Tibiofemoral Joint Modified hinge joint allowing some lateral and rotational motions to occur as well. Lateral epicondyle is larger than medial. Because of size difference there is a screwing home mechanism to bring the knee into full extension.
Menisci Semilunar fibrocartilage (half moon shapes) Attach to the superior plateaus of the tibia. Absorption and dissipation of force Lubrication Medial meniscus is semicircular and attaches to the medial collateral ligament Lateral meniscus is almost a complete circle and attaches to the posterior cruciate ligament
Bursae Suprapatellar bursa, lies between the femur and quadriceps femoris tendon Subpopliteal bursa, lies between the femur and the popliteal muscle Semimembranosus bursa, lies between the medial head of the gastrocnemius and the semimembranosus tendon. Prepatellar bursa, lies between the skin and the anterior surface of the patella
Bursae continued Superficial infrapatellar bursa is located between the skin and the patellar tendon. Deep infrapatellar bursa is located between the tibial tubercle and the infrapatellar tendon.
Ligaments Anterior Cruciate Ligament (ACL), attaches anteriorly on the tibia, and to the posterior surface of the lateral femoral condyle. Prevents: Anterior translation of the tibia on a fixed femur Posterior translation of the femur on a fixed tibia Internal and external rotation of the tibia on the femur Hyperextension of the tibia
Ligaments continued Posterior Cruciate Ligament (PCL), attaches posteriorly to the tibia, and to the anterior surface of the lateral medial condyle of the femur. Prevents: Posterior displacement of the tibia on a fixed femur.
Ligaments continued Medial collateral ligament (MCL) connects from the medial condyle of the femur to the medial tibia through the medial meniscus. Prevents: Medially directed shear forces (valgus) Rotational forces
Ligaments continued Lateral collateral ligament (LCL) connects from the lateral condyle of the femur to the head of the fibula. Prevents: Laterally directed shear forces (Varus) External rotation of the tibia
Ligaments continued Arcuate-popliteal complex composed of the semimembranosus tendon and the popliteal ligament connects the lateral condyle of the femur to the head of the fibula. Prevents: Anterior displacement of the tibia relative to the femur. Hyperextension of the knee Hyperflexion of the knee
Patellofemoral joint Triangular bone (Patella) rests between the femoral condyle to form the patellofemoral joint. Three distinct facets Increases angle of pull on the patellar tendon Glides between the femoral Trochlear groove
Patellofemoral joint cont. Greatest compressive forces occur when the knee is in 30 deg. Of flexion. Patellar positioning is maintained by: Lateral retinaculum Medial retinaculum Medial patellofemoral ligament Lateral patellofemoral ligament
Kinematics Flexion primarily carried out by the hamstrings assisted by gastroc, popliteus, gracilis, and sartorius. Secondary responsibility of these muscles is to rotate the tibia Extension primarily carried out by the quadriceps group.
Contusions Fat Pad Contusion Peroneal Nerve Contusion
Bursitis Prepatellar Deep infrapatellar bursitis Pes anserine bursitis Tibial collateral bursitis