What is a PCL Sprain? To answer that question we need to begin with some knee anatomy. Your knee is held together by ligaments, which are tough connective tissues that have a lot of strong collagen fibers in it. These structures provide stability from all motion. You have ligaments on the medial side (inside of the knee), the lateral side (outside of the knee) and these are referred to as the “Collateral” ligaments. You also have 2 paired ligaments in the middle of the knee which crisscross going in opposite directions, referred to as the “Cruciate ligaments.”
The Posterior Cruciate Ligament is one of the paired ligaments in the middle of the knee. It is made up of 2 separate bundles: The two bundles of the PCL, and the ALB (anterior lateral bundle) and the PMB (posterior medial bundle), function synergistically to provide stability. The PCL functions as one of the main stabilizers of the knee joint and serves primarily to resist excessive posterior translation of the tibia relative to the femur. The PCL also acts as a secondary stabilizer of the knee preventing excessive rotation specifically between 90° and 120° of knee flexion (1,2).
A PCL sprain happens when force is applied beyond what the PCL tensile strength is capable of resisting. The tensile strength of the PCL is well documented in the literature and ranges from 739 to 1627 N (3). Which is about a 300-360lb force!!
What Is Posterior Cruciate Ligament Sprain?
PCL sprain or PCL tears account for only 3% of all knee injuries. These injuries are classified by the severity of the injury meaning how bad the ligament is injured.
Grade 1 is a mild injury that causes only microscopic tears in the ligament. While these small tears can bend the PCL out of shape, they do not significantly affect the knee’s ability to bear weight.
Grade 2 means the PCL is partially torn and the knee becomes unstable. At this level expect the knee to give out periodically while standing and walking.
In Grade 3 the PCL is completely torn or is separated at its end from the bone that it normally anchors. At this point, the knee is very unstable and cannot bear your body weight. It usually takes a tremendous force to cause such an injury, so a grade 3 sprain is often accompanied by damage to the other ligaments of the knee.
PCL sprains or tears rarely exist in isolation as well, with up to 95% of the time there is also some additional ligament damage to other supporting ligaments in the knee.
Symptoms of PCL Sprain
With PCL sprain (grade 1) or tear (grade 2 or 3), patients typically get an inflammatory response in the knee that will lead to a multitude of symptoms.
With Mild To Moderate Pain In Knee localized swelling in the ligament can create pain in the back of the knee where the PCL attaches.
A higher grade PCL sprain (grade 2 or 3) can cause bleeding into the joint from the ligament which produces knee effusion/swelling.
Mild To Moderate Pain In Knee
Localized swelling in the ligament can create pain in the back of the knee, where the PCL attaches.
Knee mobility – Loss of Range of Motion
As a result, both the ligament swelling and knee swelling can cause loss of range of motion. Meaning, you will not be able to fully extend or fully flex the knee.
High grade (2 or 3) PCL sprain impairs the ligament’s function as well, which can lead to instability and the knee giving out!
Common Causes of PCL Sprain
PCL sprain/injuries typically occur in high velocity / high force collisions where there is a strong force applied to the tibia pushing the tibia backward in relation to the femur. At some point, the force is too much for the PCL to resist and then fibers are torn or stretched. There are common instances where this occurs.
The faster a car is going, the higher the number of forces are applied to the body creating a risk for a multitude of injuries. One being the knee. If the accident pushes the knee into the dashboard this can create backward force on the shin bone.
Sudden Twist Or Over-Extension Of The Knee
A sudden twist or a moment of hyperextension such as kicking a soccer ball or landing from a high jump in the air where your knee hyper-extends, pushes the tibia backward stressing the PCL.
Contact Sports / Significant Impact On Knee Or Shin
In multiple sports both in contact and non-contact sports, a fall or if someone falls into you, can lead to a PCL injury. Commonly in American football, a tackle called a “chop block” or tackling below the pads was outlawed because of the potential for a catastrophic knee injury! But these injuries are seen in more than just American football. They are also seen in rugby, futbol (soccer), and many other sports where the players collide in this manner and can lead to PCL and ACL injuries. There has been a conscious effort in many leagues to teach better techniques in avoiding severe knee injuries when taking down your opponent.
Common Treatments for Sprained PCL
Many times when a PCL sprain occurs you don’t know exactly what the injury is. You only get symptoms and signs that a significant injury has occurred as mentioned above. Treatment for acute knee injuries should always be assumed to be more severe than you think so you can act cautiously until a specific diagnosis is found and severity established to further guide your rehabilitation! You want to react with maximal protection of the joint to allow natural healing to occur and help facilitate the resolution of the swelling and pain.
- Avoid excessive amounts of over the counter NSAIDs (non-steroidal anti-inflammatory medications) as these can actually inhibit the proper healing of the injury. To learn more please read my in depth look at NSAIDs
- Listed in the article are healthy alternatives to the over the counter NSAIDs.
Weight-bearing can cause pain, and using supports can help you get through your day-to-day activities while you’re recovering.
if weight-bearing causes significant amounts of pain then you want to minimize weight bearing on the knee until a clear diagnosis is known. Until then, off-loading the knee with crutches can be helpful. This allows for pain reduction as well as prevents further damage to the knee.
If you have a sense of instability where the knee will not support itself and gives out then using a brace for support is needed. This will help with maximal protection of the knee to prevent additional damage
Once there is a clear diagnosis but still a substantial amount of limitations to the knee, physical therapy will be the main component of getting you back to “normal” activity. PT can help reduce the swelling in the joint and start getting the muscles that support the knee back online and working! Long-term PT is an important part of being proactive, meaning it can help prevent future knee injuries!
Like its counterpart ACL-reconstruction, PCL reconstruction surgeries come with significant risk! Like most surgical procedures major risks are known such as a 1-3% chance of infection (4) and an 8-9% risk of a blood clot (5). Given the unique location of the PCL, there is an inherent risk of neurovascular injury can happen during the procedure. The Popliteal Nerve and Artery live just millimeters away from the PCL posterior attachment. If injured this can lead to devastating vascular injury which in turn can create a compartment syndrome, requiring fasciotomy (6).
Long term, PCL reconstruction is similar to ACL reconstruction in that “Patients with PCL tears have a significantly higher risk of meniscus tear, OA (osteoarthritis) and subsequent TKR (total knee replacement) than patients without PCL tears” (7).
Alternative Treatment To Ligament Surgery For Sprained PCL
For the past 15+ years, we have have been utilizing orthobiologic procedures to promote your body’s natural ability to heal orthopedic conditions without surgery to get you back to doing what you love you faster and without the risks associated with major surgery!
A PCL strain or tear can easily be treated with bone marrow concentrate or platelet-rich plasma precise injection to maximize the healing potential of the PCL! We have completed randomized control trials with before and after pictures using bone marrow concentrate showing that even cruciate ligaments can heal. (learn more here: https://centenoschultz.com/alternative-to-acl-surgery/ )
Diagnosing Your PCL Sprain
If you have injured your knee and would like an extensive evaluation, feel free to contact us today so we can further examine your knee and order an MRI to further delineate the injury and extent the injury. With that known then we can come up with a game plan to best get you back on the field, on the trail, or whatever it is that the injury is preventing you from doing!
Preventing PCL Injury
There are many ways to avoid a PCL sprain.
- Stretching / mobility of hips / knees and ankle
- Strengthening leg muscles that protect your knees such as hamstrings and quadriceps
- Listen to your body: if you’re not getting paid millions of dollars to play a sports then if your body isn’t 100% then its not worth the injury.
PCL Sprain Is Common but Not to Be Underestimated
A PCL sprain can happen to any one of us. Regardless of how it happens (car accident, sports injury or just having fun outside) there are several ways to get you back on the field that do not involve surgery. So if you have been dealing with a knee injury, PCL strain or not, come to Centeno Schultz Clinic, or contact us, so one of our top physicians can evaluate you and see if you are a Candidate!
- Papannagari R, DeFrate LE, Nha KW, Moses JM, Moussa M, Gill TJ, Guoan L. Function of posterior cruciate ligament bundles during in vivo knee flexion. The American journal of sports medicine. 2007 Sep;35(9):1507-12.
- Ahmad CS, Cohen ZA, Levine WN, Gardner TR, Ateshian GA, Mow VC. Codominance of the individual posterior cruciate ligament bundles: an analysis of bundle lengths and orientation. The American journal of sports medicine. 2003 Mar;31(2):221-5.
- Logterman SL, Wydra FB, Frank RM. Posterior Cruciate Ligament: Anatomy and Biomechanics. Curr Rev Musculoskelet Med. 2018;11(3):510-514. doi:10.1007/s12178-018-9492-1
- Gupta R, Sood M, Malhotra A, Masih GD, Raghav M, Khanna T. Incidence, Risk Factors, and Management of Infection Following Anterior Cruciate Ligament Reconstruction Surgery. Indian J Orthop. 2018;52(4):399-405. doi:10.4103/ortho.IJOrtho_379_17
- Keller RA, Moutzouros V, Dines JS, Bush-Joseph CA, Limpisvasti O. Deep Venous Thrombosis Prophylaxis in Anterior Cruciate Ligament Reconstructive Surgery: What Is the Current State of Practice?. Sports Health. 2018;10(2):156-159. doi:10.1177/1941738117730576
- Shahrulazua A, Rafedon M, Mohd Nizlan MN, Sullivan JA. Delayed compartment syndrome of leg and foot due to rupture of popliteal artery pseudoaneurysm following posterior cruciate ligament reconstruction. BMJ Case Rep. 2014;2014:bcr2013202098. Published 2014 Jan 23. doi:10.1136/bcr-2013-202098
- Wang SH, Chien WC, Chung CH, Wang YC, Lin LC, Pan RY. Long-term results of posterior cruciate ligament tear with or without reconstruction: A nationwide, population-based cohort study. PLoS One. 2018;13(10):e0205118. Published 2018 Oct 3. doi:10.1371/journal.pone.0205118