Experts estimate more than 7% of people in their 70s and 10% of people in their 80s have had a knee replacement. 1 Maradit Kremers H, Larson DR, Crowson CS, et al. Prevalence of Total Hip and Knee Replacement in the United States. The Journal of Bone and Joint Surgery American volume. 2015;97(17):1386-1397. doi:10.2106/JBJS.N.01141. The surgery is done to alleviate pain caused by moderate to severe knee arthritis.

More than 90% of knee replacement surgeries are considered successful 2 Total Knee Replacement. American Academy of Orthopaedic Surgeons. Last reviewed August 2015. Accessed July 2018. , meaning that after recovery patients have both:

  • Less knee pain
  • Improved knee function

While common, total knee replacement is a major surgery, and recovery requires several months of physical therapy. For these reasons, patients are asked to commit efforts to non-surgical treatments before considering knee replacement.

See Knee Osteoarthritis Treatment


When Is Total Knee Replacement Surgery Recommended?

Osteoarthritis, rheumatoid arthritis, and other forms of arthritis can affect the knee. However, not everyone with knee arthritis is a candidate for total knee replacement surgery. Below are guidelines doctors use to decide when to recommend this surgery.

Who is eligible for total knee replacement surgery?
Patients eligible for this surgery have:

  • Knee pain that interferes with daily living and has not responded to appropriate nonsurgical treatments, such as exercise, weight loss, physical therapy, medications, steroid injections, and bracing.
  • Moderate to severe arthritis in the knee that can be confirmed with medical imaging

Typical candidates for knee replacement will also have some combination of the following:

  • Difficulty walking, going up stairs, and getting in and out of chairs
  • Moderate to severe pain even while resting, which may affect sleep
  • Knee deformity, such as bow-legs or knock-knees, that has resulted or been exacerbated by knee joint degeneration
  • Knee swelling and inflammation that is chronic and not controlled with medication or rest

See When to Consider Knee Replacement Surgery

Sometimes a person may meet these criteria but knee replacement surgery is not recommended for other reasons.

When Is Knee Replacement Surgery Not Recommended?

Knee replacement is not for everyone. For example, knee replacement may not be recommended if the person has a:

  • Systemic infection or is prone to infection. Infection is considered a serious post-surgical risk; infections can necessitate a revision knee replacement surgery, and in some cases can be life-threatening.
  • Significant problem affecting the muscles or soft tissues surrounding the knee, such as a neuromuscular disorder. The surrounding muscles and soft tissues are essential to knee function and the success of the knee replacement.
  • Medical condition that may interfere with safely administering anesthesia. The risks associated with anesthesia can be life-threatening.

    See Anesthesia for Orthopedic Surgery

  • Skin condition, such as psoriasis, at the area to be operated on. Skin problems can affect successful healing and increase the likelihood of infection.
  • Pain associated with arthritis that does not severely limit activities of daily living and/or negatively impact quality of life on a daily basis.

Certain health problems may need to be addressed prior to elective total knee replacement to reduce the risk of serious complications. These health problems include:

  • Uncontrolled diabetes with a blood test showing an elevated hemoglobin A1c. In these cases, the person may need diet, exercise, pills, or insulin injections to improve blood sugars to safer levels before surgery.
  • Severe vascular disease, which may be indicated by a loss of pulse in the leg, skin ulcers, and/or significant swelling. In these cases, the patient may need wound care visits, edema stockings, or even limb revascularization procedures before surgery.
  • Morbid obesity that precludes safe surgery. In these cases, the patient may benefit from a nutrition consultation, monitored weight loss programs, medications, or even bariatric procedures before undergoing knee replacement surgery.
  • Poor dentition with loose teeth, cavities, or gingivitis. In these cases, the patient is advised to complete all needed dental work before surgery. After surgery, invasive dental work increases the risk of spreading bacteria from the mouth to the knee implant via the blood stream.
  • Lab work that indicates irregularities. These irregularities can often be corrected. For example, an iron deficiency can often be corrected with iron supplementation.
  • Inadequate nutrition, which can slow down or prevent successful healing after surgery. In these cases, the person may benefit from nutrition consultation or caloric supplementation with protein shakes before surgery.
  • Active smoking or nicotine use. Patients who have a willingness to modify their behaviors can get a physician referral to a smoking cessation program and/or use medications to reduce nicotine cravings.

Advanced aged (over 80) and/or osteoporosis may still eligible for knee replacement surgery, though these factors can also affect related risks and outcomes. and should be optimized prior to considering elective knee replacement surgery.