Total Knee Replacement Outcomes After Home Physical Therapy

I have been an orthopedic physical therapist for more than 40 years.

For the past few years, I have been seeing total joint replacement patients in their homes, initiating a home physical therapy program, and transitioning them to an outpatient physical therapy facility of their choice to complete their rehabilitation process.

Prior to being a home physical therapist, I owned and operated my own physical therapy outpatient clinic. We had up to 20 employees, seeing 125 to 150 patients daily.

Prior to opening my own clinic, I was the Chief of Physical Therapy at Community Memorial Hospital. In that capacity, I saw total knee replacement patients bedside after their surgery preparing the patient for discharge from the hospital.

I know what goals and outcomes a total knee patient should achieve at every stage of the rehabilitation process.

Tip 1: Apply Cold Therapy Before Going To Bed.

All of my total knee surgery patients are using either Ice Packs or Cold Therapy Machines (Amazon affiliate links) multiple times daily to help control pain levels. Applying cold therapy for 40 minutes just before going to bed will reduce your pain while sleeping
See my article: Ice After Total Knee Replacement: A PT’s Complete Guide.

What are the total knee goals of home physical therapy after surgery?

  • Knee ROM: less than 10 degrees extension through 90 degrees or more or flexion.
  • Extremity strength 4 out of 5 or more.
  • Low fall risk.
  • Walk 1,000 feet or more.
  • Walking without a device.
  • Independent with the home exercise program.
  • Safe mobility techniques.

The goals above are achieved over about a three period of time using a home exercise plan of care using progressive strengthening exercises, range of motion exercises, and ambulation for distance and technique.

Home Physical Therapy Exercise Program

My referred total knee replacement patients are seen within 48 hours after surgery. Home physical therapy exercises are started immediately.

New total knee patients are not ready to initiate outpatient physical therapy in the first 18 to 30 days.

Most of my referring doctors request home physical therapy 3 times a week for 3 to 4 weeks for a total of 9 to 12 visits.
Their patients are usually ready for outpatient physical therapy in 7 sessions.

I progress my patients through what I call Phase 1 and Phase 2 protocols before they are ready to proceed to outpatient physical therapy.

I instruct the patient to do their home physical therapy exercises twice a day.
Once in the morning and once in the afternoon.

Usually, by the 3rd or 4th session, the patient can do both the am & pm exercises all in one session per day without difficulty and that is the cue that triggers me to begin phase 2 of the exercises.

Phase 1 is all about getting early Range of Motion (ROM) exercises started and reconnecting the patient’s brain with the muscles that need strengthening.

ROM Phase 1:
When the surgeon was ready to close the surgical site in the operating room, they made sure the ROM was full in extension as well as flexion.

Frequently the patient justifies in their mind that the ROM was restricted before the surgery so it makes sense to them that the knee is still limited in range of motion. That just simply is not the case and the patient needs to know that before they left the surgical suite their range of motion was normal and full.

Range of motion stretching exercises are started immediately.
Regaining full extension has a limited amount of time to achieve before that window closes, leaving the surgeon with no other option than to manipulate the knee under anesthesia in a surgical suite.
That window of opportunity closes in 6 to 8 weeks post-surgery.

So ROM phase 1 is all about gaining enough ROM to avoid knee manipulation under anesthesia.

Exercises Phase 1:
In phase 1 of the Home Exercise Program (HEP) it’s all about getting the brain re-connected to the target muscle. This is accomplished using isometric muscle contractions for the most part (muscle contraction but no joint movement).

Patients who have had a total knee replacement lose strength after the surgery.
They do not lose muscle!

Most average non-surgical adults, not regularly lifting weights as exercise, can only recruit at best about 60-65% of the muscle fibers that make up a specific muscle.
That is why so many people drop out of their gym membership about 5-6 weeks into their New Year’s resolution.

By week 5-6, even though the gym member has increased the amount of weight they can lift, they look into the mirror and can’t see any difference.
That is because they have increased their ability to recruit more of the muscle fibers but haven’t increased their muscle bulk.

A normal muscle has to be worked at nearly 100% recruitment before the exercise will start breaking down the muscle fibers and rebuilding with bigger muscle fibers.
The new gym member quits at about the time they are ready to build the muscle bulk they so desperately desired when starting on this New Year’s resolution exercise program.

For a patient that has undergone a total knee replacement surgery, the brain shuts down the patient’s ability to recruit the muscles of that extremity. I would guess that most total knee replacement patients are recruiting some of the muscles in that extremity at about 30-35% of total recruitment potential.

The two muscles I see most affected by this decrease in recruitment ability are:

  • Hip Flexors.
  • Knee Extensors.

Hip flexors:
Many of my patients cannot lift their knee towards the ceiling in a seated position after total knee replacement surgery, but that was not a problem the day before surgery. Hardly any of them can lift the knee towards the ceiling and resist even slight pressure to push the foot back toward the floor.

Knee extensors:
Surprisingly, the patient is usually better at muscle fiber recruitment of knee extensors, but are still not able to resist much against my attempt to bend the knee in this straightened position (and the patient will not yet be able to straighten their knee due to lack of full ROM).

So exercise Phase 1 of the home program is all about getting the brain reconnected to the muscles for better recruitment of the muscle fibers.

Phase 2:
For my patients, I expect them to be independent with their Phase 1 home exercise program (HEP) and continue phase 1 exercises independently as we add the Phase 2 components of the HEP.

Most of my patients are ready to move into phase 2 at the 3rd or 4th session.

ROM Phase 2:
In phase 2 the ROM exercises are advanced with more aggressive ROM exercises. There are a number of advanced ROM exercises I choose from and the patient’s gains in ROM and pain tolerance to the new exercises are my guide to developing that second phase of ROM exercises.

Exercises Phase 2:
Now that the patient has better recruitment skills, it is now time to get those muscles to move the joints instead of just doing isometric contractions.

The patient is still not ready for strength training using weights, but is ready to start doing functional activities moving the joint through ROM and using body-weight as the resistance.

My Expectations

ROM expectations:
Goals are set for my total joint replacement patients to have a ROM that is less than 10 degrees short of coming out completely straight through 90 degrees of bending or more.

I can’t remember the last patient that was not able to achieve this ROM within 9 treatment sessions, and most by the 7th session.

Most of my patients reach 100 degrees of flexion (or more) within this time-frame.

Exercise Expectations:
I expect my patient’s muscle strength (recruitment) to improve to move the joints through full available ROM and to be able to resist a moderate amount of manual counterpressure.
They have not yet fully recovered the strength but are ready to move to more aggressive exercises in a physical therapy outpatient setting.


Almost every total knee replacement patient receives instructions from the hospital telling them to walk up to 15 minutes at a time.

Unfortunately, walking for a specific amount of time leaves too many factors unaddressed to make a determination of the patient’s progress.

Two important unaddressed metrics in a time-contingent measurement of walking progress include:

  • Is the patient using an ambulation assistive device such as a walker or cane?
  • Is the patient a slow or fast walker?

A patient with a slow walking pace and using a walker may cover 1,000 feet in 15 minutes (about 0.8 miles per hour).
A fast walker, without any walking aid, could walk up to 4,000 feet in 15 minutes (about 3 miles per hour).

That differential in patient performance ability makes it hard to equivocate individual patient performance to the general population of total knee replacement recipients, using the time metric.

In my opinion, a distance metric is much better than a time metric to measure the patient’s progress with walking.

My expectations for my patients:
At the initial evaluation, I walk with the patient to their tolerance (where they feel like they should stop). That distance is usually less than 500 feet, often just as little as 150 feet.

If the patient reaches 500 feet, but feels they can continue to walk, I stop them at the 500 feet mark as their first attempt at walking for endurance.

Experience has taught me that allowing the patient to walk further than 500 feet at the initial evaluation is just a bad idea. They are usually still pretty medicated and pain as a limiting factor is just not a trust-able criteria on the first visit with a patient that can walk 500 feet on the first visit.

For the home program, the patient is instructed to walk 50% the distance we walked at the home visit, but walk that distance 2 or 3 times a day.

At each home visit, I increase the walking distance to their tolerance and the home program increases the walking distance to 50% of that day’s ambulation endurance, to be done 2 to 3 times a day.

By the 3rd or 4th session I expect the patient to be walking with a walker more than 1,000 feet (¼ mile is my goal which is 1,320 feet).

At about the 3rd or 4th home visit I’m listening for the patient to report they are walking around the kitchen without any walker and just touching the countertops for support.

Now is the time to start taking the walker away from the patient and start working on getting them to walk that ¼ mile again without any device.
See my article Walker: When and How Much…..

At the 1st session of walking without a device, I again allow the patient to set the baseline for endurance walking without a device, and each session thereafter that distance is increased, expecting to get the patient to 1,000 feet or more without a device over the next 3-4 home visits.

The patient, immediately after surgery, is allowed to weight bear on the knee replacement as tolerated. Most of my patients do not have a weight-bearing issue, they have a balance and/or confidence issue.

Should I use a cane after total knee replacement?

Transitioning from walker to cane (or starting with a cane) causes the patient to fall back into that old motor-memory limp they had before the surgery.
Weight bearing is not an issue, confidence in balance is usually the issue.
Occasionally a walking stick can be used for the transition, it will not reinforce bad motor memory.

I do not progress my patients to a cane between walking with a walker and walking without a device.

Walking with a walker allows me to train my patient and get rid of that motor memory.

That usually means I keep the patient on a walker for a couple of days longer than they feel like they need a walker.

For those patients that feel like they cannot transition from walker to nothing (maybe 3-4 out of 100), my recommendation is for the patient to start using a walking stick.

Walking Stick Rear view cropped and watermarked 1

A walking stick will provide that third point of reference for the patient’s balance and confidence and at this point, the patient should have zero issues with weight-bearing on the new knee.
A cane also gives that same third point of reference but also encourages the patient to “lean” on the cane, recreating the exact same limp they had before surgery.

If the patient is totally uncomfortable without using a cane I certainly will allow the use of the cane, but I warn them of the tendency to reinforce the old limp and to fight against that limp returning as a permanent gait pattern. My experience is that maybe 1 out of 100 will use the cane as a transitional tool.

Outpatient Physical Therapy

After completing 6-9 home therapy visits over about 3 weeks, the patient’s total knee replacement should be ready for more aggressive techniques of ROM and exercises that they simply were not ready to start before this time frame.

Depending on the prior condition of the total knee replacement recipient, I would expect my patients to continue with outpatient physical therapy for another 3-4 weeks to regain full ROM of the knee and improve the strength of the muscles to at least pre-surgey strengths.

Problems with skipping home physical therapy after total knee replacement and going directly to outpatient physical therapy are:

  • The patient has a 2-3 week time frame between surgery and outpatient therapy where, even in outpatient physical therapy, the therapist must severely limit the intensity of the patient’s rehabilitation program. The outpatient therapist will be limited to the same exercise program the patient could have received in a home physical therapy program.
  • The insurance carriers all limit the amount of outpatient physical therapy a patient can receive after a total knee replacement.
  • Insurance companies have 2 different physical therapy “benefits buckets”. One is under hospitalization (home health physical therapy falls into this bucket), and the other benefit bucket is outpatient physical therapy.
  • Going directly from surgery to outpatient physical therapy “burns off” those hospital home physical therapy visits and starts to burn the physical therapy benefits under outpatient physical therapy.
  • Going directly to outpatient physical therapy will “cheat” the patient out of the hospital home health treatments and the outpatient facility will still have to follow the restrictions of a new surgery.
  • The end result is the patient, at 2-3 weeks out, is at the same place they would have been with home physical therapy BUT THEY DO NOT HAVE ENOUGH VISITS LEFT UNDER THE OUTPATIENT PHYSICAL THERAPY BENEFITS TO REACH THE DESIRED OUTCOME!

A study shows patients receiving home physical therapy visits immediately after surgery benefit the most.

Read my other articles about Total Knee Replacement

Wishing You Quick Painless Rehabilitation

Perhaps you are approaching or already retired and wondering how you could earn extra money in retirement.
One option would be to do as I am doing.
Read my article How To Generate Retirement Income: Cash In On Your Knowledge.

Dr. Robert Donaldson

Dr. Donaldson is dually licensed; physical therapy in 1975 and doctor of chiropractic in 1995. He held credentials of Orthopedic Clinical Specialist in physical therapy for 20 years, QME in California, and taught at USC. He owns and operates an orthopedic physical therapy practice. See "About Me" page.

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