Medicare covers several types of recovery equipment after knee replacement, including walkers, crutches, canes, commode chairs, hospital beds, and continuous passive motion (CPM) machines. All of these fall under the durable medical equipment (DME) benefit in Medicare Part B, and your out-of-pocket cost is typically 20% of the Medicare-approved amount after you meet your Part B deductible.
The catch is that every item needs a prescription from your doctor, and Medicare only covers equipment deemed “medically necessary” for use in your home. Here’s what that looks like in practice after a knee replacement.
Mobility Aids: Walkers, Crutches, and Canes
These are the most commonly prescribed items after knee replacement and the ones you’ll use almost immediately. Most surgeons prescribe a walker for the first few weeks, then transition you to a cane as your strength and balance improve. Crutches are less common after knee replacement but still covered if your surgeon orders them. Medicare covers all three as long as your provider documents that you need them for safe movement at home.
You may be given a choice between renting and buying, depending on the item. Some equipment becomes yours after a set number of rental payments. Your surgeon’s office or the hospital discharge team will typically coordinate the prescription before you leave.
Continuous Passive Motion Machines
A CPM machine is a motorized device that slowly bends and straightens your knee while you rest, keeping the joint from stiffening during early recovery. Medicare covers CPM machines for patients who have had a total knee replacement, but the rules are specific: you must begin using the device within two days of surgery, and coverage is limited to a three-week period following the operation. Only the portion of those three weeks during which you use the machine at home is covered. Medicare does not pay for CPM use beyond three weeks or for conditions other than total knee replacement.
CPM machines are rented, not purchased. Your surgeon will write the order, and a DME supplier delivers the machine to your home, usually the day you’re discharged.
Hospital Beds and Commode Chairs
If your doctor determines that a standard bed doesn’t support safe recovery (for example, you need the head or leg section elevated and can’t manage stairs to a bathroom), Medicare Part B can cover a hospital bed for home use. This is less common after straightforward knee replacement but may apply if you have additional mobility limitations or live alone.
Commode chairs, the portable bedside toilets that eliminate the need to walk to a bathroom during the first days of recovery, are explicitly covered under Part B. Your surgeon or home health nurse can prescribe one if getting to and from the bathroom safely is a concern. After the deductible, you pay the standard 20% coinsurance.
Cold Therapy Devices
Cold therapy machines, which circulate chilled water through a pad wrapped around your knee, are a gray area that trips up many patients. Medicare can cover motorized cold therapy devices under the DME benefit, but only when they meet “reasonable and necessary” criteria laid out in a local coverage determination. That means coverage varies by region and by the specific clinical justification your surgeon provides. Simpler cold therapy items like disposable ice packs, gravity-fed reservoirs, and reusable wraps are billed under different codes and may or may not be covered depending on the same local rules.
If your surgeon recommends a cold therapy unit, ask the DME supplier to verify Medicare coverage before you accept the device. If it’s denied, these machines typically cost $150 to $300 out of pocket to rent.
What Medicare Does Not Cover
Medicare’s definition of DME requires that equipment be durable, medically necessary, used in your home, and expected to last at least three years. Items classified as “convenience” rather than medical necessity are excluded. Common post-knee-replacement items that typically fall outside coverage include:
- Shower chairs and bath benches: Generally considered safety or convenience items rather than DME, these are usually not covered unless your situation meets very specific medical criteria.
- Raised toilet seats: These make life easier after surgery but are not classified as DME.
- Grab bars and home modifications: Handrails, ramps, and bathroom grab bars are home improvements, not medical equipment, and Medicare does not pay for them.
- Exercise equipment: Stationary bikes, resistance bands, and other rehab tools used at home are not covered, even if your physical therapist recommends them.
These items are generally inexpensive enough to purchase on your own. A raised toilet seat runs $20 to $50, and a shower chair is typically under $60.
How to Get Coverage Approved
Medicare Part B covers DME only when your doctor or health care provider prescribes it for use in your home. The prescription serves as the documentation of medical necessity. For most post-knee-replacement equipment, your surgeon’s office handles this as part of the discharge process. You don’t need to file a separate application.
The more important step is making sure you get your equipment from a Medicare-enrolled supplier. Medicare has a competitive bidding program for DME, and using a non-enrolled or out-of-network supplier can leave you responsible for the full cost. Your hospital’s case manager can usually direct you to an approved supplier in your area. If a supplier tells you they “accept Medicare,” confirm they are enrolled in the Medicare DMEPOS program specifically.
What You’ll Pay Out of Pocket
For all covered DME, the cost structure is the same: you pay your annual Part B deductible first, then 20% of the Medicare-approved amount for each item. If you have a Medigap (supplemental) policy, it may cover part or all of that 20% coinsurance. Medicare Advantage plans cover the same DME categories as Original Medicare but may have different cost-sharing rules, so check with your plan directly.
Some equipment is rented rather than purchased, which means monthly payments rather than a single charge. After a certain number of rental months (typically 13 for items like hospital beds), ownership transfers to you and Medicare stops paying. For short-term recovery items like CPM machines, you’ll only rent for the weeks you need them.