Recovery guide

Pain and swelling after knee replacement: what's normal

Almost everyone has pain and swelling after knee replacement. Knowing what's typical, and what isn't, makes recovery less worrying.

The short version

Most improvement in pain happens in the first 3 months.³
About 1 in 5 people still have some pain at 3 months, and about 1 in 8 at a year.²
Mild swelling often lasts months, sometimes years, and on its own usually isn't a sign of a problem.¹
Pain that's getting worse, or new pain in a knee that was doing well, should be checked.⁹

Swelling: how long it lasts

Swelling usually peaks in the first few days after surgery.⁴ After that it comes down slowly. In a study that measured swelling for two years, most patients' knees were still slightly more swollen than before surgery at 6 months and even at 2 years. Only about 28% were fully back to their pre-surgery level at 2 years. Importantly, this leftover swelling was not linked to worse pain, strength, motion or function.¹

Swelling often gets worse later in the day or after more activity. Elevating the leg with the ankle above heart level, ankle pumps and icing all help.¹⁰

Pain: the typical course

First weeks: pain with activity and at night is common for several weeks.⁹
First 3 months: this is when most improvement in pain and function happens.³
After 3 months: in a review of 68 studies, about 22% of people still reported pain at 3 months, 14% at 6 months and 13% at 12 months.²
The long view: some people keep improving between 1 and 2 years. In one long-term study, a third of those who hadn't improved by 1 year did improve over the next year.³

Who is more likely to have lasting pain?

A meta-analysis of 30 studies found the strongest predictors of persistent pain were:⁵

A tendency to worry about or dwell on pain (called pain catastrophizing)
Severe pain in the days right after surgery
More pain before surgery
Younger age, and being female

Weight and range of motion before surgery were not linked to lasting pain in that analysis.⁵ If you're anxious about pain, tell your team before surgery; it's a recognized part of recovery, not a weakness.

What helps

Ice. Cold therapy modestly lowers pain and swelling in the first days.⁶ Simple ice packs worked as well as expensive cold-therapy machines in a meta-analysis.⁷
Exercise. Strength training after knee replacement improved mobility and reduced pain, without extra side effects.⁸ Do your physical therapy exercises consistently.
Elevation and movement. Raise the leg, keep ankles moving, and avoid sitting for long stretches.¹⁰
Take pain medicine as prescribed early on, so you can do your exercises.

See recovery supplies for what to look for in ice wraps and leg elevation pillows.

Stiffness

Some people develop a stiff knee from excess scar tissue. If the knee won't bend well despite therapy, surgeons may bend it while you're under anesthesia (manipulation under anesthesia). In a meta-analysis, doing this earlier, generally within about 3 months, gained more motion than doing it later (32° vs 19°).¹¹ If your bending is stalling, raise it with your surgeon early.

When to call your surgeon

Pain that is getting worse instead of better, or new pain in a knee that had been doing well
Fever over 100°F, chills, or increasing redness, warmth or drainage from the incision
New or increasing pain or swelling in the calf, ankle or foot
A knee that is getting stiffer rather than looser

Call 911 for sudden shortness of breath or chest pain.⁹ See also knee replacement infection.

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;41(10S1):S243-S248. doi:10.1016/j.arth.2026.04.075
Cheng HY, et al. What proportion of people have long-term pain after total hip or knee replacement? An update of a systematic review and meta-analysis. BMJ Open. 2025;15(5):e088975. doi:10.1136/bmjopen-2024-088975
Wylde V, et al. Variability in long-term pain and function trajectories after total knee replacement: a cohort study. Orthop Traumatol Surg Res. 2019;105(7):1345-1350. doi:10.1016/j.otsr.2019.08.014
Yang L, et al. Inflammatory-induced swelling after total knee arthroplasty: obesity and preoperative joint pain as key predictors. Arthroplasty. 2025;7(1):58. doi:10.1186/s42836-025-00344-9
Ashoorion V, et al. Predictors of persistent post-surgical pain following total knee arthroplasty: a systematic review and meta-analysis of observational studies. Pain Med. 2023;24(4):369-381. doi:10.1093/pm/pnac154
Aggarwal A, et al. Cryotherapy following total knee replacement. Cochrane Database Syst Rev. 2025;10:CD007911. doi:10.1002/14651858.CD007911.pub4
Liang Z, et al. Cryotherapy for rehabilitation after total knee arthroplasty: a comprehensive systematic review and meta-analysis. Orthop Surg. 2024;16(12):2897-2915. doi:10.1111/os.14266
Brown RCC, et al. Efficacy and safety of resistance training for knee osteoarthritis and subsequent knee replacement: a systematic review and meta-analysis. Ann Phys Rehabil Med. 2026;69(5):102122. doi:10.1016/j.rehab.2026.102122
American Academy of Orthopaedic Surgeons, OrthoInfo. Total knee replacement. orthoinfo.org/treatment/total-knee-replacement
Hospital for Special Surgery. Leg swelling: surgical guide to total knee replacement. hss.edu/ltkr/surgery-guide_leg-swelling.asp
Akhtar M, et al. Outcomes of early versus delayed manipulation under anesthesia for stiffness following total knee arthroplasty: a systematic review and meta-analysis. J Arthroplasty. 2024;39(11):2872-2879. doi:10.1016/j.arth.2024.05.059