Meniscal Tears and Knee Arthroscopy
Overview
The menisci are shock-distributing cartilage structures within the knee. Tears may occur suddenly during injury or develop gradually as the tissue changes with age and osteoarthritis. Many tears improve without surgery, and an MRI tear may not be the main source of pain. Arthroscopy is considered only when the symptoms, examination and tear pattern identify a problem that can reasonably be treated, such as a repairable traumatic tear or a displaced tear causing a true locked knee.
Traumatic and degenerative tears
A traumatic tear may follow a twist, pivot, deep squat or sporting injury. It may occur with an anterior cruciate ligament injury and can produce joint-line pain, swelling, catching or loss of movement. Some tear patterns with good blood supply and tissue quality may be suitable for repair.
Degenerative meniscal changes are common from middle age and frequently coexist with osteoarthritis. Clicking or an MRI tear does not prove that the meniscus is causing pain. Symptoms may improve with rehabilitation even when the scan remains unchanged. Routine arthroscopy for a degenerative tear with osteoarthritis does not provide lasting benefit for most people.
Assessment
Assessment includes the mechanism, timing of swelling, location of pain, clicking or catching, ability to fully straighten the knee and any instability. Examination assesses movement, joint-line tenderness, ligaments, alignment and hip or back sources of pain.
Weight-bearing X-rays are often more useful than MRI when osteoarthritis is possible. MRI may be requested after an acute injury when a repairable meniscal or ligament injury is suspected, when symptoms do not fit the examination or when surgery is being considered. MRI findings still need to match the symptoms and examination.
Non-surgical treatment
- Temporary modification of twisting, deep flexion or impact while swelling settles.
- Exercise to restore movement, quadriceps and hip strength, balance and gradual return to activity.
- Ice, compression and short-term pain-relieving medicine when appropriate.
- Management of underlying knee osteoarthritis when present.
- Seek review if the knee remains swollen, unstable, unable to fully straighten or does not improve as expected.
When might arthroscopy be considered?
Arthroscopy may be appropriate for a displaced tear causing a true locked knee, a repairable traumatic tear, a symptomatic loose body or a selected unstable tear that remains clearly limiting despite rehabilitation. Clicking alone, pain alone or an MRI tear alone is not an indication for surgery.
The aim may be meniscal repair, which preserves tissue but requires protection while healing, or limited removal of an irreparable unstable fragment. Removing more meniscus than necessary increases joint load and may contribute to later arthritis. Arthroscopy is not a treatment for uncomplicated osteoarthritis.
What happens during knee arthroscopy?
A camera and small instruments are inserted through small incisions. The joint is inspected, including cartilage, menisci and ligaments. A tear may be repaired with sutures or anchors when healing potential and pattern are suitable. Otherwise, only the unstable non-repairable portion is trimmed while preserving as much healthy meniscus as possible.
Findings on the day may alter the exact procedure. A structurally abnormal MRI does not guarantee that arthroscopy will relieve all pain.
Recovery
After limited trimming of an irreparable fragment, weight-bearing and movement often progress as comfort allows. A repair requires more protection and may involve a brace, crutches and temporary limits on weight-bearing or knee bend. Rehabilitation then progresses swelling control, movement, strength and sport-specific function.
Return to driving, work and sport depends on the procedure, side, strength and ability to respond safely. A repair generally has a longer rehabilitation than trimming but preserves more meniscal tissue.
Risks and limitations
- Infection, bleeding, blood clots or anaesthetic complications.
- Stiffness, ongoing swelling or persistent pain.
- Failure of a repair to heal or recurrent tearing.
- Nerve or blood vessel injury, although uncommon.
- Progression of arthritis or need for further surgery.
- No meaningful improvement when the tear was not the main pain source.
When to seek urgent assessment
- A knee locked after injury and unable to straighten.
- A large, rapid swelling after a pivoting injury, particularly with instability.
- A hot, swollen knee with fever or feeling generally unwell.
- Inability to bear weight after trauma, marked deformity or new numbness.
Frequently asked questions
Does every meniscal tear need surgery?
No. Many tears, particularly degenerative tears, improve with time and rehabilitation.
What is a true locked knee?
The knee has a persistent mechanical block and cannot fully straighten, rather than being limited only by pain or swelling. It warrants prompt assessment.
Is repair better than trimming?
Preserving and repairing meniscal tissue is preferred when the tear pattern, tissue and blood supply give a reasonable chance of healing. Not all tears are repairable.
Will arthroscopy treat knee arthritis?
No. Arthroscopy does not reverse osteoarthritis and is not recommended as a clean-out for uncomplicated degenerative arthritis.
Can an MRI tear be incidental?
Yes. Meniscal changes are common and must be matched with symptoms, examination and X-rays.
General information
This page provides general information only. It cannot diagnose your condition or replace advice from a clinician who has assessed you. Your treatment and recovery plan may differ from the examples described here. Follow the instructions from your treating team. In an emergency, call 000 or attend the nearest emergency department.