Robotic technology (ROBERT^®) to enhance muscle strength in the hip flexor muscles following spinal cord injury: a feasibility study

Study design: Feasibility study. Objective: To determine the feasibility of conducting a large trial designed to determine whether the ROBERT^® can be used to increase the strength of the hip flexor muscles after spinal cord injury (SCI). The ROBERT^® is a robotic device that provides assisted active movement while supporting the weight of the leg. Focus was on recruitment capability, suitability, and acceptability of the intervention and outcome measure. Setting: Specialised SCI centre in Denmark. Methods: All first-time admitted patients were screened to assess participant recruitment capability. Four people with SCI < 3 months tested a protocol consisting of 60 repetitions of hip flexion in supine conducted with the assistance of the ROBERT^® three times a week for 4 weeks. Feasibility was assessed based on adherence to the protocol and completion rate and from the participants’ perspectives. Maximal voluntary contraction (MVC) was accessed at baseline and four weeks. Results: The recruitment rate was 8% (7 months). The four participants completed 44 out of 48 sessions (92%). No adverse events occurred. One physiotherapist was required to set-up and supervise each session. The active exercise time varied from 7.5 to 17 min. The participants found the ROBERT^® a good supplement to their usual rehabilitation. We were able to measure MVC in even very weak hip flexor muscles with a dynamometer MicroFET2 fixed to a frame. Conclusion: The ROBERT^® was feasible and acceptable. The participants perceived it as a supplement, not a replacement to usual physiotherapy. However, recruitment to the study was slow. Trial registration: ClinicalTrials.gov NCT05558254. Registered 28th September 2022.