction in restoring the stabilities and functions of the knee joint . Methods A prospect i ve r and omized clinical study was done to compare the results of 32 cases of anatomic single-bundle ACL reconstruction and 34 cases of anatomic double-bundle ACL reconstruction with average follow-up of 16.3 ± 3.1 months . Tunnel placements of all the cases were measured on 3D CT . Clinical results were collected after reconstruction ; graft ’s appearance , meniscus status and cartilage state under arthroscopy were compared and analysed too . Results Tunnel placements , confirmed with 3D CT , were in the anatomic positions as described in literature both in SB and DB group . No differences were found between SB and DB groups in clinical outcome scores , pivot shift test and KT 1000 measurements ( average side-to-side difference for anterior tibial translation was 0.7 mm in SB group and 1.0 mm in DB group ) . More than 70 % of the single-bundle graft and AM bundle graft in DB group appeared excellent , but only 44.1 % of PL bundle grafts in DB group were excellent and 11.8 % were in poor state . No new menisci tear was found either in SB or DB group , however , in DB group cartilage damages in medial patella-femoral joint occurred in 38.2 % cases . This rate was significantly higher than in the SB group which is only 9.3 % . Conclusion Both single- and double-bundle anatomic ACL reconstruction can restore the knee ’s stability and functions very well . However , more incidences of poor PL status and medial patellar-femoral cartilage damage may occur in double-bundle ACL reconstruction . Level of evidence R and omized controlled trial , Level The aim of this study was to evaluate whether  anterior cruciate ligament ( ACL ) reconstruction using the double bundle technique ( DB ) improves stability in the knee compared with the single bundle technique ( SB ) with the femoral tunnel in a more horizontal position ( 2 or 10 o’clock ) . We conducted a r and omized , prospect i ve study . Forty patients were r and omized to the DB group ( 20 patients ) and the SB group ( 20 patients ) .  Four-str and ed semitendinosus and gracilis autologous grafts were used in the SB group and in the DB group the conventional four tunnel technique was carried out using the same tendons . The IKDC complete form was used for the preoperative evaluation , and in the follow-up the IKDC subjective knee evaluation form , IKDC current health assessment form and IKDC knee examination form were used . Anteroposterior ( AP ) laxity was evaluated by st and ardised and forced radiology in all patients . No significant preoperative between-group differences were found . During the follow-up , no differences were found between groups , except for significant between-group differences ( P < 0.05 ) between the preoperative and postoperative evaluations . The IKDC index also showed significant differences in the 2-year follow-up . Median scores increased from 48 ( range 41–54 ) to 81 ( range 75–87 ) ( P = 0.01 ) in the SB group and from 52 ( range 46–58 ) to 80 ( range 72–88 ) ( P = 0.02 ) in the DB group . There were no significant differences between the groups in terms of functional scores . In conclusion , the 2 and 10 o’clock placements showed no significant differences between SB and DB techniques in the pivot-shift test , manual and radiological anterior posterior laxity and IKDC scores . However , significant between-group differences were found between the preoperative and postoperative evaluations Twenty-six patients with anteroposterior ( AP ) laxity of the knee , associated with torn anterior cruciate ligament ( ACL ) , were prospect ively r and omized for arthroscopic lower femoral tunnel placed single- or double-bundle reconstruction using hamstring tendons . We evaluated AP and rotational stabilities under regular loads ( a 100-N anterior load and a 1.5-N m external – internal load ) before and after ACL reconstruction , comparing single- and double-bundle reconstruction with our original device for applying quantitative tibial rotation and the navigation system intraoperatively . No significant differences were found between the two groups in AP displacement and total range of tibial rotation at 30 ° and 60 ° of knee flexion . We found that a lower femoral tunnel placed single-bundle reconstruction  reproduced AP and rotational stability as well as double-bundle reconstruction after reconstruction intraoperatively We conducted a prospect i ve r and omised study of anatomical single-bundle ( A-SB group ) versus double-bundle ( A-DB group ) anterior cruciate ligament ( ACL ) reconstruction using the hamstrings tendons . Twenty patients with unilateral ACL deficiency were r and omised into two groups . We created the bone tunnels at the position of the original insertion of the anteromedial bundle footprint and posterolateral bundle footprint in the A-DB group and at the central position between these two bundles in the A-SB group . All of the patients were tested before ACL reconstruction and one year after surgery . The KT-1000 measurements , isokinetic muscle peak torque and heel-height difference were evaluated and the general knee condition was assessed by Lysholm score . For pre- and postoperative stability assessment , we used the six-degrees-of-freedom of knee kinematic measurement system using an electromagnetic device ( the EMS ) for quantitative assessment during the Lachman test and the pivot shift test . There were no significant differences in the KT-1000 measurements , isokinetic muscle peak torque , heel-height difference , and Lysholm score at one-year follow-up between these two groups . The EMS data showed there were significant differences in the acceleration of the pivot shift test between the operated knee and the contralateral normal knees in the A-SB group . In conclusion , clinical outcomes were equally good in both groups . However , the EMS data showed the anatomical double-bundle ACL reconstruction tended to be biomechanically superior to the single-bundle reconstruction PURPOSE The study was design ed to compare the clinical results of traditional single-bundle ( SB ) anterior cruciate ligament ( ACL ) reconstruction  with those of double-bundle ( DB ) ACL reconstruction . METHODS This study comprised 80 patients aged 18 to 45 years with an isolated ACL lesion : 40 patients underwent SB reconstruction , and 40 patients underwent DB reconstruction .  Patients were assessed preoperatively with functional assessment including the International Knee Documentation Committee 2000 knee subjective form and visual analog scale , as well as physical examination ( including the pivot-shift test and instrumented knee laxity measurement ) . Vertical jump assessment with the Optojump system ( Microgate , Bolzano , Italy ) has been introduced as a method to compare functional ability between the 2 surgical techniques . The same protocol was repeated 6 months , 12 months , and 2 years after surgery . RESULTS No statistically significant differences were noted between the groups concerning subjective evaluation , thigh girth difference , mean visual analog scale score , range of motion , and Lachman and anterior drawer tests ( P = not significant ) . A statistically higher number of patients in the SB group showed a positive pivot-shift test and a higher side-to-side difference when measured with the KT-1000 arthrometer ( MEDmetric , San Diego , CA ) than in the DB group ( P < .001 ) . Better mean jumping performance results were reported in the DB group compared with the SB group ( P < .001 ) . The average performance results for the injured limb were not significantly reduced compared with those of the uninjured limb in the DB group 12 months after surgery . At 2 years , a restoration of jumping ability in the ACL-reconstructed limb was achieved in both groups regardless of the technique used . CONCLUSIONS DB ACL reconstruction has been proven to be superior to the SB technique with regard to knee stability and vertical jump performance . LEVEL OF EVIDENCE Level II , prospect i ve comparative study Purpose The purpose of this study was to compare subjective , objective and radiographic outcome of the lateralized single-bundle bone-patellar tendon-bone autograft with a non-anatomical double-bundle hamstring tendons autograft anterior cruciate ligament ( ACL ) reconstruction technique at long-term follow-up . Methods Seventy-nine non-consecutive r and omized patients ( 42 men ; 37 women ) with unilateral ACL insufficiency were prospect ively evaluated , before and after ACL reconstruction by means of the above-mentioned techniques , with a minimum follow-up of 8 years ( range 8–10 years ; mean 8.6 years ) . In the double-bundle hamstrings technique , we used one tibial and one femoral tunnel combined with one “ over-the-top ” passage , cortical staple ’s fixation and we left intact hamstrings ’ tibial insertion . Patients were evaluated subjectively and objective ly , using IKDC score , Tegner level , manual maximum displacement test with KT-2000 ™ arthrometer . Radiographic evaluation was performed according to IKDC grading system , and re-intervention rate for meniscal lesions was also recorded . Results The subjective and objective IKDC were similar in both groups while double-bundle hamstrings group showed significantly higher Tegner level ( P = 0.0007 ) , higher passive range of motion recovery ( P = 0.0014 ) , faster sport resumption ( P = 0.0052 ) , lower glide pivot-shift phenomenon ( P = 0.0302 ) and lower re-intervention rate ( P = 0.0116 ) compared with patellar tendon group . Radiographic evaluation showed significant lower objective degenerative changes in double-bundle hamstrings group at final follow-up ( P = 0.0056 ) . Conclusion Although both techniques provide satisfactory results , double-bundle ACL reconstruction shows better functional results , with a faster return to sport activity , a lower re-operation rate and lower degenerative knee changes Background Haemarthrosis and pain adversely affects the functional outcome of  ACL  reconstruction , especially in case of DB ACL reconstruction due to more extensive procedure . The purpose of the study was to evaluate the effect of haemarthrosis on the rehabilitation of DB ACL reconstruction versus SB ACL reconstruction . Methods 100 patients were divided into two groups , of  SB ACL and DB ACL reconstruction  consisting of 50 patients each . An intra-articular drain was put in every patient . The pain was evaluated till week 8 using VAS ( Visual Analog Scale ) . The Functional outcomes were evaluated using the Isokinetic Dynamometer at 3 and 6 months in both the groups . Muscle bulk and Range of motion were also noted in each group . Results The results showed that there was statistically significant difference between the drain amount ( n = 60.3 ml in SB ACL group vs. n = 94.2 ml in the DB ACL group ) and haemarthrosis ( n = 0.7 in SB ACL vs n = 1.5 in DB ACL ) at week 1 post-operatively . Also the pain outcome improved on SB ACL after day 3 ( VAS , n = 1.8 ) as compared to the DB ACL group ( VAS , n = 3.7 ) . The isokinetic muscle strength was found to be statistically significantly ( p value < 0.05 ) better in the SB ACL group in the quadriceps muscle ( both concentric and eccentric ) at the end of the 3rd month . In the SB ACL group the Quadriceps Concentric strength deficit was 22.32 % as compared to 34.12 % in the DB ACL group . Both the groups had comparable flexor muscle strength at end of 3rd month . Both the groups had comparable muscle strength after 6 months of post-operative rehabilitation in both quadriceps and Hamstring muscle group . Conclusion We noted that rehabilitation of DB ACL reconstruction group lags behind that of SB ACL reconstruction during the first 3 months due to post-operative haemarthrosis & its effects , but show comparable results after 6 months . The muscle strength measured isokinetically and the muscle bulk were found to be greater in the SB ACL group initially after 3 months but was found to be similar after 6 months Purpose The effect of double-bundle ACL reconstruction on knee kinematics has recently been studied by several authors under controlled laboratory conditions however little evidence has been derived from dynamic in vivo evaluations . This study hypothesized that tibial rotation during pivoting motor tasks would be better restored after double-bundle ACL reconstructions when compared with single-bundle procedures . Methods Twenty patients with a chronic ACL rupture were r and omly assigned to receive a single- or double-bundle ACL reconstruction . Both knees were evaluated pre-operatively by kinematic 3-D gait analysis while performing low- and high-dem and motor tasks , including pivoting . At 6 months post-operatively , measurements were repeated in 16 patients . Ten healthy , sex- and age-matched subjects with no history of lower limb pathology formed the control group . The tibial rotational excursion was set as the dependent variable . Results The results indicate that at 6 months after surgery both “ anatomic ” single- and double-bundle ACL reconstruction are able to restore tibial rotational excursion when compared with the contralateral knees and with control knees from uninjured subjects . Chronic ACL-deficient patients show an increase in tibial rotation in both knees during high-dem and pivoting tasks . Conclusions Both “ anatomic ” single- and double-bundle ACL reconstruction adequately restore tibial rotational excursion in a human , “ in vivo ” kinematic model . As knee stability measurements by in vivo kinematic 3-D analysis more accurately represent actual knee loading during activities , the results of this study might better correlate with functional outcome after ACL reconstructions compared with static knee stability tests or ex vivo laboratory experiments . In such , the results of this dynamic study do not 
    Output:
    
The DB reconstruction was in general more thoroughly reported .
Conclusions There was substantial underreporting of surgical data for both the SB and DB groups in clinical studies .