Exercises After Knee Replacement: Recovery Guide for a New Knee

You've had knee replacement surgery. The arthritic joint is gone, replaced with smooth new surfaces. Now comes the real work—rehabilitation to get your new knee moving and strong.

Exercise after knee replacement isn't optional—it's essential. The success of your surgery depends largely on how well you rehabilitate. Here's your guide to each phase of recovery.

Goals of Knee Replacement Rehabilitation

Short-Term (0-6 weeks)

• Reduce swelling
• Restore range of motion (especially extension)
• Walk safely with assistive device
• Manage pain
• Prevent complications (blood clots, stiffness)

Medium-Term (6-12 weeks)

• Achieve functional range of motion (0-120 degrees)
• Walk without assistive device
• Climb stairs normally
• Return to daily activities

Long-Term (3-12 months)

• Full strength recovery
• Return to recreational activities
• Maximize knee function
• Maintain long-term mobility

The Critical Numbers: Range of Motion

What You Need

• Full extension (0 degrees): Knee completely straight—CRITICAL
• Functional flexion (90+ degrees): For sitting, stairs
• Optimal flexion (115-120+ degrees): For most activities

Why Extension Matters Most

Getting your knee fully straight is the single most important goal early on. Without full extension:

• Walking is compromised
• Long-term function suffers
• It's harder to regain later

Prioritize extension exercises from day one.

Phase 1: Hospital and Early Recovery (Days 1-14)

Exercises start immediately—often the same day as surgery.

Ankle Pumps

Purpose: Prevent blood clots, promote circulation

How to do it:

1. Pump feet up and down (like pressing gas pedal)
2. 10-20 reps, every hour while awake

Quad Sets

Purpose: Activate thigh muscles, begin strengthening

How to do it:

1. Lie with leg straight
2. Tighten thigh, pressing back of knee into bed
3. Hold 5-10 seconds
4. 10 reps, 3-4 times daily

This is crucial—your quads need to fire.

Straight Leg Raise

Purpose: Strengthen quads, maintain hip strength

How to do it:

1. Lie on back, non-surgical knee bent
2. Tighten thigh of surgical leg
3. Lift leg 6-12 inches, keeping knee straight
4. Hold 3 seconds, lower slowly
5. 10 reps, 3 times daily

Heel Slides

Purpose: Begin restoring knee flexion

How to do it:

1. Lie on back
2. Slide heel toward buttocks, bending knee
3. Go as far as comfortable
4. Slide back out
5. 10 reps, 3-4 times daily

Knee Extension (Prone or Sitting)

Purpose: Restore critical extension

Prone hang:

1. Lie face down with knee at edge of bed
2. Let lower leg hang, gravity straightening knee
3. Hold 5-10 minutes, several times daily

Sitting:

1. Sit with foot on stool, knee unsupported
2. Let gravity straighten knee
3. Add light ankle weight when tolerated

Walking

Purpose: Essential for recovery

• Use walker or crutches as prescribed
• Follow weight-bearing guidelines
• Walk multiple short sessions daily
• Gradually increase distance

Phase 2: Building Motion and Strength (Weeks 2-6)

Continue Phase 1 exercises, add:

Seated Knee Flexion

Purpose: Increase bending range

How to do it:

1. Sit in chair, feet flat
2. Slide surgical foot back, bending knee
3. Use other foot to gently push further
4. Hold 30 seconds at max comfortable bend
5. Repeat 5-10 times

Standing Knee Flexion

Purpose: Functional flexion strength

How to do it:

1. Stand holding support
2. Bend surgical knee, bringing heel toward buttocks
3. Lower slowly
4. 10-15 reps, 2 sets

Short Arc Quads

Purpose: Strengthen quads in protected range

How to do it:

1. Lie or sit with rolled towel under knee (knee slightly bent)
2. Straighten knee, lifting foot
3. Hold 5 seconds
4. Lower slowly
5. 15 reps, 2-3 sets

Terminal Knee Extension

Purpose: Target full extension strength

How to do it:

1. Sit with resistance band around something sturdy behind you
2. Loop band around back of knee
3. Start with knee slightly bent
4. Straighten knee against band resistance
5. 15 reps, 2-3 sets

Hip Abduction (Standing)

Purpose: Hip strength for walking stability

How to do it:

1. Stand holding support
2. Move surgical leg out to side
3. Lower slowly
4. 10-15 reps, 2 sets

Heel Raises

Purpose: Calf strength, ankle mobility

How to do it:

1. Stand holding support
2. Rise on toes
3. Lower slowly
4. 15 reps, 2 sets

Stationary Bike

Purpose: Range of motion, cardiovascular fitness

Start when: You have about 90 degrees flexion

How:

• Start with seat high (less knee bend required)
• Partial rotations initially if needed
• Low resistance
• 5-10 minutes, progress to 15-20

Phase 3: Functional Progression (Weeks 6-12)

Stair Training

Going up: Lead with surgical leg Going down: Lead with non-surgical leg ("Up with the good, down with the bad")

Progress from:

1. One step at a time with railing
2. Alternating steps with railing
3. Alternating steps without railing

Mini Squats

Purpose: Functional leg strength

How to do it:

1. Stand, feet shoulder-width
2. Hold support if needed
3. Bend knees to 45-60 degrees
4. Keep weight in heels
5. 10-15 reps, 2-3 sets

Step-Ups

Purpose: Functional strength, stair prep

How to do it:

1. Low step (4-6 inches)
2. Step up with surgical leg
3. Bring other foot up
4. Step down, leading with non-surgical leg
5. 10 each leg, 2 sets

Lunges (Modified)

Purpose: Functional strength and range

How to do it:

1. Hold support if needed
2. Step back with non-surgical leg
3. Lower body slightly
4. Return to standing
5. 10 reps, 2 sets

Progress to stepping back with surgical leg when stronger.

Balance Exercises

Purpose: Stability, fall prevention

• Single-leg stand (with support nearby)
• Weight shifts
• Tandem standing (heel to toe)

Phase 4: Advanced Strengthening (Months 3-12)

Progressive Resistance

• Increase resistance/weight in exercises
• Leg press machine
• Knee extension machine (light weight, limited range if needed)
• Hamstring curls

Walking Program

• Progress to 30+ minutes
• Include hills
• Increase pace

Low-Impact Cardio

• Swimming (after incision healed)
• Elliptical
• Cycling (outdoor when balance allows)

Return to Activities

Follow surgeon's guidance on:

• Golf (often 3-4 months)
• Doubles tennis (4-6 months)
• Hiking (3-6 months)
• Dancing (3-6 months)

Sample Weekly Schedule

Weeks 1-2

3-4 times daily:

• Ankle pumps: 20 reps
• Quad sets: 10 reps
• Straight leg raises: 10 reps
• Heel slides: 10 reps

Continuous:

• Knee extension (prone hang): 5-10 min, 3x daily
• Walking: Multiple short sessions

Weeks 3-6

Daily:

• Walking: Increasing distance
• Range of motion exercises
• Extension work

2-3 times daily:

• All Phase 1 exercises (reduced frequency)
• Add Phase 2 exercises

Stationary bike: 10-15 minutes daily (when ROM allows)

Weeks 7-12

Daily:

• Walking: 20-30 minutes
• Range of motion maintenance

3-4 times weekly:

• Strengthening circuit
• Stationary bike: 20 minutes
• Stair training
• Balance exercises

Range of Motion Milestones

Week 1: 70-90 degrees flexion, working toward full extension Week 2: 90+ degrees flexion, full extension Week 4: 100-110 degrees flexion Week 6: 110-115 degrees flexion Week 12: 115-125 degrees flexion

Note: Individual variation exists. These are targets, not requirements.

Managing Pain and Swelling

Ice

• Apply 15-20 minutes after exercise
• Multiple times daily in early weeks
• Wrap ice pack (don't apply directly to skin)

Elevation

• Elevate leg when resting
• Reduces swelling

Medication

• Take pain medication as prescribed
• Don't wait until pain is severe
• Adequate pain control allows better exercise

Compression

• Use compression stockings if prescribed
• Helps with swelling

Warning Signs: When to Contact Your Doctor

Call immediately if you have:

• Fever over 101°F
• Increasing redness, warmth, or drainage at incision
• Severe pain not relieved by medication
• Sudden increase in swelling
• Calf pain, swelling, or warmth (possible blood clot)
• Chest pain or shortness of breath

Keys to Success

Attend Physical Therapy

Professional guidance is invaluable. Attend all sessions.

Do Your Home Exercises

PT visits aren't enough. Daily home exercises are essential.

Prioritize Extension

Full extension is more important than flexion in early weeks. Don't neglect it.

Be Patient

Recovery takes 3-6 months for most activities, up to a year for maximum improvement.

Don't Overdo It

More isn't always better. Follow the program, don't add extra exercises without guidance.

Control Swelling

Swelling limits motion and slows healing. Ice and elevate consistently.

The Bottom Line

Knee replacement surgery gives you a new joint surface. Exercise gives you a functioning knee.

The essentials:

1. Start immediately (exercises begin day of surgery)
2. Prioritize full extension (most critical early goal)
3. Build flexion gradually (aim for 115-120+ degrees)
4. Progress through phases (don't skip steps)
5. Attend physical therapy (professional guidance matters)
6. Be consistent (daily exercises, not occasional)
7. Be patient (full recovery takes months)

Your new knee is designed to last 15-25+ years. The work you do in rehabilitation determines how well it functions for all those years.

Commit to the process. Your future self will thank you.