Enhancing mobility with knee orthoses: Design considerations and patient needs through case study

Knee orthoses are critical in many conditions from pain due to arthritis to knee instability during sports.However, there are very serious challenges regarding usability, comfort, and aesthetics in designing knee orthoses.This paper takes a design approach for the knee orthosis specifically targeted toward arthritis patients and young athletes.From these requirements, it became imperative to have a lightweight, skin-friendly device capable of providing real-time feedback through embedded sensors.A bi-modal methodology was adopted: theoretically, the leg and spring fixtures were modeled in SOLIDWORKS to compute muscle forces with and without the use of orthosis; experimentally, three sets of springs and a brace were manufactured and tested.Kinematic and kinetic data were captured using the G-Walk system; EMG measurements were used to evaluate upper leg muscle activity in controlled tests.This study compared knee braces with spring wires of diameters 1.6 mm, 2.0 mm, and 2.25 mm against an unbraced condition during the Squat Jump Test performed with the G-Walk system.All braced conditions reduced dynamic performance; flight height, center of mass, and average concentric speed was reduced by up to 15%, 20%, and 40% respectively.Kinetic analysis indicated stable takeoff force, lower impact force by 10%, and coupled reduction of eccentric phase rate by 80% with increase in concentric phase by 300%.Increased brace stiffness resulted in lower Quadriceps and Patella forces; EMG data indicated the 2.0 mm brace as providing the optimal balance.Some discrepancies were noted against theoretical models.