Knee arthroscopy is a minimally invasive surgical procedure where a surgeon inserts a small camera into your knee joint through incisions roughly 4 to 5 millimeters wide. The camera sends real-time video to a monitor, allowing the surgeon to diagnose problems and make repairs using tiny instruments inserted through a second small incision. It’s one of the most commonly performed orthopedic surgeries and is typically done as an outpatient procedure, meaning you go home the same day.
How the Procedure Works
The surgery begins with anesthesia. You’ll typically receive one of three options: local anesthesia that numbs just the knee while you stay awake, spinal anesthesia that blocks sensation below the waist, or general anesthesia that puts you fully to sleep. A regional nerve block in the groin or leg is sometimes used alongside general anesthesia to reduce pain after you wake up. Your surgical team will recommend the best option based on the complexity of the procedure and your health history.
Once the anesthesia takes effect, the surgeon makes two or three small incisions (called portals) around the knee. Through one portal, they insert the arthroscope, a narrow tube with a camera and light source on the end. Through the other, they insert surgical instruments. Fluid is pumped into the joint to expand the space and improve visibility.
The surgeon systematically examines each compartment of the knee: the area behind the kneecap, the inner and outer sides of the joint, the space between the two large leg bones where the cruciate ligaments sit, and the back of the knee. They check cartilage surfaces for damage, inspect the meniscus (the rubbery shock absorber between the bones), evaluate the ligaments, and look for loose fragments of bone or cartilage. By rotating the camera and adjusting the angle of the knee, the surgeon can see nearly every structure inside the joint. If a problem is found, the repair can often happen during the same procedure.
Most knee arthroscopies take between 30 minutes and an hour, depending on what needs to be done.
Conditions Treated With Arthroscopy
According to the American Academy of Orthopaedic Surgeons, the most common arthroscopic knee procedures include:
- Meniscus tears: trimming the torn portion, repairing it with sutures, or in severe cases, transplanting donor tissue
- Ligament reconstruction: rebuilding a torn ACL or PCL using grafted tissue
- Cartilage damage: smoothing roughened cartilage or restoring damaged areas on the joint surface
- Loose bodies: removing fragments of bone or cartilage floating inside the joint
- Inflamed tissue: removing the irritated joint lining (synovium) that causes swelling and pain
- Kneecap problems: addressing issues like a kneecap that tracks incorrectly
- Joint infection: washing out and treating bacterial infection inside the knee
What to Do Before Surgery
Your surgeon will review every medication and supplement you take. Some, particularly blood thinners, may need to be stopped days or weeks before the procedure because they increase bleeding risk. Others you may be told to continue as normal. You’ll receive specific fasting instructions for the hours leading up to surgery, and you’ll need to arrange a ride home since you won’t be able to drive afterward.
Recovery Timeline
Recovery depends heavily on what the surgeon actually does inside the knee. A simple cleanup procedure heals much faster than a meniscus repair or ligament reconstruction.
For most arthroscopic procedures, you can begin walking the same day of surgery, though your movement will be limited for the first two to four weeks. Some repair procedures and cartilage restoration techniques require a longer period of restricted weight-bearing, sometimes with crutches. If you have a desk job, plan for one to two weeks off work, possibly with modified duties when you return. Physical labor and jobs that require standing or walking take longer.
By weeks four to six, many patients can transition back to normal daily activities. Light jogging and leg exercises are often possible at this point if swelling and pain have decreased enough. High-impact sports like running, jumping, and heavy lifting require clearance from your surgeon and typically take longer.
Physical Therapy After Surgery
Physical therapy usually starts within the first few weeks and plays a major role in how well you recover. In the initial protection phase (roughly the first three weeks), you’ll attend one to two sessions per week focused on reducing swelling, restoring range of motion, and reactivating the muscles around the knee. The quadriceps muscle on the front of the thigh tends to weaken quickly after knee surgery, so early exercises target that area specifically.
As you progress, therapy shifts toward strengthening and functional movement. Some rehabilitation programs incorporate blood flow restriction training, a technique where a cuff gently restricts blood flow to the leg during low-intensity exercises, allowing you to build muscle strength without putting heavy stress on the healing joint. This is typically used twice a week for up to ten weeks. The total length of rehab varies, but expect several weeks to a few months depending on the procedure.
Success Rates and Long-Term Outcomes
Outcomes vary by procedure. For meniscus repairs, a meta-analysis of 864 patients followed for an average of about seven years found an overall failure rate of 19.1%, meaning roughly four out of five repairs held up over time. One important detail: about 30% of meniscus repair failures happen after the second year, so even if your knee feels great at the one-year mark, continued care and strengthening matter for long-term durability.
Simpler procedures like removing loose bodies or trimming a damaged meniscus (partial meniscectomy) generally have quicker recoveries and high rates of symptom relief, though removing meniscus tissue does change the long-term mechanics of the joint.
Risks and Complications
Knee arthroscopy is considered low-risk compared to open surgery, but complications can occur. The most commonly studied risk is blood clots. One study of 222 patients found that 16.7% developed a deep vein thrombosis (a clot in the leg veins) within two weeks of surgery, and one patient developed a clot that traveled to the lungs. This rate reflects a screened population, so some of those clots may not have caused symptoms, but it underscores why surgeons pay close attention to clot prevention.
Other possible complications include infection inside the joint, stiffness that limits range of motion after surgery, bleeding, and nerve irritation near the incision sites. Serious complications are uncommon, and the small incision size reduces the risk of wound-healing problems compared to traditional open surgery. Your surgical team will discuss your individual risk factors, such as obesity, smoking, or a history of blood clots, before the procedure.