Nina Dobrev Uses Controversial CPM Machine To Heal Knee Injury

In a series of slide posts on her Instagram story, Nina Dobrev shared an update on her recovery from knee surgery earlier this month.

“Eat. Sleep. CPM machine. Physical therapy. Repeat,” she posted, with a photo of her eating waffles and a smoothie in bed.

In a smaller font at the bottom of her story post, Nina added, “If you’ve had this injury you know what a CPM is…the rest of you won’t.”

Nina is referring to her injury from a dirt bike accident in May. She underwent surgery earlier this month to repair a fractured knee, her meniscus and her ACL.

Here’s more about the machine Nina is using for her recovery and how it could help heal knee injuries.

What is a CPM machine?

A CPM machine, or a continuous passive motion machine, is “a motorized device that passively moves a joint through a pre-set range of motion,” according to Healthline.

CPM devices are used after surgery to reduce joint stiffness and improve range of motion, Healthline reports. The machine is often used as part of rehabilitation after knee surgery. But can also be used following surgery in other joints, like the elbow, hip or shoulder. The goal of the machine is to prevent joint stiffness, control pain, reduce inflammation, improve range of motion and help the joint heal properly.

The therapy is called passive because you let the machine do the work, per Verywell Health.

The machine can be used in the hospital or at home, per Healthline says. It is used while lying down, either in bed or on another comfortable surface.

The machine often comes with a remote control that allows the user to set the extension and flexion limits, as well as the speed. There are multiple knobs and straps that allow users to fit the machine to their leg. The device can also be set to different speeds and ranges of motion.

What does a CPM machine do to help heal knee injuries?

Joint stiffness is a common concern after surgeries, since it can cause scar tissue to build up and permanently impair range of motion.

CPMs help restore the range of motion of a joint to its pre-treatment level and prevent scarring that can result in a loss of joint mobility, Verywell Health explains.

However, the use of CPM is somewhat controversial. Recent studies have shown little to no impact on patients who use the devices post-op. A 2014 study found that patients who used CPM use after surgery to repair intra-articular knee fractures saw little to no benefit. The American Physical Therapy Association even recommended avoiding CPM machines after total knee replacements.

Other studies show some positive results. A 2019 study showed patients who received CPM treatment were less likely to need a second surgery to break up scar tissue in the six months following surgery.

If you are undergoing surgery that may warrant the use of a CPM device, speak with your doctor to discuss if a CPM machine could have benefits to your recovery process.

How did Nina Dobrev hurt her leg?

In an appearance on The Talk on June 12, Nina said she had an accident when trying out a dirt bike for the first time.

Nina said she was “in a wheelie, lost control, whisky throttled, and the bike flew.”

“Luckily it didn’t fall on me, which is what the doctor said would have been a lot worse. But when I landed, I landed on one leg, straight, and my knee just, like, snapped.”

She first shared the news of her injury in a Instagram post on May 20 captioned “how it started vs how it’s going 🤕”. The first slide shows Nina on the dirt bike, and the second shows her in a hospital gown with an IV, blood pressure cuff and neck and leg braces.

Nina’s appearance on The Talk was her first public appearance in two months. she told the hosts she still “can’t really walk” on her own yet.

“Cuddle puddle is my life these days,” she said. “It’s just the puppies, and at home watching movies, physical therapy, eat, sleep or pee is kind of the schedule.”


Sela Breen (she/her) is the 2024 summer editorial intern at Women’s Health. She is a rising senior at Northwestern University, where she studies journalism, international studies and theatre. She previously interned at Dotdash Meredith, worked on the Northwestern campus magazine and contributed to the Northwestern Medill Investigative Program.


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