Swelling after Knee Replacement

Total knee replacement is a common orthopedic surgery and one of the most successful surgeries in medicine. Complications after knee replacement surgery are rare but persistent pain or swelling are the most common complaints after knee replacement.

While some swelling is normal even up until 6 months post-surgery, swelling may also occur as a result of serious complications such as deep vein thrombosis or prosthetic joint infection.

Arthritis of the knee joint is the most common indication for replacement surgery. During replacement surgery, the surgeon gives an incision in front of the knee and cuts/separates tissues to reach the diseased knee joint. During the entire surgery, the patient remains under either general anesthesia or spinal anesthesia.

X-ray showing a total knee replacement.

X-ray showing a total knee replacement.

The surgeon further proceeds to cut and remove the diseased ends of the thigh bone and the shin bone. The removed ends are replaced with metal alloy and plastic parts. The prosthetic joint functions to recreate the motion and alignment of the natural joint.

Swelling and pain are the most common complaints after knee replacement. The swelling is normal and is usually moderate to severe in the first week but gradually decreases for the next weeks and months. Mild swelling may persist normally as long as six months post-surgery.

Swelling is defined as a protuberance of a body. In the case of the knee after replacement surgery, the swelling occurs as a result of the accumulation of excess fluid in the tissue of the knee joint. During surgery, the skin, soft tissues, and bones are cut to perform the surgery. As they take time to heal, there may be excess fluid accumulation in the tissue as a part of the inflammatory chain leading to healing.

The swelling persists even after the skin incision heals as the tissues in the body take a long time to get back to their condition before the surgery. The patients may complain of swelling around their knees, below or above their knees. The swelling may get worse at the end of the day with activity.

Intraoperative image showing knee replacement implants.

Intraoperative image showing knee replacement implants.

Regular icing is recommended for the management of swelling after knee replacement. The patients are advised to apply an ice pack as cold temperature helps in the control of both pain and swelling. Icing induces narrowing of the blood vessels in the region and that leads to decrease the flow of fluid to the area and decreases the swelling.

Similarly, patients are advised to slightly elevate their leg just above their heart level. The elevation helps in flow of the fluid back to the body from the legs. The patients after knee replacement surgery are advised ankle pumps and other home exercises.

Ankle pumps involve pushing the ankles down and up repeatedly. The movement of the ankle brought about by the contraction of the calf muscles not only decreases the swelling but also helps in preventing deep vein thrombosis. The patients may also use compression stockings to decrease swelling. Compression stockings also help decrease the incidence of deep vein thrombosis.

While the normal swelling after knee replacement surgery gradually improves, at times the swelling may represent a serious pathology such as deep vein thrombosis or infection. The infection of the prosthetic joint may occur in the immediate postoperative period, in a few weeks/months after the surgery or even years after the surgery.

The swelling of the knee joint secondary to infection may present with redness and pain. The infection may also cause fever and in severe cases of infection, a discharge may be present. The swelling associated with infection is due to the inflammation and fluid formation secondary to bacterial activity. The infected prosthetic joint needs blood and radiological investigations as well as need revision surgery.

The swelling may also be caused as a result of deep vein thrombosis. Deep thrombosis occurs as a result of the formation of a blood clot inside the veins of the legs. Major surgery such as knee replacement is a significant risk factor for deep vein thrombosis.

The blood clot formed in the leg may cause swelling of the leg especially the calf region. The swelling may extend above the knee. The blood clot may travel up the veins and to the lungs, a condition known as pulmonary embolism. Pulmonary embolism may lead to shortness of breath and may be fatal if not treated.

Patients are advised to do ankle pumps and start moving as soon as possible after the knee surgery to prevent deep vein thrombosis. Patients are usually able to walk the day of the surgery or the next day.

Besides movement, the patients are prescribed a blood-thinning medication such as aspirin or enoxaparin to decrease the chances of blood clots. Compression stocking (TED stocking) may also help to prevent deep vein thrombosis after knee replacement surgery.

Swelling after knee replacement surgery is common but it is important to bring the swelling to your surgeon’s attention in case of swelling is increasing or associated with other symptoms.

My name is Dr. Suhirad Khokhar, and am an orthopaedic surgeon. I completed my MBBS (Bachelor of Medicine & Bachelor of Surgery) at Govt. Medical College, Patiala, India.

I specialize in musculoskeletal disorders and their management, and have personally approved of and written this content.

My profile page has all of my educational information, work experience, and all the pages on this site that I've contributed to.