Evaluation of the knee kinematic after anterolateral ligament reconstruction: comparison with extra-articular tenodesis

Introduction & Aims: We hypothesized that reconstruction of the anterolateral ligament (ALL) compared to a procedure of extra-articular tenodesis (LET) was more anatomical and suggested a better return to normal knee kinematics. Our objective, through a Motion analysis protocol, was to compare knee kinematics after ALL reconstruction and after LET procedure.

Method: The kinematic analyses of 10 cadaveric knees were performed using a Motion Analysis® 3D optoelectronic system. For each knee, 5 conditions were successively applied: intact knee (intact), knee with ACL and ALL resection (ALL + ACLsec), knee with only ACL reconstruction (ACLrec), knee with combined ACL and ALL reconstruction (ACL + ALLrec) and knee with an ACL reconstruction associated with a LET procedure (Christel procedure) (ACL + LETrec). We analyzed successively the 5 knee conditions comparing it respectively with intact knee, on the internal rotation (IR) and on the antero-posterior tibial translation to 30 and 60 ° of knee flexion (AP30, AP60).

Results: ALL and ACL resection leads to a significant IR and AP translation increase (p<0.05). The isolated ACL reconstruction (ACLrec), restored normal knee kinematic while correcting the IR and the AP translation (p>0.05). After ACL and ALL reconstruction, the kinematics remained comparable to a healthy knee, with a nonsignificant tendency to decrease IR; AP translation was not affected (p>0.05). After ACL reconstruction and LET procedure, the kinematics are altered with a shift in the range of motion towards external rotation, regardless of the degree of knee flexion. There is a significant decrease in IR and AP translation (p<0.05).

Conclusions: With normal knee kinematics, the ALL reconstruction appears to be more anatomically and physiologically correct than LET procedure. However, unlike LET, it did not induce any major additional control over knee stability in terms of IR and AP translation limiting. ALL reconstruction seems to be a mechanical reinforcement to protect the ACL graft during ligamentization process to avoid re-breaking, while remaining anatomical to avoid stiffness and over constraints.