Does additional reconstruction of the anterolateral ligament during a primary anterior cruciate ligament reconstruction affect tibial rotational laxity - A case series

- To prevent excessive rotation in the knee, a structure needs to be present away from the centre axis; at the edge of a plane, resisting rotational motion.
- The graded pivot-shift is a useful clinical test to help delineate extent of ligamentous laxity within the knee.
- The higher the grade of the pivot-shift in the ACL deficient knee, the greater the TRR present.
- The ALL plays a significant role in ACL deficient knees with a grade-3 pivot shift, restoring TRR at time-zero.
- Further research is required assessing long-term patient-centered clinical outcomes.

BackgroundThe current evidence suggests that rotational stability in not restored in patients with anterior cruciate ligament (ACL) ruptures, despite reconstructive surgery. The graded pivot-shift is a useful clinical test to delineate extent of ligamentous laxity within the knee. Given its lateralised position, we hypothesized that reconstruction of the anterolateral ligament (ALL) would provide restraint to excessive internal rotation, restoring rotational stability.Methods10 patients with MRI confirmed diagnosis of an isolated ACL rupture were included. Patients assigned a grade-3 pivot-shift underwent dual-ligament reconstruction for the ACL and ALL (Group 2), whilst patients with an absent pivot-shift, grade-1 or grade-2 underwent single ligament reconstruction for just the ACL (Group 1). Total range of rotation (TRR) was measured using a 3D-kinematic system at 30°,60°and 90° of knee flexion. Data was collected on the pathology-free contralateral normal knee (CNK), ACL-deficient knee (ADK) and the ACL-reconstructed knee (ARK).ResultsA statistically significant pre-operative difference in TRR between the CNK and ADK was noted between Group 1 and 2 (4.04° vs. 1.53°; p < 0.05). Postoperatively, both groups achieved a TRR that was either equivalent, or surpassed values that were observed on the CNKs. The absolute and percentage reduction in TRR at 30° of knee flexion was significantly higher in Group-2 compared to Group-1 (−8.15° vs. −2.96°; p < 0.001) and (28.04% vs. 13.31%; p < 0.001) respectively.ConclusionOur findings are based primarily in anaesthetized patients, with kinematic values at time-zero postoperatively. Patients presenting with significant rotational instability following a primary ACL injury and assessed to have a grade-3 pivot-shift may benefit from dual-ligament reconstruction. Further research is required to assess long-term patient-centered clinical outcomes.