How long does the swelling last after a knee replacement?

Last reviewed: September 29, 2026

Longer than most people expect: months, not weeks. Some mild swelling often stays for a year or more.

Swelling is worst in the first few days after surgery. It then goes down steadily, fastest in the first three months, but it is usually still there at three months.

It often does not go away completely. In one study that measured swelling carefully, most people still had more swelling than before surgery at six months and at two years. That leftover swelling was not linked to more pain, less satisfaction, or a knee that worked less well.

What matters is the direction. Swelling that is slowly going down is part of healing. Swelling that stops going down, comes back, or gets worse is different.

Two problems can show up as swelling. A blood clot in the leg often brings a cramping or pulling pain in the calf or thigh. An infection most often shows up as pain that keeps getting worse, often with redness and warmth. Fever is present in fewer than half. Because the operated leg is already swollen, these signs can overlap with ordinary healing. The clot signs come from studies of clots in general, not of knee replacements.

In general:

• Swelling for months after a knee replacement is expected.
• It should keep going down. Swelling that stops improving or gets worse needs to be checked.
• New pain, tenderness or a pulling feeling in the calf needs to be seen promptly.
• Swelling with worsening pain, redness, fever or drainage from the incision needs to be seen promptly.
• Sudden shortness of breath or chest pain needs emergency care.

Drafted with AI assistance from published sources, reviewed and edited by Babak Sheikh, MD.

Sources:

• Barton KI, et al. Postoperative Swelling Did Not Return to Preoperative Levels in Most Patients Two Years After Total Knee Arthroplasty. J Arthroplasty. 2026. https://doi.org/10.1016/j.arth.2026.04.075
• Pua YH. The Time Course of Knee Swelling Post Total Knee Arthroplasty and Its Associations With Quadriceps Strength and Gait Speed. J Arthroplasty. 2015. https://doi.org/10.1016/j.arth.2015.02.010
• Yang L, et al. Inflammatory-Induced Swelling After Total Knee Arthroplasty: Obesity and Preoperative Joint Pain as Key Predictors. Arthroplasty. 2025. https://doi.org/10.1186/s42836-025-00344-9
• Chopard R, et al. Diagnosis and Treatment of Lower Extremity Venous Thromboembolism: A Review. JAMA. 2020. https://doi.org/10.1001/jama.2020.17272
• Hoveidaei AH, et al. Clinical Signs and Symptoms of Chronic Periprosthetic Joint Infection in the Hip and Knee: A Systematic Review and Meta-Analysis. Arch Orthop Trauma Surg. 2026. https://doi.org/10.1007/s00402-025-06171-6

This is general information about what published research shows. It is not medical advice and it is not about your situation. Reading it does not create a doctor-patient relationship with me. I am a retired orthopedic surgeon and I do not see patients. Talk with your own doctor before changing anything about your care. If something feels suddenly or seriously wrong, get medical care promptly rather than waiting.

This page is provided as is. I make no guarantee that it is accurate, complete or current, and medical evidence changes. Use of it is at your own risk.

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