Development of a Knee Actuated Exoskeletal Gait Orthosis for Paraplegic Patients with Incomplete Spinal Cord Injury: A Single Case Study

Abstract

Gait training for paraplegic patients is effective in preventing various complications due to prolonged sitting. In these patients, the use of powered exoskeletal-gait-orthosis (EGO) consumes lower energy than traditional training methods using non-powered EGO, such as a reciprocating-gait-orthosis (RGO). Thus, long-term training is possible and effective in increasing the activity level of the trunk muscles. However, more than 60% of paraplegic patients have incomplete injuries with residual function, which is inversely related to the functional role of the orthosis. We hypothesized that the gait ability in incomplete paraplegia could be improved by knee joint activation, and we developed a lightweight knee-actuated EGO (KAEGO). We verified its effectiveness in one patient with an incomplete spinal cord injury by comparing the metabolic cost of transport (COT) measured by a six minute walk test to a traditional non-powered EGO. We found that with increasing assist torque to the knee joint, the COT decreased by up to 24.5%, and the gait performance, including walking speed and travel distance, significantly improved up to 37% compared to that of the non-powered EGO. Future studies should verify the KAEGO system’s effectiveness in a larger number of patients with various injury levels.

Keywords

• exoskeletal gait orthosis
• reciprocating gait orthosis
• spinal cord injury