Poster 297: Deep medial collateral ligament reconstruction of the knee restores rotational stability throughout full range of motion while contemporary MCL reconstruction only does in extension

Objectives: The past decade has taught the importance of identifying and treating concomitant injuries that frequently occur at time ACL rupture. Failure to do so can result in increased stresses on graft subsequently risk failure. While focus largely been menisci anterolateral soft tissues, recent studies have highlighted high frequency which medial structures previously presumed isolated tears poor outcomes when they are not addressed. Injuries ligament complex valgus anteromedial rotatory instability (AMRI). Historic MCL reconstruction techniques focused superficial an effort restore stability while ignoring deep controlling tibial external rotation. recognition led multiple revisiting sided anatomy questioning contemporary techniques. objective this study is assess compare ability a collateral (MCL) (dMCL) rotational knee. Methods: Six pairs fresh-frozen cadaveric knee specimens were included with intact tissue, distal femur tibia potted PVC pipes facilitate biomechanical testing using customized multi-axial activity simulator. Four states tested: 1) 2) after sectioning sMCL dMCL, 3) as described by LaPrade et al, 4) dMCL reconstruction. In each state, knees tested under four loading conditions varying flexion angles (0°, 20°, 40°, 60° 90°): 8 Nm torque, 5 rotation 90N anterior drawer, combined 90 N drawer plus torque. Results: Transection resulted laxity application all angles. restored levels (all p<0.05) throughout degrees (Figure 1), yet did any angle 2). Contemporary 0° 20° 40° (p<0.01). response rotation, back level improved between 90° (Figures 3 4). contrast, degree (p>0.05). Conclusions: Deep range motion but stability. only near full extension.