Pain Control After Total Knee Surgery: (A Complete Guide)

As a home health physical therapist, I see total knee replacement patients in their homes within two days after the surgery.

Upon leaving the hospital, often these patients are at pain levels of 4/10 or less at rest and have an excellent range of motion, but by the time I see them in their home, a couple of days after the surgery, most have more pain that at their discharge from the hospital the day after their surgery, and their range of motion has significantly decreased.

This is the result of swelling over time and the washing out of their body the really good drugs they received in the hospital.

Weight-bearing is almost never a pain-producing factor.

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.

How Can I Control Pain After Total Knee Replacement?

  • Pain medications.
  • Rest.
  • Cold packs.
  • Leg elevation.
  • Positional change.
  • Home physical therapy program.
  • Walking.

Pain Medications:

The patients I see are sent home with two different types of pain medications:

  • Break-through pain medication.
  • Maintenance pain medication.

Follow your surgeon’s prescription. Speak with the surgeon’s office if you are planning on using the medication differently than prescribed by the surgeon.

Break-through medications are usually an opioid and acetaminophen combination medication such as Norco and Percocet. They are usually reserved for times when the patient’s pain level reaches or exceeds 7/10 and they need an extra “kick” to get the pain back under control.They are short-acting pain medication meant to break the pain intensity. They are meant to be taken pain contingent, not time contingent.

Most patients, regardless if they are a high-pain-tolerant or low-pain-tolerant patient have trouble getting the pain under control without break-through pain medication when they reach a 7/10 pain or higher.

Maintenance pain medication is prescribed to relieve mild to moderate pain (1/10 – 6/10). The maintenance pain medication I see prescribed most frequently is Tramadol.

Maintenance pain medications are slow-release and are meant to control pain. The patients I see are taking the maintenance pain medication on a time-contingent-bases every 4 to 6 hours.

Patients take these medications on a time-contingent-bases because the medication needs to build up in the bloodstream over time to reach the levels of optimum effectiveness.

Both the break-through and maintenance pain medications are classified as addictive and are not recommended for long periods of time.

Most of the patients I see are off all opioid pain meds within three weeks and only using Tylenol on an as needed basis.

My patients, who have been taking pain medications for a long time before surgery, seem to have less relief with these post-surgical medications than patients that were not taking them before surgery.


After total knee replacement surgery, the patient will tire much more quickly than before surgery.
This is the result of the anesthesia and medication the patient received while in the hospital. It usually takes my patients 5 days or more for all these chemicals to wash out of their system, but when it does, it seems to happen all at once.

Usually, somewhere in the 5 to 9 days after surgery, I hear the patient say “I have turned the corner”.

Once that “turn the corner” event happens, most of my patients have a much easier time progressing their rehabilitation program. Pain control takes a back seat to increasing ambulation tolerance and gaining knee range of motion.

Resting to control pain becomes less and less important as the patient gains more function and returns to their more normal lifestyle.

This “turn the corner” moment is both a blessing and a curse at the same time.

While the ability to be more functional with less pain becomes the blessing, it can lead the patient to believe they are able to do more than they should.

At the initial evaluation, I emphasize to my total knee patient the importance of following instructions. This is what I tell them:
“I see three kinds of patients”:

  • Most patients “stay in the lane”, that means doing exactly as they are instructed with walking and exercises. Follow these instructions to a “T” and in 3 weeks you will be free to return to near-normal life.
  • Some patients, because of apprehension usually, need to be pushed a little to get “into the lane”. They do fine as well and in about 3 weeks are able to return to near-normal pre-surgery activities.
  • The third kind of patient is the typical “type A” personality, and if they are told to do 10 of something they think 20 would be better. About 50% of the patients I see that fall into this category will set themselves back a week to 10 days at some point in that first 3 week program.

The takeaway is “only do what is in the home program and REST with the leg elevated when not doing the home program”.

Cold Application

Ice is the patient’s best friend.
It can’t be used too much, but it can be used for too short a period of time.

Almost every total knee replacement patient I see tells me they have been instructed to put ice packs on for 15 minutes, take them off for twenty minutes, then repeat this process as needed.

That is exactly the wrong advice!

Applying cold therapy using this technique can cause increased swelling, and swelling is what we are trying to prevent. Almost all post-surgical knee pain is the result of swelling.

Let me give you an example.
If I put an ice pack on the back of my hand, the first thing the body says is “don’t send any more blood down to that hand because I want to protect my core temperature and that cold pack will decrease my core temperature”.

If I take that ice pack off the back of my hand in about 15 minutes, the body says “we also like that hand, so let’s send a bunch of blood down to that hand and warm it up again”.

Well, that bunch of blood is exactly what we don’t want.
That bunch of blood carries a significant amount of fluids which can add to the swelling.

However, if I put that same ice pack on the back of my hand and I leave it there for 40 minutes or longer, the body has the same initial reaction. It will stop sending blood down to the back of my hand to protect its core temperature.

But when I take the ice pack off on my hand, after about 40 minutes, it will say “I like that hand, but I don’t trust that hand, so I’m going to warm it up slowly”.

That’s what I want for my patients.  I want to cool the Joint down for pain control without adding any swelling to that joint.

If you’re a football fan you will know what I’m saying is correct because when those valuable players injure their knee in the first half of the game, they return to the bench for the second half of the game with a huge ice pack on their knee and they do not remove for the entire second half of the game.

Those highly paid trainers are fully aware of the swelling that may occur if that ice pack is removed too soon.

Many total knee patients have not only been instructed incorrectly on the use of ice, but they have also been sent home with completely inadequate cold packs, most of which freeze into a solid block of ice or so small they can only stay cold for a few minutes.

Cold Packs:
Cold packs must be large enough to cover the area and also have enough bulk to remain cold for a long period of time.

The best size cold packs for a total knee replacement patient is 9” x 12”.
I recommend having two of these cold packs so when one loses its coldness the second one is ready to go.

One Big Caution Using Cold Packs:
The cold packs come out of the freezer at about -20 degrees Fahrenheit so the patient should not apply the cold pack directly to the skin.

A simple hand towel between the cold pack and the patient’s skin is usually sufficient to prevent freezer burn, and about 20 minutes into the cold application, the hand towel can usually be replaced with a pillowcase for the remainder of the cold application.

Because the kneecap is bone, and so close to the surface of the skin, it would be wise to add a little extra padding of insulation over the kneecap, however, bandages usually give that extra insulation for the kneecap.

The same logic is applicable for patients that have their surgery site closed with staples. Staples are made of metal and can become much more cold more quickly than vascularized skin.

The hand towel or pillowcase being used to protect against frostbite MUST BE DRY!

ANY wet spots on the insulation can be frozen into ice by the cold pack and that ice patch can cause frostbite as well.

Just be very cautious when using cold packs coming out of the freezer at zero to  -20 degrees Fahrenheit!

Cold Therapy Machine:
In a perfect world, all total knee replacement patients would be discharged from the hospital with a cold therapy machine.

But, believe it or not, after approving a surgery costing thousands of dollars, many insurance companies cheap-out when it comes to making the patient comfortable after surgery and only approve inexpensive cold packs that are too small, freeze solid, and are totally inadequate when for a couple hundred dollars, they could afford the patient the best chance of controlling the pain with as few EXPENSIVE AND ADDICTIVE pain medications as possible.
After all, the insurance company just paid out several thousands of dollars to do the surgery!

A Cold Therapy Machine requiring ice as the coolant, regardless of the manufacturer, will never have the possibility of causing damage to healthy tissue. Since it uses ice-cooled water to circulate through plastic channels, the circulation water will never be cold enough to cause frostbite in healthy tissue (and a total knee replacement recipient’s tissue is healthy, or the surgery would not have been done).

The average temperature of circulating water in a Cold Therapy Machine is about the same temperature as the inside of a refrigerator, about 40 degrees Fahrenheit.

Regardless, the recommendation is to place some protective material between the patient’s skin and the Cold Therapy Machine circulation pad. Something like a pillowcase in addition to the surgical bandage and compression hose should be sufficient insulation.

The Cold Therapy Machine will keep the circulation water cold for about 6 hours and eliminates the need to continually replace the cold apacks every hour.

Even though the instructions in most Cold Therapy Machines talk about adding ice to the water container in the machine, the average refrigerator’s ice machine cannot keep up with the amount of ice needed.
Swapping out the melted ice water for more ice can be a messy process leaving water on the floor, a potential risk factor for causing an already balance-challenged patient to slip and fall.

A much better solution to using ice in the Cold Therapy Machine is to freeze a few bottles of bottled water in the freezer and simply replace the frozen water bottles with new frozen water bottles as the ice in them melts.

I personally have and use an Osser Cold-Rush Cold Therapy Machine (Amazon link).
I chose the model that our local durable medical equipment rents to patients.
They choose this model because of its durability and lack of operation issues.
I also choose the Universal Pad as the pad of choice, it works well for many painful areas.
See my article Ice After A Total Knee Replacement…..

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Osser Cold-Rush Cold Therapy Machine

Leg Elevation

Leg elevation is important to decrease swelling and swelling is the primary reason for a total knee replacement patient’s pain.

Swelling (edema) in the knee is just a fact after the surgery, but swelling of the calf and ankle is present in about half of all the patients I see. And that is with the patient wearing those white compression hose called TED hose. That ankle and calf swelling is a circulation issue, the lymphatic circulation.

Most hospital instructions tell the patient to elevate the leg above the heart. If the patient has chronic heart failure, that is great advice, but for my average patient elevation above the heart is not mandatory.

The leg-above-heart position is very difficult for most patients to maintain. It requires the patient to be lying down on their back and placing the feet on something that elevates the legs above the heart.

Some of my total knee patients are using a CPM which comes close to the position required to elevate the leg above the heart. They are usually instructed by the surgeon to use the CPM 3 times daily for 2 hours at each session.

While most of these patients do well with the CPM, most complain about the amount of time they are required to spend in this leg-above-heart position.

Almost all of my patients do fine with using a recliner chair which brings the leg up to just short of horizontal to the floor.


Sitting with the feet flat on the floor can be a problem for the patient, I usually ask the patient to restrict the sitting with feet flat on the floor for no more than 15 minutes at a time before getting up, moving around, and elevating the leg.

I have seen patients, without cardiac issues, that have sat at the desk working on their computer for longer than 15 minutes, start to develop stasis ulcers. These are the blister-like pockets of fluid that usually appear on top of the foot first. If left unattended, they can develop into a serious complication for the patient.

After 2-3 weeks this should no longer be an issue but I still advise my patients to get up from the desk or table and walk around for a couple minutes every ½ hour.

121213 Stasis blister dorsum of foot 3 cropped watermarked
Huge Stasis Blister From Sitting & Sleeping In A Chair With The Feet On The Floor

Positional Change

Static positioning of the body for a person without any surgery will become uncomfortable after a period of time. The pain receptors will tell the brain it is time to change that position and allow some other part of the body to take over the stress of maintaining a slightly different static position.

After a total knee replacement surgery, the surgerized knee will be far less tolerant of static positioning, so frequent positional changes of the knee will help keep the knee pain in check.

Remember, the knee is limited in range of motion after total knee surgery (secondary to the swelling). The most comfortable position is going to be about halfway between the patient’s current extension and flexion range of motion.

A recliner chair is usually perfect for this positioning of comfort.


A pillow under the knee can be helpful for alleviating knee pain in the recliner or in bed, however, this pillow under the knee position can inhibit gaining full extension of the knee and full extension of the knee has a window of about 8 weeks to get the knee straight before the surgeon will start considering manipulation under anesthesia. Flexion is not as time sensitive as extension.

Home Physical Therapy

A study Effectiveness of Physiotherapy Exercises Following Total Knee Replacement concluded total knee replacement patients receiving programmed regular physical therapy treatments benefitted in both pain reduction and improved physical function when they were involved with a physical therapy rehabilitation program compared to patients that received minimal physical therapy intervention.
Patients receiving home physical therapy visits immediately after surgery benefitted the most.

I generally start the home exercise program at the time of the first home visit for physical therapy, just a day or two after surgery.

No pain no gain does not work for post-surgical total knee replacement rehabilitation.
Physical therapy home exercises, like all other activities, need to be done to pain but not through pain tolerance.

I expect that some of the home therapy program exercises will cause increased pain while doing them, primarily the exercises designed to increase flexion and extension.

My patients are instructed that any activity, including the physical therapy home exercise program, causing increased pain that lasts for longer than 3-4 minutes after stopping the activity is too much and needs to be cut back or eliminated. There are many ways to gain range of motion; we just need to find the correct ones for that specific patient.

ROM Exercises:
The range of motion exercises may cause some pain when doing them but the pain should go away within seconds upon stopping the stretching exercise.

As a orthopedic physical therapist I must be able to judge how much pain the range of motion exercises are causing the patient, therefore I ask my patient to abstain from taking any kind of pain medications at least two hours before my arrival. Pain needs to be my guide also.

Strengthening Exercises:
Most strengthening exercises are initially isometrics and it is rare for the isometric exercises to cause any pain.
Progressing the patient to more aggressive through-range exercises are rarely a problem either, it’s the exercises designed to increase the range of motion that are painful for the patient.

My Expectations:
I expect my home health physical therapy patient’s resting pain to drop by a full point after each visit when I progress the patient’s ambulation and exercise tolerance.

Exercise and walking should decrease the patient’s pain if the guidelines are followed.


Walking is an excellent way to help control the pain after a total knee replacement surgery but there is a fine line between not doing enough and doing too much.
See my article on Walking After Total Knee Replacement (When & How Much)…..

Should I Take Pain Medication Before Home Physical Therapy For Knee Replacement?

Total Knee surgical patients should not take pain medications for 2-3 hours before the home physical therapist arrives.
The therapist needs pain as a guide to the intensity of the visit.
Taking pain meds masks the pain and the therapist will need to work at suboptimal levels to prevent a flare-up of the patient’s pain.

Unfortunately, most of my patients, at the initial eval, report they just took pain medication before my arrival because “the nurse said to be sure to take pain meds before physical therapy arrives because physical therapy hurts”.

This is just simply not the case. Home physical therapy after total knee replacement should not increase the patient’s pain. In fact, I expect my patient’s pain level to drop by about 1 point (on a zero-to-ten scale) after each therapy session.

Outpatient Physical Therapy

Once home health physical therapy goals are met (in about 3 weeks), the patient should not be experiencing any pain greater than 3/10 at rest.

Outpatient physical therapy will take a more aggressive approach to strengthening and range of motion exercise, and the knee should be able to handle this more aggressive program just fine at 3-4 weeks post-surgery.

Seeing total knee replacement patients in my outpatient clinic, I always worked them slightly past what I thought the patient could tolerate but countered any potential pain increase with the cold application and interferential electrical stimulation to knock down any residual pain the outpatient rehabilitation might cause.

Declining ice or electrical stimulation was not an option at my clinic, even though the icing was never paid by the insurance carrier.
Even if the patients had the equipment to cool their knee at home, the 10-15 minutes for them to get home was too long a time after treatment for cold packs to be effective at holding the post-physical therapy pain down.

Read my other articles about Total Knee Replacement

Wishing You Good Pain Control After Your Total Knee Replacement.

Paying It Forward

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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