Different Degrees Of Knee Flexion Research Articles

Effect of knee flexion angle on ground reaction forces, knee moments and muscle co-contraction during an impact-like deceleration landing: Implications for the non-contact mechanism of ACL injury

Investigating landing kinetics and neuromuscular control strategies during rapid deceleration movements is a prerequisite to understanding the non-contact mechanism of ACL injury. The purpose of this study was to quantify the effect of knee flexion angle on ground reaction forces, net knee joint moments, muscle co-contraction and lower extremity muscles during an impact-like, deceleration task. Ground reaction forces and knee joint moments were determined from video and force plate records of 10 healthy male subjects performing rapid deceleration single leg landings from a 10.5 cm height with different degrees of knee flexion at landing. Muscle co-contraction was based on muscle moments calculated from an EMG-to-moment processing model. Ground reaction forces and co-contraction indices decreased while knee extensor moments increased significantly with increased degrees of knee flexion at landing (all p < 0.005). Higher ground reaction forces when landing in an extended knee position suggests they are a contributing factor in non-contact ACL injuries. Increased knee extensor moments and less co-contraction with flexed knee landings suggest that quadriceps overload may not be the primary cause of non-contact ACL injuries. The results bring into question the counterbalancing role of the hamstrings during dynamic movements. The soleus may be a valuable synergist stabilizing the tibia against anterior translation at landing. Movement strategies that lessen the propagation of reaction forces up the kinetic chain may help prevent non-contact ACL injuries. The relative interaction of all involved thigh and lower leg muscles, not just the quadriceps and hamstrings should be considered when interpreting non-contact ACL injury mechanisms.

Femoral seating position of the EndoButton in single incision anterior cruciate ligament reconstruction: an anatomical study

Arthroscopic EndoButton fixation of anterior cruciate ligament (ACL) grafts over the femoral cortex has become popular in recent years. However, elongation of fixation materials has lead to tunnel enlargement, graft tunnel motion and instability. Synovial fluid passages along femoral tunnels following ACL reconstruction may result in destruction of tissues. The purpose of the present study was to identify the seating position of the EndoButton in regard to the boundaries of the knee capsule in single-incision arthroscopic ACL reconstruction. A total of 20 cadaveric knees were dissected and arthroscopic drill guides were used to create tibial and femoral tunnels. The distances between the exit points and boundaries of the suprapatellar bursa at three different degrees of knee flexion were measured. The average distances from the exit points to the superior boundaries of the suprapatellar bursa were 6.89 +/- 5.40 mm (range, 16.87-1.21). However, in knee flexion of greater than 90 degrees , tunnel exits were placed below the superior boundaries of the suprapatellar bursa (-7.08 +/- 3.69 mm, range, -3.24 to -12.87). In order to place the EndoButton extraarticularly, a safe degree of knee flexion during femoral tunnel drilling was defined as 80 degrees .

The dynamic relations of the posterior cruciate ligament

This study attempts to identify the immediate relations of the posterior cruciate ligament (PCL) during different degrees of knee flexion. Cadaveric dissection and magnetic resonance imaging of living subjects found that the popliteal artery is tethered to the oblique popliteal ligament behind the knee, but is free to move above and below this level. Movement of the neurovascular structures as a whole occurs during motion of the knee. These factors have implications for surgical practice, not only for PCL reconstruction, but also for any procedure requiring instrumentation to the back of the knee, such as total knee arthroplasty.

Knee diagram for the documentation of arthroscopic findings of the knee — cadaveric study

There is a need for an accurate representation of arthroscopic knee findings on a diagram. The first time in the literature this Knee Diagram is generated, using three-dimensional projection of the four dissected cadaveric knees articular surfaces. Computer-aided design and drafting software is utilized to find the average dimensions of the four cadaveric knee surfaces. Mercator earth projection principle is applied in drawing the `latitude lines' on the femoral condyles at different degrees of knee flexion, corresponding to the anterior edge of the tibial articular surface as the reference point. This Knee Diagram using the tibial articular margin as a reference point, is not only useful for the accurate representation of the arthroscopic knee findings but also the most useful way to correlate the MRI findings of the femoral cartilage defect with the arthroscopic findings. Most useful of all are the reference latitude lines of the femoral condyles that remain a fixed landmark for that particular knee and thus helps to locate the same lesion at repeated arthroscopic evaluations, by different observers. A grid on the diagram helps to map the cartilage defect in millimetres. In this era of research on cartilage grafting, we think this Knee Diagram will be particularly useful to document and follow-up knee lesions in a more scientific way.

Anatomy of the posterior cruciate ligament. A review.

PCL injuries are major injuries of the knee. Most of the literature on PCL injury has focused on mechanism of injury, diagnosis, and treatment. We are presenting a review of the anatomy of the PCL. Different portions of the PCL are taut at different degrees of knee flexion and extension. The PCL, thus, along with the ACL, contributes to the "screwhome mechanism" of the knee. The anatomy of the meniscofemoral ligaments (ligaments of Wrisberg and Humphrey) reveals the intimate relationship among the PCL, the popliteus muscle, and the lateral meniscus. Understanding the anatomy of the PCL is important in the diagnosis and treatment of ligamentous injuries and also in total knee arthroplasty.