Medial Meniscus Injury is a crescent-shaped, cartilaginous band found between the medial tibia and medial femur. The primary function is to decrease the amount of stress on the knee joint. The medial meniscus receives vascular supply via a capillary network formed by the medial, lateral and middle geniculate arteries and receives its innervation from the posterior tibial, obturator, and femoral nerves.
The medial meniscus is a fibrocartilage semicircular band that spans the knee joint medially, located between the medial condyle of the femur and the medial condyle of the tibia. It is also referred to as the internal semilunar fibrocartilage. The medial meniscus has more of a crescent shape while the lateral meniscus is more circular. The anterior aspects of both menisci are connected by the transverse ligament. It is a common site of injury, especially if the knee is twisted.
A tear to the meniscus (also known as a cartilage tear) is a common injury that can cause pain and problems with sports and daily activities. The meniscus is a vital component of the knee that acts like a cushion between the femur (thigh) and tibia (shin) bones, providing shock absorption and stability.
Anatomy and Physiology
The meniscus is a C-shaped cartilage that serves as a cushion between the proximal tibia and the distal femur, comprising the knee joint. The average width is 10 mm to 12 mm, and the average thickness is 4 mm to 5 mm. The meniscus is made of fibroelastic cartilage. It is an interlacing network of collagen, glycoproteins, proteoglycan, and cellular elements, and is about 70% water. Three ligaments attach to the meniscus. The coronary ligaments connect the meniscus peripherally. The transverse (inter-meniscal) ligament is anterior and serves as a connection between the medial and lateral meniscus. The meniscofemoral ligament joins the meniscus to the posterior cruciate ligament (PCL) and has two components: the Humphrey ligament anteriorly, and the ligament of Wrisberg posteriorly. The meniscofemoral ligament originates from the posterior horn of the lateral meniscus. The meniscus is supplied blood from the medial inferior genicular artery and the lateral inferior genicular artery. The meniscus is known to have a very poor blood supply, especially the central portion, which gets most of its nutrition via diffusion. The cartilage structure of the meniscus serves as a shock absorber and cushion or for the knee joint. There are several types of possible tears of the meniscus. These include flap tear, radial tear, horizontal cleavage, bucket handle tear, longitudinal tear, and degenerative tear.[rx]
Types of Medial Meniscus Injury
There are two categories of meniscal injuries – acute tears and degenerative tears.
- An acute tear – usually occurs when the knee is bent and forcefully twisted, while the leg is in a weight bearing position. Statistics show that about 61 of 100,000 people experience an acute tear of the meniscus.
- Degenerative tears – of the meniscus are more common in older people. Sixty percent of the population over the age of 65 probably has some sort of degenerative tear of the meniscus. As the meniscus ages, it weakens and becomes less elastic. Degenerative tears may result from minor events and there may or may not be any symptoms present.
A meniscal tear can be classified in various ways, such as by anatomic location or by proximity to blood supply. Various tear patterns and configurations have been described.[rx] These include
- Radial tears
- Flap or parrot-beak tears
- Peripheral, longitudinal tears
- Bucket-handle tears
- Horizontal cleavage tears
- Complex, degenerative tears
These tears can then be further classified by their proximity to the meniscus blood supply, namely whether they are located in the “red-red,” “red-white,” or “white-white” zones.
The functional importance of these classifications, however, is to ultimately determine whether a meniscus is repairable. The repairability of a meniscus depends on a number of factors. These include:
- Activity level
- Tear pattern
- Chronicity of the tear
- Associated injuries (anterior cruciate ligament injury)
- Healing potential
There are different types of meniscal tears, describing the morphology of the injury. Identifying and accurately describing the type of meniscal tear can help the surgeon in patient education and planning of the surgical procedure. Meniscal tear types include
- longitudinally oriented tears
- horizontal tear (cleavage tear)
- parallel to the tibial plateau involving one of the articular surfaces or free edge
- divides the meniscus into superior and inferior parts
- longitudinal tear (vertical tear)
- perpendicular to the tibial plateau and parallel to the long axis of the meniscus
- divides the meniscus into medial and lateral parts
- Wrisberg rip – is a specific subtype
- ramp lesion – is a specific subtype
- horizontal tear (cleavage tear)
- radial tear – perpendicular to both the tibial plateau and the long axis of the meniscus
- root tear – typically radial-type tear located at the meniscal root
- complex tear – a combination of all or some of horizontal, longitudinal and radial-type tears
- displaced tear – tear involving a component that is displaced, either still attached to the parent meniscus or detached:
- flap tear: displaced horizontal or longitudinal tears
- bucket-handle tear: displaced longitudinal tear
- parrot beak tear: oblique radial tear
Causes of Medial Meniscus Injury
- Inward (valgus) force – Usually, the medial collateral ligament, followed by the anterior cruciate ligament, then the medial meniscus (this mechanism is the most common and is usually accompanied by some external rotation and flexion, as when being tackled in football)
- Outward (varus) force – Often, the lateral collateral ligament, anterior cruciate ligament, or both (this mechanism is the 2nd most common)
- Anterior or posterior forces and hyperextension – Typically, the cruciate ligaments
- Weight bearing and rotation at the time of injury – Usually, menisci
- Motor vehicle accidents – A “dashboard injury” occurs when the driver’s or passenger’s bent knee slams against the dashboard, pushing in the shinbone just below the knee and causing the posterior meniscus tear.
- Contact sports – Athletes in sports such as football and soccer can tear their posterior meniscus ligament when they fall on a bent knee with their foot pointed down. The shinbone hits the ground first and it moves backward. Being tackled when your knee is bent also can cause this injury.
- The knee is hit directly – especially during sports like soccer, rugby, and football
- A person lands on a bent knee – such as during a fall or misstep
- Landing directly on the front of the shinbone – such as when a dancer comes down from a leap and falls
- A person makes cutting or pivoting maneuvers – such as when an athlete plants a foot and shifts directions
- A person lands on one leg – which can happen after a jump in basketball or volleyball
- A direct blow to the bent knee in an automobile injury
- A sports-related injury in which the knee bends
- Pulling on the ligament in a twisting injury or hyperextension
- A misstep on uneven terrain
Symptoms of Medial Meniscus Injury
If you’ve torn your meniscus, you might have the following signs and symptoms in your knee:
- Localized pain near the area of the tear – In tears of the lateral meniscus, this discomfort will be present along the outside edge of the knee. Pain will manifest on the inside edge of the injured knee for tears of the medial meniscus.
- Immediate pain after the injury – A torn meniscus will often be obvious from the moment that the injury occurs. In these instances, the tearing of the meniscus is typically accompanied by the feeling of a pop or snap within the leg during an overexerting twisting or stretching motion.
- Slow onset of symptoms – Conversely, for some, the meniscus can tear without much of a sign or initial pain. This slow onset of symptoms is more common in older individuals and those with damaged knee cartilage from osteoarthritis.
- Pain with movement – The pain will reflect the location of the tear but extend throughout the knee with movement. In the event that the knee has locked, bending it will cause searing pain to worsen.
- Pain after resting – Pain will likely diminish somewhat with rest; however, it will return with movement in most cases. Movement may also exacerbate swelling.
- Fluid accumulation within the knee joint – This accumulated fluid will cause the entire area to swell up and reduce mobility. This symptom, which may occur as a result of a number of knee injuries, is known as “water on the knee.”
- Knee locking – If a piece of the meniscus breaks free of the disc structure due to a tear, it may lodge within the joint of the knee itself. This lodging can cause knee locking, in which a person loses the ability to fully straighten the leg when sitting or standing.
- A popping sensation
- Swelling or stiffness
- Pain, especially when twisting or rotating your knee
- Difficulty straightening your knee fully
- Feeling as though your knee is locked in place when you try to move it
- difficulty moving your knee or inability to move it in a full range of motion
- the feeling of your knee locking or catching
- the feeling that your knee is giving way or unable to support you
- Feeling of your knee giving way
- Pain in the knee
- A popping sensation during the injury
- Difficulty bending and straightening the leg
- A tendency for your knee to get “stuck” or lock up
What are the signs?
You might feel a ‘pop’ if you tear your meniscus. Many people find they can still walk on their injured knee. However, it might become gradually stiffer and more swollen over the next day or so. Common symptoms include the following.
- Pain in your knee, although this can vary. Some people only have mild pain, and for others, the pain may come and go.
- Swelling, usually several hours after the injury.
- Feeling as though your knee is catching or locking, usually when your knee is bent. You may notice it making clicking or popping sounds too.
- Your knee feeling ‘loose’, as though it’s going to give way.
- Being unable to bend and extend your knee fully.
Symptoms of severe meniscus tears
- Popping, locking or catching
- Inability to straighten the knee
- Knee that gives way
- Stiffness and swelling right after the incident
Diagnosis of Medial Meniscus Injury
During your doctor’s appointment, he will ask you several questions about your knee pain. Examples of such questions include:
- Where exactly is your knee pain located?
- Did your knee swelling come on suddenly or did it gradually develop over days?
- Are you experiencing any other symptoms besides pain and swelling, like your knee giving out or an inability to bend or extend your knee?
- Have you experienced any trauma or injury to the knee?
- Do you have a known history of knee osteoarthritis?
After noting symptoms, a physician can perform clinical tests to determine if the pain is caused by compression and impingement of a torn meniscus. The knee is examined for swelling. In meniscal tears, pressing on the joint line on the affected side typically produces tenderness.
- Stress testing – Stress testing to evaluate ligament integrity helps distinguish partial from complete tears. However, if patients have significant pain and swelling or muscle spasm, testing is typically delayed until x-rays exclude fractures. Also, significant swelling and spasm may make joint stability difficult to evaluate. Such patients should be examined 2 to 3 days later (after swelling and spasm have subsided). A delayed physical examination of the knee is more sensitive than MRI of the knee (86% vs 76% [rx]) for diagnosis of meniscal and anterior cruciate ligament injuries.
- Steinmann test – Steinman test is done to diagnose meniscal pathology at the knee joint.The test is divided into 2 parts i.e Steinman part 1 and Steinman part 2 or Steinman’s tenderness displacement test. This test is useful to distinguish meniscal pathology from injury to the ligament or osteophytes.
- The McMurray test – involves pressing on the joint line while stressing the meniscus (using flexion–extension movements and varus or valgus stress). The test is often used to indicate cartilage injuries. With the patient laying on their back the therapist holds the knee with the upper hand and the heel with the lower hand. The therapist then applies a valgus (inward) stress to the knee whilst the other hand rotates the leg externally (outwards) and extends the knee. Pain and/or an audible click while performing this maneuver can indicate a torn medial meniscus.
- Apley’s grind test – (a grinding maneuver while the person lies prone and the knee is bent 90°) and the Thessaly test (flexing the affected knee to 20 degrees, pivoting on the knee to see. Apley’s test is also used in cases of suspected meniscal tears. The patient is positioned on their front with the knee bent. The therapist grasps the heel and ankle and applies a compressive force through the lower leg. At the same time, they rotate the lower leg. Any reproduction of symptoms, pain or clicking is a positive response, suggesting a torn meniscus.
- The Lachman test – is the most sensitive physical test for acute anterior cruciate ligament tears (rx). With the patient supine, the examiner supports the patient’s thigh and calf, and the patient’s knee is flexed 20°.The lower leg is moved anteriorly. Excessive passive anterior motion of the lower leg from the femur suggests a significant tear.
- Imaging tests may be ordered to confirm a tear of the meniscus. These include:
- This test won’t show a meniscus tear. However, it can be helpful to determine if there are any other causes of your knee pain, like osteoarthritis.
- An MRI uses a magnetic field to take multiple images of your knee. An MRI will be able to take pictures of cartilage and ligaments to determine if there’s a meniscus tear.
- While MRIs can help your doctor make a diagnosis, they aren’t considered 100 percent reliable. According to a study from 2008 published in the Journal of Trauma Management & OutcomesTrusted Source, the MRI’s accuracy for diagnosing lateral meniscus tears is 77 percent.
- Sometimes, meniscus tears may not show up on an MRI because they can closely resemble degenerative or age-related changes. Additionally, a doctor may make an incorrect diagnosis that a person has a torn meniscus. This is because some structures around the knee can closely resemble a meniscus tear.
- An ultrasound uses sound waves to take images inside the body. This will determine if you have any loose cartilage that may be getting caught in your knee.
- If your doctor is unable to determine the cause of your knee pain from these techniques, they may suggest arthroscopy to study your knee. If you require surgery, your doctor will also most likely use an arthroscope.
- With arthroscopy, a small incision or cut is made near the knee. The arthroscope is a thin and flexible fiber-optic device that can be inserted through the incision. It has a small light and camera. Surgical instruments can be moved through the arthroscope or through additional incisions in your knee.
- After an arthroscopy, either for surgery or examination, people can often go home the same day.
Treatment of Medial Meniscus Injury
Non Surgical Injury
- Protection – the joint from further injury by taping/strapping the knee joint, or wearing a knee support which has additional support at the sides.
- Rest – Avoid activities that aggravate your knee pain, especially any activity that causes you to twist, rotate or pivot your knee. If your pain is severe, using crutches can take pressure off your knee and promote healing.
- Ice – Ice can reduce knee pain and swelling. Use a cold pack, a bag of frozen vegetables or a towel filled with ice cubes for about 15 minutes at a time, keeping your knee elevated. Do this every four to six hours the first day or two, and then as often as needed. Ice your knee to reduce pain and swelling. Do it for 15-20 minutes every 3-4 hours for 2-3 days or until the pain and swelling is gone.
- Elevate your knee – with a pillow under your heel when you’re sitting or lying down.
- A stabilized knee brace – has flexible springs in the sides for additional support or for more severe injuries a hinged knee brace with solid metal supports linked by a hinge will help protect the joint from sideways or lateral movement. Compression will also help reduce swelling.
- Rest the knee – Limit activities to include walking if the knee painful. Use crutches to help relieve pain.
- Compress your knee. Use an elastic bandage or a neoprene type sleeve on your knee to control swelling.
- Use stretching and strengthening exercises to help reduce stress to your knee – Ask your doctor to recommend a physical therapist for guidance.
- Avoid impact activities such as running and jumping
- Full weight bearing is not permitted for 1 – 6 weeks – after surgery, depending on the type of injury and repair. Crutches will be used initially following surgery. Many surgeons brace the knee and restrict motion for 6 weeks, to prevent excessive flexion and extension.
- Range of motion exercises – begin anywhere from 0 – 6 weeks after surgery, depending on the type of repair.
- Strengthening exercises – begin once full range of motion has returned.
- Return to vigorous activities – such as sports, may begin 3 – 4 months after repair.
- A professional therapist will undertake a thorough assessment and make an accurate diagnosis to confirm cartilage meniscus injury and they may undertake an MRI scan to determine the extent of the injury.
- A physical therapist will focus on improving mobility, strength, flexibility, and balance, which can help speed up recovery time and improve performance once the injury has healed.
- Walking (weight-bearing) is initiated as soon as possible.
- Knee straightening (extension) and bending (flexion) are encouraged. Pool therapy is helpful.
- Stationary cycling is initiated as soon as adequate motion is achieved.
- Quadriceps strengthening exercises are started, such as standing squats with toe raises and leg press.
- Hamstring exercise may be modified for 6 months.
- Surgery is avoided in most cases unless other major ligaments are disrupted.
- Take anti-inflammatory medications. Non-steroidal anti-inflammatory drugs (NSAIDs), like will help with pain and swelling. However, these drugs can have side effects, such as an increased risk of bleeding and ulcers. They should be only used occasionally, unless your doctor specifically says otherwise.
- Antibiotic – Cefuroxime or Azithromycin, or Flucloxacillin or any others cephalosporin/quinolone antibiotic must be used to prevent infection or clotted blood remove to prevent furthers swelling and edema.
- NSAIDs – Prescription-strength drugs that reduce both pain and inflammation. Pain medicines and anti-inflammatory drugs help to relieve pain and stiffness, allowing for increased mobility and exercise. There are many common over-the-counter medicines called non-steroidal anti-inflammatory drugs (NSAIDs). They include and Ketorolac, Aceclofenac, Naproxen, Etoricoxib.
- Corticosteroids – Also known as oral steroids, these medications reduce inflammation.
- Muscle Relaxants – These medications provide relief from associated muscle spasms.
- Neuropathic Agents – Drugs(pregabalin & gabapentin) that address neuropathic—or nerve-related—pain. This includes burning, numbness, and tingling.
- Opioids – Also known as narcotics, these medications are intense pain relievers that should only be used under a doctor’s careful supervision.
- Topical Medications – These prescription-strength creams, gels, ointments, patches, and sprays help relieve pain and inflammation through the skin.
- Calcium & vitamin D3 – to improve bone health and healing fracture. As a general rule, men and women age 50 and older should consume 1,200 milligrams of calcium a day, and 600 international units of vitamin D a day.
- Antidepressants – A drug that blocks pain messages from your brain and boosts the effects of endorphins (your body’s natural painkillers).
- Glucosamine & Diacerein, Chondroitin sulfate – can be used to tightening the loose tension, cartilage, ligament, and cartilage, ligament regenerates cartilage or inhabits the further degeneration of cartilage, ligament. They are structural components of articular cartilage, and the thought is that a supplement will aid in the health of articular cartilage.
- Intra-articular corticosteroid injections – may be useful for symptomatic menicus injury especially where there is a considerable inflammatory component. The delivery of the corticosteroid directly into the knee may reduce local inflammation associated with meniscus injury and minimize the systemic effects of the steroid.
- Intra-articular hyaluronic acid injections (HA) – injections are another injectable option for knee meniscus injury. HA is a glycosaminoglycan that is found throughout the human body and is an important component of synovial fluid and articular cartilage. HA breaks down during the process of meniscus injury and contributes to the loss of articular cartilage as well as stiffness and pain. Local delivery of HA into the joint acts as a lubricant and may help increase the natural production of HA in the joint.
Grade 3 meniscus tears usually require surgery, which may include:
- Arthroscopic repair — An arthroscope is inserted into the knee to see the tear. One or two other small incisions are made for inserting instruments. Many tears are repaired with dartlike devices that are inserted and placed across the tear to hold it together. The body usually absorbs these over time. Arthroscopic meniscus repairs typically takes about 40 minutes. Usually you will be able to leave the hospital the same day.
- Arthroscopic partial meniscectomy – The goal of this surgery is to remove a small piece of the torn meniscus in order to get the knee functioning normally.
- Arthroscopic total meniscectomy – Occasionally, a large tear of the outer meniscus can best be treated by arthroscopic total meniscectomy, a procedure in which the entire meniscus is removed.
Trephination/ Abrasion Technique
- This procedure is used for stable tears located on the periphery near the meniscus and joint capsule junction, where there’s a good blood supply. Multiple holes or shavings are made in the torn part of the meniscus to promote bleeding, which enhances the healing process.
- This surgical procedure is used for tears located in the inner 2/3 of the meniscus where there is no blood supply. The goal is to stabilize the rim of the meniscus by removing as little of the inner meniscus as possible. Only the torn part of the meniscus is removed. If the meniscus remains mostly intact with only the inner portion removed, the patient usually does well and does not develop early arthritis.
- This procedure involves the complete removal of the damaged meniscus. This technique is only performed if absolutely necessary. Removal of the entire meniscus frequently leads to the development of arthritis.
- Repairs are performed on tears near the outer 1/3 of the meniscus where a good blood supply exists, or on large tears that would require a near-total resection. The torn portion of the meniscus is repaired by using either sutures or absorbable fixation devices. These devices include arrows, barbs, staples, or tacks that join the torn edges of the meniscus so they can heal.
- Experimental attempts to replace damaged meniscus are seen as important recent advances in orthopaedic medicine. The new technology mentioned here has been performed at a few surgical centers across the country on a small number of patients
Collagen meniscus implant
- This is a scaffold of collagen inserted into the patient’s knee. Over time, a new meniscus may grow within the joint. This procedure is currently in FDA trials in the United States and has just been approved as an accepted surgical procedure in Europe.
- This procedure involves transplanting a meniscus from a donor into the injured knee. Only a limited number of surgeons perform this procedure on a routine basis. The long-term outcomes are still being evaluated.
Meniscus transplants are accomplished successfully regularly, although it is still somewhat of a rare procedure and many questions surrounding its use remain. Side effects of meniscectomy include:
- The knee loses its ability to transmit and distribute load and absorb mechanical shock.
- Persistent and significant swelling and stiffness in the knee.
- The knee may be not be fully mobile; there may be the sensation of knee locking or buckling in the knee.
- The full knee may be in full motion after tear of meniscus.
- Increases progression of arthritis and time to knee replacement.
After a successful surgery for treating the destroyed part of the meniscus, patients must follow a rehabilitation program to have the best result. The rehabilitation following a meniscus surgery depends on whether the entire meniscus was removed or repaired.
If the destroyed part of the meniscus was removed, patients can usually start walking using a crutch a day or two after surgery. Although each case is different, patients return to their normal activities on average after a few weeks (2 or 3). Still, a completely normal walk will resume gradually, and it’s not unusual to take 2–3 months for the recovery to reach a level where a patient will walk totally smoothly. Many meniscectomy patients don’t ever feel a 100% functional recovery, but even years after the procedure they sometimes feel tugging or tension in a part of their knee. There is little medical follow-up after meniscectomy and official medical documentation tends to ignore the imperfections and side-effects of this procedure.
If the meniscus was repaired, the rehabilitation program that follows is a lot more intensive. After the surgery a hinged knee brace is sometimes placed on the patient. This brace allows controlled movement of the knee. The patient is encouraged to walk using crutches from the first day, and most of the times can put partial weight on the knee.
There are three phases that follow meniscal surgery. Each phase consists of rehabilitation goals, exercises, and criteria to move on to the next phase. Phase I starts immediately following surgery to 4–6 weeks or until the patient is able meet progression criteria. The goals are to restore normal knee extension, reduce and eliminate swelling, regain leg control, and protect the knee (Fowler, PJ and D. Pompan, 1993). During the first 5 days following the surgery, a passive continuous motion machine is used to prevent a prolonged period of immobilization which leads to muscular atrophy and delays functional recovery.[rx] During the 4–6 weeks post-surgical, active and passive non-weight bearing motions which flex the knee up to 90° are recommended. For patients with meniscal transplantation, further knee flexion can damage the allograft because of the increased shear forces and stresses.
This phase of the rehabilitation program is 6 to 14 weeks after the surgery. The goals for Phase II include being able to restore full ROM, normalized gait, and performing functional movements with control and no pain (Fowler, PJ and D. Pompan, 1993). Also, muscular strengthening and neuromuscular training are emphasized using progressive weight bearing and balance exercises. Exercises in this phase can increase knee flexion for more than 90°.[rx] Advised exercises include stationary bicycle, standing on foam surface with two and one leg, abdominal and back strengthening, and quadriceps strengthening. The proposed criteria include normal gait on all surfaces and single leg balance longer than 15 seconds (Ulrich G.S., and S Aroncyzk, 1993).
Patients begin exercises in phase III 14 to 22 weeks after surgery. Phase III’s goal and final criteria is to perform sport/work specific movements with no pain or swelling (Fowler, PJ and D. Pompan, 1993). Drills for maximal muscle control, strength, flexibility,[rx] movements specific to patient’s work/sport, low to high rate exercises, and abdominal and back strengthening exercises are all recommended exercises (Ulrich G.S., and S Aroncyzk, 1993). Exercises to increase cardiovascular fitness are also applied to fully prepare the patients to return to their desired activities.
Tips to help you get the most from a visit to your healthcare provider:
- Know the reason for your visit and what you want to happen.
- Before your visit, write down questions you want answered.
- Bring someone with you to help you ask questions and remember what your provider tells you.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
- Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
- Ask if your condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if you do not take the medicine or have the test or procedure.
- If you have a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your provider if you have questions.
Although it’s hard to prevent accidental knee injuries, you may be able to reduce your risks by:
- Warming up and stretching before participating in athletic activities
- Exercising to strengthen the muscles around your knee
- Avoiding sudden increases in the intensity of your training program
- Wearing comfortable, supportive shoes that fit your feet and your sport
- Wearing appropriate protective gear during activities, including athletic activities, in which knee injuries are common (especially if you’ve had knee injuries before).
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