Knee Replacement Incision Healing

How To Spot a Problem and What You Can Do To Prevent Healing Concerns

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Knee replacement surgery is among the most common treatments for severe arthritis of the knee joint. Healing of the surgical incision is a concern for many people undergoing this surgery. It is well known that infection of a knee replacement is a serious complication, and having an incision that heals well is a concern many patients have fears with. Here are some of the signs of healing problems, how they can be prevented, and what may need to be done for treatment.

The likelihood of healing problems after knee replacement varies depending on different studies, but it is between 1 percent and 10 percent in most reports. This means there is a small chance of a healing problem, but this is not a rare complication, and one that people undergoing knee replacement surgery need to understand and recognize.

Of particular concern is that the chance of a serious knee replacement infection in people without problems of incision healing is less than 1 percent, but in people who have healing problems, the chance of a serious infection in the first-year after surgery is over 10 percent! That's why we as surgeons want to make sure we doing everything possible to help you heal properly, and immediately manage any wound that doesn't seem to be healing.

Healing of Incisions

Healing of the skin and soft-tissues are critical steps to prevent the entry of bacteria from the surface of the skin and external environment.

Until that barrier is healed, there is the potential risk of bacterial entry and infection of the knee replacement implant—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. The first stage is inflammation; this stage that begins immediately following closure of the incision. In this first stage, the wound clots through a so-called clotting cascade, and signals are sent through the body that attracts healing cells to the site of the incision. The inflammatory stage lasts for the first few weeks after surgery.
  2. The second stage is proliferation; this stage begins about a week after surgery and overlaps the inflammatory stage of healing. The proliferative stage is important to develop the necessary vascular supply and healing tissues around the incision.
  3. The final stage of healing is maturation; this stage begins after 3 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 percent of normal skin strength within 3 months. A scar is never quite as strong as normal skin tissue.

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 having any type of joint replacement surgery to optimize these conditions prior to surgery. For example, ensuring proper nutrition, controlling blood sugar (hemoglobin A1C less than 8.0), managing rheumatoid drugs, weight loss, and tobacco cessation are all steps that people can take to lower their risk of wound healing complications after knee replacement surgery.

In addition, some surgeons may recommend against performing knee replacement surgery in particularly high risk individuals.

While everyone wants to believe their surgery will go well and without complication, there are individuals who may be better and more safely managed with nonsurgical treatments, particularly if they are at high risk for healing complications after knee replacement surgery.

Another factor that can cause problems with wound healing are having prior surgical incisions over the knee joint. This is particularly a problem when the prior incision is located such that it cannot be re-used and a new incision needs to be placed over the knee joint. Each incision causes a disruption to the normal vascular supply to the skin tissue, and 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, leaving an area that may require skin or soft-tissue grafts.

How to Spot a Problem

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, but drainage beyond 72 hours after wound closure is not considered normal. While some spotting on a bandage after this time may not be a cause for concern, more than 2 centimeters of drainage on a gauze bandage is not considered normal and 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, he or she will need to determine if the drainage shows signs of infection. If the drainage is from the deeper part of the wound or potentially infectious, then surgery will likely be necessary for treatment.

What To Do When an Incision Doesn't Heal

If you have a non-healing wound, you need to involve your surgeon as soon as possible. If the surgical incision is draining more than 72 hours after surgery, people should either remain in the hospital for observation or have very close out-patient follow up to ensure the wound does continue to heal. In situations where the drainage is declining, and there is no other sign of infection, these wounds can slowly heal. However, they do require close follow-up as a change in direction should signal more aggressive intervention.

Often physical therapy will be limited in these patients, and bending the knee beyond about 45 degrees may be held for a few days. Bending the knee increases the pressure on the tissues around the scar, and also can lower the oxygenation of those tissues. Keeping the leg straight can help dry an incision in some instances. Blood thinning medications can also contribute to a draining wound, and for this reason sometime anticoagulation will be held for a period of time in someone who has a persistently draining surgical incision.

If a wound is draining beyond 1 week after surgery, surgery should be undertaken to ensure there is no sign of a deeper infection and to prevent infection from becoming a problem. There is no role for the administration of antibiotic treatment in the absence of surgical treatment for this type of problem.

If there is evidence of wound necrosis or a gap forming in the incision, it is possible that additional healthy tissue, either in the form of a skin graft or a more robust soft-tissue transfer, may be necessary to provide adequate coverage to the wound. In these situations, you should also seek the advice from a plastic surgeon who can work along side your orthopedic surgeon to advise the best way to gain a well-covered, healing surgical scar.

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.

Sources:

Simons MJ, Amin NH, Scuderi GR "Acute Wound Complications After Total Knee Arthroplasty: Prevention and Management" J Am Acad Orthop Surg. 2017 Aug;25(8):547-55.

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