Knees & Ankles

The knee is the largest joint in the body and vital to movement. Due to its high use, this joint is most vulnerable to injury.

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The Flexionater can generate loads from zero to several hundred foot-pounds of torque to accommodate the specific mechanical characteristics of scar tissue found in each patient. Studies have shown success rates of more than 90 percent in patients who would otherwise have returned for surgical manipulation of flexion loss.

After knee injury or surgery, the inability to achieve motion similar to your uninjured knee is the biggest risk factor for later complications. The high-intensity ERMI Knee Flexionater® helps restore motion and function more effectively than with low-intensity devices, reducing the occurrence of reoperation and other complications.

Strong Enough to Do the Job

​More Motion, Less Time

​Cost Savings

  • Greater motion means less need for additional surgeries, use of medications, and other downstream costs.  Use of the Knee Flexionater® has been demonstrated to save more than $8,500 per patient when compared to other stretching modalities on the market.

Common procedure indications: TKA, ACL reconstruction, meniscal repair, fractures of the tibia, femur, or patella, and quad tendon repair are just some examples of motion loss cases successfully treated with the use of the Knee Flexionater®

View Device Video

Download Suggested Instructions for Use (pdf format), but make sure you follow all recommendations from your treating physician or physical therapist.



75% of people with ankle fractures develop severe stiffness (called Arthrofibrosis), limiting their ability to walk normally or perform many of the functions necessary for work or play.  The high-intensity ERMI Ankle Flexionater® has been engineered to specifically target the anatomic structures most affected by Arthrofibrosis.

  • The ankle moves in two main directions (dorsiflexion, or toes upward and plantar flexion, or toes pointing downward)
  • Loss of dorsiflexion more common, and more difficult to treat
  • Greater force needed to stretch structure like Achilles tendon, posterior capsule
  • The Ankle Flexionater®  allows for forces to be directed to the Achilles tendon, posterior capsule structures.
  • Common indications: ankles fractures, Achilles tendon repair, tibial fractures, calcaneous fractures, or any injury that results in prolonged ankle immobilization.


The ERMI Knee Extensionater is a portable, easy-to-use device that uses patented pneumatic air bladder technology to create overpressure to treat extension loss. While previous techniques involved hanging uncomfortable weights over the restricted joint, the ERMI Knee Extensionater gives patients complete control — they can add or remove load on the joint in very small increments.

The inability to straighten your knee is like having one leg shorter than the other, and can result in not only knee pain, but pain and dysfunction in your other knee, hips, or low back. The high-intensity ERMI Knee Extensionater® allows you to recreate the proper body alignment and force application used by Physical Therapists to help you increase knee motion and get back to normal function faster.

View Device Video

Download Suggested Instructions for Use (pdf format), but make sure you follow all recommendations from your treating physician or physical therapist.