What you do in the days and weeks after knee surgery often determines how well your knee moves months down the road. At Angelo Mattalino, M.D., continuous passive motion (CPM) therapy is one of the tools used to help patients keep their knee moving safely after surgery, protecting range of motion before stiffness has a chance to set in.
If you are preparing for a procedure such as knee arthroscopy, ACL reconstruction, or another knee surgery, understanding how CPM therapy fits into your recovery plan can help you feel more prepared for what comes next and can make the transition from surgery to rehabilitation feel far less overwhelming.
Why It’s Important to Move After Knee Surgery
The knee relies on regular motion to stay healthy. It is a complex joint, connecting the thigh bone, shin bone and kneecap through a network of ligaments, tendons, and cartilage that all depend on consistent movement to function well. After surgery, swelling, pain and the body’s natural healing response can all limit how far the joint bends and straightens. Left unaddressed, this reduced motion can allow scar tissue to form around the joint, and scar tissue does not stretch the way healthy tissue does.
Once scar tissue builds up, regaining lost motion becomes far more difficult and can require additional treatment, including a manipulation procedure or further therapy, to restore range of motion.
This is why early, controlled movement is such a priority in the days right after knee surgery, particularly following procedures like meniscus repair or arthroscopic microfracture surgery, where protecting the healing tissue while still restoring motion requires a careful balance. Move too little, and stiffness can take hold. Move too aggressively, too soon, and the surgical repair could be put at risk.
What Is Continuous Passive Motion (CPM) Therapy?
Continuous Passive Motion therapy uses a motorized device that gently and slowly moves your knee through a set arc of motion without requiring you to use your own muscles. The machine supports your leg and carries it through a bending and straightening cycle at a controlled speed, so the joint stays in motion while your muscles rest.
Because the movement is passive, meaning the machine does the work rather than your leg muscles, CPM therapy can begin very early in recovery, often within the first day after surgery. The arc of motion typically starts small and is gradually increased as your knee tolerates more movement, allowing your surgeon to progress your recovery at a pace that matches your healing.
How Continuous Passive Motion Therapy Works
Once your surgery is complete, your leg is positioned in the CPM device, which is typically used while you are resting in bed. The machine is set to a specific range of motion and speed, both determined by Dr. Mattalino based on your procedure and how your knee is healing.
In the earliest sessions, the arc of motion is usually modest, often somewhere in the range of a few degrees of bending. As your comfort and tolerance improve, the arc is expanded a little more each day. Sessions may last anywhere from one to several hours and are often repeated multiple times a day during the initial recovery period, whether at the hospital, a rehabilitation facility, or at home with a rented or purchased unit.
Throughout this process, you remain relaxed while the device does the work, which allows the joint to move without placing strain on the surrounding muscles and healing tissue. Many patients find the gentle, repetitive motion reduces stiffness and makes the transition into active physical therapy more comfortable.
Benefits of Continuous Passive Motion (CPM) Therapy
Reduces the Burden on Caregivers
Because the device handles the motion on its own, family members or caregivers are not required to manually stretch or reposition the knee during the earliest, most fragile stage of recovery.
Provides Measurable Day-to-Day Progress
Since the arc of motion is set and adjusted in specific increments, both you and Dr. Mattalino can track incremental gains in flexibility with a level of precision that is hard to get from self-guided movement alone.
Requires No Effort From You
CPM therapy asks nothing of your muscles while your body is focused on healing. This is especially valuable in the first days after surgery, when pain and fatigue make active exercise difficult to sustain.
Works Across Multiple Recovery Settings
The device can be used at the hospital, a rehabilitation facility, or at home, allowing your motion therapy to continue on the same schedule no matter where you are in your recovery.
CPM Therapy vs. Other Recovery Methods
Patients often ask how CPM therapy differs from standard physical therapy or simply moving the knee on their own.
Physical Therapy
Traditional physical therapy relies on active exercises, where you use your own muscles to bend and straighten the knee under a therapist’s guidance. This builds strength alongside motion, but it can be more demanding in the earliest days after surgery when pain and swelling are at their peak.
Research reviewed by the Cochrane Database of Systematic Reviews found that CPM therapy can offer a modest advantage in early range of motion and may lower the likelihood of needing a manipulation procedure to address stiffness, though most patients still need supervised physical therapy alongside it.
Unassisted Movement
Attempting to regain motion without any structured device or therapy program leaves too much room for inconsistency. Pain naturally causes people to protect the joint and move less, which can allow stiffness to develop before a formal therapy program even begins.
CPM therapy is typically used as a complement to physical therapy, not a replacement for it. The two work together, with CPM addressing early passive motion while physical therapy builds the strength and control needed for a full return to activity.
What to Expect From CPM Therapy
Before
If Dr. Mattalino recommends CPM therapy as part of your recovery plan, he will discuss the specific device settings, expected session schedule and how the therapy fits alongside your broader rehabilitation. You will also learn whether the equipment will be used at the surgical facility, a rehabilitation center, or at home.
During
You will be positioned comfortably with your leg secured in the device. The machine moves your knee slowly and steadily through the prescribed arc, and you can typically rest, read or watch television during sessions. Some mild discomfort as the joint moves is normal, especially early on, but the therapy should not cause sharp or significant pain. Report any concerning discomfort to Dr. Mattalino’s team right away.
After
As your recovery progresses, CPM sessions are gradually reduced and eventually phased out as you transition to active physical therapy. Most patients continue building strength and range of motion through supervised exercises for several weeks to months, depending on the procedure performed. Dr. Mattalino and his team will monitor your progress at follow-up visits to confirm your knee is healing on schedule.
Preparing for CPM Therapy
If CPM therapy is part of your recovery plan, a few simple steps can help the process go smoothly.
Arrange for the device to be delivered to your home or rehabilitation facility ahead of time, if it will not be used at the surgical center. Set up a comfortable spot, such as a bed or recliner, where you can rest during sessions. Keep your post-operative instructions, pain medication and ice packs within easy reach, since sessions can run for extended periods. Ask a family member or caregiver to be available to help you get into and out of the device during the first few days.
Follow the schedule and settings recommended by Dr. Mattalino rather than adjusting the machine on your own, since this helps ensure the therapy supports your specific surgical repair. If anything about the device or your session schedule feels unclear once you are home, reach out to our office rather than guessing, as small adjustments made too early or too aggressively can affect your recovery timeline.
Who Can Benefit From CPM Therapy?
CPM therapy is most commonly recommended after surgeries where maintaining range of motion is a central part of recovery. Dr. Angelo Mattalino may recommend CPM therapy after:
- Total or partial knee replacement, where regaining flexion and extension quickly supports a smoother return to daily activity. Total knee replacement is one of the most frequently performed orthopedic procedures in the country, with roughly 790,000 performed in the United States each year, according to the American College of Rheumatology.
- Complex knee arthroscopy procedures, including cartilage restoration or ligament reconstruction, where prolonged stiffness could interfere with the surgical repair.
- Cases where a patient has a history of developing scar tissue or motion loss after previous joint procedures.
Not every knee surgery calls for CPM therapy, and Dr. Mattalino will determine whether it is appropriate for you based on your specific procedure, your baseline mobility and your overall recovery goals.
Frequently Asked Questions About CPM Therapy
Is CPM therapy painful?
Some mild discomfort during the earliest sessions is common, particularly as the arc of motion increases. The therapy is designed to work within a comfortable range, and settings can be adjusted if movement becomes too uncomfortable. Sharp or significant pain should always be reported right away.
How long will I need to use the CPM machine?
This depends on the procedure performed and how your knee responds to therapy. Some patients use the device for just a few days, while others continue for a few weeks. Dr. Mattalino will provide a specific schedule based on your surgery and recovery progress.
Can I use CPM therapy instead of physical therapy?
No. CPM therapy addresses passive range of motion, while physical therapy builds the strength, balance and control needed for a full recovery. The two are typically used together rather than as substitutes for one another.
Will I need to rent or purchase a CPM machine?
In most cases, the device is rented rather than purchased, and arranged through a durable medical equipment supplier once Dr. Mattalino prescribes it as part of your recovery plan. Depending on your insurance, some or all of the rental cost may be covered when the device is considered medically necessary for your procedure. Our team can help coordinate these arrangements and confirm the specific settings your surgery requires.
Why Choose Dr. Angelo Mattalino For CPM Therapy
With more than 25 years of orthopedic experience, Dr. Angelo Mattalino has guided patients throughout the Scottsdale and Phoenix area through every stage of knee recovery, from the initial knee arthroscopy or replacement procedure through the rehabilitation that follows. His approach centers on matching each recovery plan, including whether CPM therapy is appropriate, to the specific surgery performed and the patient’s individual healing progress.
Patients at Angelo Mattalino, M.D. receive clear guidance at every step, from the decisions made in the operating room to the therapy schedule that follows. Dr. Mattalino and his team remain closely involved throughout recovery, adjusting your plan as needed to support a smoother return to daily activity and the movement you rely on most.
Schedule Your Knee Recovery Consultation in Scottsdale, AZ
A well-planned recovery is just as important as the surgery itself. If you are preparing for knee surgery or want to understand how CPM therapy could support your recovery, Dr. Angelo Mattalino and his team are ready to walk you through your options. Contact Angelo Mattalino, M.D. today to schedule a consultation and learn more about building a recovery plan suited to your surgery and your goals.
