Knee Ligaments Part 2 - ACL & PCL

This week we’re going to finish off our focus on the knee these past two months. Hopefully, you’ve been able to learn a little more about the knee and all of the many different structures. There are four main ligamentous stabilizers of the knee, last week we covered the MCL and LCL and this week we’ll focus on the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL).

The ACL and PCL are two ligaments that cross over the other and connect the femur and tibia and are located inside of the joint capsule. The PCL is the strongest ligament in the knee and the largest ligament located inside of the joint capsule. The ACL runs from the posteromedial corner of lateral femoral condyle and attaches anterior to the intercondyloid eminence of the tibia and blends with anterior horn of medial meniscus, whereas, the PCL runs from the anterolateral medial femoral condyle and attaches to the posterior aspect of the tibial plateau. Each ligament is comprised of two bundles and each bundle will resist motion in certain directions depending on the amount of knee bend for increased stability.  

The ACL & PCL are the primary stabilizers of anterior and posterior translation respectively. The ACL restricts 85% of total anterior translation and also prevents excessive tibial medial and lateral rotation and medial and lateral translation also known as varus and valgus stress. The ACL and PCL work together to control the center of rotation in the knee.

ACL injuries are fairly common especially in athletes and usually occur in sports involving cutting and pivoting. Non-contact injuries account for 70% of ACL injuries and females are between 2.4-9.7x more likely to sustain an injury compared to males based on an article by Agel et al in 2005 American Journal of Sports Medicine. ACL injuries rarely occur alone and commonly occur at the same time as medial meniscus and MCL injuries including up to 50% of all ACL tears occur with a medial meniscus injury. PCL injuries are very rare and occur less often than ACL injuries due to the strength and size of the ligament.

Common Signs & Symptoms of an ACL tear:

-70% noncontact injury with cutting, jumping, or landing

-Audible “pop”

-Feeling of instability at time of injury followed by episodes of giving way

-Immediate onset of pain and swelling

-Decreased knee ROM and difficulty fully straightening knee

-Pain and tenderness medial knee and possibly widespread

ACL tears are usually managed with surgical reconstruction followed by extensive physical therapy to return the person to sport or full normal activity. However, depending on the age and amount of stability still present in the knee, in certain cases, the ACL tear can be managed with conservative care.

If you are interested in learning more or about treatment options, don’t hesitate to call/text 701-318-4731 or email connectptnd@gmail.com to learn how we can help. Don’t forget to follow on Facebook and Instagram to stay up to date on the happenings at Connect Physical Therapy.

- Alison Fuhrman, PT, DPT, CMPT, OCS