A common knee injury that we treat here at Joint Ventures is a tear in the meniscus (plural, menisci), or as a more common reference, a tear of the knee cartilage. For the purpose of this post, we will consider the menisci to be the primary name for what lies between the two bones in the knee.
The knee has two crescent shaped rings that lay between the femur and the tibia. The two rings are called the lateral (outside) meniscus and the medial (inside) meniscus. The primary role of the menisci is to translate forces through the knee when the body undergoes load while performing some kind of movement. For example, when you run, your knee bends and the menisci translate the load up the kinetic chain towards your head, as well as disperse some of the load upon contact.
The menisci move happily forwards and backwards when you bend and straighten your knee, performing the function of distributing and absorbing some of the load that is transmitted through the knee itself.
The menisci are subject to injury when the knee is placed in a compromising position. This compromising position involves some form of torsion (twisting). This twisting is usually coupled with some of flexion or extension, creating a motion almost like an ice cream being scooped. The torsion catches the menisci as they sit in their troughs below the joint line of the knee and can create a tear in the menisci with this scooping motion.
These tears may present as a small peripheral (outer) tear, which quite often do not require any surgical intervention and can heal with the treatment of a Physical Therapist, or there are larger tears that can often be referred to as bucket handle tears, which are quite often operable due to the disruption of the meniscus as a whole. They are called bucket handle tears as they literally look like a bucket handle, and can hang over the edge of the knee joint. Patients may complain of knee “locking” as a result, which is characteristic of a bucket handle tear.
The outer part of the meniscus has a blood supply, and can regenerate with assistance, but the inner part of the meniscus cannot readily regenerate and this is why the bucket handle tears of the larger part of the meniscus are often operated on by surgeons. The meniscus is a key load bearer in the knee and if this load bearing is disrupted, the whole loading of the leg can be affected. From heel strike to toe off in the walking or gait cycle, force and shock from the ground is transmitted up the leg. The knee is in extension when the heel strikes the ground at the beginning of the cycle, and goes through a large range of flexion during the cycle. The meniscus moves with the knee to absorb and transfer the force that the ground provides with every single step.
Disruption to the meniscus alters this pattern, and the kinetic chain is ultimately altered. This can lead to irritation or injury of any of the structures in the lower leg.
Your physical therapist can help you to restore range of motion and improve your function to return to activities of daily living post meniscal injury. If you have any questions about injuries to the Menisci, please contact me at Luke@JointVenturesPT.com.