Can arthroscopic techniques contribute to further development of PLC injury treatment?
Dr Matthias Krause (right) at the first AO Sports Advanced Course--Knee Injuries and Deformities, AO Davos Courses, 2021
By: Matthias Krause, MD, PhD
Senior physician, specialist in orthopedics and trauma surgery
Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
Injuries to the posterolateral corner (PLC) are common in posterior instabilities of the knee but may also be found in anterior cruciate ligament (ACL) injuries. The PLC consists of the popliteus muscle/tendon unit (PLT), the popliteofibular ligament (PFL), the fabellofibular ligament, and the popliteomeniscal fibers (arcuate complex [AC]).
PLC injury may lead to increased posterior, external rotational, and/or varus instability and, thus, provide the biomechanical basis for graft failure following cruciate ligament reconstruction due to missing load sharing support. Accordingly, anatomical reconstruction techniques have been proposed to stabilize the PLC better than nonanatomical techniques.
Arthroscopic procedures for the treatment of posterolateral instabilities
Recently, arthroscopic procedures have gained popularity for the treatment of posterolateral instabilities. Some targeted techniques, such as the arthroscopic popliteus bypass, are designed to address isolated rotational instabilities (eg, Fanelli type A). Other technical descriptions have focused on arthroscopic techniques for complex anatomical PLC reconstruction. Although these techniques show promising biomechanical and clinical results, they are technically demanding and require a fundamental understanding of the arthroscopic posterolateral anatomy.
Fibular tunnel placement
The accurate and reliable anatomical tunnel placements for arthroscopic PLC reconstruction at the femoral and tibial sides have already been described. With respect to the fibular tunnel, “anatomical” typically refers to the single-tunnel fixation from anterolateral inferior to posteromedial superior, mimicking the fibular collateral ligament (FCL) and PFL footprints in contrast to a nonanatomical anteroposterior tunnel trajectory. As the PFL is the most important static stabilizer against tibial external rotation, exact and reliable fibular tunnel placement is crucial, especially as the fragile fibular head is prone to fracture, graft loosening, and subsequent laxity. With the recent progress of arthroscopic PLC reconstruction techniques, anatomical fibular tunnel placement might be improved but has not yet been validated, especially in direct comparison to open reconstruction. In a recent study, the accuracy of arthroscopic fibular tunnel placement was compared with the open technique in terms of their safe distance to surrounding cortical edges of the fibular head.