Knee Replacement Complications

Total Knee Replacement (also known as total knee arthroplasty) is generally a highly successful procedure with excellent long-term results. In a recent study, 97% of patients remained “revision-free” at 10 years 1. Despite these favorable outcomes, complications may still occur. Listed below are some of the more common complications of total knee replacement surgery.


Several steps are taken to prevent infection. For example, antibiotics are often given before, during and after knee replacement surgery. Still, a small percentage of knee replacements become infected. In a recent study of over 3000 replacements, 2.9% experienced “superficial” infections while 0.8% of infections occurred within the joint. An increased rate of infection was observed in patients who experienced complex surgery or who had certain characteristics such as obesity or poor pre-operative health. 2


Knee replacement components are affixed to the bone in two ways. In “press-fit” implants, long term fixation relies on the growth of bone into what is typically a porous surface or coating on the underside of the implant. Alternatively, the implants may be “cemented” into place with a strong polymer (PMMA) which is mixed and applied at the time of surgery. Both of these fixation methods can fail over time for a variety of reasons causing the implant to become loose and requiring revision (see Implant Poly Wear)


Deep Vein Thrombosis (DVT) is a rare but potentially very serious complication. Blood clots (thrombus) can sometimes form in the “deep” veins near the surgical site. This can cause pain, redness and swelling. Sometimes, the clot can become dislodged and travel through the bloodstream and into the lungs where it can become trapped. This is called a pulmonary embolism and can be fatal. Obviously, many, many precautions are taken to prevent this serious complication.

Patellar Clunk Syndrome

This complication involves interaction of the scar tissue at the top of the patella with the femoral component. See our article on Patellar Clunk Syndrome for more information.

Joint stiffness

Obviously, the joint will be soar and relatively stiff immediately after surgery, however, limited flexion after the immediate post-operative period is undesirable. To read more on stiffness following knee replacement surgery, visit our article joint stiffness following knee replacement surgery.

Allergic Reaction

A small number of patients may experience an allergic reaction or hypersensitivity to the metallic elements in the implants. A more detailed explanation of this complication can be found our article on this topic.

1 Barrington JW, SahA, Malchau H, Burke DW. Contemporary cruciate-retaining total knee arthroplasty with a pegged tibial baseplate. Results at a minimum of ten years. JBJS (Am.). 2009;91:874-878.

2. Jämsen E, Varonen M, Huhtala H, Lehto MU, Lumio J, Konttinen YT, Moilanen T. Incidence of Prosthetic Joint Infections After Primary Knee Arthroplasty. J Arthroplasty.2008 Dec 3.


10 Responses to “Knee Replacement Complications”

  1. Kuldip Kumar Vij on January 30th, 2014 5:41 am

    Can a Diabtic Patient who is on Insuline can undergo orthoplasty,if so is it absolutely safe?what should be the time difference between the surgery of two knees?

  2. Judy Miles on February 8th, 2014 5:45 pm

    I find after having my left knee replaced that my right leg is shorter. Is this a common problem with knee replacement surgery?

  3. Judy Miles on February 8th, 2014 5:47 pm

    After knee replacement surgery is it common for one leg to be longer than the other leg? Is this a common side effect from knee replacement surgery.

  4. gerald burris on April 28th, 2014 2:37 pm

    i”m 47 years old needing a knee replacement and i’m wondering how much durablity do they have i work long will they last ?

  5. charles on May 23rd, 2014 4:17 pm

    in year 2001 I had both knees replaced two years later I had total knee revision (2004) then in2004,2006,2009 I also had revisions then somewhere in 2007 I had a total right hip replacement at this time in my life the quality of life is (o) had many test done no signs of infection, or blood clogs even had a metal sensitivity test nothing positive and now my knees are loosening again may have to go back in for surgery but wont pain is starting to get to me What’s wrong ??????????/

  6. laura on June 21st, 2014 9:59 pm

    I am 49 and when I was 47 years old I had a total knee replacement from a slip and fall at work, 6 months later it broke off my femur and left me in my front yard unable to move. had to have emergency surgery, now I have a rod in my leg to hold my femur together and attach it back together, now I live with constant pain and with excersise it get worse. and sitting and walking and everything make it hurt. good luck to everyone that has to have a knee replacement done! ;0

  7. Kathy Cummins on July 15th, 2014 1:20 pm

    Has anyone had an osteophyte grow from implant causing knee not to bend? I am in that position 4 years after implant never worked correctly.
    does anyone know about neurological problems that can come after an implant. 2 years later I got peripheral neuropathy in calfs and muscle tightening in thighs. No problems health wise before implant.

  8. william on September 19th, 2014 7:08 am

    had a total knee replacement .it went great for about a year .some times it goes out of joint. my knee cap when I push on it I can hear it clicking like tap tap and it my knee is draing still . been over a year

  9. George on June 18th, 2015 5:25 am

    I had a total knee replacement of left knee 8 weeks ago (5/24/15).
    Everything went great. I had no pain in the joint itself,(after years of
    bone on bone grinding) the pain was gone, the only pain I had was
    from the surgery itself. I did however had a small area of the incision
    That was made that refused to heal, and continued to leak blood and
    fluid the whole time I was in rehab. (The dressing had to be changed
    3 times a day). I was taking antibotics and receiving an antibiotic inter-vinously for cellulitis that developed. After 2weeks I went home and
    that small area continued to leak a yellowish fluid but not as much, it
    would scab over but the would fall off and fluid would out. My doctor
    wants to do a procedure to remove the Unhealing area with an oliptial
    Type incision,to see if there is an superficial infection or if it is worse he had me agree to either a joint washout or a total replacement of all
    of the parts that were put in. I totaly trust this Dr he has a great track record, he is a member of a large successful group of Orthophedics,
    and it was at his concern that I have this done,( I was not complaining
    about any pain or the cosmetic appearance) I am just wondering if this
    is something that has happened to some else before,(an area of the incision not healing and leaking) and what was the outcome.(I’m a little nervous, my surgery is Monday and he moved his other surgerys
    Around to get me in. Should I be worried?

  10. Heleane on August 9th, 2015 11:38 pm

    After total knee replacement, I had 10 days of therapy at a rehab center, then 2 weeks of home health care rehab. I had no knee pain and I was able to walk like normal. I had to see the surgeon again and he insisted that I must have 8 weeks of out patient therapy. The PT only did my evaluation and a few hands on things in the 8 weeks. Other than that, I was on my own and had part timers working there to acknowledge what I did and to give me a few instructions. They were not techs either. I started to have severe pain and I told that my knee was clicking. They did nothing about it. I had to see the surgeon again. He agreed that it was clicking with pain. He sent me to a different therapy place for a month. The PT’s work hands on with me and are trying to rid the clicking and pain that I still have. Seems to be tendonitis they think. But clicking and pain are still there. Never had that until the other place that ignored it. Anyone have this issue.

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