Feasibility study for a controllable orthotic knee joint

Purpose. The purpose of this study was to demonstrate the feasibility of producing an orthotic knee joint that could lock andunlock during ambulation for eventual use in a reciprocating gait orthosis (RGO) for severely disabled patients.Method. Three prototype orthotic knee joints incorporating braking mechanisms were designed and manufactured todemonstrate their ability to withstand a maximum calculated sagittal plane bending moment of 73 Nm. Each was thensubjected to bench trials to test their performance against the required specification.Results. Although all three joints achieved the requirement to sustain the specified externally applied bending moments, thehydraulic disc brake system proved significantly superior and was selected for more comprehensive testing.Conclusions. The results confirmed the feasibility of utilising a hydraulic braking mechanism within an orthotic knee joint towithstand the knee flexing moments during walking in a lower limb orthosis. This gave the development group confidence toprogress to the prototype design phase with the specific aim of eventually incorporating such a joint in an RGO designed forseverely disabled patients such as those with complete paraplegia up to level T4 and those with severe neurologicaldysfunction