The Influence of Knee Flexion Angle for Graft Fixation on Rotational Knee Stability During Anterior Cruciate Ligament Reconstruction: A Biomechanical Study

Arthroscopy. 2016 Nov;32(11):2322-2328. doi: 10.1016/j.arthro.2016.03.018. Epub 2016 May 14.


Purpose: To evaluate the effect of knee flexion angle for hamstring graft fixation, full extension (FE), or 30°, on acceleration of the knee motion during pivot-shift testing after either anatomic or nonanatomic anterior cruciate ligament (ACL) reconstruction using triaxial accelerometry.

Methods: Two types of ACL reconstructions (anatomic and nonanatomic) using 2 different angles of knee flexion during graft fixation (FE and 30°) were performed on 12 fresh-frozen human knees making 4 groups: anatomic-FE, anatomic-30°, nonanatomic-FE, and nonanatomic-30°. Manual pivot-shift testing was performed at ACL-intact, ACL-deficient, and ACL-reconstructed conditions. Three-dimensional acceleration of knee motion was recorded using a triaxial accelerometer.

Results: The anatomic-30° group showed the smallest overall magnitude of acceleration among the ACL-reconstructed groups (P = .0039). There were no significant differences among the anatomic-FE group, the nonanatomic-FE group, and the nonantomic-30° group (anatomic-FE vs nonanatomic-FE, P = .1093; anatomic-FE vs nonanatomic-30°, P = .8728; and nonanatomic-FE vs nonanatomic-30°, P = .1093). After ACL transection, acceleration was reduced by ACL reconstruction with the exception of the nonanatomic-FE group that did not show a significant difference when compared with the ACL-deficient (P = .4537).

Conclusions: The anatomic ACL reconstruction with the graft fixed at 30° of knee flexion better restored rotational knee stability compared with FE. An ACL graft fixed with the knee at FE in anatomic position did not show a significant difference compared with the nonanatomic ACL reconstructions.

Clinical relevance: Knee flexion angle at the time of graft fixation for ACL reconstruction can be considered to maximize the rotational knee stability.

MeSH terms

  • Aged
  • Anterior Cruciate Ligament Injuries / surgery*
  • Anterior Cruciate Ligament Reconstruction / adverse effects
  • Anterior Cruciate Ligament Reconstruction / methods*
  • Arthroscopy / adverse effects
  • Arthroscopy / methods
  • Biomechanical Phenomena
  • Cadaver
  • Female
  • Humans
  • Joint Instability / prevention & control*
  • Joint Instability / surgery*
  • Knee Joint / physiology*
  • Knee Joint / surgery*
  • Male
  • Middle Aged
  • Movement
  • Postoperative Complications / prevention & control
  • Rotation
  • Tendons / transplantation
  • Transplantation, Homologous