Posterolateral knee instability in patients with anterior cruciate ligament lesion - clinical and MRI evaluation (case presentation)

Abstract

This paper is a retrospective study between January 2007 - September 2012, and refers to a group of 1347 patients with acute or old traumatic injury, with instability of the knee (anteroposterior or combined) and Magnetic Resonance Imaging (MRI) examination showed isolated or associated lesions of anterior cruciate ligament (ACL). Out of 1347 patients a group of 117 (8.6%) patients was selected, in whom MRI examination revealed associated lesions to the stability structures from the postero-lateral compartment. The paper is showing the spectrum of lesions identified by MRI in the postero-lateral compartment and their correlation with the mechanism of injury and the data from the clinical exam and the special tests for the clinical assessment of rotational instability. The study will present statistics on identified injuries and their MRI images. The highest incidence of lesions that have generated rotational instability included the popliteal anatomical complex formed by the popliteofibular ligament, postero-lateral capsule, arcuate ligament, fabelofibular ligament, fibular collateral ligament, biceps femoris tendon and lateral gastrocnemius tendon. To be able to give fast and accurate diagnostic information to the surgeon, with therapeutic significance, to confirm or rule out the clinical diagnostic of posterolateral rotational instability requires a good knowledge of the anatomy of the posterolateral compartment being known the vast anatomical variation and the small dimension of these structures. Not being able to recognise and treat the posterolateral compartment lesions contribute to ACL reconstruction failure due to significantly increased forces that will stress the graft with varus loading at various degrees of flexion.

Key words:

knee instability, traumatic injury, Magnetic Resonance Imaging