Knee Replacement: Complications and Injuries from Defective Implants
Knee replacement complications and injuries from defective implants include loosening of the implant, device failure, chronic pain and the need for additional surgeries. Milder, less severe complications that resolve with treatment include knee stiffness and difficulty bending the knee after surgery.
- Last update: July 1, 2025
Common Complications After Knee Replacement Surgery
Knee replacement surgery has a high success rate, though complications may occur. Two of the most commonly reported complications after knee replacement surgery are joint stiffness and difficulty straightening or bending the knee.
- Clicking or popping when bending the joint
- Knee stiffness and limited range of motion (often improved by physical therapy and rehabilitation exercises)
- Pain or swelling
Complications may differ depending on a variety of factors, like the hospital or a patient’s social or economic situation.
Other factors that may make you more likely to have complications are your age and general health. Older adults and seniors may be more likely to suffer complications, though younger people are more likely to need follow-up surgery to address normal long-term wear and tear.
Make sure you talk to your doctor about what to expect before and after knee replacement surgery.
Rare, Serious Knee Replacement Surgery Complications
Knee replacement surgery is generally safe and effective, and serious complications occur in less than 2% of patients. The risk of death is very small, occuring after only about one in 200 knee replacement surgeries, or 0.6%.
Below is a list of possible serious complications, including frequency (where possible).
- Allergic reaction to metal in the implant (less than 1% for metal implants)
- Blood clots (0.6% to 3%)
- Blood vessel injuries (0.05%)
- Death (0.6%)
- Implant failure (5% at 10 years after implantation, may be more or less depending on the implant)
- Implant fracture (0.2% to 2.5%)
- Implant loosening or wear (varies by implant)
- Infection at the surgical site (less than 2%)
- Nerve injury
- Wound complications, such as slow healing and fluid buildup (7%)
Serious short-term complications, such as blood clots, pain and infections, may arise soon after your initial surgery. Long-term complications, such as implant failure, persistent pain that lasts for years or loosening, occur over more time.
Signs That Your Knee Replacement May Be Failing
The most common signs that your knee implant may be failing include worsening knee function, pain, swelling, and weakness and instability in the joint.
- Increased pain or stiffness
- Infection
- Knee buckling or instability
- Noises (clicking, popping) when walking or standing
- Persistent pain or swelling around the joint
- Reduced mobility or range of motion
Tell your doctor about these symptoms right away. Your medical provider may order lab tests to determine if you have an infection. They may also take imaging tests, such as X-rays, an MRI or a CT scan, to check on the condition of your knee.
Why Do Some Knee Replacements Fail Prematurely?
Knee replacements generally last 15 to 20 years, but some fail early because of design flaws, defective packaging or surgical technique.
- Poor Bone Fixation
- If the implant isn’t fully fixed to the bone, which is more likely with certain designs, it can loosen. For example, the cementless designs of the Zimmer NextGen CR and CR-Flex can cause this problem.
- Packaging and Manufacturing Defects
- Some recalled implants have had manufacturing or packaging flaws that made them more fragile and prone to early failure. Some Exactech knee replacements, for instance, came in defective packaging that could have exposed implant parts to oxygen. This exposure could lead to quicker wear and failure.
- Design Flaws
- Some knee replacements fail because they are poorly designed. For example, the Attune Knee System from Johnson & Johnson subsidiary DePuy failed at higher rates because the surface was too smooth for glue to properly stick to it. This led to the implant becoming loose and failing.
- Poor Implant Fit and Malpositioning
- Implants of the wrong size or with parts in the wrong position may lead to pain, stiffness and early mechanical failure. A software defect for the ShapeMatch Cutting Guide used with the Stryker Triathlon knee, for example, displayed the wrong measurements for cutting bone and positioning of implant components. This led to joint instability and fracture.
Which Knee Replacement Devices Have Been Recalled?
Some of the most notable knee replacement recalls involved implants made by DePuy, Exactech, Stryker and Zimmer.
| Year | Product | Reason for Recall |
|---|---|---|
| 2013 | Stryker Triathlon | Software problem with ShapeMatch Cutting Guides |
| 2015 | DePuy Attune | Spring coil breaking during surgery and potentially entering the patient’s body |
| 2015 | Zimmer Persona | Increased complaints of loosening |
| 2016 | Zimmer NextGen CR | High failure rate |
| 2018 | Smith & Nephew Journey BCS Knee | Revision surgery rate over 1.5 times the average |
| 2022 | Exactech Optetrak | Defective packaging could cause oxidation, which can degrade parts of the implant and lead to early failure and revision surgery |
You can learn more about the recalls on our knee implant recall page. The FDA also has a Medical Device Recalls page where you can search for implants to see if they’ve been recalled.
What to Know About Revision Knee Replacement Surgery
If your knee replacement has failed, your doctor may recommend revision surgery. This surgery replaces the failed implant.
This procedure is more complicated than an initial knee replacement surgery. Infections are the most common reason for knee replacement revision, followed by implant loosening.
Because revision surgery is more complex, it comes with increased risks of complications like blood clots, bleeding, blood vessel damage and infection.
Recovery time is also longer for revision surgery because doctors have to make larger incisions and may use larger implants. In addition, more than twice as many people have pain after revision surgery than after an initial implant.
The success of knee implant revision surgery is between 75% and 80% at 10 years. Up to 20% of people experience some pain after the revision surgery, and that can persist for several years.
Can You Sue for a Failed Knee Replacement?
If your knee implant fails, you could sue your device’s manufacturer if the device was defective or you weren’t warned about relevant risks.
In general, you may qualify for compensation if you received a recalled or defective implant and suffered complications that required revision surgery. Common reasons people sue include device loosening, implant breakage or failure and bone fracture.
Drugwatch’s legal partners aren’t currently accepting cases, but some lawyers are evaluating claims. If you are interested in filing a lawsuit, talk to a lawyer about your options. Be ready to provide your medical and surgery records, especially your revision surgery documentation.
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