Common Causes of Knee Pain

The specific location of knee pain can give some insight to what the trouble might be. The major concerns are the meniscus and ligaments. However, issues can certainly occur in the patellofemoral (knee cap) and tibiofemoral joints (primary knee). Below you will find the most common mechanical diagnoses for knee pain.

Meniscus Pathology

The menisci (plural of meniscus) are two cartilaginous pads in the inside and outside of the knee joint. Their purpose is to protect the joint, help to make motion more fluid, and act as a shock absorber. We name these two pads by their position: the medial (inside) and the lateral (outside). Menisci can become injured during activity or simply wear out if the dynamics in the joint become altered. This usually leads to tearing and the pain is felt as a sharp or lancing sensation deep inside the joint. Altered positions of the joint are important considerations when evaluating the knee as a source of lower extremity pain. People who are valgus (knock-kneed) tend to wear on the lateral meniscus, while people who are varus (bow-legged) tend to wear out the medial meniscus. Chiropractors can help by repositioning the joint and retraining the knee to function correctly again.

Medial and Lateral Collateral Ligaments

There are two collateral ligaments in the knee and they are named just like the menisci. The inside of the knee has a medial collateral ligament and the outside has a lateral collateral ligament. The purpose of ligaments is to provide stability in the joint and keep the joint from falling out of place during movements. The MCL and LCL mostly help to keep side-to-side movement in check, but also help to prevent rotation of the knee. A valgus position of the knee stresses the medial collateral ligament while a varus position stresses the lateral collateral ligament. Damage to this structure is felt more superficially as a sharp achy soreness on the inside or outside of the knee and usually causes the knee to be tender on the inside or outside aspect.

Anterior and Posterior Collateral Ligaments

Just like the ligaments above help to keep side-to-side motion in check, the anterior collateral ligament (ACL) and the posterior collateral ligament (PCL) help to keep front-to-back motion in check and also contributes to keeping rotation in check. The more common injury is to the ACL which usually happens in sports when abruptly changing the direction of motion as when breaking and cutting a run during football or soccer. This situation usually results in immediate collapse of the individual and most of the time requires surgery. The PCL is less commonly injured because it is a bit beefier than the A CL, but injury still occurs. The mechanism of injury of the PCL is typically during a tackle where a substantial amount of force is applied to the front of the lower leg while the knee is bent. Hyperextension-type injuries can also lead to PCL damage. Just like its cousin the ACL, the PCL typically requires surgery. The balance of the quadriceps and hamstring have more to do with protecting the ACL and PCL, so there is definitely training that can be done to give these structures some extra defense against injury. But… in many situations, the trauma is so great that no amount of training would have prevented the injury. Luckily a good surgeon can repair and re-pin the torn ligament the majority of the time. However, after the surgery, a good rehab program is essential for regaining functionality.

Chondromalacia Patella & Patellar Tracking Disorders

You may not know this, but your knee cap (patella) is not really a normal bone. It is a sesamoid bone. No, not the seeds that come on hamburger buns. A Sesamoid is a bone that develops inside of a tendon. The bone helps to protect and guide the tendon as it glides over a hard surface. Sesamoid bones occur in several places in the body, but the knee cap is the biggest one. Without the patella, your tendon would fray and become damaged when you move your knee. The knee cap is shaped to fit and slide across a groove in the front of the knee joint. When you contract your quadriceps muscle, the knee straightens and the knee cap helps to guide the motion keeping the tendon centered across the front of the knee. People who have varus or valgus positions of the knee experience scraping of the patella. The underside of the knee cap is made of a slick cartilage that helps to reduce friction. When the knee cap tracks to the inside or outside of the groove, it can wear on that surface. As a result, micro damage accumulates over time and the once slick surface now becomes rough. If the damage gets bad enough, then the surface is significantly changed resulting in grinding and symptoms. The pain is felt under the knee cap. Pain occurs especially when the knee is flexed under a load as when walking up and down stairs. Chondromalacia patella is the name we use to describe the damage under the knee cap, while patellar tracking refers to the movement of the knee cap across the front of the knee. As you can see, these two conditions are often related.

Knee Pain: Osteoarthritis

Also known as degenerative joint disease and nicknamed the “wear and tear” arthritis, OA is the most common type of arthritis. OA can occur in any joint in the body, but is much more common in the weight bearing joints of the body.

Mechanism of Injury

The knee is commonly affected by OA. Osteoarthritis is ALWAYS secondary to mechanical insult. Most of time this means misalignment and muscle imbalance. Just like the nickname implies, wear and tear that occurs over time is the underlying reason for all kinds of osteoarthritis. Any of the above problems if left unchecked will eventually lead to arthritis. That old trick knee or sports injury can cause enough repetitive damage in the joint that the cartilage will be lost and joint will begin to calcify and change shape. Please don’t ever tell yourself that your arthritis is just due to old age. This is not true, and usually leads to a person thinking that there is nothing that can be done, so they don’t.

Treatment

Maybe the joint can’t be 100%, but there is sure a lot we can do to improve the dynamics of the joint and at least stop it from getting worse. You will note one reoccurring theme throughout this article: Knee problems are almost always due to a dysfunction in the alignment and movement pattern of the joint. Even if the injury requires surgery, rehabilitation of the knee is still necessary to address the underlying altered joint dynamics. It is much more preferable to address these joint dynamics before injury occurs rather than after.