Swelling is a normal and expected part of the body’s healing process after a Total Knee Replacement (TKR). The surgical process involves manipulating and cutting through soft tissues, which triggers a natural inflammatory response. This response causes an increase in blood flow and the accumulation of fluid around the joint to aid in tissue repair. The duration and intensity of this swelling are influenced by the extent of the surgical trauma, the patient’s overall health, and adherence to post-operative care instructions.
The Post-TKR Swelling Timeline
The progression of swelling following TKR surgery is divided into distinct phases, helping set realistic expectations. The Acute Phase occurs in the first one to two weeks, where swelling is most noticeable and often severe. Swelling usually peaks around two to five days post-surgery, making the knee area feel tight and potentially warm. During this time, the body’s inflammatory reaction is at its height as it attempts to repair damaged tissues.
The Subacute Phase covers approximately weeks three through six, during which a gradual reduction in fluid retention should occur. While overall swelling decreases, it may still be noticeable, particularly after periods of increased activity or standing. Consistent management strategies are important to prevent swelling from hindering physical therapy and range of motion exercises.
The Long-Term Resolution phase spans from three months up to a full year after surgery. Significant improvement is usually seen by the three-month mark, but mild or intermittent swelling can persist for six to twelve months. This residual swelling is often triggered by overexertion, prolonged weight-bearing, or warm weather, and it subsides with rest and elevation. Complete resolution takes time because the deeper soft tissues and lymphatic channels require many months to fully regenerate.
Strategies for Reducing Knee Swelling
Patients can actively manage post-operative swelling through physical and mechanical strategies to facilitate fluid drainage.
Elevation
Elevation is a foundational technique that uses gravity to encourage fluid return from the lower leg toward the torso. The operated leg should be positioned so the ankle is raised slightly above the level of the heart for 20 to 30 minutes several times a day. Support the ankle and calf without placing a pillow directly under the knee, as this can lead to stiffness and limit full straightening of the joint.
Icing
Icing the knee is effective because cold temperatures cause local blood vessels to narrow, limiting fluid flow and reducing inflammation. Cold therapy should be applied for 15 to 20 minutes every one to two hours, especially after physical therapy or exercise. Always use a thin cloth or towel between the ice pack and the skin to prevent the risk of skin damage or frostbite.
Compression and Movement
Compression garments, such as wraps or stockings, provide external pressure that prevents excessive fluid from pooling in the lower leg. When worn as directed, these garments support circulation and reduce the risk of blood clots. Controlled movement and gentle exercises, such as ankle pumps, activate the calf muscles. This muscle contraction acts as a natural pump, helping to push accumulated fluid out of the leg.
Identifying Abnormal Swelling and Red Flags
While some swelling is expected, certain changes signal a potential complication requiring immediate medical attention. A sudden and severe increase in the size or tightness of the knee or calf is a warning sign, especially if swelling had previously been improving. This sudden change, particularly if it does not respond to elevation and icing, warrants prompt evaluation by a healthcare professional.
An infection may be indicated by swelling accompanied by increased localized warmth, intense redness, or shiny skin around the incision site. Serious indicators also include fever, chills, excessive drainage, pus, or a foul odor from the wound.
Another serious concern is deep vein thrombosis (DVT), a blood clot in the deep veins of the leg. Signs of a DVT include new or sharply increased swelling localized specifically to the calf, often accompanied by pain or tenderness. Any extreme, disproportionate pain that is not managed by prescribed medication, or pain that is worsening, should be reported immediately.