Structural and Kinetic Analysis of Knee Joint Injury

Knee injuries are common occurrences in every sport, especially due to tearing of
anterior cruciate ligament or the menisci. Anterior cruciate ligament deficiency causes altered
stability of the knee. ACL (anterior cruciate ligament) deficient knee shows pathological
laxity causing instability in the knee. Kinetic measure of laxity involves assessing the force
and magnitude of the movement, hence the close association with the biomechanical element
of compliance. Rotation is the magnitude of movement of the tibia in relation to femur and is
measured in degrees. The turning force applied primarily by the anterior cruciate ligament
and other structures contributed to the joint movement and is measured in newton-meters.
There are numerous studies that have been carried out to study rotation of the tibia in knee
injuries related to defective ACL.
Anatomy

The knee is considered an intricate joint in the body, and also the largest. It joins the femur,
shin bone, fibula and the knee cap. Since it has a fluid filled capsule that helps smooth
movement because it is a synovial joint. It is also helps an individual bear weight during body
movements and consists of bones, ligaments, meniscus, and tendons. The femur, tibia, and
patella- also known as the knee cap, comprise the bones of the knee. The meniscus are the
discs that act a shock absorber so that the bones of the knee can rotate through their degree of
motion without rubbing against each other. The medial meniscus is positioned on the inner
part of the joint while the lateral meniscus is more on the outer side. The knee also has
ligaments, tough and fibrous tissues, which connect bones to other bones increasing stability
and minimizing motion. The ligaments in a healthy, normal knee include the: anterior
cruciate ligament (ACL), the posterior cruciate ligament (PCL), medial collateral ligament
(MCL), and lateral collateral ligament (LCL). During movement, tendons also play a crucial
role by connecting bone to muscle.

The complex anatomy of the knee makes it vulnerable to strains and sprain injuries to the
ligaments and menisci. The medial collateral ligament and anterior cruciate ligaments are the
most often injured and happen in sports like basketball, handball, and football where the knee
might experience a sudden twisting movement, an incorrect landing when the player jumps,
or abrupt change in motion. In most case, a ‘pop’ sound is heard followed by inflammation.
Other symptoms include tenderness on the injured area and pain when walking. Rotational
moments in ACLD knees during natural movements have also been reported in including

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walking, jumping, or running. During walking, observations were described by Heiden,
Llyoyd and Ackland (2009), who discovered lower internal rotational moment ACL deficient
knees compared to a healthy group. It is mainly Tsarouhas et al. Who investigated the
rotational moments of force on the same injury during pivoting and, no notable differences in
rotational moments was discovered in both knees (Wilson et al., 2011, Tsarouhas et
al., 2011). In some contexts, rotational movements during running have not been reported in
ACLD participants in the past. Overall external knee joint movements in both knees of the
ACL-injured patients are higher, and kinematic results during walking and running show both
knees of the ACLD group to be inherently different from a healthy control group. This
indicates that there could be presence of compensatory or adaptive strategy for both knees of
the ACLD group. Ffurthermore, kinetics of the contralateral limb are not quite different or
indicative of healthy knees during an ACL.

Biomechanics and Osteokinematics
Knee joint activities are three-dimensional and include the backward and forward movement
of the femur and the axial rotation of the tibia. The extension and flexion of the tibia is
between 0 to 150 degrees, taking the vertical axis of the knee joint as the focal point. The
condyles of the femur facilitate a stable mechanism for the sliding of the patella and the force
in the muscle group varies based on extension and flexion movements of the knee joints,
which is normally stable within the range of 90 to 135 degrees. In most cases, injury to the
knee during exercise is related to the meniscus, which reduces the stability of the knee joint
and increases the stress. The knee moves primarily by flexion-tension, where the patella and
tibia act in accordance to the movement or position of the femur. The movement of the knee
is also aided by the contraction of the quadriceps and hamstring muscles. During quadriceps
contraction, the range of motion (ROM) is inferred to extension at 0 0 . ROM for the hamstring
group of muscles flex, contributing to 140 0 flexion.

One study found out that meniscus injury leads to reduction on speed and endurance
when an injured group was compared with a healthy group. Stress in knee joint decreased
with the increase in flexion angel, exerting more pressure. For instance, increment in flexion
angle from 0 to 120 degrees in healthy people led to decreased pressure for 12.468 to 5.443
cm 2 (Zhou, 2018). These results indicate that stressed part of the knee joints of the injured
participants was significantly smaller than that of the healthy participants without knee injury
during any flexion angles. Moreover, the mean observed and recorded pressure of the

STRUCTURAL AND KINEMATICS OF KNEE JOINT INJURY 4
participants in the injury experimental group was significantly higher than that of their
healthy counterparts.

References

Heiden, T. L., Lloyd, D. G., & Ackland, T. R. (2009). Knee joint kinematics, kinetics and
muscle co-contraction in knee osteoarthritis patient gait. Clinical biomechanics, 24(10),
833-841.
Lin, C. F., Hua, S. H., Huang, M. T., Lee, H. H., & Liao, J. C. (2015). Biomechanical
analysis of knee and trunk in badminton players with and without knee pain during
backhand diagonal lunges. Journal of sports sciences, 33(14), 1429-1439.
Tsarouhas, A., Iosifidis, M., Kotzamitelos, D., Spyropoulos, G., Tsatalas, T., & Giakas, G.
(2010). Three-dimensional kinematic and kinetic analysis of knee rotational stability
after single-and double-bundle anterior cruciate ligament reconstruction. Arthroscopy:
The Journal of Arthroscopic & Related Surgery, 26(7), 885-893.
Wilson, J. A., Deluzio, K. J., Dunbar, M. J., Caldwell, G. E., & Hubley-Kozey, C. L. (2011).
The association between knee joint biomechanics and neuromuscular control and
moderate knee osteoarthritis radiographic and pain severity. Osteoarthritis and
Cartilage, 19(2), 186-193.
Zhou, T. (2018). Analysis of the biomechanical characteristics of the knee joint with a
meniscus injury. Healthcare technology letters, 5(6), 247-249.