Do you often hear popping, clicking, or grinding in the knee when you're walking or going up stairs? You may have a meniscus injury.
What is it?
There are two mesnisci in the knee, one medial and one lateral. The main purpose of these structures is a shock-absorbent when stepping or landing on feet. They are fibrocartilage discs which form and sit on top of the medial (inside) and lateral (outside) “notches” on the top of the tibia (shin bone) bone.
About one-third of the meniscus is vascular and innervated for pain. The other two-thirds is avascular (no blood supply) and lacks nerve supply which diminishes the potential for the natural healing process to occur.
The menisci play a very important role in knee biomechanics. The menisci absorbs about 50-70 percent of compressive loads when the knee is in extension and absorbs up to 85-90 percent in knee flexion.
Other mechanical duties of the menisci include shock absorption, prevention of synovial impingement (bone rubbing bone due to different reasons), synovial fluid (thick liquid in joint to lessen friction when it moves) distribution, and lubrication.
The lateral meniscus plays a greater role in load transmission, whereas the medial meniscus provides stability. The medial meniscus is more commonly damaged than the lateral, resulting in acute tears often involving the middle and back areas. 80% of meniscal tears are classified as vertical or oblique tears, which is where it “flaps” off the corners.
Meniscal tears may be classified as traumatic or degenerative. They can happen within any age group. When occurring in children or adolescents, injuries usually result from a traumatic event resulting from a forceful rotation of the knee. However, older populations are predisposed to degenerative tears because the menisci grow weak as we age.
Acute (sudden injury) meniscus injuries may accompany a fracture or ligamentous injury.
About one-third of meniscus tears are associated with ACL injuries. Patients with unrepaired ACL ruptures have an elevated risk of a medial meniscus injury.
Meniscal injuries are very common, affecting 60-70 every 100,000 people annually.
Symptoms
There are different clinical presentations for a meniscus depending on the age of the patient. It is typical to see a younger patient come in after a traumatic injury resulting from a twisting of the knee. This is different from older patients because they will not be able to report any type of incident that caused the injury.
Patients of any age will complain of intermittent, movement related pain within the joint line. If the injury is acute they may have difficulty putting full weight down when walking or have an altered (limped) gait. The feeling of clicking, catching, or locking may be felt when moving the knee to an extended or straight position. The patient may also complain of a giving-way or buckling sensation when putting weight on the affected knee.
One of the biggest indicators that there might be a meniscus tear is joint line tenderness. When palpating the knee joint synovial fluid, swelling, and cysts may be felt. Range of motion may be limited with both flexion and extension. Total knee flexion and deep squatting will usually be very uncomfortable.
Diagnosis
Plain film radiography may be needed if there is a suspected fracture, a loose body, or degenerative changes. An MRI is the most recommended imaging modality for evaluation of the menisci, however MRI images of the meniscus may show a false positive.
Management
Chiropractors can play an important role in the rehabilitation of most degenerative and some traumatic meniscal injuries. About one-third of the younger population, acute tears can be treated conservatively with full recovery. For older patients with degenerative tears, conservative therapy is most appropriate. Patients with manageable pain and swelling, without a loss of function (can still bend it) have shown functional improvement through conservative care equal to or greater than those who have gone through surgery.
The majority of acute tears in younger patients will require surgery, however only about 6% of patients over the age of 40 require an operation. Acute tears accompanied with joint locking usually warrant a surgical referral. Those who require surgery later in life there is a high probability that they will develop degenerative issues.
The main goals for a rehabilitation program for a meniscus injury includes reducing pain and inflammation while trying to restore range of motion, strength, and function.
When the injury is in the initial stages management can include rest, ice, compression, and elevation (RICE). Ice will help with any inflammation and swelling. Also NSAIDs may be appropriate only in the beginning.
Activity modifications are essential to prevent further damage. Patients should avoid twisting of the knee of any kind, be careful with knee flexion, and temporarily discontinue high activity sports. In some instances, a brace may be necessary to limit range of motion.
Stretching and myofascial release techniques: Stretching and myofascial release techniques may be necessary for the hamstrings, quadriceps, gastrocnemius calf muscle, soleus, adductors, and popliteus.
IASTM: IASTM (instrument assisted soft tissue mobilization) of the knee capsule and the muscle that attach to the knee can provide some benefit.
Chiropractic Manipulation: Manipulation of the ankle joint, fibular head, hip, sacroiliac joints, and the spine may be necessary for any joint restrictions. Biomechanical defects in the hip and knee should be addressed as well. Arch supports or orthotics may be necessary if a patient has overpronation in their feet.
Exercises: As swelling and inflammation goes down, stationary biking, walking in water, and isometric strength training should be incorporated. Later, dynamic exercises including single leg calf raises, knee flexion, knee extension, and lunges should be added to the exercise routine. Gluteal weakness and patellofemoral tracking (kneecap not moving the way it should) should also be considered.