The knee joint is made up of the femur (thigh bone), tibia (shin bone), and patella (knee cap). The ends of the bones are lined with a specialized tissue called articular cartilage that creates a smooth gliding surface. Between the femur and tibia, on both the inside and outside of the knee, are two structures called menisci.
Menisci look like crescent moons and cushion the cartilage lining the femur and tibia. The blood supply for each meniscus comes in from the periphery, which means that the central portion of the meniscus has little to no blood supply. This is important because when the meniscus is torn, the recommended treatment depends not only on the type of tear, but where it is torn. Tears involving the central portion of the meniscus will not heal on their own, while some tears toward the periphery may.
Meniscus tears, like ACL tears, are frequently a result of a traumatic twisting knee injury and frequently occur together. Some meniscus tears are degenerative, which means they happen over time. As we age, the meniscus tissue becomes more brittle, so instead of stretching when the meniscus is under stress, it may break. Meniscus tears that are not associated with pieces that catch in the knee, or do not cause pain, can be treated without surgery; however, most meniscus tears require surgery to allow the patient to return to sport or activities more quickly. Surgery can involve stabilizing the tear with sutures or cleaning up the torn portion of the meniscus.
- Knee buckling
- Catching sensation in the knee
- Knee pain
- Knee swelling
- Knee stiffness and decreased range of motion due to pain and swelling
- Physical Therapy - A formal course of physical therapy (PT) is often the first line of treatment. PT can help patients regain the knee range of motion and strength.
- Injections - An injection into the knee joint can be considered to help alleviate pain, but this is usually temporary and reserved for patients who are not able to have surgery. The injectable options include steroid, hyaluronic acid, and platelet rich plasma.
- Anti-inflammatories - Nonsteroidal anti-inflammatory medications such as Ibuprofen or Aleve can help decrease inflammation and pain caused by a meniscus tear. This can be beneficial in addition to physical therapy, so patients can have less pain while regaining their motion and strength. Prescription-strength anti-inflammatory medications are occasionally prescribed if over-the-counter medications are not working.
- Surgery - Because the meniscus has a poor blood supply, it does not typically heal on its own. When patients have persistent pain that interferes with their activities, surgery is usually the best option to address the meniscus tear. The two surgical options are a meniscus debridement or repair. Several factors are evaluated when determining which surgery is the best option and include: age/activity level of the patient, the type and location of the tear, and quality of the tissue. The best surgical option is often not determined until the time of the knee arthroscopy when some of these factors are easier to evaluate.
Patients with a meniscus tear often have localized pain to the inside or outside part of the knee. The knee will also typically swell. Patients frequently experience painful catching in the knee. After taking a detailed history, performing a thorough exam, and looking at knee X-rays, an MRI is often ordered. An MRI allows for evaluation of the soft tissue structures such as the menisci, cartilage, and knee ligaments.
Often, patients will be advised to have surgery instead of conservative treatment if the meniscus tear occurred due to a specific injury/event. If the tear is degenerative in nature and has torn over time, conservative treatment is recommended first. Additionally, patient factors such as age and activity level/goals are considered when deciding between surgery and more conservative treatments.
The most common risks are stiffness, persistent pain, and weakness from decreased use of the knee. Some meniscus tears do not cause symptoms and do not need to be treated.