Biomechanical analysis of the anterolateral rotatory instability in combined anterior cruciate ligament and lateral extra-articular soft tissue reconstruction.

Approximately 5% of ACL reconstructions will fail and require revision surgery.
Traditionally, failure of the primary ACL reconstruction was believed to be
technical, traumatic, biological or a combination of these. Recent interest has
been given to the anterolateral extra-articular structures of the knee, which
might be injured during the initial ACL injury. Failure to recognize and manage
these concomitant injuries might result in persistent postoperative instability
of the knee and lead to failure of the primary ACL reconstruction. It is
believed that concomitant LES reconstruction to the ACL reconstruction might be
able to better restore the kinematics of the knee. However, no in vivo
information on the LES reconstructions exists; and the optimal flexion angle
for fixation and pre-tensioning of the graft are unknown.

The purpose of this study is to determine whether the concomitant LES
reconstruction of the knee in combination with standard revision ACL
reconstruction results in restoration of normal in vivo tibiofemoral joint
kinematics. By evaluating the in vivo kinematics using a combined dual
fluoroscopic and magnetic resonance (MR) imaging technique, of revision ACL
surgery accompanied by one of the two different LES reconstruction techniques
used in this study.

Prospective, observational cohort study with 6 months follow-up,consisting of
20 patients in total.
Patients will receive the standard ACL revision surgery as given in our clinic.
An additional anterolateral extra-articular soft tissue reconstruction will be
done. Pre-operatively an extra MRI scan will be made of the healthy
contralateral knee. Also, two additional 'dual fluoroscopic' films will be made
to evaluate the in vivo kinematica of the knee. After the surgery, standard out
clinic appointments will be scheduled. Preoperatively and postoperatively; knee
and ACL specific questionnaires will be taken (KOOS, IKDC and Tegner).

Standard orthopaedic care will be given to all patients. As this is an
observational study, there is no direct benefit for the patient. An additional
MR scan of the contralateral knee will be made. Also, two observational tests
to the regular treatment will be made by means of a dual fluoroscopic
technique, exposing the patient to additional Rontgen rays. Future patients
will benefit from this study as surgical techniques will be optimized based on
these results.