Knee Meniscal Injury
The meniscus is the term used to describe the weightbearing cartilage in the knee. Each of your knees has two menisci – C-shaped pieces of cartilage that act like a cushion between your shin bone and your thigh bone, and are important for distributing load, absorbing shock and stabilizing the knee joint. As we walk, run, and jump the knee absorbs tremendous forces. Your meniscus helps to absorb these forces so that the bone surfaces are not damaged.
The medial (inside of the knee) meniscus is ‘C’ shaped whereas the lateral (outside of the knee) meniscus is a shorter incomplete circle with closer spaced ‘horns’. The medial meniscus is more frequently torn, partly because of this different shape but also because of its attachment to the medial joint capsule which decreases its mobility, whereas the lateral meniscus is much more mobile and gets pulled out of the way of compression by the popliteus muscle across the back of the knee.
Meniscus injuries/tears can be traumatic or degenerative. In traumatic cases, this is most common in contact sports like football but can also occur in noncontact sports that require a lot of jumping and cutting such as tennis, basketball, volleyball and soccer. The mechanism of injury is most often when there is a twisting movement on a slightly flexed knee, such as when a person changes direction suddenly while running. Meniscal injuries are also highly associated with Anterior Cruciate Ligament injuries as the mechanism of injury is very similar.
As we age the menisci become dehydrated and more brittle and hence older people are more prone to degenerative tearing of the meniscus. In these cases, rough arthritic bone can cut into the softer, brittle meniscus causing tearing. Simple movements like an awkward twist when getting up from a chair may be enough to cause a tear, if the menisci have weakened with age. These tears tend to be horizontal tears.
There are 6 types of meniscal tears:
1. Intrasubstance/Incomplete tear: A common finding on MRI especially when people reach their 20’s or 30’s. Often these are a sign of early degeneration. They are considered a stable injury and generally do not require any surgical treatment.
2. Radial tear: The most common type of meniscus tear. Due to the fact that these tears are within the avascular zone (no blood supply) of the meniscus, they don’t normally heal well and often require surgical repair or excision.
3. Horizontal tear: Treatment of these tears depends on their location. If located within the vascular portion of the meniscus (near the outer edge) then there is healing potential when sewn together through surgery. When located more centrally, these tears will not heal, even if repaired.
4. Flap tear: Uncommon, though when they do occur the flap can cause symptoms of catching and locking in the knee, these normally require surgery to remove.
5. Complex tear: Is a large combination of tear patterns, often both radially and horizontally. Again, due to the poor vascularity around the tear they don’t heal well on their own and require surgical correction.
6. Bucket-Handle tear: A large type of horizontal tear, when the inner portion of the meniscus acts like a bucket handle. These tears often cause the knee to lock as the torn portion of the meniscus gets caught between the femoral condyles, blocking normal knee motion. These tears must be surgically corrected.
Signs and Symptoms
You might feel a “pop” when you tear a meniscus. Most people can still walk on their injured knee. Many athletes keep playing with a tear. Over 2-3 days, your knee will gradually become more stiff and swollen. The most common signs and symptoms including:
· Pain, especially when twisting or rotating your knee, localised to the side of the joint. The pain might come as a sharp stab lasting for a few seconds, often followed by a dull ache for several hours.
· Difficulty straightening or bending the knee fully
· Possible catching, clicking, locking of the knee in partial flexion.
· Two things to be aware of are:
1. Generally, the worse (larger) a meniscal tear is the less you can bend the knee!
2. Swelling with meniscal injuries tends to take 24-48 hours to appear post injury. This is because the menisci are located inside the knee joint capsule and it takes time for the fluid to move though this structure. In larger injuries (which may also include meniscal damage) the joint capsule is commonly torn as well and swelling is apparent much more immediately.
On examination, there may be joint swelling, joint line tenderness, and the joint is held in a flexed position from the effusion. In late presentations, there may be significant quadriceps wasting. McMurray and Apley tests performed by your therapist are often positive, but negative results don’t exclude meniscal damage. The most useful clinical test is the Thessaly (pivot) test. MRI is the gold standard, first choice for investigation of suspected meniscal tears.
Nonoperative treatments performed by your chiropractor, physiotherapist and massage therapist are an important part of treatment plan. Immediate conservative measures for the first 48-72hours include the RICE regimen: Rest, Ice, Compression bandaging, and Elevation of the affected limb to minimise acute swelling and inflammation. The No HARM protocol should also be applied: no heat, no alcohol, no running/activity, and no massage.
People who have no loss of joint function, suffer minimal pain or swelling, and are willing to reduce their activities, are best treated with conservative care. A well-rounded longer-term treatment plan should focus on restoring range of motion, proprioceptive work and muscle strengthening exercises.
A meniscal tear that is symptomatic even after nonsurgical intervention may need to be addressed surgically by arthroscopic surgery. Rehabilitation after meniscus surgery should focus on early mobilization of the knee and quadriceps and hamstring strengthening exercises.
Knee Meniscus Exercises Program
Here is a sample of exercises that focus on improving knee range of motion and strength and improving the overall function of your knee joint. Exercises should not cause any extra pain in your knee.
1. Knee range of motion exercises
To improve knee flexion ROM, you can perform heel slide exercises. Lie on your back, and then slowly slide your heel up towards your bottom, allowing your knee to bend as far as possible. Then slowly allow your heel to slide back to the straight-knee position. Repeat the exercise 10 times, moving slowly as you bend and straighten your knee.
To improve knee extension ROM, you can perform the prone leg hang exercises. Lie on your stomach with your leg over the end of the bed, put a rolled-up towel just above your knee and allow gravity to slowly pull your knee into full extension. Hold this position for 15 to 30 seconds, and then bend your knee up. Repeat 3 times.
2. Quadriceps exercises
Lie on your back with your knee out straight. Place a small rolled-up towel underneath your knee. Press the back of your knee down into the towel while tightening your quad muscle. Hold it for 5 seconds, and then slowly release the contraction. Repeat 10 times.
3. Straight leg raise
Lie on your back with your injured knee out straight and your other knee bent. Tighten your quad muscle on your straight leg, and raise the leg up about 12 to 15 inches. Be sure to keep your knee straight the entire time. Hold your straight leg up for a few seconds, and then lower it down slowly. Repeat the exercise 15 times.
4. Balance and proprioception
Stand upright with your feet together. To remain safe while performing the test; have a stable object like a chair or kitchen counter nearby so you can grab it if you start to feel unsteady. Lift one foot off the ground. Do not to allow your legs to touch (this may give you extra stability). Watch a clock to see how many seconds you are able to stand on one foot and record this number. If you are able to stand on one foot for 60 seconds or greater, try the single leg stance test while standing on a soft surface like a pillow.
Some tips to help minimise the risk of injuring your knee meniscus includes:
· Warming up, stretching and cooling down before activities.
· Undertaking fitness programs to develop strength, balance, coordination and flexibility
· Allowing adequate recovery time between workout or training sessions.
· Wearing the right footwear to keep knees stable and providing adequate cushioning.
So that’s a brief overview of how meniscal injuries occur, If you have questions or comments feel free to e-mail us at firstname.lastname@example.org and we will be happy to answer them for you.
If you think you may already be suffering from a meniscal injury, then addressing it sooner rather than later is crucial. So, if you want relief now, call us on (08) 9486 8653 and we will arrange an appointment for you.