Knee replacement Surgery in 2025- Advances, expectations and recovery
Knee replacements have been constantly evolving over the last half a century. Initial designs used a simple hinge mechanism which went through many modification with current modern designs boasting ultra-congruent designs and medial pivots that attempt to mimic the natural knee closely as much as possible. Biomaterial advances have led to better metal compositions and finishes as well as improvements in the polyethylene insert, the artificial cartilage substitute, to make it more resilient. Other advances such as patient specific (custom instrumentation) and Robotic Assisted Knee replacements are discussed below.
Customised implants – ‘The tailor made suit’
Not all knees look the same. In fact, there is a variety of recognised shapes and alignments in knees in the general population, and every knee is unique. Despite this uniqueness, conventional methods of knee replacement aim at making the knee a ‘straight line’ construct, also known as a ‘mechanically aligned’ knee. This remains the most common method of knee replacement surgery in Australia today, often assisted by technology such as robotic-assisted surgery, VR-assisted tools, navigational systems, etc.
It is also being recognised more and more that perhaps changing a bowed leg or a knock-knee aligned leg to a straight one may not result in a ‘happy knee’ after replacement. Some postulate that this may be one of the major reasons for poor outcomes after knee replacement.
In this context, the concept of ‘personalisation’ has been gaining a lot of traction over the last five years or so. This concept is about getting the knee and leg to be as close as possible to what they were like prior to the development of arthritis. These attempts are largely focused on recreating the alignment of the knee — i.e., keeping a bow-legged knee in bow-legged alignment and a knock-knee in knock-knee alignment after replacement. This concept is known as ‘Kinematic Alignment’.
The vast majority of knee replacements, irrespective of alignment philosophy, are still performed with an ‘off-the-shelf’ generic implant that is the closest best fit to that patient’s knee, despite the large variability in knee shape from one patient to another.
In recent years, the capability of customising implants to match a patient’s native anatomy has become a realistic possibility, taking the concept of ‘personalisation’ to another level. This means that not just the instrumentation or alignment, but the actual implant can be customised to replicate the patient’s native knee anatomy as closely as possible to the way it was before arthritis developed.
Only two decades ago, this would have been in the realm of science fiction, but with the advent of 3D printing, it is a reality today. It’s like having a tailor-made suit made for you, as opposed to buying an off-the-shelf suit at the shop. Whilst it is an exciting development, it is still just one element in the recipe to recreate nature’s ‘Gold Standard’.
Pioneering the concept, A/Prof Qurashi has been performing these procedures for some time now, with excellent success. The technology is available in Australia, and appropriate patients have scans to assess their current joint shape and alignment. With this information, a pre-disease state model is created using complex but highly accurate computerised algorithms. Once approved by the surgeon, the implants are then manufactured specifically for that patient in Europe and shipped back to Australia, ready to be implanted — giving the knee its best-fitting suit!
They do require a fair bit of preparation, and therefore, a run-up time of about 6–8 weeks is required. If you would like to know more about them, please let us know and we will be happy to discuss further, including your suitability for this option.
The video below is an excerpt from a lecture A/Prof Qurashi gave at the Asia Pacific Arthroplasty Society Conference in 2024 and is aimed at summarising the concept. We hope you find it useful.
Expectations from a successful Knee Replacement
The expectation of a successful knee replacement is a pain-free knee that allows a patient to function in their day-to-day life. It’s important to remember that most patients undergoing knee replacement are often unable to carry out normal activities due to pain prior to their surgery. As such, expectations must be realistic.
A replaced knee is not as good as the one we are born with. While the goal is to get as close as possible to what the knee was like before the onset of arthritis, it will never be exactly like the natural knee. It will have some limitations. We all hope not to encounter these limits during our daily activities — and many don’t! In fact, we have patients who have even climbed Mt Kilimanjaro after their knee replacement. However, for most people, the disabling pain of arthritis is gone, and they become significantly more mobile, agile, and functional.
Recovery is influenced by many factors, but initial functional recovery is generally quite quick. Most patients are up and walking with a frame or crutches just a few hours after their operation. They may leave the hospital as soon as they are safe on crutches or stairs — usually between 1 to 4 days, often just a couple of days.
One of the most important factors in determining outcomes is how motivated and proactive the patient is with rehabilitation. This is largely patient-driven. Whether it’s going to a rehabilitation facility for a week or two after leaving the hospital, going straight home, attending an outpatient rehab clinic, or visiting a local physiotherapist — all options can work well. There is no right or wrong approach, as long as the patient stays motivated and actively follows their prescribed exercise program.
The main goal during this stage is to recover range of motion before scar tissue forms, which can stiffen the knee and negatively affect the final outcome.
Patients should expect some discomfort or even pain for several months, though this typically improves day by day. The full healing process may take up to a couple of years. Sometimes, this ongoing healing may feel like tightness or discomfort in the knee.
‘Clicking’ in a knee replacement is quite normal. Most patients adapt to it over time, and it becomes less noticeable. On rare occasions, a new clicking sensation could indicate a problem and may need further evaluation.
The following videos are intended to show what most patients’ mobility typically looks like at different stages following their operation.
Modern joint can often be expected to last a couple of decades. Patients can expect to get back to most if not all of their pre-operative or sometimes even pre-arthritis activities.
There is no such thing as “you need a hip or knee replacement!”. Need is something the patient determines and should be guided strictly and only by the patient’s level of symptoms and after non operative measures have been exhausted.
