Low Impact Aerobic Exercise - Swimming and riding a stationary bike are great low impact exercises that help build strength in your knee. Stop any exercise that causes increasing pain.
Short-Arc Knee Extensions - Roll up several towels in a roll 6-8 inches thick. Lay in bed with the towels under one knee. Bend the other knee. Keeping your knee on the towels, lift your foot to straighten the knee. Hold for a few seconds and lower the foot.
Ankle Pumps - While lying in bed, point your toes downward and then bring your toes back up towards your head, tightening your calf.
Heel Slides - Slide your heel along the bed pulling your foot towards you as your knee bends.
Straight Leg Raise - Start by tightening your quadriceps, the muscles in the front of your thigh. Then with toes toward the ceiling, lift your leg 6-12 inches from the bed.
Quadriceps Sets - Lie on your back, legs straight. Tighten the muscle in the front of your thigh as you press the back of your knee toward the bed. Hold for a few seconds, then relax the leg.
Standing Knee Bends - Stand while holding onto a steady surface, such as a table. Bend your knee as far as it will go comfortably. Hold for a few seconds and lower the leg.
Increasing upper body strength is also important because of the need to use a walker or crutches after knee replacement.
Bicep Curls - In a sitting position, keep you elbow close to your body and your wrist straight. Bend you arm, moving your hand up to your shoulder, then lower slowly.
Triceps Extensions - Sit, leaning forward from the waist. Bend your elbow so that your forearm is parallel to the floor. Then straighten your elbow as you extend your arm behind you.
Seated Press Ups - Sit in a sturdy chair with armrests. With palms on the armrests, press down to lift yourself from the chair. Hold for 3-5 seconds. Bend your elbows slowly to ease back down.
Talk to your doctor before starting any exercise program and remember to call your doctor if you experience increased pain or swelling in your knee after exercise.