You may have heard of an anterior cruciate ligament (ACL) tear, which is the most common of all knee ligament injuries, but have you heard of posterior cruciate ligament (PCL) tears? Although much less common, PCL injuries can lead to a host of issues at the knee if left untreated or diagnosed. Follow along in this article as we discuss everything related to PCL injury rehab.
What is The Posterior Cruciate Ligament?
The posterior cruciate ligament (PCL) sits just behind the ACL within the knee joint and is the primary restraint to the posterior translation of the tibia on the femur. Similar to the ACL, the PCL has a connection to the tibia (shin bone) and femur (thigh bone). The term ‘cruciate’ translates to cross-shaped, as the ACL and PCL create a cross with one another, with the ACL sitting in the front and the PCL in the back.
How Is The PCL Injured?
The PCL is typically injured due to a hyper-flexion mechanism of the knee (knee being in a far, bent position). This can occur in a variety of ways, one of which being in motor vehicle accidents, if the knee hits the dashboard upon collision while in a bent position, which is known as a “dashboard” injury. It may also occur if someone falls onto their knee while it is in a bent position, forcing the tibia to move backward on the femur, thus damaging the PCL. Finally, it may also occur during contact sports if someone comes in contact with a bent knee, causing the same mechanism of injury as the aforementioned examples.
If someone has an isolated PCL injury, what you will see is a sag sign when the knees are in a bent position. A lag sign of the knee is depicted by the shin bone on the injured leg being in a sagged position in comparison to the uninvolved knee.
Are You Looking For Guidance For PCL Injury Rehab?
The Knee Rehab Program is a physical therapist-developed, step-by-step program that teaches you how to optimize your knee health. This program will expose you to various knee and lower body strengthening and stabilization exercises supported by science.
ACL Versus PCL Tears
ACL and PCL tears both may occur in sports, but have different mechanisms of injury. Firstly, ACL tears are much more common and tend to occur either when landing from a jump awkwardly, during a twisting or cutting motion when attempting to change directions quickly, or if another player comes in contact with the knee from the outside. On the contrary, as previously stated, PCL tears will occur with the knee in a bent position.
Another key difference here is the anatomical make-up of these ligaments. The ACL is smaller and weaker than the PCL; therefore, it is more likely to sustain a complete tear, whereas most PCL tears are partial. Both of these knee ligament injuries can occur in tandem with other injuries of the knee, including injury to the MCL, LCL, and meniscus.
What Does PCL Injury Rehab Look Like?
Because many PCL injuries only result in a partial tear of the ligament, treatment can often be conservative. Early on, similar to other soft tissue injuries, the POLICE principle is utilized in order to protect the tissue while introducing a healthy, healing response. Now, it does certainly complicate rehab a bit if there are more knee structures involved in the injury, which is often the case. If someone takes a hit from the inside of the knee towards the outside of the knee (varus force), and the shin also rotates outwards (externally rotates), the PCL and the posterolateral corner may also be injured.
If you decide that you are not going to have surgery, the early goals of PCL injury rehab are restoring range of motion of the knee, promoting weight bearing in safe positions, reducing pain and swelling, and restoring activation of the quad muscle.
Regaining the ability to bend the knee after any knee injury is important, second to regaining knee extension (straight knee position).
Tips To Restore Knee Flexion After Surgery
The quadriceps muscle is crucial for the stability of the knee. This simple quad set exercise may not feel so simple after a PCL injury, and this is because the muscle becomes inhibited after any trauma to the knee. What you will notice is that when you try to squeeze your thigh muscle on your injured leg, it may not feel as strong of a contraction if you were to do it on your uninjured leg.
The knee cap movements shown here can help desensitize the knee early after injury while also restoring any mobility deficits of the knee cap, which helps for optimal bending and straightening of the knee.
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What About Surgery For PCL Tears?
If you have a full thickness tear, have suffered multiple injuries, or if you fail conservative treatment, surgery to repair or reconstruct the PCL is the best option for optimal, long-term outcomes. Similar to an ACL tear, you likely will be in a knee immobilizer brace for the first couple of weeks to protect the surgical site. Early weight bearing is encouraged with crutches, and once you have a stable knee with an active quad muscle, that brace and crutches can go bye-bye! Activation of the hamstring muscles is a precaution in the early phase of PCL injury rehab after these surgeries in order to protect the surgical site as well.
What About ACL Tears? Do They All Require Surgery?
Yes, we did mention that ACL tears are usually more extensive, and often require surgery; however, there are cases where individuals can ‘cope’ with an ACL tear. The ACL is most at risk when there is a twisting component of the knee. So, if you are someone whose daily activity requirements and hobbies only require straight plane (sagittal) movements, such as walking, stairs, and so forth, the ACL is not at risk. With the right rehab and activity modification, you may not need a surgical reconstruction of the ACL. Listen to our discussion with Mick Hughes on ACL Copers HERE.
Later Stage PCL Injury Rehab
Once the PCL has begun to heal either from surgery or conservatively, rehab will look similar to other knee ligament injuries, with a focus on regaining joint proprioception, strength, and return to sport movements.
Agility Drill – Cutting, Diagonal Snaked
Step Up – High Box, Weight
Single Leg Eccentric Box Squat
Can ACL and PCL Tears Happen At The Same Time?
Although quite rare, ACL and PCL tears can happen at the same time, and will often be a result of a knee dislocation. In these types of instances, it is also likely there will be other extensive trauma to the knee, including potential tearing of the MCL or LCL, osteochondral defects, or damage to the surrounding neurovascular structures. Depending on which structures are injured, and what type of surgery is performed, similar principles of tissue healing and precautions will follow for rehab, with a much longer course of treatment.
Although rarer than ACL tears or other injuries to the knee complex, it is important to understand that PCL injuries do still occur. PCL injuries tend to heal very well due to their strong ligamentous make-up, and usually not being completely torn. In cases where surgery may need to occur, rehab principles will be similar to other soft tissue injuries of the knee.
Take Control of Your Knee Health
The knees are true hard-nosed blue-collar workers! They get the job done when the hips and ankles may be taking some extra rest breaks. In this program, you will learn how to restore mobility, learn to get your powerful quadriceps cooperating with you, along with starting the journey to addressing the hip and ankle. In this program, you will learn how to restore mobility, learn to get your powerful quadriceps cooperating with you, along with starting the journey to addressing the hip and ankle.
Pepe MD, Harner CD. Assessment and surgical decision making for PCL injuries in athletes. Athl Ther Today. 2001;6:9
Safran MR, Harner CD, Giraldo JL, et al. Effects of injury and reconstruction of the posterior cruciate ligament on proprioception and neuromuscular control. J Sport Rehab. 1999;8:304-321.
Noyes FR, Mooar LA, Moorman CT, 3rd, et al. Partial tears of the anterior cruciate ligament. Progression to complete ligament deficiency. J Bone Joint Surg Br. 1989;71:825-833.
Boden BP, Sheehan FT, Torg JS, et al Noncontact anteri- or cruciate ligament injuries: mechanisms and risk fac- tors. J Am Acad Ortho Surg. 2010;18:520-527.
About The Author
Sherif Elnaggar, PT, DPT, OCS, SCS
[P]Rehab Head of Content
Sherif graduated from Temple University with a Bachelor’s of Science Degree and a concentration in Kinesiology. He then received his Doctorate of Physical Therapy Degree from DeSales University, graduating with honors of the professional excellence award and research excellence award. After his graduate studies, he served as Chief Resident of the St. Luke’s Orthopedic Physical Therapy Residency Program. Sherif is a Board Certified Orthopedic Clinical Specialist. Sherif focuses on understanding how movement impairments are affecting function while also promoting lifestyle changes in order to prevent recurrences of injury. His early treatment interests include running related injuries, adolescent sports rehab, and ACL rehab in lower extremity athletes. He also has been involved in performance training for youth soccer players. Outside of working as a physical therapist, he enjoys traveling, running and cycling, following Philadelphia sports teams, and spending time with his family.
Disclaimer – The content here is designed for information & education purposes only and is not intended for medical advice.