A knee arthroscopy is a minimally invasive surgery where a surgeon inserts a small camera and thin instruments through tiny incisions to diagnose or repair problems inside your knee joint. It’s one of the most commonly performed orthopedic procedures, used to treat everything from torn meniscus cartilage to damaged ligaments. Most people go home the same day and return to normal activities within six to eight weeks.
How the Procedure Works
The surgeon makes two or three small incisions, each only a few millimeters long, around your knee. Through one incision, they insert an arthroscope, a narrow tube with a tiny camera and light on the end. The camera sends a magnified image to a monitor, giving the surgeon a detailed view of the inside of your joint. Sterile fluid is pumped into the knee to expand the space and clear away debris, making structures easier to see.
Through the other incisions, the surgeon inserts specialized instruments to trim, repair, or remove damaged tissue. The entire procedure typically takes under an hour for straightforward cases, though more complex repairs like ligament reconstruction take longer.
Conditions It Treats
Knee arthroscopy serves two purposes: diagnosis and treatment, often in the same session. A surgeon can look inside the joint to identify a problem and then fix it right there. The most common reasons for the procedure are:
- Meniscus tears: The surgeon trims away the damaged portion of cartilage or stitches the tear back together.
- ACL reconstruction: A torn anterior cruciate ligament is replaced with a graft, frequently performed alongside meniscus repair.
- Other ligament repairs: Damage to the MCL or PCL can also be addressed arthroscopically.
- Cartilage damage: Loose fragments of cartilage floating inside the joint are removed, or damaged surfaces are smoothed and treated to encourage healing.
- Synovitis: Inflamed joint lining tissue is trimmed away to reduce pain and swelling.
- Scar tissue removal: Excess scar tissue (sometimes called arthrofibrosis) that restricts movement can be cut free.
One important exception: the American Academy of Orthopaedic Surgeons recommends against using arthroscopy to clean out or flush a knee when osteoarthritis alone is the problem. The evidence shows it doesn’t help. However, if you have a meniscus tear alongside mild to moderate arthritis and nonsurgical treatments haven’t worked, a partial meniscus trimming can still be appropriate.
Anesthesia Options
You’ll typically have a choice between being fully asleep (general anesthesia) or staying awake while your lower body is numbed (regional anesthesia, such as a spinal or epidural). Both approaches work well for outpatient knee arthroscopy, and discharge times are similar with modern short-acting medications. The decision often comes down to personal preference: whether you’d rather be unconscious during the procedure or awake. Your anesthesiologist will help you weigh the options based on the complexity of the surgery and your medical history.
What Recovery Looks Like
The first 24 hours are the most restrictive. You’ll use crutches and avoid putting weight on the leg. After that first day, you can gradually start bearing more weight while still relying on crutches for support. Icing is critical for managing pain and swelling early on. Plan to ice for up to 20 minutes every hour during the first two days, then at least three times daily for the following two weeks. Always keep a layer of fabric between the ice and your skin.
You’ll likely go home with compression stockings that run from your foot to your upper thigh. These reduce the risk of blood clots and help control swelling in your lower leg. Wear them consistently for the first two weeks, removing them only for sleep and showers.
Recovery timelines vary depending on what was done inside the knee. A simple cartilage trimming heals faster than a full repair. For meniscus repairs specifically, expect a more structured recovery: you’ll wear a hinged knee brace locked straight for walking during the first four weeks, stay completely off the leg for two weeks, then gradually increase weight-bearing. The brace comes off around six weeks. Physical therapy begins once your incisions have healed and continues for weeks to rebuild strength and range of motion. Most people return to their usual activities within six to eight weeks, though athletes doing high-demand sports may need longer.
Success Rates for Meniscus Repair
Meniscus repair, one of the most common arthroscopic procedures, holds up well for the majority of patients. A large meta-analysis tracking outcomes over an average of about seven years found an overall failure rate of roughly 19%, meaning about four in five repairs remain intact long-term. Younger patients (under 40) fare better, with failure rates closer to 12%.
Not all tears respond equally. Vertical or longitudinal tears have a failure rate around 18%, while bucket-handle tears, a more severe pattern, fail closer to 30% of the time. Interestingly, having an ACL reconstruction done at the same time as a meniscus repair doesn’t hurt outcomes and may slightly improve them, likely because the increased blood flow during healing benefits the repair.
When repairs do fail, it often happens later than you might expect. Many failures show up after the second year, which is why surgeons monitor repaired knees over time rather than declaring success at the first follow-up.
Risks and Complications
Knee arthroscopy is generally safe, but no surgery is risk-free. The most notable concern is blood clots. A meta-analysis of studies where patients received no blood clot prevention found a deep vein thrombosis rate of about 10%, with clots reaching the upper leg in about 2% of cases. This is why compression stockings, early movement, and sometimes blood-thinning medication are standard parts of post-operative care.
Other possible complications include infection at the incision sites, stiffness in the joint, and ongoing pain. Nerve or blood vessel injury is rare given how small the incisions are. Swelling and bruising around the knee are normal and expected, not complications. If you notice increasing redness, warmth, fever, or calf pain and swelling in the weeks after surgery, those warrant prompt medical attention.