Knee Pain: Arthritis vs Meniscus Tear

Not all knee pain is arthritis, even when you are older than 65! Arthritis is the result of damage to the articular cartilage.  The meniscus is a C-shaped fibro-cartilaginous structure located between the femur and tibia on the inside and outside of the knee.   The meniscus acts as a shock absorber, protecting the articular cartilage.

Tears of the meniscus are common and can affect people of all ages.  As you age, the meniscus is more prone to tearing with minima trauma, particularly with bending and twisting activities.  Common complaints are locking, catching, and a feeling of instability, particularly with bending and twisting.  The medial meniscus, located on the inside of the knee is more commonly torn than the lateral meniscus on the outside of the knee.

X-rays are important to determine if there is arthritis in the knee.  An MRI will show damage to the meniscus, ligaments, and cartilage.  While knee pain caused by arthritis will often improve with anti-inflammatory medications, physical therapy, and corticosteroid injections, pain from a meniscus tear is often not helped with these treatments.  With severe arthritis, the meniscus is inevitably damaged.  However, removing a torn meniscus will not help knee pain due to arthritis and may make it worse.  If the meniscus is torn in a knee with only mild arthritis, symptoms often improve with surgery.

Meniscus tears are often treated with arthroscopic surgery.  A camera is placed into the knee joint and the torn tissue is repaired or removed.  In older patients, the tear is often not repairable.  Removal of the entire meniscus increases contact pressure in the knee and results in arthritis, so only the damaged portion of the meniscus is removed.   After surgery, patients typically go home the same day, often using crutches for three to five days.

Results after surgery vary.  Most patients do very well.  Good to excellent results can be expected in 95% of patients without arthritis, but only in 65% of patients with arthritis.  One study found that up to 20% of patients went on to have a total knee replacement within 2 years of their knee arthroscopy.  If the meniscus is torn and there is minimal arthritis in the knee, arthroscopic surgery can often provide excellent relief of symptoms.  However, surgery is less effective when there is significant arthritis in the knee.