Micro CPM Machine for High-Frequency Short-Arc Knee Motion
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Solution Overview
Problem
Existing constant passive motion (CPM) machines primarily focus on slow, long-arc motion, which may not optimally promote joint health through high-frequency short-arc movement, and often limit movement to a single plane, neglecting the benefits of multi-planar motion.
Innovation Solution
A micro CPM machine designed for high-frequency short-arc movement, incorporating sliding, translational, and rotational mechanisms to facilitate movement in multiple planes, utilizing motors, belts, and pivot systems to achieve dynamic support and oscillation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional CPM machines use slow long-arc motion, then full ROM is established, but high-frequency short-arc movement needed for optimal joint health is not achieved
Solution Approach 1:
The patent implements a dynamic motion delivery system that can adapt between slow long-arc and high-frequency short-arc motion patterns. The motor assembly with adjustable speed and the linkage mechanism enable the device to transition between different motion regimes, allowing optimization for specific joint healing phases rather than being fixed to one pattern.
Solution Approach 2:
The device employs periodic high-frequency oscillatory motion through the motor assembly that drives the linkage mechanism to create repeated short-arc movements. This periodic action at high frequency (e.g., 1-10 Hz) provides the vibratory and oscillatory stimulation needed to promote joint health, cartilage regeneration, and prevent adhesions, while maintaining a controlled motion arc through the mechanical linkage.
2Adaptability or versatility
If CPM machines limit motion to a single plane, then device complexity is reduced, but multi-planar motion benefits for joint health are neglected
Solution Approach 1:
The motor assembly and linkage mechanism are designed to deliver motion in multiple planes simultaneously or sequentially. The motor can drive the linkage to produce motion in the sagittal plane (flexion/extension), coronal plane (abduction/adduction), and transverse plane (internal/external rotation), making a single device capable of providing comprehensive multi-planar motion for various joint types without requiring separate machines for each plane.
Solution Approach 2:
The patent extends motion from a single-plane limitation to multi-planar capability by designing the linkage mechanism to accommodate movement in three-dimensional space. The motor assembly positioned and oriented to drive the linkage can induce rotational and translational components in multiple directions, adding dimensional complexity to the motion output and enabling comprehensive joint rehabilitation.
3Reliability
If high-frequency short-arc motion is applied, then joint lubrication and blood flow improve, but control of motion parameters becomes more difficult
Solution Approach 1:
The device incorporates feedback mechanisms through the motor assembly that can sense and adjust motion parameters in real-time. The motor controller receives feedback signals to maintain desired frequency, amplitude, and duration of the high-frequency short-arc motion, ensuring consistent delivery of therapeutic parameters while compensating for variations in joint response and patient positioning.
Solution Approach 2:
The patent replaces purely mechanical motion control with an electromechanical system where the motor assembly provides precise electronic control of motion parameters. The motor controller can programmatically adjust frequency, amplitude, and pattern of motion, substituting mechanical adjustment mechanisms with electronic control that offers greater precision and ease of parameter modification for optimizing joint health effects.
Data Source
AI summary
A micro constant passive motion machine for applying short arc constant passive motion to a knee joint of a user includes a base member and a sliding member secured to the base member so as to permit sliding, translational movement of the sliding member relative to the base member. The machine further includes a leg receiving member secured to the sliding member, and one or more motors. The machine further includes a primary rotative component whose rotation is configured to effect, via a connection strut secured to the primary rotative component and the base member, short arc sliding, translational movement of the sliding member relative to the base member. The machine still further includes a second rotative component whose rotation is configured to effect, via a pivot member, continually alternating rotation of the leg receiving member.