A small but significant change in surgical technique - switching from a straight midline incision to a curved lateral approach - has dramatically improved functional outcomes in total knee replacement. Approximately 80% of my patients can now kneel comfortably after surgery, and the scar is both functionally and aesthetically superior.
Why I Changed My Approach
When I first began performing total knee replacements, we never truly considered the skin incision or its impact on patient function. The standard approach was a straight vertical incision running down the midline of the knee - it made the surgery easier to perform. About 5 years ago, I switched to a curved lateral incision specifically to improve patients' ability to kneel on their replaced knee.
The results have been transformative. Fast-forward to today, and this change has become one of the most valued aspects of my surgical technique. Not only can significantly more patients kneel comfortably after surgery, but the incision itself is also more aesthetically pleasing because the curved scar blends better with natural skin folds around the knee.
"Small changes in surgical technique can have profound benefits for patient function and cosmetic satisfaction."
- Dr Chien-Wen LiewHow It Works
The curved lateral incision wraps around the side of the knee rather than running straight up and down the midline. While technically the incision can be slightly longer when measured in a straight line, it appears shorter visually because of its curved nature and the way it nestles into natural skin folds and contours around the knee. More importantly, it preserves the anterior knee structures that are critical for kneeling.
Early mobilisation and physiotherapy after surgery help ensure that this advantage is realised. By avoiding damage to the tissues at the front of the knee that are essential for kneeling, we preserve your ability to perform this functionally important movement.
Dr Chien-Wen Liew explains why he uses a lateral curved incision for knee replacement and how it relates to numbness and kneeling.
Read transcript
0:00 · Introduction
Today, we're going to talk a little bit about the incision on for a knee replacement. I'm an orthopaedic surgeon from Adelaide, South Australia. I work at Orthopaedics 360 and I specialise just in hip and knee replacement surgery. The incision on a knee replacement can be sometimes critical to the function of a knee. About four years ago, I changed the incision of my knee replacements. Prior to that, I was doing this standard knee replacement incision.
What that was a midline incision going straight down the middle of the knee that we use to access the actual knee itself. Underneath the skin, the incision to the deeper layers of the knee go alongside the muscle, tendons and ligaments and are on this side or inner aspect of the knee. This is called a medial parapatellar approach. Now, whilst the inside layer has not been changed due to my approach, we have changed the outer layer.
1:04 · The lateral curve incision
The key difference with the approach to the knee that has changed over the years is the fact that I now place my skin incision very lateral on the knee, this looks like a curved incision that curves around the knee. The reason for the change is that we place the incision in that location to decrease the pain when a patient kneels on the knee. And we have actually found that it has increased the ability for our patients to kneel comfortably after the surgery.
1:33 · Why the lateral curve incision
Whether or not this may make a difference or not for you, is something that you should consider and ask your surgeon about before you have a knee replacement. The lateral skin incision has been something that I've found to enhance the overall aesthetic and functional aspects of a knee replacement. What it allows us to do is to place the incision off of the midline, aesthetically, because it is not a straight incision down the middle of the knee. It is something that does tend to hide within the skin folds of the knee and is certainly not as noticeable.
2:07 · Healing time
After the operation has fully healed, the healing time for an incision is whilst it will seal within a few weeks. After the surgery can take between 6 to 12 months to completely fade to its bare minimum. After that, it should be just a very thin white line on the outer aspect of the knee, because we're placing it on the outside aspect of the knee. It is something that when you kneel on the knee, you do not place any pressure directly on the wound.
Some of my patients have asked why we don't place the incision on the inside of the knee, close to where we access the deeper layers of the knee. The reason is for the nerve supply to the knee skin itself, all of the nerves go from inside to outside, underneath. And because of this, we opt to place the incision as further down the track, down the nerve pathway as we can.
In order to reduce the size of the numb patch that arises after a knee replacement with an incision that is on the medial aspect of the knee. There is a larger skin area which goes numb compared to a skin incision that is on the outer aspect of the knee. And whilst all skin incisions will end up with a small area of numbness after the surgery. We find that with a lateral skin incision, the area is smaller now.
3:21 · Kneeling
Whilst I said before that, our main reason is for kneeling, that's certainly the case, and although our patients can kneel a lot more comfortably than they used to. On the incisions that I was performing straight down the middle of the knee,
3:42 · Hard surfaces
it is still a bit uncomfortable to kneel on very hard concrete or surfaces such as gravel or anything else that may be uncomfortable to the knee replacement now, it's not because you're going to damage the knee replacement underneath, but because the soft tissue is a little bit hypersensitive after you have placed an incision onto it. So some of our patients like to wear a knee pad. When kneeling on very hard surfaces, it is to be expected that you should be able to kneel on soft surfaces like the bed, the couch, carpet and grass.
However, anything beyond that is a bit of a bonus. And some of our patients, although they can kneel on harder surfaces, find it more comfortable with a kneeling pad or knee pad.
4:12 · Conclusion
I hope that answers your questions about whether or not you can kneel on the knee. But also while we place our skin incision on the outer aspect of the knee. It's something that we've only picked up in the last probably four to five years. And certainly, it does not change the underlying knee replacement underneath. But it's just one of those little enhancements which I feel has made a reasonably good difference to some of my patients already.
Thank you so much for watching. And if you want to follow us for more information about hip and knee replacements, please do not hesitate to follow us on Facebook and YouTube. Thanks for listening and I'll see you next time.
Transcript edited lightly for readability.
Can I Kneel After My Knee Replacement?
Approximately 80% of my knee replacement patients can now kneel comfortably after their procedure. This is a significant improvement and directly reflects the shift to the lateral curved incision technique. Some factors can decrease the likelihood of being able to kneel, particularly if you have had previous incisions on the front of your knee.
If you have an existing midline incision from a previous surgery or injury, we would typically follow that pre-existing scar rather than add a new one. However, if your previous scar is small - such as from an ACL reconstruction - we can often still perform the lateral curved incision and achieve kneeling capability.
What Your Knee Replacement is Made Of
All knee replacements I perform use Cobalt Chromium metal components with a highly specialised polyethylene bearing. This composition is specifically designed to increase longevity and wear resistance. Under an electron microscope, the surface of the Cobalt Chromium component is extremely smooth, which reduces wear on the plastic bearing.
Importantly, there is no metal-on-metal contact in your replacement knee. The specialised polyethylene plastic sits between the metal components, eliminating any metal-on-metal friction and ensuring the long-term durability of your implant.
Orthopaedic Surgeon, Adelaide
Download Knee Replacement Guide
Learn about incision placement, kneeling recovery, and implant materials in total knee replacement.