Background:To perform anatomical anterior cruciate ligament reconstruction(ACLR),tunnels should be placed relatively higher in the femoral anterior cruciate ligament(ACL)footprint based on the findings of direct and i...Background:To perform anatomical anterior cruciate ligament reconstruction(ACLR),tunnels should be placed relatively higher in the femoral anterior cruciate ligament(ACL)footprint based on the findings of direct and indirect femoral insertion.But the clinical results of higher femoral tunnels(HFT)in double-bundle ACLR(DB-ACLR)remain unclear.The purpose was to investigate the clinical results of HFT and lower femoral tunnels(LFT)in DB-ACLR.Methods:From September 2014 to February 2016,83 patients who underwent DB-ACLR and met the inclusion and exclusion criteria were divided into HFT-ACLR(group 1,n=37)and LFT-ACLR(group 2,n=46)according to the position of femoral tunnels.Preoperatively and at the final follow-up,clinical scores were evaluated with International Knee Documentation Committee(IKDC),Tegner activity,and Lysholm score.The stability of the knee was evaluated with KT-2000,Lachman test,and pivot-shift test.Cartilage degeneration grades of the International Cartilage Repair Society(ICRS)were evaluated on magnetic resonance imaging(MRI).Graft tension,continuity,and synovialization were evaluated by second-look arthroscopy.Return-to-sports was assessed at the final follow-up.Results:Significantly better improvement were found for KT-2000,Lachman test,and pivot-shift test postoperatively in group 1(P>0.05).Posterolateral bundles(PL)showed significantly better results in second-look arthroscopy regarding graft tension,continuity,and synovialization(P<0.05),but not in anteromedial bundles in group 1.At the final follow-up,cartilage worsening was observed in groups 1 and 2,but it did not reach a stastistically significant difference(P>0.05).No statistically significant differences were found in IKDC subjective score,Tegner activity,and Lysholm score between the two groups.Higher return-to-sports rate was found in group 1 with 86.8%(32/37)vs.65.2%(30/46)in group 2(P=0.027).Conclusion:The HFT-ACLR group showed better stability results,better PL,and higher return-to-sports rate compared to the LFT-ACLR group.展开更多
Background Several reports have shown the progression of articular cartilage degeneration after anterior cruciate ligament （ACL） reconstruction. No report has been published about the cartilage comparing changes aft...Background Several reports have shown the progression of articular cartilage degeneration after anterior cruciate ligament （ACL） reconstruction. No report has been published about the cartilage comparing changes after single-bundle （SB） and double-bundle （DI3） ACL reconstructions. The purpose of this study was to evaluate the articular cartilage changes after SB and DB ACL reconstructions by second-look arthroscopy. Methods Ninety-nine patients who received arthroscopic ACL reconstruction were retrospectively reviewed at an average of 14 months after reconstruction, 58 patients underwent SB ACL reconstruction and 41 patients underwent DB ACL reconstruction. Hamstring tendon autografts were used in all patients. Second-look arthroscopy was done in conjunction with the tibial staple fixation removal at least one year after the initial ACL reconstruction. Arthroscopic evaluation and grading of the articular cartilage degeneration for all patients were performed at the initial ACL reconstruction, and at the second-look arthroscopy. Results The average cartilage degeneration at the patellofemoral joint （PFJ） was found significantly worsened after both SB and DB ACL reconstructions. This worsening were not seen at medial tibiofemoral joint （TFJ） and lateral TFJ. Grade II cartilage damage was the most common. At second-look arthroscopy, the average patellar cartilage degeneration was 1.14±0.14 （at first look 0.52±0.11） for the SB group, and 1.22±0.15 （at first look 0.56±0.12） for the DB group. The average trochlear cartilage degeneration was 1.05±0.16 （at fist look 0.10±0.06） and 0.66±0.17 （at fist look 0.17±0.09）, respectively. The average patellar cartilage degeneration showed no significant difference in both groups. However, the average trochlea cartilage degeneration in DB group was significantly less than in SB group. Conclusions Patellofemoral cartilage degeneration continued to aggravate after ACL reconstruction. DB ACL reconstruction could significantly decrease the trochlea cartilage degeneration compared with SB ACL reconstruction.展开更多
Background In clinical studies there is still a lot of controversy about the increased anterior and rotational stability between double-bundle （DB） and single-bundle （SB） anterior cruciate ligament （ACL） reconst...Background In clinical studies there is still a lot of controversy about the increased anterior and rotational stability between double-bundle （DB） and single-bundle （SB） anterior cruciate ligament （ACL） reconstruction. The aim of this study was to evaluate the clinical results of four-tunnel DB ACL reconstruction.Methods Sixty-four consecutive patients with ACL ruptures from May 2005 to May 2006 were randomly assigned into two groups： 32 cases for SB ACL reconstruction and 32 cases for DB ACL reconstruction. Clinical data, including KT 2000, Biodex test, Lysholm score, Tegner score and IKDC score, were prospectively collected until at least 10 months post-operative.Results The average values of KT 2000 were （1.47±1.17） mm and （1.68±1.14） mm for the SB and DB ACL reconstruction groups at 30° of knee flexion （P 〉0.05）, and were （1.04±0.98） mm and （1.13±0.98） mm at 90° of knee flexion （P 〉0.05）. There were also no significant differences in Lysholm score, Tegner score, IKDC score and Biodex test scores between the two groups （P 〉0.05）. The operation time of DB ACL reconstruction was 20 minutes longer than the SB ACL reconstruction （P 〈0.05）Conclusion Double bundle ACL reconstructions have no obvious clinical advantages over single bundle ACL reconstructions.展开更多
In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transfer...In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.展开更多
基金supported by the Beijing Natural Science Foundation of China(No.J210011)the National Natural Science Foundation of China(No.U22A2051)the Ministerial Commission of Science and Technology(No.JK-2022-07).
文摘Background:To perform anatomical anterior cruciate ligament reconstruction(ACLR),tunnels should be placed relatively higher in the femoral anterior cruciate ligament(ACL)footprint based on the findings of direct and indirect femoral insertion.But the clinical results of higher femoral tunnels(HFT)in double-bundle ACLR(DB-ACLR)remain unclear.The purpose was to investigate the clinical results of HFT and lower femoral tunnels(LFT)in DB-ACLR.Methods:From September 2014 to February 2016,83 patients who underwent DB-ACLR and met the inclusion and exclusion criteria were divided into HFT-ACLR(group 1,n=37)and LFT-ACLR(group 2,n=46)according to the position of femoral tunnels.Preoperatively and at the final follow-up,clinical scores were evaluated with International Knee Documentation Committee(IKDC),Tegner activity,and Lysholm score.The stability of the knee was evaluated with KT-2000,Lachman test,and pivot-shift test.Cartilage degeneration grades of the International Cartilage Repair Society(ICRS)were evaluated on magnetic resonance imaging(MRI).Graft tension,continuity,and synovialization were evaluated by second-look arthroscopy.Return-to-sports was assessed at the final follow-up.Results:Significantly better improvement were found for KT-2000,Lachman test,and pivot-shift test postoperatively in group 1(P>0.05).Posterolateral bundles(PL)showed significantly better results in second-look arthroscopy regarding graft tension,continuity,and synovialization(P<0.05),but not in anteromedial bundles in group 1.At the final follow-up,cartilage worsening was observed in groups 1 and 2,but it did not reach a stastistically significant difference(P>0.05).No statistically significant differences were found in IKDC subjective score,Tegner activity,and Lysholm score between the two groups.Higher return-to-sports rate was found in group 1 with 86.8%(32/37)vs.65.2%(30/46)in group 2(P=0.027).Conclusion:The HFT-ACLR group showed better stability results,better PL,and higher return-to-sports rate compared to the LFT-ACLR group.
文摘Background Several reports have shown the progression of articular cartilage degeneration after anterior cruciate ligament （ACL） reconstruction. No report has been published about the cartilage comparing changes after single-bundle （SB） and double-bundle （DI3） ACL reconstructions. The purpose of this study was to evaluate the articular cartilage changes after SB and DB ACL reconstructions by second-look arthroscopy. Methods Ninety-nine patients who received arthroscopic ACL reconstruction were retrospectively reviewed at an average of 14 months after reconstruction, 58 patients underwent SB ACL reconstruction and 41 patients underwent DB ACL reconstruction. Hamstring tendon autografts were used in all patients. Second-look arthroscopy was done in conjunction with the tibial staple fixation removal at least one year after the initial ACL reconstruction. Arthroscopic evaluation and grading of the articular cartilage degeneration for all patients were performed at the initial ACL reconstruction, and at the second-look arthroscopy. Results The average cartilage degeneration at the patellofemoral joint （PFJ） was found significantly worsened after both SB and DB ACL reconstructions. This worsening were not seen at medial tibiofemoral joint （TFJ） and lateral TFJ. Grade II cartilage damage was the most common. At second-look arthroscopy, the average patellar cartilage degeneration was 1.14±0.14 （at first look 0.52±0.11） for the SB group, and 1.22±0.15 （at first look 0.56±0.12） for the DB group. The average trochlear cartilage degeneration was 1.05±0.16 （at fist look 0.10±0.06） and 0.66±0.17 （at fist look 0.17±0.09）, respectively. The average patellar cartilage degeneration showed no significant difference in both groups. However, the average trochlea cartilage degeneration in DB group was significantly less than in SB group. Conclusions Patellofemoral cartilage degeneration continued to aggravate after ACL reconstruction. DB ACL reconstruction could significantly decrease the trochlea cartilage degeneration compared with SB ACL reconstruction.
文摘Background In clinical studies there is still a lot of controversy about the increased anterior and rotational stability between double-bundle （DB） and single-bundle （SB） anterior cruciate ligament （ACL） reconstruction. The aim of this study was to evaluate the clinical results of four-tunnel DB ACL reconstruction.Methods Sixty-four consecutive patients with ACL ruptures from May 2005 to May 2006 were randomly assigned into two groups： 32 cases for SB ACL reconstruction and 32 cases for DB ACL reconstruction. Clinical data, including KT 2000, Biodex test, Lysholm score, Tegner score and IKDC score, were prospectively collected until at least 10 months post-operative.Results The average values of KT 2000 were （1.47±1.17） mm and （1.68±1.14） mm for the SB and DB ACL reconstruction groups at 30° of knee flexion （P 〉0.05）, and were （1.04±0.98） mm and （1.13±0.98） mm at 90° of knee flexion （P 〉0.05）. There were also no significant differences in Lysholm score, Tegner score, IKDC score and Biodex test scores between the two groups （P 〉0.05）. The operation time of DB ACL reconstruction was 20 minutes longer than the SB ACL reconstruction （P 〈0.05）Conclusion Double bundle ACL reconstructions have no obvious clinical advantages over single bundle ACL reconstructions.
基金Supported by National Natural Science Foundation of China(Grant Nos.11001146,11101179)the Beijing Higher Education Young Elite Teacher Project
文摘In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.
