Feasibility study for a controllable orthotic knee joint.

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Orthotics and Prosthetics

Background:

• Severely disabled patients often require advanced orthotic devices for mobility.
• Reciprocating gait orthoses (RGOs) can aid ambulation but require robust knee joint mechanisms.
• Existing orthotic knee joints may not adequately withstand biomechanical forces during gait.

Purpose of the Study:

• To demonstrate the feasibility of an orthotic knee joint with lock/unlock capabilities for RGOs.
• To develop a knee joint suitable for severely disabled individuals, including those with paraplegia.
• To assess the potential of a novel braking mechanism for enhanced orthotic function.

Main Methods:

• Designed and manufactured three prototype orthotic knee joints with integrated braking systems.
• Subjected prototypes to bench trials to evaluate performance against a 73 Nm sagittal plane bending moment.
• Compared the efficacy of different braking mechanisms under simulated biomechanical stress.

Main Results:

• All three prototype joints successfully sustained the required bending moments.
• The hydraulic disc brake system demonstrated superior performance compared to other designs.
• The hydraulic system was selected for further, more detailed testing.

Conclusions:

• A hydraulic braking mechanism is feasible for orthotic knee joints, capable of withstanding walking-induced knee flexion moments.
• This technology provides confidence for developing RGOs for patients with severe neurological dysfunction.
• The findings support the progression to prototype design for advanced lower limb orthoses.