Closed Chain Rehabilitation Device for Lower Extremity Joint Mobility
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Solution Overview
Problem
Current rehabilitation devices for lower extremity joints after surgery, such as knee and hip replacements, often use open chain motions that are counterproductive and cause patient apprehension due to lack of control, leading to ineffective therapy and increased pain.
Innovation Solution
A rehabilitation device that employs a closed chain motion, allowing patients to control the mobilization of their joints through a seated position with a fixed foot, mimicking natural knee, hip, and ankle flexion, reducing friction and patient apprehension by enabling patient-driven force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open chain motion is used in rehabilitation devices, then the device structure is simpler, but the therapy effectiveness deteriorates and patient apprehension increases
Solution Approach 1:
The patent inverts the traditional open-chain motion approach by implementing closed-chain motion where the foot is fixed and the seat moves, reversing the conventional rehabilitation mechanism to better replicate natural joint mechanics and improve therapy effectiveness
Solution Approach 2:
The device copies natural lower extremity mechanics by recreating the closed-chain motion pattern of squatting and natural knee flexion, where the femur and tibia roll on each other, rather than using artificial sliding motion
2Extent of automation
If therapist-controlled mobilization is used, then the therapy can be standardized, but patient control and comfort deteriorate
Solution Approach 1:
The device enables self-service rehabilitation by allowing patients to control their own mobilization through the drive mechanism, eliminating the need for therapist control and giving patients direct control over the therapy process, which reduces apprehension and improves comfort
3Device complexity
If sliding motion of tibia around femur is used, then the device mechanism is simpler, but the natural joint mechanics are not replicated
Solution Approach 1:
The patent inverts the motion mechanism by fixing the foot and allowing the seat to move, which reverses the motion pattern from artificial sliding to natural rolling motion of the knee joint, accurately replicating how the femur and tibia interact during natural flexion
Data Source
AI summary
A lower extremity mobilizer for use in rehabilitation is provided. A seat is slidably maintained upon a base, with a foot support brace being provided at an end of the base to receive the foot of a leg provided for arthrokinematic treatment. A cord and pulley system is provided between the seat and the end of the base. In use, a patient is seated with a foot received by the foot support brace. The patient provides arthrokinematic motion to his leg by pulling himself and the seat toward the end of the device having the foot support brace. The procedure is undertaken in a closed chain motion, with the foot constantly engaging the foot support brace, and is done so as a rate, timing and extent under the control of the patient.