Most recovery symptoms are expected. A short list is not, and the difference is worth knowing before you go home.

What is normal in the first weeks

Some pain with activity and at night is common for several weeks after knee replacement ¹. Most patients resume ordinary daily activities within three to six weeks after knee replacement ¹. Swelling is expected, and it lasts longer than many patients anticipate. In a study of 56 knee replacements measured with bioimpedance, leg swelling rose about 10% a day for the first three days ². It peaked six to eight days after surgery, at 25% above baseline for the least swollen tenth of patients and 47% for the most swollen tenth ². In another series of 85 knee replacements, swelling was about 35% above preoperative levels on day one and still about 11% above at 90 days ³.

Warmth around a healing joint and bruising that tracks down the leg belong to the same process. The useful question is direction: is this week better than last week? The problems below tend to get worse rather than better.

Symptoms that need a same-day call to the surgical team

AAOS patient guidance for knee replacement lists the warning signs of infection to report to the surgeon ¹. They are persistent fever above 100°F, chills, increasing redness, tenderness, or swelling of the wound, drainage from the wound, and increasing pain with both activity and rest ¹. AAHKS guidance adds prolonged wound drainage beyond three days, and a dull ache or persistent stiffness in a joint that had been doing well ⁴.

Sources differ on fever. The AAOS page on joint replacement infection says fever is no longer considered a sign of infection after a joint replacement ⁵. It lists pain that does not change with activity, fatigue, redness and swelling at the incision, and drainage more than 10 days after surgery ⁵. Those are the signs it says to watch ⁵. The practical reading is that fever should prompt a call, and its absence does not rule infection out.

Early infections typically appear within four to six weeks ⁴. Reporting early matters. Bacteria form a protective biofilm on an implant within about three weeks, and early treatment may allow the implant to be kept ⁴.

• Fever, chills, or sweats ¹⁴.
• Drainage from the wound, or redness that is increasing or spreading ¹.
• New or increasing calf pain, or new swelling of the thigh, calf, ankle, or foot, which can signal a blood clot ¹.
• A fall, even one that seemed minor. A fall in the first weeks can damage a new knee and may lead to more surgery ¹.
• A joint that suddenly does not feel right, or that you can no longer put weight on. AAHKS guidance is direct: contact your surgeon if the joint does not feel right ⁴.

Falls are not rare in this period. In a prospective cohort of 134 knee replacements, 17.2% of patients fell at least once in the six months after surgery ⁶. Most falls happened while walking, from slipping or tripping, and most occurred at home or indoors ⁶.

Symptoms that need emergency services

A clot that travels to the lungs is why chest symptoms are treated differently from leg symptoms. AAOS guidance lists sudden shortness of breath, sudden chest pain, and localized chest pain with coughing as warning signs that a clot has reached the lungs ¹⁷. Coughing up or vomiting blood is listed alongside them ⁷. Call emergency services rather than the clinic.

• Sudden shortness of breath, or sudden chest pain ¹⁷.
• Coughing up blood ⁷.

What to have ready before you go home

• The number for the surgical team, day and night, and the after-hours route.
• Your written discharge instructions on wound care, including the day by which drainage should have stopped.
• Your clot-prevention plan as the team set it: which medication, for how long, and what to do about a missed dose. The team sets that plan, not this page.
• The walking aid the team wants you to use, and their advice on stairs.

What to ask your surgeon

• How much drainage is normal for my wound, and on what day should it be dry?
• Which symptoms do you want a same-day call about, and which should go straight to emergency services?
• How much swelling should I expect, and when should it start to come down?
• If I fall, do you want to hear about it even if nothing hurts?