The complication rate following total knee replacement is low. Serious complications, such as a knee joint infection, occur in fewer than 1-2% of patients. At Mount Auburn Hospital and New England Baptist, our rates are <1%. Major medical complications such as heart attack or stroke occur even less frequently. Chronic illnesses may increase the potential for complications. Although uncommon, when these complications occur, they can prolong or limit full recovery.

Factors known to increase surgical risks include diabetes, obesity, peripheral vascular disease, prior joint infections, and major depression or mental health concerns. Please talk with your surgeon if you have concerns about your risk for surgery.

Complications associated with knee replacement procedures include:

Infection

Infection may occur in the wound or deep around the prosthesis. It may happen while in the hospital or after you go home. It may even occur years later. Minor infections in the wound area are generally treated with antibiotics. Major or deep infections may require more surgery and removal of the prosthesis. Any infection in your body can spread to your joint replacement.

Blood Clots

Blood clots in the leg veins are one of the most common complications of knee replacement surgery. These clots can be life-threatening if they break free and travel to your lungs. The best way to minimize your risk is to move and walk. While in the hospital, you will receive sequential compression devices (SCDs) and you may even go home with a portable pair. You will also receive medications to thin the blood. We typically use either Aspirin, Eliquis, Arixtra, Lovenox, or Coumadin. If you have any personal or family history of bleeding or clotting disorders, please alert your surgeon. 

Implant Problems

Although implants and surgical techniques continue to advance, implant surfaces wear with time and the components may loosen. Additionally, although an average of 115° of motion is generally anticipated after surgery, scarring of the knee can occasionally occur, and motion may be more limited, particularly in patients with limited motion before surgery.

Instability

Knee replacement is really a recapping of the bones with careful attention and care for the soft tissues. In time, ligaments may stretch and cause the knee to feel “loose”. This often occurs in patients who have large weight shifts.

Continued Pain

A small number of patients continue to have pain after a knee replacement. This complication is rare, however, and the vast majority of patients experience excellent pain relief following knee replacement.

Neurovascular Injury

While rare, injury to the nerves or blood vessels around the knee can occur during surgery.

Pre-admission Testing

Within 1 month of your surgery, you will be asked to undergo several laboratory tests, an electrocardiogram, and a chest x-ray. This is called pre-admission testing. This will help us to tell whether there are any conditions which might increase the risk of surgery. A physical examination, performed by your primary care physician and cardiologist/pulmonologist (if necessary), is also a part of pre-admission testing.

Joint Class

All patients should attend a joint class prior to their surgery. This will be arranged by your surgical coordinator and plays a very important role in your surgical preparation. Patients who attend this class have demonstrated a more predictable and successful recovery.

Just Before Surgery

You will be asked to arrive 1.5-2 hours prior to your scheduled surgery time.

You will not be allowed to drink or eat anything after midnight and on the day of your surgery. In some cases, you may be allowed to take a medication you normally take in the morning with a minimal amount of water. If instructed to do so, you will need to let the admitting nurse know.

Anesthesia

You will be seen by the anesthesiologist on the day of surgery. The anesthesiologist can answer specific questions you might have. Most of our surgeries are performed under spinal anesthesia, though we will also use regional and general anesthesia when a spinal does not seem to be the best option.

You may receive some medications in the holding area prior to your surgery. These may include specific pain medications and antibiotics for your surgery.

The Surgery

Joint replacement involves the removal of all of the damaged bone and cartilage. The next step is to prepare the bone for the prosthesis. This involves using specialized tools to shape the bone so that the prosthesis will fit properly. The artificial joint is then placed into the bone with or without bone cement. The surgery itself takes between 1.5-3 hours, depending on the complexity of your case.

Total knee prostheses can be attached to the bone using a material called methylmethacrylate or, more simply, bone cement. With proper technique,this gives an immediate fixation of the prosthesis to the bone. Another method is called biologic fixation. This method uses no cement and with time, bone grows into the pores of the prosthesis. This is similar to how most hip replacements are fixed to the bone. There are advantages and disadvantages to each type of “fixation.” The type recommended to you will depend on your age, weight, activity level, and surgeon preference.

Recovery Room

When your surgery is completed, you will go to the recovery room where you will be closely monitored until the effects of the anesthesia and intra-operative medicines are decreased and you are relatively awake and comfortable.

Orthopedic Unit

When you have completed your stay in the recovery room, you will be transferred to your hospital room in the orthopedic nursing unit. As long as you feel well, you will be out of bed on your day of surgery, taking your first steps. The therapists will instruct you how to use crutches or a walker, and some of the precautions that are necessary in the immediate post-operative period. Our therapists will help you navigate these first challenging days.

Discharge

Most patients will be able to go home 1-2 days after surgery. Some will stay for a 3rd day and others may go to a short-term rehab facility to help improve strength and gait. In order to be discharged, you need to be safe moving out of your bed/chair, have pain controlled by medications you can take at home, and be able to tolerate food.

There are several components to the rehabilitation and recovery process. Each one is integral to the entire course of healing. These components include:

Physical Therapy

During the first several days/weeks of physical therapy, some degree of discomfort and stiffness is expected. As the therapy continues, your body will adjust to the new prosthetic, allowing it to operate as part of your leg. Even after physical therapy is concluded, the knee needs to continue being active. Walking or other mild activities are perfect to increase mobility over time. It may take 12-18 months for your muscles to fully strengthen.

Incision Care

A sterile dressing will be applied in the operating room. If dry, this dressing will often remain for 1 week. Afterwards, it can be removed and covered with a dry dressing. You must keep the incision dry for the first 10-14 days. Do not soak the knee for 4 weeks after surgery.

DVT Prophylaxis

Lower extremity surgery poses an increased risk for blood clots. In mobile patients, Aspirin 2x/day for 6 weeks will thin the blood enough to minimize this risk. In patients with a history of clotting, decreased mobility, or GI issues, alternatives such as Eliquis, Lovenox, Arixtra, or Coumadin will be prescribed.

Follow-up

For the first year following surgery, scheduled follow-up appointments will ensure that recovery is going as planned. We would like to see you at 2 weeks, 6 weeks, 3 months, and one year after your surgery. After that, annual visits may be expected to keep your knee in peak condition.