Risks of Knee Arthroscopy

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Arthroscopic surgery of the knee joint is one of the most common surgical procedures performed. When a surgeon performs an arthroscopic surgery, this means that they are looking inside the joint, and assessing and treating the abnormalities that are found within that joint space. A knee arthroscopy is performed to evaluate the knee joint and to manage various conditions that can cause knee pain.

While not every knee problem can be managed with an arthroscopic surgery, there are many conditions that are amenable to treatment. Performing knee arthroscopy is felt to be a very safe treatment, but there are possible complications that can occur.

Anyone considering knee arthroscopy should consider the potential risks of surgery. Your surgeon should be able to carefully explain possible complications that can occur, how likely they may be, and the steps that you can take to avoid complications associated with knee arthroscopy.

The Surgical Procedure

what to expect during knee arthroscopy
Illustration by Emily Roberts, Verywell

A knee arthroscopy surgical procedure is performed as an outpatient. This means that the surgical procedure is performed without you staying in the hospital overnight. Arthroscopic knee surgery can last less than 30 minutes, or over an hour, depending on exactly what needs to be performed at the time of surgery.


Options for anesthesia include:

  • Local anesthetic: Where the knee joint is numbed, but the individual having surgery can be awake.
  • Regional anesthetic: Where the lower extremities are numbed from the area around the spine, and again the patient can remain awake, or they may choose to be sedated.
  • General anesthesia: Where the person having surgery is asleep during the operation.

The selection of the anesthesia depends both on the preference of the individual patient, and the recommendations from the anesthesiologist. For people with certain medical conditions, or having a particular procedure, a specific anesthetic option may be more favorable than another.

Once the patient has been appropriately anesthetized, the surgical procedure is performed by creating two or more small incisions around the knee joint. In one of the incisions, your surgeons will place a fiberoptic camera with an attached light source. Saline irrigation is circulated throughout the joint, and your surgeon will use the camera to evaluate the different structures within the knee joint.

Through the other incisions, small instruments can be placed to remove or repair damaged structures including cartilage, ligaments, and other structures.

Following the procedure, a bandage is placed on the knee joint. Depending on the type of surgery, people may be able to place their full weight on their leg, or they may be told to limit the amount of weight on the affected extremity. Rehabilitation will also depend on the specific procedure performed. For some surgical procedures, specialized braces or knee immobilizers may be used to protect the healing joint.

Common Risks

The overall risk of complications associated with knee arthroscopy has been estimated to be approximately 5 percent.

The likelihood of a serious complication resulting from knee arthroscopy is much less than 1 percent.

The most common risks of surgery are typically not life-threatening, but they can be an inconvenience. These risks include:


Swelling is a sign of inflammation within a joint. Often people undergoing knee arthroscopy have swelling of their joint before any surgical intervention. Sometimes, the knee swelling can be persistent after surgery, and may even worsen. Swelling can occur as a result of persistent inflammation within the joint, bleeding within the joint, or infection.

There are steps you can take to reduce swelling, including resting the knee joint, ice application, compression bandages, and elevating the extremity. However, for some people, the swelling becomes persistent and can be a frustrating source of discomfort following arthroscopic surgery. Worsening swelling can also be a sign of a more significant problem.


Stiffness of the knee joint can occur as a result of scar tissue formation around the knee joint, or as a result of persistent swelling of the knee joint. Most people can find resolution of stiffness with appropriate therapeutic intervention following surgery.

However, for some people, the stiffness does not improve and can be a frustrating source of ongoing discomfort and disability after knee arthroscopy. Bending the knee and performing regular rehabilitation exercises in the early phase following surgery can help prevent excessive stiffness.

Progression of Cartilage Damage

Many people who undergo arthroscopic knee surgery have some early damage to the cartilage of their knee joint. In general, arthroscopic surgery is not a good treatment for arthritis, and many people who have arthritis will have a progression of their condition.

Sometimes, people who have arthroscopic surgery can actually have a more rapid progression of arthritis following their surgical intervention.

There is also a medical condition called osteonecrosis that can spontaneously occur following arthroscopic surgery. This condition, abbreviated SONK (spontaneous osteonecrosis of the knee), can lead to a much more rapid deterioration of the knee joint cartilage, and ultimately may require knee replacement.

Less Common Risks

Uncommon risks of knee arthroscopy represent roughly 1% of people who undergo this surgical procedure. These are the risks that most people are concerned about, and fortunately, they are exceedingly infrequent following arthroscopic knee surgery. However, they can occur, and anyone who is considering arthroscopic knee surgery should be aware of the following possible complications:


Infection is an unusual complication of knee arthroscopy, but it certainly can occur. Infection can either occur around the incisions, where it is considered a superficial infection, or it can occur within the knee joint, where it is a more serious, deeper infection.

When infection does occur, additional surgical procedures to clean out the infection may become necessary. Having bacteria within the knee joint can cause significant damage to the cartilage of the joint, and therefore urgent treatment of any suspected infection is necessary.

If the infection is only in the superficial area around the incision, sometimes antibiotics alone will be sufficient to cure the infection. When the infection is deeper within the knee joint, additional surgery in addition to antibiotics is typically necessary to eradicate the infection.

Blood Clot

The risk of blood clots in the deep veins of the lower extremity is small after arthroscopic knee surgery, but it does occur. Blood clots can occur in anyone, but they are more common in people with specific risk factors for developing a clot.

One of these risk factors for developing a blood clot is lower extremity surgery with prolonged immobilization. For that reason, it is important to follow your healthcare provider's advice and move your extremity as much as possible to keep blood flowing to the extremity and prevent the formation of blood clots.

For people with other risk factors (including smoking, oral contraception, clotting disorders, and others) additional precautions may be necessary.


The risk of mortality following knee arthroscopy is exceedingly small. In fact, the risk of mortality in patients undergoing knee arthroscopy has been found to be smaller than in the general population. This has been attributed to the fact that people undergoing arthroscopic surgery tend to be more active individuals.

The overall risk of mortality associated with arthroscopic knee surgery has been estimated at 0.008 percent within 30 days of the surgery.

The bottom line is that it is exceedingly unlikely to have mortality associated with an arthroscopic knee surgery.

Avoiding Complications

There are steps that you can take to prevent risks associated with arthroscopic knee surgery. As is always the case, your healthcare provider should provide specific instructions regarding your recovery from arthroscopic knee surgery. It is important to follow these instructions carefully, to ensure that the outcome of surgery is as good as possible.

Some signs that you should contact your surgeon include:

  • Signs of infection, including fever, chills, or sweats
  • Drainage or bleeding from the incisions
  • Worsening swelling or redness around the knee joint
  • Pain in the calf and swelling extending down the leg
  • Increasing difficulty placing weight on the leg

Some of the specific steps that you can take to prevent complications include:

  1. Keep the incision site clean and dry. If your surgeon has placed a bandage, follow their instructions carefully. Do not remove the bandage or get the area wet until your surgeon has told you that is okay.
  2. Try to move the muscles of your lower extremity frequently. Even if not placing weight on the leg, perform frequent ankle pumps and bend the knee as allowed.
  3. Take the medications as prescribed by your healthcare provider. Pain that is not controlled by the prescribed medications can be a sign that something more significant is going on.

As with many medical conditions, it is often easier to address a complication early on, rather than waiting for a more serious problem to develop.

If things do not seem right, or your symptoms are not appropriately responding to the treatments prescribed, make sure you let your healthcare provider know. If something more serious is going on, it may be easier to address in the early stages.

A Word From Verywell

Knee arthroscopy is a very safe surgical procedure that is performed very commonly. That said, there are risks associated with arthroscopic knee surgery, and any patient considering treatment of their knee condition with surgery should understand these risks.

Fortunately, the risks associated with knee arthroscopy are generally not life-threatening, and most can be managed with appropriate treatment. Preventing complications of knee arthroscopy is the most important step to staying healthy. Following your surgeon's directions as carefully as possible can help to ensure that you will not have problems following your knee arthroscopy.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jonathan Cluett, MD
Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams.