Total Knee Replacement

What are the risks of knee replacement surgery? 

Total knee replacement is a well-established and generally safe procedure, but like all surgeries, it carries potential risks. Understanding these risks can help you make an informed decision and prepare for your recovery. 

• Infection – This may occur at the incision site or deeper around the implant. The risk of infection involving the prosthesis is approximately 1 in 100, despite the use of sterile surgical techniques and intravenous antibiotics. If infection occurs, further surgery may be required to clean the joint and administer a course of antibiotics. In rare cases, the implant may need to be replaced.  

• Blood clots – Deep vein thrombosis (DVT) can form in the legs after surgery, and in rare cases, clots can travel to the lungs (pulmonary embolism). To minimise this risk, preventive measures such as early mobilisation and a period of blood-thinning medication are used. 

• Numbness – Temporary numbness over the front of the knee is common. It is usually mild and improves over time. 

• Stiffness – Scar tissue can limit movement after surgery. Most stiffness improves with physiotherapy, though occasionally further treatment is required. 

• Nerve or blood vessel injury – Rarely, nearby nerves or blood vessels can be injured during surgery. 

• Implant issues – Over time, the implant may wear, loosen, or fail, potentially requiring revision surgery.  

• Persistent pain or stiffness – While most patients experience significant improvement, a small number may continue to have discomfort or reduced mobility. 

• Allergic reactions – Rare allergic responses can occur to medications, anaesthetic agents, or implant materials. 

This will vary depending on the nature of your work. If your job is sedentary or office-based, you may return as early as 6 weeks post-surgery. For more physically demanding jobs, this may take 3-4 months. Dr Free will discuss this in more detail with you prior to surgery and will continue to assess your progress during follow-up visits to help guide a safe return to work. 

Most patients can return to driving approximately 6 weeks after a total knee replacement. You must be off strong pain relief medications, be walking without crutches, and have a comfortable pain-free motion of your knee before you commence driving. Always check with Dr Free before getting behind the wheel. 

Keep the surgical wound dry until your 2-week post-operative review. After this, you may shower without a dressing. Swimming pools, spas, and hot tubs should be avoided for at least 3-4 weeks to reduce infection risk. 

Yes, the metal components can trigger security alarms. This is common, and airport staff are accustomed to it. Simply inform them you have a joint replacement if questioned.  

Results from our national joint registry show that 90-95% of replacements are still functioning well at 15 years post-surgery. Most knee replacements can now be expected to last beyond 20 years, however for patients younger than 65 years at the time of surgery, the risk of needing revision surgery is slightly higher.