Is a knee replacement the answer?

Posted on 1 October 2022

If you suffer from knee pain that makes daily life a struggle, knee replacement surgery could be an option – and more accessible than you think. A Mediclinic orthopaedic surgeon explains more. 

Having a knee replacement may seem like a major, complex operation. In fact, the procedure is straightforward, says Dr Edwin Dillon, an orthopaedic surgeon at Mediclinic Winelands Orthopaedic Hospital – a specialist hospital for non-emergency musculoskeletal conditions. Here, he clarifies what a knee replacement is, what it isn’t, and what you can expect. 


“Firstly, the traditional naming of this procedure is misleading,” says Dr Dillon. “It is not the insertion of a complete ‘bionic’ knee.” In other words, you’re not getting a whole new joint. “A knee replacement is a surgical procedure to replace the worn-out joint surfaces of the knee with synthetic materials.” He says a more accurate description would be “metallic resurfacing of the knee”.  


Two large bones meet at your knee – the femur (thigh bone) and tibia (shin bone) – and both need to be resurfaced, explains Dr Dillon. This involves removing 6mm from each bone to make room for a prosthetic surface, which is then cemented firmly in place using bone cement. Some people will also need their patella (kneecap) to be resurfaced.  


Your anterior cruciate ligament (ACL) – the ligament at the front of your knee – will always be removed, but the prosthesis is designed to compensate for this. In some cases, the ligament at the back of your knee – the posterior cruciate ligament (PCL) – will also need to be removed, but again, the prosthesis will accommodate for this.  


The operation generally takes 60-80 minutes and is relatively straightforward if performed by an experienced surgeon. As with any surgery, there’s a small possibility of complications – mainly from infection – but this is very rare, says Dr Dillon. 


There are various ways the joint surface can become damaged. “The most common is osteoarthritis (OA), where gradual wear and tear results in thinning of the joint surfaces, and eventually the underlying bone is exposed,” he explains. OA is often genetically determined, but it can also be the result of injury, infection or previous knee surgery.  


When surgery is appropriate 

A knee replacement would generally not be the first line of treatment. “Knee replacement surgery can be considered when the knee joint surfaces are extensively damaged, resulting in pain and loss of function – and only after non-operative treatment options have been attempted,” explains Dr Dillon.  


If you are a candidate, doing some “prehab” exercises leading up to the operation to strengthen the muscles around the knee and increase fitness will help you recover better post-op.  


You can be discharged from hospital once the post-op pain is under control and you’re able to do all of the following: 

  • Get in and out of bed unaided. 
  • Walk comfortably with two crutches or a walking frame. 
  • Climb a short flight of stairs. 
  • Bend your knee to 90°. 


“It’s important to understand that healing is a slow process. There will be progressive improvement in the knee for up to a year after the operation,” says Dr Dillon. However, you can start using your knee immediately – albeit cautiously. You can walk around the house with two crutches in the first week; by the end of the fourth week, you can go for unaided walks of up to 2km. 


As for sport, people who have had knee replacement surgery should be able to go for hikes, cycle, surf, and play golf, lawn bowls and doubles tennis as early as three months after surgery, and swim after just two weeks.  


A successful knee replacement can have an enormously positive impact on your life, removing pain, improving function, delaying the onset of osteoporosis and allowing you to be active again. Dr Dillon says many patients assume they’re too old – but before you give up on the idea, rather meet with an orthopaedic surgeon to weigh up the risks. It may be an option for you after all! 


Published in Orthopaedics

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