JII BCS Exam: Knee Design And Function! Quiz

The JBCS Knee System is able to restore normal knee function by increasing anterior-posterior stability throughout knee flexion and promoting a normal kinematic pattern. By doing so, it helps to improve the overall movement and stability of the knee joint. The option "A & B" correctly represents these two aspects of the JBCS Knee System.

The JBCS knee system was designed to restore normal knee function by incorporating several novel design features. One of these features is an anatomically correct joint line and articulating surface, which helps to mimic the natural movement of the knee. Additionally, the knee system includes an anterior and internally rotated position of the femur in extension, which further enhances stability and function. Lastly, the system incorporates a dual cam design that replicates both the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), providing additional stability and promoting a normal kinematic pattern. Therefore, all of the above design features contribute to the goal of restoring normal knee function.

The correct answer is 15 degrees. In the JBCS, the posterior femoral condylar surfaces were extended with minimal bone resection through a 15-degree flexed cut. This procedure involved completely replacing the articular surfaces and restoring the original posterior offsets.

The JBCS (Joint Bi-Cruciate Stabilized) implant allows for the restoration of the posterior femoral condylar articular surfaces and offsets, as well as the lateral femoral rollback. This combination of features enables deep flexion of the knee joint. Among the given options, the highest degree of flexion mentioned is 155 degrees, making it the correct answer.

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The JOURNEY BCS (JBCS) was the first 'guided-motion' kinematically accurate knee design on the market. This suggests that this particular knee design incorporated a guided-motion system that accurately replicated the natural movement of the knee joint. The other options, Triathlon CR, Vanguard PS, and ADVANCE Medial-Pivot Knee, do not have the same distinction of being the first 'guided-motion' kinematically accurate knee design.

The correct answer is that the JBCS tibial insert was designed with a concave medial and convex lateral shape, which mimics the native articular surfaces of the tibial plateau. This design feature provides medial stability and increased posterior translation of the lateral condyle during flexion, similar to the natural movement of the knee joint.

The normal screw home position of the JBCS refers to the natural alignment of the knee joint, where the tibia rotates externally to lock the knee in extension. In this position, the knee is stable without the need for the quadriceps muscle to actively maintain stability. Therefore, the statement is true.

As the JBCS knee moved out of screw home, the external rotation of the femur would result in straightening of the quadriceps mechanism. This would reduce the Q angle to 0, which in turn would reduce patella-femoral shear forces in deep flexion. Therefore, the correct answer is "Straightening of the quadriceps mechanism (reduction of Q angle to 0) thereby reducing patella-femoral shear forces in deep flexion."

The given statement is false. The explanation states that the JBCS design had a larger lateral than medial femoral condyle and higher lateral than medial tibial plateau, resulting in an anatomically correct 3-degree joint line. However, the question does not provide any information about what the correct joint line should be. Therefore, it is not possible to determine if the given statement is true or false based on the information provided.

The JBCS knee resisted paradoxical motion by using both the cam post construct, which replicated the function of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), and an inherent screw-home mechanism that supported a relative anterior and internally rotated position of the femur in extension. These features helped to stabilize the knee joint and prevent the anterior sliding of the femoral component on the tibia during flexion.

The correct answer is that the global full market release of the JBCS knee system took place in March 2006 at the AAOS where it won the most innovative product award. Additionally, over 65,000 JBCS knees have been implanted globally by over 600 surgeons, with 3346 of these being implanted in Australia. This information is provided in the statement itself and is therefore true.

The results of the study showed that all patients with JBCS demonstrated a combination of relatively normal locomotion and gait. Additionally, they exhibited clear femoral external rotation and translation. This more physiological knee motion led to the recovery of normal extensor and flexor muscle function. The researchers attributed this recovery to the more anatomical knee design.

The correct answer is that the anterior cam and post replicated the function of the ACL preventing anterior tibial translation (posterior femoral translation) and providing stability early in gait, while the posterior cam and post replicated the function of the PCL, providing posterior stability and limiting posterior translation of the tibia (femoral anterior translation). This means that the anterior cam and post are responsible for preventing the shin bone from moving forward in relation to the thigh bone, while the posterior cam and post are responsible for preventing the thigh bone from moving backward in relation to the shin bone. This arrangement provides stability and control during the early stages of walking.