European Union of Private Hospitals

EPHA Awards finalists 2022 – Model of clinical innovation – Hospital Universitario la Zarzuela HULZ Aravaca in Madrid

Clinical study on Knee rehabilitation after arthroplasty with a robotic exoskeletons

The Hospital Universitario la Zarzuela HULZ Aravaca in Madrid conducted a study to assess the safety and efficacity of a rehabilitation therapy with a monoarticular exoskeleton for patients who have undergone knee arthroplasty.

  • The use of robotic exoskeletons for knee rehabilitation after arthroplasty is a new avenue of rehabilitation treatment for this type of patient.
  • There are a growing number of studies in the literature on the effects of the use of exoskeletons in the clinical setting of gait support or rehabilitation of various pathologies.
  • About 75,000 knee replacements are performed in Spain every year.
  • The most frequent cause of total knee replacement is to relieve the pain caused by wear and tear or advanced osteoarthritis, which incapacitates patients from carrying out their activities of daily living.
  • The Hospital Universitario la Zarzuela HULZ Aravaca in Madrid (100 beds) perform approximately 80 to 100 prostheses each year.


The study demonstrated that rehabilitation with the Exoskeleton in immediate postoperative knee replacement patients is safe, effective (healing, swelling and mobility), fast (12 sessions) and painless.

One month after surgery, an evaluation was performed consisting of measuring the participant’s walking and balance ability (6MWT 6 Minutes Walking Test, FAC Functional Ambulation Categories and TUG Time Up and Go), the biomechanical and inflammatory properties of the operated knee (ROM Joint Range, BM Muscle Balance and perimeter) as well as the user’s perception of the device (QUEST 2.0).

On walking and balance, patients were able to walk an average of 238.7 metres in 6 seconds one month after the intervention. On balance, participants obtained an average of 18.8 seconds to complete the test. On the FAC scale, a score of 4 out of 5 meant that patients are able to move on most terrains, needing assistance to go up and down stairs and ramps.

Biomechanical and inflammatory properties of the knees were measured by knee and quadriceps circumference, joint range with all patients achieving full extension 0 degrees and flexion between 95 and 120 degrees. The BM muscle balance, both in flexion and extension of the knee was 4 out of 5.

The user’s perception of the device by means of the QUEST 2.0 scale, to the general question about the level of satisfaction was 4.6 out of 5, so the evaluation was positive.

View the full study report