The knee is a synovial hinge joint. This means that it has fluid within the joint to help with movement and can move in mainly 2 main directions; flexion and extension. The knee can also move internally (medial rotation) and externally (external rotation). It is made up of 3 bones; the tibia, femur and patella.
The knee joint has 2 menisci, sometimes referred to as the ‘shock absorbers’ of the knee due to their cartilaginous nature. They are the mechanical spacers of the knee to increase stability.
The medial meniscus is C-shaped and attaches to the anterior cruciate ligament (ACL), medial collateral ligament (MCL) and tibia.
The lateral meniscus is circular and posterior cruciate ligament (PCL) and the popliteus muscle (which helps to unlock the knee from a flexed position).
Anterior Cruciate Ligament (ACL); Weaker then PCL. It prevents the tibia from going forward on the femur in knee extension.
Posterior Cruciate Ligament (PCL); It prevents the tibia from going backwards on the femur in knee flexion. It prevents hyper-flexion of the knee joint.
Medial Collateral Ligament (MCL); extension of vastus medialis from the quadriceps muscle. It helps to limit medial rotation of the knee.
Lateral Collateral Ligament(LCL); extension of the vastus lateralis from the quadriceps muscle. It helps to limit lateral rotation of the knee.
Patellar Ligament; attaches the quadriceps muscle group to the tibia
Conditions & Injuries of the Knee
Knee injuries never usually happen in isolation. Most often the cause of the knee pain in question has nothing to do with the knee but is occurring because another area of the body is not moving properly affecting the biomechanics of the knee joint. Other areas that can cause aberrant motion and pain in the knee are; the low back, hip, foot and ankle. All of these structures have a direct impact and influence on the knee and must all be addressed when assessing and treating the knee.
ACL tears are common. Females are known to be more predisposed to ACL tears than males due to smaller intercondylar notches, hormones and imbalances between hamstring and quadriceps strength. ACL tears typically occur with the ‘unhappy triad.’ Which means that when the ACL is torn, most typically the MCL and medial meniscus are torn or damaged as well due to the mechanism of injury. The mechanism of injury is a blow to the outside of the knee or twisting of the flexed knee when the foot is planted.
Some common symptoms of an ACL injury are history of significant trauma with give way weakness, immediate pain or no pain at all, swelling and discolouration within 12 hours and decreased range of motion.
The PCL is typically torn due to a ‘dash board’ injury where there is a fall on a flexed knee with the toes pointed driving the tibia back into the ligament. The symptoms are vague. The individual might report unsteadiness and patellofemoral symptoms because now the quadriceps are stabilizing the knee.
Patellar tendinitis (jumper’s knee)
Patellar tendinitis presents with anterior knee pain that is usually localized above or below the patella. Knee flexion is typically painful. Patellar tendinitis occurs typically due to over-use, over-training, jumping, running downhill, and interval training.
These conditions are hard to differentiate from one another. This is the abnormal softening and degeneration of the patellar cartilage due to poor alignment of the knee cap as it slides over the femur. This is the most common cause of chronic knee pain. PFS typically affects young athletes.
There are 9 bursae in the knee. Bursae are fluid filled sacs that help to decrease friction in a joint. Any one of the bursae can become inflamed and cause pain. Pre-patellar bursitis is common and has swelling occur just in front of the knee cap (patella). This typically occurs with individuals who work on their knees.
Iliotibial band (ITB) syndrome
ITB syndrome occurs due to friction of repetitive knee flexion/extension in running or cycling. There is typically inflammation of the bursae underlying the bottom part of the knee on the lateral (outside) of the knee where the ITB attaches. Typically, the hamstrings, quadriceps and tensor fascia latae (TFL) are all tight and pull on the ITB creating more friction and pain. Pain is usually felt on the outside of the knee.
Meniscal injuries are typically associated with ligament damage, degenerative changes, or it could be an abnormal shape or attachment.
The medial meniscus is typically injured with compressive forces and is injured 5x more than the lateral meniscus twisting of knee while bearing weight on the knee. The lateral meniscus is typically injured with torsional or twisting forces. The most common symptom of meniscal tears is pain at the joint line.
The menisci only have partial nerve supply to the outer third of the meniscus meaning that healing is often slow and can require surgery if the tear is extensive.
Knee Osteoarthritis (OA)
Osteoarthritis is the most common form of arthritis most commonly affecting large weight-bearing joints. Symptoms of knee OA include; instability, pain on weight bearing and/or at rest, reduced range of motion, disuse atrophy (muscles become smaller) and weakness of the quadriceps muscles. Pain and loss of quadriceps strength reduces the quality of life in individuals with knee OA.
Chiropractic Treatment for Knee Pain
Depending on what the injury is, how old the individual is, current health conditions and the past history of the individual all contribute to how an individual will be treated. As always a thorough history and physical examination with be performed with orthopaedic and neurological testing. The most important goal with the initial assessment is to find the cause of the pain which often times does not come from the knee.
Your chiropractor will look at the joints above and below the knee to determine where the pain and dysfunction are actually coming from. So just because you have knee pain does not mean your chiropractor will just focus on your knee.
Some common chiropractic treatments for knee pain are:
-low back chiropractic adjustments and mobilizations
-knee and ankle adjustments and mobilizations
-soft tissue trigger point therapy
-rehabilitation and strengthening of muscles that weak and not firing properly