Biomechanical Analysis of Tibial Torque and Knee Flexion Angle

Abstract

Knee injuries are common in sports activities. Understanding the mechanisms of injury allows for better treatment of these injuries and for the development of effective prevention programmes. Tibial torque and knee flexion angle have been associated with several mechanisms of injury in the knee. This article focuses on the injury to the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL) and the meniscus of the knee as they relate to knee flexion angle and tibial torque. Hyperflexion and hyperextension with the application of tibial torque have both been implicated in the mechanism of ACL injury. A combination of anterior tibial force and internal tibial torque near full extension puts the ACL at high risk for injury. Hyperflexion also increases ACL force; however, in this position, internal and external tibial torque only minimally increase ACL force. Several successful prevention programmes have been based on these biomechanical factors. Injury to the PCL typically occurs in a flexed or hyperflexed knee position. The effects of application of a tibial torque, both internally and externally, remains controversial. Biomechanical studies have shown an increase in PCL force with knee flexion and the application of internal tibial torque, while others have shown that PCL-deficient knees have greater external tibial rotation. The meniscus must endure greater compressive loads at higher flexion angles of the knee and, as a result, are more prone to injury in these positions. In addition, ACL deficiency puts the meniscus at greater risk for injury. Reducing the forces on the ACL, PCL and meniscus during athletic activity through training, the use of appropriate equipment and safe surfaces will help to reduce injury to these structures.

Contraction type influences the human ability to use the available torque capacity of skeletal muscle during explosive efforts

“…Earlier studies have also reported reduced agonist activation during voluntary contractions at more extended knee angles [4,20,30,31], and this effect is thought to be a neural mechanism that protects the knee joint near full extension, where loading of the anterior cruciate ligament is greatest [32].…”

Risk Factors for Meniscal Tears: A Systematic Review Including Meta-analysis

“…38,46 Our systematic review is limited by the fact that most of the findings were derived from a very small number of studies. This was, in part, the result of excluding articles based on study design 3,9,10,12,38,47,49,[51][52][53]63,64,66 and the age of participants. 13,30,31,36,37,40,44,54,57,60 For a factor to be considered as a "risk" for meniscal tears, the prospective and retrospective period of exposure to the risk had to be sufficiently long.…”

Is Noncontact ACL Injury Associated with the Posterior Tibial and Meniscal Slope?

“…When assessed on a lateral radiograph, a high-degree measurement error can exacerbate the variability [16,26]. It remains unclear whether noncontact ACL injury is a result of a greater medial PTS, lateral PTS, or both [6,39,43]. Regardless of which plateau is associated with an injury risk, the menisci play a role in AP knee stability and may modify this stability when injured or resected [25,36].…”