***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: 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 Abstract Purpose This study aims to determine the outcome of double-bundle anterior cruciate ligament ( ACL ) reconstruction  using an allograft in comparison with ACL reconstruction using a double-bundle autograft or a single-bundle allograft . Methods A total of 424 patients who accepted primary ACL reconstructions were divided r and omly into three groups : double-bundle technique with autograft ( DB-AU group , n = 154 ) , double-bundle technique with allograft ( DB-AL group , n = 128 ) , and single-bundle technique with allograft ( SB group , n = 142 ) . The KT-1000 arthrometer and pivot-shift tests were performed at 3 , 12 , and 36 months after surgery , and clinical outcome measurements include the Lysholm score and the IKDC rating scales . Radiological assessment s evaluated arthritic changes and tunnel expansion at 36 months postoperatively . Results The KT-1000 test scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at 12 and 36 months postoperatively ( P < 0.05 ) . The pivot-shift tests scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at the 3 , 12 , and 36 month follow-ups ( P < 0.05 ) . Based on the IKDC score and Lysholm score , there were no significant difference between the three groups during follow-up ( P > 0.05 ) . At 36 months postoperatively , 42.3 % of patients in the SB group showed a progression in arthritic changes , which was greater than in the DB-AU ( 29.2 % ) and DB-AL ( 27.3 % ) groups ( P < 0.05 ) . At 36 months , the rates of tunnel expansion in the DB-AU group and the DB-AL group were lower than in the SB group ( P < 0.05 ) . Conclusions Double-bundle ACL reconstruction can be used to achieve better anterior and rotational stability and has a lower rate of arthritic progression and tunnel expansion than the single-bundle procedure . Level of evidence Purpose To prospect ively assess the anterior tibial translation and rotational kinematics of the knee joint as well as the clinical outcome after  single-bundle ( SB ) and double-bundle ( DB ) anterior cruciate ligament ( ACL ) reconstruction .  Methods Forty-two patients r and omly underwent single-bundle ( Group SB , n = 21 ) or double-bundle ( Group DB , n = 21 ) ACL reconstruction using hamstring tendon autografts .  Anterior tibial translation and rotatory laxity were measured prior to and after fixation of the graft during reconstruction under the guidance of a navigation system . Clinical outcome measurements included the evaluation of the joint stability and functional status . Results Anterior tibial translation and rotatory laxity were improved significantly at all degrees of knee flexion in both groups . The postoperative total rotation ( sum of internal and external rotation ) at 30 ° and 60 ° ( 26.6 ° vs. 24.0 ° ; 28.7 ° vs. 25.1 ° ) as well as postoperative change in external rotation at 60 ° ( −1.4 ° vs. −4.6 ° ) , and a change in total rotation at 30 ° and 60 ° ( −7.0 ° vs. −11.5 ° ; −6.1 ° vs. −8.9 ° ) differed between the two groups , with better stability in the DB group . At 2 years follow-up , IKDC subjective satisfaction score was significantly different between two groups ( 70.9 vs. 79.6 ) , while manual and instrumented laxity , pivot shift tests , modified Lysholm score , Tegner activity score , thigh muscle strengths were not different . Correlation analysis showed little correlations between anterior laxity tests at follow-up , and the kinematic variables measured by navigation during surgery while pivot shift test , IKDC subjective satisfaction score , modified Lysholm score , and Tegner activity score were mainly correlated with navigation-measured rotations in both groups . Conclusions The kinematic tests in this study found evidence suggesting that the DB ACL reconstruction  improved rotatory laxity better than the SB ACL reconstruction at 30 ° and 60 ° of flexion , but there was no difference in functional outcome at 2 years follow-up between SB and DB groups . Level of evidence Prospect i ve comparative study , Level II 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 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 PURPOSE To evaluate the mid-to long-term results of a r and omized controlled trial of single-bundle ( SB ) versus double-bundle ( DB ) anterior cruciate ligament ( ACL ) reconstruction using a semitendinosus tendon . METHODS Seventy-eight patients who underwent primary ACL reconstruction with an autologous semitendinosus tendon  were prospect ively r and omized into 2 groups : SB reconstruction ( n = 39 ) and DB reconstruction ( n = 39 ) . In both groups , grafts were fixed at 30 ° of flexion with a total tension of 80 N. The following evaluation methods were used : clinical examination , KT-1000 arthrometer ( MEDmetric , San Diego , CA ) measurement , muscle strength , Tegner activity score , Lysholm score , subjective rating scale regarding patient satisfaction and sports performance level , graft retear , contralateral ACL tear , and additional meniscus surgery . RESULTS Fifty-three patients ( 25 in SB group and 28 in DB group ) who were followed up for a minimum of 3 years ( mean , 69 months ; range , 36 to 140 months ) were evaluated . Preoperatively , there were no differences between the groups . Postoperatively , the Lachman and pivot-shift test results were better in the DB group ( P = .024 and P < .0001 , respectively ) . KT measurements were better in the DB group ( mean , 1. 
    Output:
    
However , subgroup analysis suggested no difference between the treatment procedures at long-term follow-up .
This meta- analysis demonstrated that the DB technique could result in better rotational stability and higher subjective function score and was effective in preventing OA compared to SB in the mid-term treatment of the injured ACL .