A surgeon may be able to repair a torn meniscus to help relieve knee pain and other symptoms. But not all meniscal tears need surgery to heal, and some tears are easier to surgically repair than others. Factors such as the location, size, shape, and underlying cause of the tear affect the likelihood of a successful surgery.
1. Not All Meniscal Tears Require Surgery
Most small meniscal tears (less than 5mm) have the potential to heal on their own, without surgery. In these cases, a doctor may recommend the patient wear a brace to immobilize the knee for 4 to 6 weeks and participate in physical therapy. 1 Miller RH III, Azar FM. Knee Injuries. In: Canale ST, Beaty JH, eds. Campell’s Operative Orthopaedics, 12th ed. Philadelphia, PA: Mosby, Inc; 2013:2052-2211.
Small meniscal tears tend to heal better and faster in younger patients (under 40) than in older patients. Older patients who have small tears are more likely to develop osteoarthritis in the affected knee. (However, this does not necessarily mean that surgery is a better option for older patients with small tears.)
2. The Location of a Meniscus Tear Matters
A meniscus is shaped like a crescent, or C. Tears at or next to the meniscus’ outer edge tend to heal better than tears at the inner edge, close to the center of the knee. Why? The outer edge of the meniscus contains blood vessels, and blood cells are essential for healing. Medical professionals call the outer rim of the meniscus the “vascularized zone.”
In addition, which meniscus is torn can matter. Each knee has two meniscal pads, and the natural placement of tendons and other soft tissue sometimes make it more difficult for a surgeon to repair the lateral meniscus than the medial meniscus. (To understand the difference between lateral and medial, stand with knees together and hands at the sides. The medial sides of the knees touch each other, while the fingers point down to the lateral sides.)
3. The Shape of a Meniscus Tear Matters
A meniscus is a crescent-shaped piece of cartilage made up of collagen fibers running in different directions. The direction and shape of a meniscal tear affects its ability to be surgically repaired.
Different types of tears are described below.
A radial tear occurs on the inside edge of the meniscus’ crescent and radiates outward.
A flap tear usually occurs on the meniscus’ top surface, when a layer of meniscal tissue pulls away from its bottom. This type of tear forms a rounded, loose tab that can flap back and forth.
A longitudinal tear can be straight or curved and occurs inside the meniscus—the outer edge of the meniscus remains in tact. (A longitudinal tear can look similar to a buttonhole in a shirt.)
A buckethandle tear is like a longitudinal tear, but the meniscal tissue has pulled apart and separated, creating an obvious hole. Often the curved outer rim of the meniscus is separated from the rest of the meniscus, making it look like a bucket handle. A longitudinal tear can turn into a bucket tear over time.
In general, radial and flap tears tend to be more challenging to surgically repair than longitudinal tears. 1 Miller RH III, Azar FM. Knee Injuries. In: Canale ST, Beaty JH, eds. Campell’s Operative Orthopaedics, 12th ed. Philadelphia, PA: Mosby, Inc; 2013:2052-2211.
4. How the Meniscus Tear Occurred Matters
A meniscal tear can occur:
- After a trauma, such as a fall or sudden stop while playing sports
- Over time, though chronic wear-and-tear
Chronic degeneration tends to result in a thinner meniscus and produce a tear that has ragged edges, making repair challenging. A trauma to a healthy meniscus tends to produce a clean tear that is easier to repair. (However, patients who have a degenerative tear should not assume that their tear cannot be surgically repaired.)
When Is Meniscus Repair Surgery Recommended?
A doctor’s recommendation to have meniscal repair surgery will be based on the factors listed above—the tear’s underlying cause, location, shape, and size—as well as other factors, such as the patient’s overall health and whether the patient’s knee has other injuries or conditions, such as severe knee osteoarthritis.
A doctor can assess an individual’s meniscal tear, present a surgical plan, and discuss reasonable expectations for surgery.
- 1 Miller RH III, Azar FM. Knee Injuries. In: Canale ST, Beaty JH, eds. Campell’s Operative Orthopaedics, 12th ed. Philadelphia, PA: Mosby, Inc; 2013:2052-2211.