The anterolateral incision: reducing numbness after knee replacement
The most common complaint after knee replacement isn’t pain or stiffness. It’s a patch of numb skin on the front of the knee. It’s usually harmless, but it can be bothersome, and it can make kneeling uncomfortable. For suitable patients, a small change to where the skin is cut can reduce it.
Why the front of the knee goes numb
A small nerve, the infrapatellar branch of the saphenous nerve, crosses the front of the knee just below the kneecap. It supplies sensation to the skin on the outer side of the knee. A traditional knee replacement uses a straight cut down the middle of the front of the knee, and that cut often divides this nerve. The result is a numb area on the front or outer side of the knee. The numbness isn't dangerous and often improves over time, but it's the single most common thing patients notice afterwards, and a numb area can make kneeling feel strange.
What the anterolateral incision changes
The anterolateral skin incision is a curved cut placed slightly to the outer (lateral) side of the kneecap, rather than straight down the middle. The aim is to pass to the side of the nerve instead of across it. Only the position of the skin cut changes. Once through the skin, the deeper part of the operation, how the surgeon reaches the joint and fits the implant, is the same as a standard knee replacement. The offset cut also avoids an area at the front of the knee with a poorer blood supply, which may help the wound heal.
What the research shows
A 2026 meta-analysis combined eight randomised trials involving 609 patients.¹ Compared with the traditional midline cut, the anterolateral incision:
- lowered the risk of numbness at one year by about 64%
- reduced the size of the numb patch by roughly two-thirds (around 7 cm² versus 19 cm²)
- produced the same results for knee movement, pain relief and satisfaction
That last point matters. The anterolateral incision changes where the skin is opened, not how the knee replacement works, so the functional result is no different.¹,² A separate study followed patients who had both knees replaced, one with each type of incision. Those patients consistently preferred the knee with the anterolateral incision, and recovery of sensation was better at every point over the first year. Early wound healing was quicker, and the scars looked similar by one year.³
Is it right for me?
The anterolateral incision suits many first-time knee replacements, but not all. Previous surgery, scarring, or the particular anatomy of your knee can make a midline approach the better choice. It's one of the things Dr Tsung will assess and discuss with you. As with any part of surgery, results vary between individuals.
Common questions
Does the anterolateral incision change the knee replacement itself?
No. Only the position of the skin cut changes. The deeper surgery is the same as a standard knee replacement.¹
Will I definitely avoid numbness?
No. It reduces the risk and the size of the numb area on average, but it doesn’t remove the possibility, and individual results vary.¹
Does it affect how well the knee works afterwards?
Studies show no difference in knee movement, pain relief or satisfaction between the two incisions.¹,²
Speak to Dr Tsung
Dr Tsung performs knee replacement and uses the anterolateral incision for suitable patients. To discuss your knee, you'll need a referral from your GP or another specialist. Call reception on (07) 5676 9930 to book your first appointment, or email hello@sgco.au. New patients can pre-register online before the visit; the form prepares your records and does not book an appointment. More on knee replacement.
References
- Mostafa AAS, et al. Effect of anterolateral skin incision on numbness after total knee arthroplasty: a meta-analysis. 2026.
- Laffosse JM, et al. Anterolateral skin incision in total knee arthroplasty: a randomised controlled trial. 2011.
- Maniar RN, et al. Anterolateral versus midline incision in bilateral total knee arthroplasty: a prospective randomised study. 2017.