If hip replacement rehab is about gait, knee replacement rehab is about motion. The new joint removes the worn, arthritic surfaces that caused your pain, but the knee comes out of surgery swollen, stiff, and guarded by muscles that have switched off. The window for restoring bend is early, the first six to twelve weeks are when the knee is most responsive to the work, and the people who take that window seriously are the ones kneeling in their gardens a year later.
The two goals, in order
Straight first. A knee that cannot fully straighten makes every step a limp and tires the thigh muscle constantly. Heel propped on a pillow with nothing under the knee, several times a day, lets gravity do quiet, effective work. It is mildly uncomfortable and completely worth it.
Bend second, steadily. Heel slides, seated knee bends, stationary bike rocking back and forth once you have enough range, flexion returns in degrees per week, not overnight. Around 90 degrees by the early weeks and 110 to 120 by three months are common targets, but your surgeon’s goals for you are the ones that count.
What the evidence says
A systematic review and meta-analysis of physiotherapy exercise after total knee replacement (Artz and colleagues, 18 trials and 1,739 patients) found that structured exercise improved physical function and reduced pain at three to four months, and that home-based programs produced results comparable to outpatient clinic programs. A second line of research comparing supervised versus well-designed home programs reaches a similar conclusion for most patients: the active ingredient is the progressive exercise itself, plus someone checking your motion and progressing you properly. That is the service we provide in your home, measuring the bend, pushing the program forward at the right pace, and catching problems (a knee losing extension, swelling that will not settle) while they are still easy to fix.
The twelve weeks, roughly
- Weeks 0 to 2: walker, ice and elevation like a job, extension work, heel slides, quad activation; short walks every hour or two you are awake
- Weeks 2 to 6: cane transition, flexion pushing toward and past 100 degrees, sit-to-stand and step-ups, gait retraining
- Weeks 6 to 12: progressive strengthening (this is where real loading starts), balance work, walking distance building, stationary cycling with a full pedal revolution
- Months 3 to 6: strength and endurance keep climbing; stairs foot-over-foot; most people feel the new knee is clearly better than the old one somewhere in this stretch
Normal versus not
Clicking in the new joint is common and usually meaningless. Bruising can be spectacular. Sleep is disrupted for weeks, normal. What is not normal: fever or wound drainage, calf swelling and pain, pain escalating after week two instead of trending down, or losing motion week over week. Those get a call to the surgical team or to us, promptly.
One more honest point: recovery hurts some. Bending a freshly operated knee is genuinely uncomfortable work, and there is no way around doing it, only through it, dosed sensibly, with ice and elevation as the reward. Everyone who has done it tells us the same thing at three months: worth it.
References
- Artz N, Elvers KT, Lowe CM, Sackley C, Jepson P, Beswick AD. Effectiveness of physiotherapy exercise following total knee replacement: systematic review and meta-analysis. BMC Musculoskeletal Disorders. 2015;16:15. Full text (PMC)
General information only, not medical advice. Your surgeon’s protocol and precautions govern your recovery where they differ from general guidance.