Knee replacement complications

Although knee replacement surgery is often referred to as a "mainstream procedure," and is considered one of the most successful procedures in all of medicine1, every surgical procedure comes with risk of complications. That's why it is important to dininescuss with your doctor and your orthopaedic surgeon the full balance of risks and benefits of knee replacement surgery, before you make your treatment decision. Remember, the information in this section is not intended to replace professional medical advice. If you have questions or concerns, turn to your doctor for answers.

Possible complications following surgery

According to the American Academy of Orthopaedic Surgeons (AAOS), the rate of serious complications following total knee replacement surgery, such as infection in the knee joint, is very low, under two percent.1 If your health is already challenged by a chronic medical condition, the chance of complication can be greater. Uncommon as they are, if complications occur they can delay or limit your ability to recover fully from your surgery. These are some of the complications that can occur:

Blood clotting (thrombophlebitis)

Blood clots occur naturally and perform a vital role in the body's healing process to stop bleeding. However, blood clots can also form when blood stops flowing properly and pools in large veins, such as those in the legs. In a condition known as Deep Vein Thrombosis, blood clots formed in the veins can travel to the lungs where they lodge in the capillaries, causing a very serious blockage called pulmonary embolism. These are measures your care team may use to avoid blood clots:

  • You may be prescribed blood-thinning medicines known as anticoagulants
  • In the hospital and later at home, you may be instructed to wear elastic stockings (TED hose: the acronym stands for "thromboembolic disease") to help blood return from your lower leg veins to your circulatory system
  • You may be assigned foot and ankle exercises for the same reason: to help increase blood flow and enhance venous return in the lower leg.2

IMPORTANT NOTE: Watch for signs of trouble, such as swelling, redness, pain and tenderness in your calf muscle. If any of these symptoms occur, report them to your orthopaedic surgeon or internist right away.


Even though doctors, nurses and technicians take great precautions before, during and after surgery to avoid infection, it can occur. If a significant infection should occur, additional surgery and/or the removal of the knee implant may be necessary.

Signs of infection can appear either before your release from the hospital, or later after you have returned home. Your care team may suggest these steps to minimize the chance of problems with infection:

  • Monitor your incision closely and immediately report any redness, swelling, tenderness, increased drainage, foul odor, persistent fever above 100.4 degrees, or increasing pain
  • Take your antibiotics as directed and don't stop until you finish the complete course, even if you're feeling better
  • Ask for incision care instructions in writing, and follow them carefully and completely. As your incision heals, ask when it's OK to stop your incision care routine2.


Many people wake up from anesthesia feeling weak and sore, so they find it uncomfortable to breathe deeply. However, if you don't inhale and exhale fully, fluids could pool in your lungs, causing congestion or pneumonia. Your care team may take these steps to minimize the risk:

  • Incentive spirometer: This is a simple device that shows you whether your breathing is deep enough to avoid congestion. Your nurse or respiratory therapist will demonstrate how to use your breath to lift and suspend balls in a plastic tube.
  • Deep breathing exercises: Your nurse or respiratory therapist may have you place a hand on your belly, then inhale slowly and deeply through your nose as your belly expands. Next you will exhale through your mouth at a slow and controlled rate.

Long term pain

While the great majority of patients - nine out of ten, according to statistical studies1 - experience steady reduction of pain after their procedure, a small number of people report that pain persists over a longer term after knee replacement surgery.

Knee stiffness

In some cases, the mobility of your knee following surgery may be significantly restricted and you may develop a contracture, or restriction in the joint, that causes stiffness during walking or other daily living activities. Your care team may prescribe steps or treatments to help you achieve maximum range of motion following surgery:

  • A Continuous Passive Motion (CPM) unit to slowly and gently bend and straighten your knee. The object is to help you regain your greatest range of motion as quickly as possible
  • Early physical therapy, starting on day one or two after surgery, including range of motion
  • exercises and a supervised walking program
  • Edema control to reduce swelling. Measures can include ice, compression stockings, and
  • elevating your lower legs when you lie down or sit
  • Adequate pain control so you can put maximum effort into your rehabilitation program

This rare complication is more likely in people whose range of motion was impaired before the procedure.

Implant wear or failure

The design of knee implants and the materials they're made from are improving all the time. It is possible, however, for the hinge surfaces to wear or deteriorate, and for other components to loosen. In rare cases another surgery might be needed to correct or replace the implant.

Fortunately, recent advances such as implants made with OXINIUM technology can help offset implant wear.

Nerve or vascular complications

It's uncommon, but possible, for nerves or blood vessels in the area around the knee to be damaged during surgery.

Important safety notes

Individual results of joint replacement vary. Implants are intended to relieve knee pain and improve function, but may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, wear and infection that may result in the need for additional surgery. Patients should not perform high impact activities such as running and jumping unless their surgeon tells them that the bone has healed and these activities are acceptable. Early device failure, breakage or loosening may occur if a surgeon's limitations on activity level are not followed.


  1. OrthoInfo article: Total Knee Replacement, American Academy of Orthopaedic Surgeons, accessed March 8, 2017:
  2. S&N Brochure: PE 07505 V1 JOURNEY XR full brochure 12.16 - ORBIS comments

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