Meniscus Tear
A torn meniscus is one of the more common injuries of the knee. Any activity that involves forceful twisting or rotation at the knee, combined with weight-bearing can result in injury.
What is the meniscus?
The meniscus is a ‘C-shaped’ rubbery section of tough cartilage called fibrocartilage. There are two meniscus or menisci in each knee (a lateral and medial) and are positioned on top of the tibial plateau (top of the main shin bone). They act as shock absorbers cushioning the knee joint and helping transmit load. They also help in providing joint fluid (synovial fluid) and improving joint congruity. As the ends of the femoral condyles are round and the top of the tibial plateaus is flat, the curved surfaces of the meniscus further help stabilise between the thigh bone (femur) and shin bone (tibia).
How is it injured?
Meniscus tears can occur through an acute injury or through degenerative changes. Acute injuries often occur when the knee is slightly bent and there is a rotation at the knee. In particular a partial or full thickness tear occurs when the foot is planted on the ground, and the thigh is quickly twisted or rotated. They may occur in isolation or combined with other soft-tissue injuries including ligament damage.
However as we get older, it is also not uncommon for knees to have meniscus tears with or without any incident. In these cases, tears have occurred though natural age-related cumulative stress. This tends to occur more in males, with a peak incidence rate at 41-60years (Valdez et al, 2021).
In older adults, an acute meniscal tear may still occur. However, this is often on the background of an aging meniscus that will no longer be the pristine surface it once was. As a result, the incident that causes the injury may be very minor.
The meniscus may be injured on the inside of the knee (medial meniscus) or on the outside of the knee (lateral meniscus).
Tears come in different sizes and shapes, which will affect the symptoms experienced after the tear. There is no universally agreed system to classify meniscal tears. Generally they tend to be classified by their tear pattern, which includes longitudinal, radial, horizontal, oblique and bucket-handle tears or complex tears (more than one pattern). They may be further described as partial or full-thickness depending on the vertical depth of the tear.
Typical symptoms
Symptoms of a meniscal tear will depend on the size and location of the tear. Some of the common signs and symptoms include:
Knee Pain. This is often localised to the knee joint and usually in the area of the tear. Most will feel pain at the time of an acute injury but can vary in severity. It can also be aggravated further with twisting or squatting movements.
Swelling. Swelling around the knee joint may occur immediately or within several hours. In some cases, especially in smaller tears, the swelling may occur up to 24hours later.
Stiffness and limited knee range. The knee may feel stiff, making it difficult to fully extend or bend the leg.
Clicking or popping sensation. During an acute injury, some people report hearing or feeling a popping sound at the time or even a sensation of tearing. This may be followed by ongoing clicking, popping, or catching sensations within the knee.
Instability. The knee may feel unstable or as though it is giving way, especially when walking on uneven ground or during sudden movements which involve twisting or pivoting.
Locking/Catching/Buckling. These mechanical symptoms often occur in more severe injuries, larger tears or where a fragment has displaced. In these cases the joint congruity is lost.
How to diagnose a torn meniscus
Diagnosing a meniscus injury involves understanding the history and mechanism of injury, physical examination and potential imaging. They can occur both in isolation and in combination with other soft tissue injury such as ligamentous tears (ACL, MCL).
History
For acute tears, it’s important to understand the mechanism of injury. In particular determining if there was a twisting injury through a weight-bearing knee joint. Recurrent pain can also occur when there is further rotating, compressive or twisting activities.
Signs and symptoms help determine not only the diagnosis but also severity. Minor or mild injuries may be associated less pain, delayed swelling and the ability to continue to ambulate. More significant injuries often have mechanical symptoms such as locking/catching or buckling.
Degenerative tears, typically occur without incident or might become symptomatic after minor slips/twisting injuries.
Physical examination
There is no single physical test that can conclusively determine a meniscus tear. Most provocative tests also are less reliable when there is associated degenerative tears or ligament injury. Therefore, a good healthcare provider will examine the knee using a combination of tests backed by the history to help determine the diagnosis. These tests should include:
Inspection. Observing the knee for any obvious swelling or deformity.
Palpation. Assessing around the knee joint to identify any tenderness. A positive test is when palpating along the medial or lateral joint line reproduces tenderness. This has been shown to have a sensitivity from 55%-83% and specificity of 58%-98%.
Range of Motion/Functional Testing. Assessing the range of motion, walking pattern and ability to squat is important. Limited ability to fully bend or straighten the knee could suggest a meniscal injury. This assessment can also reveal mechanical symptoms like catching or locking of the knee.
McMurray Test. The practitioner bends the knee, then rotates the leg either into full internal and external rotation while straightening the knee. A positive test is when a clicking or popping sensation is felt. It is reported to have to have a sensitivity from 16%-63% and specificity of 57%-78%.
Apley Grind Test. With the patient lying face down and the knee bent to 90 degrees, the practitioner applies downward pressure on the foot while rotating it. Pain or discomfort indicates a positive test, and has a sensitivity from 13%-43% and specificity of 72%-90%.
Thessaly Test. This dynamic test aims to stress the meniscus in a weight-bearing position. It involves the patient standing on one leg with a slight bend in the knee (5 degrees) while rotating their body 3 times. This is also repeated with a 20 degree knee bend. Pain or a locking sensation during this movement indicates a positive test. Studies have shown a sensitivity from 66.7%-89% and a specificity 37.9%-97%.
Strength and Stability/Ligamentous Tests. Testing the strength of the surrounding muscles, such as the quadriceps and hamstrings, and assess the knee’s stability is important to test for another associated injury.
Imaging
Investigations can be useful, with MRI being the best imaging to show a torn meniscus. Often X-rays are used- although they do not detect the meniscus tears, they can help rule out other conditions (particularly any bone fractures) which may give similar symptoms.
Do they need surgery
The treatment of a meniscus tear depends on the severity of the injury, age and sporting/work requirements.
Most meniscal tears are treated without surgery and respond well conservatively, particularly for mild degenerative tears or knee with osteoarthritis.
Occasionally surgery may be needed for certain tear, for example if the knee continually locks, or does not progress with conservative management.
Best treatment for meniscus injury
Early management is often aimed at reducing pain and inflammation, and settling down the knee. This may include gentle mobility work and some basic strength work.
After the acute setting, it is important to abolish any swelling, restore full range of movement, and restore strength and balance. This will aid a return to sport or normal activity quickly and as well as aiming to prevent further injury.
Correct and thorough rehabilitation will ensure you return safely to your chosen activity and help to prevent future problems with your knee.
Who do I see for a meniscus injury
Physiotherapists are highly skilled in initially diagnosing meniscus pathology. At SportsFit, we have over 70 years combined experience in treating knees! For over 10 years we have been helping the locals of Glen Iris, Malvern East and Ashburton recover from their knee injuries. Our expert knee physiotherapists can:
– Accurately assess your knee through your history and objective testing;
– Provide you with a referral for investigations (MRI, X-ray) if required;
– Guide your rehabilitation back to recovery.
Tom Feikema
Physiotherapist
Want to learn more? Read below for some more related information
References:
Image 1: Reproduced from the American Association of Orthopaedic Surgeons, OrthoInfo.
Image 2: Reproduced from Moulton, Samuel G., B.A, Bhatia, Sanjeev, M.D, Civitarese, David M., B.A, Frank, Rachel M., M.D, Dean, Chase S., M.D, & LaPrade, Robert F., M.D. (2016). Surgical Techniques and Outcomes of Repairing Meniscal Radial Tears: A Systematic Review. Arthroscopy, 32(9), 1919-1925.
German Valdez, MD, Abid Haque, MD, and Richard G. Chang, MD, MPH (2021), Meniscus injuries of the knee, PM&R KnowledgeNow.
Logerstedt, D., Arundale, A., Lynch, A., & Snyder-Mackler, L. (2015). A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC). Journal of Orthopaedic & Sports Physical Therapy, 45(6), 410-426.
American Academy of Physical Medicine and Rehabilitation. (n.d.). Meniscus injuries of the knee. PM&R KnowledgeNow. 2024.
Sherman, S. L., DiPaolo, Z. J., Ray, T. R., & Sachs, B. M. (2022). Meniscus injuries in athletes: A review of imaging and treatment strategies. Sports Medicine and Arthroscopy Review, 30(2), 89-97.
Hagmeijer, M. H., Geurts, G., Renard, R., Schurink, M., Claessen, F. M. A. P., Maas, M., & van Geenen, R. C. I. (2022). Diagnostic accuracy of clinical tests for meniscal tears in the knee: A systematic review and meta-analysis. Journal of Orthopaedic Surgery and Research, 17(1), Article 358