Knee Replacement Incision Healing

How to spot a problem and what you can do to prevent healing concerns

Knee replacement incision healing is an important concern for anyone undergoing knee replacement surgery. Infection of a knee replacement is a serious complication.

This article discusses some of the signs of knee replacement healing problems, how they can be prevented, and what may need to be done for treatment.

Leg following a knee replacement surgery
Lauren Marek / EyeEm / Getty Images

Healing of Knee Replacement Incisions

The likelihood of healing problems after knee replacement surgery varies according to different studies. Most reports estimate the prevalence at between 1% and 11%. This means healing complications aren't rare. If you're going to have this procedure, it's important to understand and know how to recognize them.

The skin and soft tissues need to heal to prevent the entry of bacteria from the surface of the skin and the external environment. Until that barrier is healed, there is the potential risk of bacterial entry and infection. This is a potentially serious complication. For that reason, ensuring the rapid healing of incisions is critical to the success of knee replacement surgery.

There are several stages of healing that occur after a knee replacement (or any surgical incision) is performed:

  1. Inflammation: The first stage begins immediately following closure of the incision. In this stage, the wound clots through a so-called clotting cascade. Signals are sent through the body that attract healing cells to the site of the incision. The inflammatory stage lasts for the first few weeks after surgery.
  2. Proliferation: This stage begins about a week after surgery and overlaps the inflammatory stage. The proliferative stage is important to develop the necessary blood supply and healing tissues around the incision.
  3. Maturation: This stage begins after three weeks and can last up to a year. During wound maturation, the healing tissue becomes stronger and more like normal skin. Healed scar tissue is very weak in the early stages, and ultimately regains about 80% of normal skin strength within three months. A scar is never quite as strong as normal skin tissue.

How to Spot a Problem With an Incision

The signs to look out for when inspecting an incision suspected of having a healing problem include:

  • Persistent or worsening drainage from the incision
  • Gaps or holes in the incision
  • Grey or dusky tissues around the incision
  • Broken sutures or skin staples that have come out of the scar area

The most common signs of a wound healing problem are persistent or worsening drainage after surgery. It is normal for a surgical wound to have some drainage immediately following surgery. Drainage beyond 72 hours after wound closure, however, is not considered normal.

While some spotting on a bandage after 72 hours may not be a cause for concern, more than 2 centimeters of drainage on a gauze bandage is not considered normal. When this happens, it should be monitored by your surgeon.

Your surgeon will need to determine if the drainage is coming from around the incision or from deeper around the knee replacement implant. In addition, they will need to determine if the drainage shows signs of infection. If the drainage is from the deeper part of the wound or is potentially infectious, surgery will likely be necessary for treatment.

Reasons Some Incisions Don't Heal

Many medical conditions can significantly impact the stages of healing and the strength of the final scar. Some of these conditions can be prevented or at least minimized, while others may not be as easy to modify. A few of the common conditions that impact wound healing and strength include:

  • Malnutrition
  • Diabetes
  • Rheumatoid arthritis
  • Obesity
  • Smoking

For these reasons, most joint replacement programs will advise people to get these conditions under control prior to surgery.

Some of the steps you can take to lower your risk of wound healing complications after knee replacement surgery include:

  • Ensuring proper nutrition
  • Controlling blood sugar
  • Managing rheumatoid drugs
  • Losing weight

Some surgeons may advise against knee replacement surgery in particularly high-risk individuals. While everyone wants to believe their surgery will go well and without complication, there are some who may be more safely managed with nonsurgical treatments. This is particularly true for people at high risk for healing complications after knee replacement surgery.

Another factor that can cause problems with wound healing is having prior surgical incisions over the knee joint. This is a particular problem when the prior incision is located where it cannot be reused, so a new incision needs to be placed over the knee joint.

Each incision causes a disruption to the normal blood supply to the skin tissue. Multiple incisions can leave areas of skin without sufficient blood supply. If that happens, then tissue necrosis (an area of dead skin tissue) can occur. This may mean skin or soft-tissue grafts will be needed.

What to Do When an Incision Doesn't Heal

If you have a non-healing wound, you need to see your surgeon as soon as possible. If the incision is draining more than 72 hours after surgery, you should either remain in the hospital for observation or have a very close outpatient follow-up to ensure the wound does continue to heal.

If the drainage is declining and there is no other sign of infection, the wound can slowly heal. However, it will require close follow-up as changes could signal more aggressive intervention is needed.

If your wound is producing drainage, you may be able to do only limited physical therapy. You may not be able to bend your knee beyond about 45 degrees for a few days. This is because bending the knee increases the pressure on the tissues around the scar. It can also can lower the oxygenation of those tissues. Keeping the leg straight may help dry the incision.

Blood-thinning medications can also contribute to a draining wound. For this reason, anticoagulation will sometimes be held for a period of time in someone who has a persistently draining surgical incision.

If a wound is still draining past one week after surgery, you may need additional surgery to prevent infection and ensure there is no sign of a deeper infection.

If there is evidence of wound necrosis or a gap in the incision, it is possible that additional healthy tissue may be needed to cover the wound. This can be done with a skin graft or a more robust soft-tissue transfer.

In these situations, you should also seek the advice of a plastic surgeon who can work alongside your orthopedic surgeon to ensure a well-covered, healing surgical scar.


It is common for there to be some healing problems after knee replacement surgery. Since these complications can be serious, it's important to look out for signs such as worsening drainage from the incision, gaps or holes in the incision, and broken sutures.

If you notice signs that your incision might not be healing correctly, contact your surgeon right away. You may need to be admitted to the hospital for observation. In some cases, you may need additional surgery.

A Word From Verywell

An essential part of successful knee replacement surgery is a well-healed surgical incision. If the incision does not fully heal, infection can get from the skin down to the knee replacement implant, causing concerns for serious complications.

If there are concerns with the healing of your skin, let your surgeon know immediately. Aggressive and early treatment of skin healing problems are critical to preventing a more serious complication.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Jonathan Cluett, MD
Jonathan Cluett, MD, is board-certified in orthopedic surgery. He served as assistant team physician to Chivas USA (Major League Soccer) and the United States men's and women's national soccer teams.