The medial surface of the tibia

Hyaluronic acid injections or PRP therapy may also be prescribed to improve joint function. These treatments help improve the joint's nutrition and speed healing.

Table of contents

Fracture of the knee
Vascularization and innervation of the kneecap 1.
Subluxations of the knee
Meniscus sprains

Fracture of the knee

The anatomy of the knee joint has already been discussed in detail in previous articles. We therefore focus on the structure and function of the kneecap.

The kneecap is nothing more than a large sesamoid bone that is embedded in the thickness of the quadriceps tendon (quadriceps femoris) that runs in front of the knee joint. It is characterized by an upper broad end, the so-called base patella, and a lower pointed end, the apex patella. The posterior surface is provided with a smooth articular surface, the facies articularis, with which the kneecap adheres to the previously mentioned patellar facies of the femur.

a. Base of kneecap b. Front surface c. Tip of the kneecap d. Articular surface

The kneecap serves as a center of rotation and allows the quadriceps to work effectively in transferring loads to the knee joint. Loading on the center of rotation is complex, involving both tension and compression with minimal friction. The anatomy of the bony and cartilaginous part of the kneecap reflects the complex relationship of the forces acting on it. The front surface of the kneecap is convex and contains the tendon of the rectus femoris muscle, which inserts here, as well as openings for blood vessels. The posterior articular surface consists of three frontal surfaces covered by a thick layer of cartilage. The largest surface, the lateral facet, extends from the base to the apex of the kneecap and connects to the outer condyle of the thigh. It is separated from the medial facet by an elongated medial ridge that merges into the intercondylar sulcus. The medial epicondyle is at the same level as the medial epicondyle but is about a third narrower; it connects to the inner condyle of the thigh. The medial epicondyle is even more medial and only touches the medial condyle when the knee is fully extended.

Vascularization and innervation of the kneecap 1.

Vascularization of the patella and knee joint 2. Innervation a. Calf nerve b. Tibial nerve c. Popliteal artery/vein d. Common peroneal nerve e. Tibial nerve

The kneecap is supplied by an extensive network of vascular plexuses, which are divided into an extra-articular and an intra-articular vascular system. This vascular network consists of six different arteries that help maintain the blood supply to the bone even in the event of multiple fractures of the kneecap. The patellar artery arises from the femoral artery at the level of the intervertebral disc canal, and the four popliteal arteries arise from the popliteal artery. The anterior recurrent tibial artery arises from the anterior tibial artery approximately 1 cm below the proximal intercondylar joint. The upper part of the choroid plexus is located behind the quadriceps tendon, the lower part runs deep into the patella and fatty tissue. Scapinelli R. showed that the main blood flow to the patella occurs intraoperatively in the middle anterior third and the distal pole and ascends to the proximal part. This retrograde perfusion pattern is important for understanding the risk of osteonecrosis after a patellar fracture. The ligamentous apparatus of the patella is supplied by deep vessels that lie in the fat pad of the patella through branches of the medial and inferior lateral patellar arteries. The anterior surface of the tendon is supplied by the vascular network of the inferior medial patellar artery and the anterior recurrent tibial artery. The blood supply to the patellar ligament occurs via the fatty body of the subscapularis (Goff body) and via anastomoses with the inferior lateral artery of the patella from the supporting ligaments. The presence of this number of blood vessels is the cause of the frequent hemarthrosis in patellar injuries.

Subluxations of the knee

Subluxations of the knee (knee joint) are much more common - anterior and posterior subluxations. Subluxations are due to the rupture of only one cruciate ligament, either the anterior or posterior, evident from the history and hemarthrosis, with the rupture of the anterior cruciate ligament resulting in acute tactile pain below the patellar ligament at its insertion on the tibial plateau, and the rupture of the posterior cruciate ligament in the hamstring fossa at its insertion on the posterior tibia.

There is also a symptom of anterior and posterior subluxation of the tibia called 'drawer syndrome', in which the tibia becomes slightly displaced at the ends of the thigh. If the anterior cruciate ligament of the knee is torn and the thigh and foot are immobilized, the shin bone is tilted slightly forward away from the femoral condyles with both hands; If the posterior cruciate ligament is torn, the shinbone is pushed backwards by the femoral condyles. Patients learn how to extend or retract the tibial box by placing the foot on the end of the bed or another foot and contracting the muscles of the slightly flexed knee to bring the tibia forward or backward from the condyles.

Fresh subluxations are treated like dislocations - normal positioning of the ends of the knee with a bandage that keeps the limb in an upright position for 3-4 weeks, followed by massage and passive and active exercises.

With the development of skiing, soccer, ice skating and snowboarding, knee subluxations have become more common. Long-term subluxations that recur frequently and hinder walking sometimes require surgery. Several plastic surgeries have been proposed to repair torn cruciate ligaments, including arthroscopic, minimally invasive procedures using endoscopic techniques.

Meniscus sprains

In the past, meniscus sprains, especially of the medial meniscus, were considered very common. With the widespread use of MRI scans of the knee joint today, it is now clear that meniscal tears (fractures) are more common than dislocations. The crescent-shaped meniscus, which is connected to the capsule on the outside and to the cruciate ligaments at the rounded ends, prevents lateral dislocation of the knee joint. Meniscal dislocations, like tears, most often occur when the trunk is rotated with the foot stationary. A pure meniscus dislocation is difficult to distinguish from a meniscus tear or fracture without an MRI scan of the knee joint.