Stiffness After Knee Replacement: Causes and Coping Tips

Medically Reviewed By William C. Lloyd III, MD, FACS
senior adult woman walking slowly and carefully outside with walker after knee replacement

Receiving an artificial knee can improve your quality of life if you’ve been living with a painful joint. But stiffness after knee replacement is a common development, and one worth addressing with your surgeon in advance. By learning how long stiffness might last after knee replacement surgery (and what you can do about it), you can increase your mobility and satisfaction with total knee replacement surgery.

What causes a stiff knee after surgery?

During the immediate postoperative period, swelling within the joint can cause your knee to feel very stiff. Your range of motion might be very limited in the first weeks because of this swelling.

As time goes on, knee replacement stiffness may linger due to scar formation or adhesions (fibrous tissue that grows and attaches to the knee implant and other tissues, restricting movement). Scar formation helps heal the incision, but too much scar tissue can cause problems. Rarely, nerve damage during total knee replacement surgery can cause feelings of stiffness (or a loss of sensation) in the joint. If your joint stiffness lasts longer than three months—or worsens with time instead of improving, be sure to notify your surgeon.

What to do for knee stiffness after joint replacement surgery

You can try many approaches for preventing or minimizing knee stiffness after your joint replacement surgery. First, read and follow your surgeon’s postoperative instructions to the letter. Never “push yourself” to exercise beyond the scope of what your doctor prescribes. Keep using your crutches (or other assistive devices) until your care team gives you the green light to do so.

To minimize knee stiffness after you get home from surgery, try:

  • Applying warm or cold packs to the joint as advised by your care team. Typically, you apply cold packs until swelling subsides, then you can begin using warm packs, or alternating cold with warm compresses. (Some physical therapists recommend cold packs after a PT or exercise session.)
  • Gently massaging the scar and around the knee after the incision has fully healed
  • Performing knee exercises as prescribed to keep stiffness at bay.
  • Soaking in a warm tub and performing gentle range-of-motion exercises after the incision has fully healed
  • Walking as much as allowed by your recovery plan

Exercises for knee stiffness

Physical therapy after knee replacement varies between patients and providers. To get ahead of knee stiffness and improve long-term range of motion, the knee exercises you do in the first few to several weeks are critical for healing. Keep in mind, these knee exercises are in addition to walking as prescribed by your physician. You’ll walk with a walker or crutches at first.

Early recovery

Many knee replacement exercises focus on the thigh muscle (quadriceps), which is actually four large muscles. Contracting the quadriceps straightens your knee. It will be weak at first because your surgeon has to detach the quadriceps tendon from your knee and reattach it after placing the knee implant. You will likely perform some of these in the recovery room before you go home, according to the American Academy of Orthopedic Surgeons.

  • Quad/thigh squeeze: Lie down with your unaffected knee bent. If desired, roll a towel and place it under the affected (operated) knee. Gently and slowly squeeze your thigh muscles, hold for 5 seconds, then release. Repeat about 10 times, which should take you about 2 minutes; rest 1 minute, then repeat the set of 10. Stop when your muscle feels tired. Practice this exercise every 1 to 2 hours, or as prescribed.
  • Knee straightening: Start as above for the quad squeeze, placing a rolled towel under your ankle. When you engage your thigh, very slowly try to straighten your knee so that it touches the bed. Do not lift your leg; focus on straightening the knee. Hold for 5 seconds, then release. Repeat about 10 times or until your leg is tired. Do other sets throughout the day as you’re able.
  • Ankle pumps: While lying down, alternate flexing and extending your ankle, which requires contracting your calf and shin muscles. You can perform this exercise for up to 3 minutes, 2 to 3 times an hour.
  • Knee bends (bed-supported): Lying flat in bed or on a mat, slowly slide the foot of your operated leg toward your butt as you bend (flex) your knee. Bend it as far as you can and hold for 5 to 10 seconds. Release, sliding your leg slowly back to your starting position. Repeat until you feel muscle fatigue.
  • Knee bends (sitting-supported): Sitting in a sturdy chair or firm bed, place the foot of your healthy leg behind the foot of the operated leg. Slowly bend your operated knee as far as you’re able to and hold up to 10 seconds, then release. Repeat until your knee is fatigued.
  • Knee bends (sitting-unsupported): Slowly bend your knee until it rests on the floor. You slide forward on the chair to intensify the bend. Hold up to 10 seconds, then release and straighten your knee. You will work on this exercise until you can fully bend your new knee.

3 to 6 weeks

Further activate your quadriceps with step-ups and straight leg raises—when your surgeon gives you the OK:

  • Step-ups: Stand at the foot of a set of stairs that has a handrail, or place a sturdy stool (no higher than a stair riser) next to a countertop. Bend your operated knee and simply place your foot on the step or stool. Hold onto the railing or sturdy surface. Activate your thigh and butt muscles and slowly step up onto the step/stool as you try to straighten your leg. Hold for 5 seconds, then very slowly bend your knee and bring your foot back to the ground, next to your other foot. Repeat several times in a row, resting in between each repetition.
  • Straight leg raises: Lie on a bed with your healthy knee bent and your affected knee straight. Engage your thigh muscles to slowly lift the leg, keeping your leg straight. Try to get your thighs next to each other, pause for 5 seconds, then gently lower your leg back to the starting position. Repeat.

6 weeks and later

When you get clearance, you can progress to wall squats. Stand with your back against the wall and your feet about 18 inches out, hip-width apart. Slowly slide down the wall while engaging your butt and thigh muscles. Stop before you feel knee pain. Hold for 5 seconds, then slowly slide back up the wall to your starting position. It may take several weeks of this and other exercises to regain your strength, but it’s worth the effort.

You can also continue with the early exercises.

What to avoid with knee stiffness after knee replacement

Approaches you should avoid when coping with knee stiffness after surgery:

  • Aggressively massaging or manipulating the joint
  • Bearing your full body weight on the joint before your surgeon says it’s OK
  • Forcing the knee to bend beyond a comfortable range-of-motion
  • Increasing your physical activity too quickly
  • Taking over-the-counter pain relievers unless advised to do so by your surgeon

Lastly, you may be able to avoid some postoperative knee stiffness by losing weight, if you’re overweight. This also might extend the life of your new knee implant.

Chronic knee stiffness after knee replacement

In severe cases, where stiffness vastly restricts the knee joint’s range-of-motion, your surgeon may recommend a follow-up procedure to break up scar tissue or remove adhesions. Arthroscopy to actively release adhesions is effective at increasing range of motion.

Even with lingering stiffness, most people express great satisfaction after total knee replacement surgery. By following your postoperative treatment plan and performing your physical therapy exercises as prescribed, you might find your new knee gets you back to your active life quickly and painlessly.

Was this helpful?
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  2. Knee Joint Replacement – Discharge. MedlinePlus, U.S. National Library of Medicine.
  3. Total Knee Replacement. American Academy of Orthopaedic Surgeons.
  4. Ghani H, Maffulli N, Khanduja V. Management of stiffness following total knee arthroplasty: a systematic review. Knee. 2012 Dec;19(6):751-9.
  5. Fitzsimmons SE, Vasquez EA, Bronson MJ. How to treat the stiff total knee arthroplasty?: a systematic review. Clin Orthop Relat Res. 2010 Apr;468(4):1096-106.
  6. Soft tissue rehabilitation is a mainstay of massage therapy in orthopedic settings. American Massage Therapy Association.
  7. 5 Quad Exercises to Do After Knee Replacement. Veritas Health, LLC.

Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Feb 23
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