The knee is a truly amazing machine of a hinge joint. It is home to a variety of structures that work together to make sure you stay upright and stable. Aside from structure and stability, there are also some parts that work to withstand all of the different types of inversions, flexions, and extensions that come with every day movement.

The bursa sacs are little fluid filled pillows within the knee that work to cushion the area and preventing two or more structures from banging into each other and causing complications. These sacs are filled with a fluid known as synovial fluid which also exists freely outside of the bursa. This free fluid provides a liquid means of cushioning and also helps to nourish the cells that make up the structures of the knee.

The other significant structures of the knee other than the focus of this information are the menisci. A meniscus is a cartilaginous o-ring of a structure that each knee has two of. Its primary function is to work as a shock absorber, preventing bone on bone contact.

Menisci help displace the stress forces that the weight of your upper body puts on the knees. They also make movements such as extensions and other sharp physical activity regarding the legs much less harmful to less strenuous as they are able to spread out the force instead of having it isolated to a single area in the knee.

knee Diagram

The PCL or Posterior Cruciate ligament works in concert with the ACL within the knee to provide structural support a stability for the crucial weight/bearing hinge joint. The PCL is known as the posterior ligament because it sits behind or posterior to the ACL.

The Posterior Cruciate ligament functions to prevent your shin bone from collapsing backwards past your thigh bone. The PCL luckily tends to be the strongest of the four knee ligaments, but injuries to the support system do occur. Linking your thigh bone to your shin bone is a stress in itself, but a centered blow to the front of the shin is usually a recipe for PCL problems.

What is a Ligament?

Before going into the potential problems caused by trauma or degeneration it is important to first know what a ligament is and what it is made out of.

A ligament is known as a specialized fibrous connective tissue. Connective tissue functions to provide support within the body and in many cases, just as its name suggests, connects two or more body parts together.

The PCL works to connect your thigh bone to your shinbone and is able to do so thanks to its tremendously high college and content. Collagen fibers are very flexible and are capable of returning back to its initial state even after constant stretching. Sometimes, however, the ligament snaps back into place with some damage occurred. The most common injury in ligaments is the dreaded sprain.

The 3 Grades of Sprains

A sprain is a partial to complete tear of a ligament. It is the most common injury regarding the specialized fibrous connective tissue. Sometimes it can be difficult to discern the difference of a sprain and strain, but just know that a sprain is an injury to a ligament that connects one bone to another, while a strain is an injury to a tendon, which connects a bone to a muscle.

A grade 1 sprain is the least significant of the 3 and is a slight tear that can be thought of as an over-stretching that causes some fibers of the connective tissue to snap.

A grade 2 strain is the same thing as a moderate sprain and is past the super stretch phase. Several fibers within the ligament have been broken to create a tear that can be anywhere past a grade 1, but before a total tear.

A grade 3 sprain is actually just another name for a rupture or full tear.

Rehabbing All Three Strains

Injured Knee

Out of the four knee ligaments including the ACL, PCL, MCL, and LCL, a PCL injury is the rarest to occur for a few reasons. The Posterior Cruciate Ligament rests behind the ACL, so a blow to the from of the knee will affect the front ligament before reaching the PCL. In this configuration, the ACL effectively guards the PCL from stressful forces.

The duties of the PCL also lend to the infrequency of injury. The PCL prevents an over-flexion of the lower leg past the thigh. Normal activity usually can’t do this. It would require a blow to the back of the knee to first weaken the PCL significantly, followed by an opposite force to the front of the knee that would take out the ACL and finish off the PCL for good.

Compile the above information with the fact that the PCL is the strongest ligament of the knee supporters and you can see why it is so very rare that an isolated PCL injury occurs without also having the neighboring ligaments affected beforehand.

Grades 1 and 2 Rehab

The incomplete tears of grade 1 and 2 sprains can generally heal themselves without the need for surgery.

Following the RICE method is the greatest possible thing you could do to assist your body in providing the optimal conditions it needs to heal. This method does not showcase some magic all grain diet that promotes healing, but is actually an acronym for rest, ice, compression, and elevation. These four steps are some of the best possible actions you can take to aid in the healing process of your PCL injury.

Rest means exactly what it sounds like. For an injured body part to heal properly, it must have adequate rest to repair. By not putting weight on the affected knee, you are also stopping any potential chances of further injury to the PCL, or possible new injury to the other ligaments.

Ice to the affected area will help constrict blood flow to the knee and also reduce pain and swelling. By keeping blood in the area, you are increasing the likelihood that much needed healing factors found within the blood can have as much contact with the injured fibrous connective tissue as possible.

Compression does a lot of the same, but it can be utilized through a compression sleeve for much longer periods of time than ice.

The last step of RICE is elevation and works in concert with the first three actions to provide the best atmosphere possible for healing. To properly elevate, lift the leg carefully above the heart while laying on your back. This will ensure that the most blood possible makes it down to the area, allowing for quicker natural healing.

Grade 3 Strain

As previously stated, a grade 3 sprain is another term for a complete tear of rupture. Since ligaments have an extremely poor blood supply to begin with, a complete tear will make self-healing almost a physical impossibility in most cases.

If the tear is right in the middle of the PCL, the surgeon will choose to suture the two frayed ends together, effectively tying it with itself. If the tear is closer to the thigh bone or the shin bone, it will be re-anchored to that bone.

In either case, new tissue connective tissue from another part of the body or a donor ligament will have to be supplemented with the ruptured one to ensure proper healing.

Utilizing the RICE method of injury care both before and after the surgery can greatly expedite the healing process. Physical therapy after surgery will work to both strengthen the reinvigorated ligament and also strengthen all other surrounding knee structures to dramatically lower the chance of re-injury.

Key Takeaways from a PCL Injury

A PCL injury, although rare, is possible. It takes a perfect storm of stressful motion and force to enact a tear of the ligament, but if it does occur, surgery is the only option.

Partial tears associated with grades 1 and 2 can be healed naturally by the body, but you can greatly help it out by utilizing the RICE method to provide it with the increased blood flow that is necessary.

Surgery is most the likely route for a grade 3 PCL tear. If this does occur, other parts of the knee such as the ACL will most likely need some sort of correcting as well.

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