HC Chang Orthopaedic Surgery | Singapore

Tears of the anterior cruciate ligament (ACL) are some of the commonest conditions seen and treated in my practice.

The natural ACL is made up of 2 anatomically and functionally distinct bundles.  They are named the anteromedial bundle (AMB) and the posterolateral bundle (PLB) based on the position of the fibres in the central part of the knee joint.

ACL reconstruction surgeons have traditionally reconstructed the larger and functionally more important bundle and that was the anteromedial bundle (AMB).   The understanding of the role of the posterolateral bundle (PLB) was lacking and the ability to reconstruct this bundle was not well accepted until recent years.

Through cadaveric knee anatomical dissection studies as well as biomechanical studies, sports and knee surgeons now have a better understanding of the importance of the once neglected posterolateral bundle (PLB)  of the ACL.

Criticism of Single Bundle ACL Reconstructions

Biomechanical studies with cadaver knees

• 1 bundle  ACL reconstruction cannot completely restore the normal anterior laxity
• 1 bundle ACL reconstruction has no effect on the rotatory instability
  Woo et al: JBJS, 84A:907, 2002
  Yagi, et al: AJSM, 30: 660, 2002

Kinematic analyses with patients

• 1 bundle ACL reconstruction cannot improve the rotatory instability during walking or running, independent of the graft (BTB, Hamstring, etc)
  Georgoulis et al:  AJSM, 31: 75, 2003
  Ristanis et al: Arthroscopy, 21: 1323, 2005
  Chouliaras et al: AJSM, 35:189, 2007
  Tashman et al: Clin Orthop, 454: 66, 2007

What Are The Roles of Each ACL Bundle?

Posterolateral bundle (PLB) acted dominantly in extension, while the anteromedial bundle (AMB) mainly resisted against anterior tibial load in flexion. Hence each bundle have specific role in providing knee stability at different knee flexion angle.

Comparing Single Bundle to Double Bundle ACL Reconstructions

Double Bundle ACL Reconstruction Gives a More Stable Knee

8 papers showing Double Bundle ACL Reconstruction is Clinically Better than Single Bundle ACL Reconstruction

2006  Yasuda et al: Arthroscopy  (level 2)  n=  72
2007  Agllieti et al: CORR  (level 2)   n=  75
2007  Yagi, Kurosaka, et al: CORR  (level 1)  n=  60
2007  Jarvela: KSSTA  (level 1)   n=  65
2007  Muneta et al: Arthroscopy  (level 1)  n=  68
2008  Siebold et al: Arthroscopy  (level 1)  n=  70 
2008  Streich et al: KSSTA  (level 1)   n=  50
2008  Kondo, Yasuda, et al: AJSM  (level 2)  n=  328 

Double Bundle ACL Reconstruction

What Have I Found Out After Doing More Than 60 Cases of Double Bundle ACL Reconstructions?

• The reconstructed knee feels more stable when examined. 
• The rotatory control or knee pivoting stability is superior to single bundle reconstructions. 
• Patients are generally more satisfied with their surgical outcome.

For more information on Double Bundle ACL Reconstructions, please contact us at 683 666 36 or email hcchang@ortho.com.sg.