Efficacy of a newly designed trunk orthosis with joints providing resistive force in adults with post-stroke hemiparesis

Background: Few studies have examined the efficacy of trunk orthoses that support the upper trunk and a paretic limb in stroke patients. To improve stability and alignment of the trunk and pelvis in hemiparetic patients, we developed a newly designed trunk orthosis that provides resistive force through spring joints. Objectives: This study aimed to determine the newly designed trunk orthosis's biomechanical effects during level walking. Study design: Before-after trials must be better. Methods: Measurements were taken for nine chronic-phase (>2years post-onset) stroke patients using a three-dimensional motion capture system and force plates under three experimental conditions: self-selected gait speed without the newly designed trunk orthosis, with the newly designed trunk orthosis, and after newly designed trunk orthosis removal. We analyzed and compared spatiotemporal and kinetic parameters of the paretic and non-paretic limbs and kinematic parameters of the trunk and bilateral limbs. Results: Several pre-swing gait parameters (e.g. hip joint flexion moment and ankle joint plantar flexion angle) after newly designed trunk orthosis removal were significantly increased compared to those without newly designed trunk orthosis. Step length of the paretic limb tended to increase after newly designed trunk orthosis removal. Conclusion: The newly designed trunk orthosis effectively modified trunk alignment, but larger improvements in kinetic and kinematic parameters were observed in the bilateral limbs after newly designed trunk orthosis removal than with the newly designed trunk orthosis. Clinical relevance Stroke patients improved only trunk malalignment while wearing the newly designed trunk orthosis. Gait after newly designed trunk orthosis removal was better than with the newly designed trunk orthosis. Positive changes after removal were mostly observed in pre-swing of the hemiparetic limb. The newly designed trunk orthosis might be effective for gait training in stroke patients.