Evaluation of the mechanical properties of posterolateral structures and supporting posterolateral instability of the knee

Abstract

The objectives of this study are to evaluate the contributions of the popliteofibular ligament (PFL), the popliteus tendon (PT), and the lateral (fibular) collateral ligament (LCL) to the posterolateral stability of the knee by changing the sequence of selective transection. Twelve fresh-frozen cadaveric knees were divided into two groups. Group 1 has a cutting sequence as follows: PFL, PT, LCL. Group 2 has a cutting sequence as follows: PT, PFL, LCL. Each specimen was mounted on the apparatuses using the Ilizarov external fixator for measuring external rotatory and varus laxities at every 308 from 08 to 908 of knee flexion. In both groups, there was no significant difference between the PFL and PT in the increment of respective external rotatory laxity after transection at each knee flexion angle, except 08 in group 2. The transection of the LCL significantly increased the external rotation laxity at 08 and 308. Varus instability was increased significantly only after cutting the LCL at every knee flexion angle. In conclusion, both the PFL and PT equally contribute to the external rotatory stability. The LCL also contributes to the external rotatory stability at early range of knee flexion. The LCL is a main structure for varus stability in the knee. ß

Biomechanical influence of deficient posterolateral corner structures on knee joint kinematics: A computational study

“…The advantage of computational simulations for a single subject is that the effects of component alignment within the identical subject can be determined and the effects of variables such as weight, height, bony geometry, and ligament properties can be excluded . In addition, most in‐vitro biomechanical studies are performed using cadavers of older individuals, in which repeated exertion in mechanical testing can not only loosen the connection between the device and specimen, but may also cause some attenuation of the tissue itself . Conversely, the MSK model is capable of including all of the tendons in the knee under daily dynamic activity, representing a realistic in‐vivo condition of the knee joint, unlike quasi‐static in‐vitro experimental conditions that utilize only partially applied muscle forces …”

“…The PT complex is a dynamic structure and a prime medial rotator of the tibia during initial flexion, releasing the lateral meniscus to supply rotatory stability to the knee . When these structures are injured, instabilities due to external rotation and posterior tibial translation are accompanied primarily by varus instability . In addition, PT injuries are present in up to 68% of patients treated for posterolateral instability, and are accompanied by frequent injuries to other structures in the knee joint …”

“…The selective resection method leads to changes in the intricate interactions and relationships between remaining knee structures, and although it removes the effect of specific sectioned structures it is advantageous for studying static stability in knee joint. However, the outcomes of studies utilizing selective resection depend on the sequence in which the structures are resected . Computational modeling has also been used to predict the kinematics and kinetics of the knee joint in order to challenge the results of in‐vivo movement assessment, and is also useful for determining the forces, pressures, and stresses on bones and soft tissues .…”

Posterior Cruciate Ligament and Posterolateral Corner Deficiency Results in a Reverse Pivot Shift

“…The multiplanar instability patterns present in the ACL-deficient knee have been previously described [9,[33][34][35]. Additionally, there have been investigations related to the uniplanar kinematics of the PCL-and PLCdeficient knee [3,8,12,13,18,24,26,27,30]. These Dr. Pearle received research funding from the Hospital for Special Surgery Institute for Sports Medicine Research.…”

Popliteus Tendon Resection During Total Knee Arthroplasty: An Observational Report

“…In extension, the popliteus tendon is posterior to the lateral collateral ligament and in flexion it resides just anterior to the lateral collateral ligament [12]. The popliteus muscle-tendon unit is an important part of the posterolateral corner of the native knee [4,9,11]. It is considered one of the main structures assisting in dorsolateral stability of the native knee [12].…”