Almost every patient asks me about the knee replacement scar before they ask me about the implant. It is a fair question. The scar is the part of the operation you can see every single day, and it is the part your friends will ask about at church, at the gym, and at the grandkids’ ball games.
After more than twenty years and over 700 joint replacements a year at the Bone and Joint Institute of Tennessee, here is what I tell patients in Franklin, Nashville, Columbia, and across Middle Tennessee about what that scar will actually look like.
What Does a Knee Replacement Scar Look Like Right After Surgery?
Right after surgery, the knee replacement scar is a single closed line on the front of the knee, surrounded by swelling and bruising that usually looks worse than the incision itself. The line is pink to red, slightly raised, and often bordered by adhesive strips or a waterproof dressing.
In my practice I close the skin with dissolvable stitches placed under the surface. There are no staples to pull and no railroad-track marks on either side of the line.
Bruising is the part that surprises people. Blood tracks down the leg with gravity, so a purple or yellow-green stain can show up around the calf and ankle a few days after surgery. That is drainage from the joint following the path of least resistance, not a sign that something went wrong.
How Long Is a Knee Replacement Incision?
Most knee replacement incisions are 4 to 10 inches long, and the exact length depends on your anatomy rather than on any marketing claim. Taller patients, larger thighs, and stiffer knees all need a little more room.
Why incision length varies from patient to patient
Studies of incision length in knee replacement show that height correlates with it more strongly than weight does. Longer bones simply need more exposure.
Deformity matters too. A knee that has drifted badly into bow-leg or knock-knee alignment takes more work to correct and more room to do it safely.
Does a smaller incision mean a better knee?
No. A shorter incision does not produce a better knee, and chasing the smallest possible cut can produce a worse one.
Here is what I tell my patients: the incision needs to be exactly long enough for me to see the joint, place the implant accurately, and balance the ligaments. An implant that is a degree off will bother you for twenty years. An extra inch of skin will not. You can read more about the honest limits of minimally invasive knee replacement and what the term really covers.
Where Is the Incision Made, and Does the Surgical Approach Change the Scar?
The location of the incision depends on the surgical approach, and it does change where the scar sits on your knee. A traditional knee replacement uses a vertical midline cut straight over the kneecap, which is the scar most people picture and the one most visible when the knee is bent.
I perform most of my knee replacements through the subvastus approach, which slides underneath the quadriceps muscle instead of cutting through the tendon. That approach uses a medial oblique incision: the line angles along the inner side of the knee rather than running down the center. Patients tell me it is easier to live with, because it falls away from the front of the kneecap when they kneel or wear shorts.
I pair that approach with Mako® robotic-arm assisted guidance, which lets me work accurately through a more confined exposure. In the interest of full disclosure, I serve as a paid consultant to Stryker on the Mako platform. You can read more about how I use robotic-assisted joint replacement in the operating room.
How Does a Knee Replacement Scar Heal Over Time?
A knee replacement scar heals in three stages: it seals in the first two weeks, flattens and fades over the next several months, and finishes remodeling somewhere between 12 and 18 months after surgery. The line you see at your six-week visit is not the line you keep.
Weeks 0 to 2: sealing
Expect redness along the whole incision, swelling around the knee, and warmth to the touch. A little clear or pink spotting on the dressing in the first few days is normal.
My patients wear a waterproof dressing and can shower whenever they want. We remove that dressing at the two-week visit.
Weeks 2 to 12: flattening
By two weeks the redness starts to pull back and the bruising is fading. Somewhere around weeks 4 to 8 the scar often feels firm, thick, or ropey underneath the skin.
That firmness is normal collagen laying down under the surface. It peaks, then softens.
Months 3 to 18: fading
Between three months and a year and a half, the scar loses its pink color and flattens into a thin pale line. Fair skin usually fades to white or silver. Darker skin tones often stay slightly darker than the surrounding skin, and sometimes lighter.
A small number of people form thickened, raised scars called hypertrophic scars or keloids. If you have made one before, tell me at your consultation so we can plan for it.
Why Is My Knee Replacement Scar Numb, Tingly, or Tender?
Numbness and tingling around the scar happen because small sensory skin nerves are cut during the incision, and that is unavoidable in any knee replacement. The patch of numbness usually sits on the outer side of the scar, because those nerves travel across the front of the knee from the inside out.
The numb patch normally shrinks over the first year. In some patients a small area never fully returns, and that is well tolerated. It does not affect how the knee works.
The knee is also a harder place to heal a scar than the hip. It sits right under the skin with very little padding, and it bends through a big arc hundreds of times a day, so the skin over it is repeatedly stretched.
Sharp, electric zings when you brush the area are nerve endings waking up. They fade.
How Do You Care for a Knee Replacement Scar?
Good knee replacement scar care has two phases: protect the wound until it is fully sealed, then work on it daily once it is closed. Doing the second phase too early is the most common mistake I see.
The first two weeks: protect it
- Leave the dressing, strips, or sutures alone until your surgeon removes them.
- Keep the incision clean and dry unless you have a waterproof dressing.
- Wear loose clothing so nothing rubs the fresh line.
- Do not apply lotion, ointment, oil, or vitamin E to an incision that is not closed.
- Look at the incision once a day so you notice changes early.
Knee replacement scar massage and desensitization
Once the wound is completely closed with no scabs and no drainage, usually around three to four weeks, start working on it.
- Massage: press with two clean fingers and move the skin in small circles and side to side for 5 minutes, twice a day. You are loosening the tissue underneath, not scrubbing the surface.
- Moisturize: a plain unscented lotion keeps the skin supple and makes the massage easier.
- Desensitize: stroke the area with different textures such as a soft cloth, a towel, and your fingertips. This calms the oversensitive nerves faster than avoiding the area does.
- Silicone: medical-grade silicone gel or sheeting has the best evidence of any over-the-counter option for softening and flattening a raised scar. Start only after the wound is fully closed.
- Sunscreen: cover a new scar with SPF 30 or higher for the first year. Sun exposure on young scar tissue causes permanent darkening.
Protect numb areas too. If you cannot feel part of your knee, be careful with heating pads and ice packs, because you may not notice a burn.
When Should You Call Your Surgeon About Your Incision?
Call your surgeon for any incision that is getting worse instead of better after the first week. Early trouble is easy to treat; late trouble is not.
Reach out promptly for:
- Fever of 101.5 F or higher
- Drainage that increases, lasts more than five days, or turns yellow, cloudy, or foul smelling
- Redness that spreads outward from the incision rather than shrinking
- Pain or swelling that worsens each day instead of easing
- Blisters, an opening in the skin, or edges that separate
- New calf firmness, calf pain, or sudden shortness of breath
I would rather look at a normal knee than miss an early joint replacement infection. Nobody in my office has ever been annoyed by a patient who called.
Getting Answers About Your Knee Replacement Scar in Middle Tennessee
The scar is real, and it is permanent. It is also, for nearly every patient I have treated, the smallest part of the story once the knee stops hurting.
If you are weighing knee replacement and you want a straight answer about incision placement, approach, and what your scar will look like, come see me. I see patients from Franklin, Nashville, Brentwood, Spring Hill, and Columbia at the Bone and Joint Institute of Tennessee, 3000 Edward Curd Lane, Franklin, TN 37067. No referral is required.
Schedule a consultation or call (615) 791-2630.
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Sources worth reading: the American Academy of Orthopaedic Surgeons guide to total knee replacement, the AAOS review of minimally invasive total knee replacement, and the NIH MedlinePlus instructions for surgical wound care.
Medical disclaimer: This article is for educational purposes only and is not a substitute for medical advice. Individual healing varies. Always follow the specific incision care instructions given by your own orthopedic surgeon. In a medical emergency, call 911.
References
- American Academy of Orthopaedic Surgeons. Total Knee Replacement. OrthoInfo. orthoinfo.aaos.org
- American Academy of Orthopaedic Surgeons. Minimally Invasive Total Knee Replacement. OrthoInfo. orthoinfo.org
- Phruetthiphat OA, Apinyankul R, Chanpoo M, Chotanaphuti T, Kosuwan W, Callaghan JJ. Anterior skin numbness after total knee arthroplasty: a prospective comparison study between diabetic and non-diabetic patients. Journal of Orthopaedics. 2020;22:12-16. PMC7132145
- Yilmaz S, Demirkiran ND, Kuyubasi SN, Kozlu S, Kurt M, Akkurt A, Oner SK. The length of incision in unicondylar knee arthroplasty is more affected by the patient’s height than their weight. Cureus. 2023;15(8):e44444. PMC10470024
- Jiang Q, Chen J, Tian F, Liu Z. Silicone gel sheeting for treating hypertrophic scars. Cochrane Database of Systematic Reviews. 2021;9:CD013357. doi.org/10.1002/14651858.CD013357.pub2
- MedlinePlus, U.S. National Library of Medicine. Surgical wound care: closed. medlineplus.gov
