Curved Orthopedic Shaft for Knee Offloading During Gait
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Solution Overview
Problem
Pain or mechanical instability following knee injuries or procedures disrupts the loading response phase of the gait cycle, leading to reduced knee flexion, compensatory gait mechanics, muscle atrophy, joint stiffness, and delayed healing.
Innovation Solution
An orthopedic device with a continuous main shaft, including a superior and inferior vertical extension and a curved portion designed to mimic the maximum knee flexion angle during the loading phase, providing continuous support and offloading weight from the knee.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a subject uses compensatory gait mechanics to reduce pain and discomfort by shifting body weight towards the unaffected leg, then pain and discomfort are reduced, but muscle atrophy, joint stiffness, and altered gait mechanics occur that delay healing
Solution Approach 1:
The orthopedic device acts as an intermediary between the subject's body weight and the affected knee. The device with its specific curvature (10-20 inches radius) provides a mechanical lever arm that redistributes forces, allowing weight offloading during loading response while maintaining proper knee flexion geometry, thus preventing the harmful compensatory mechanics without requiring complete weight avoidance
Solution Approach 2:
The device changes the mechanical parameters of knee loading by introducing a curved shaft with specific radius (10-20 inches) that alters the moment arm and force distribution. This parameter change enables the knee to experience appropriate flexion angles (15-45 degrees) during loading response, transforming the harmful stiff-legged gait into a healthier movement pattern that promotes healing
2Force
If a subject exhibits reduced knee flexion during loading response phase to minimize weight on the affected leg, then weight on the affected leg is minimized, but blood flow to the injured area is reduced and healing is delayed
Solution Approach 1:
The orthopedic device serves as a mechanical intermediary that allows controlled weight acceptance on the affected leg. The curved shaft geometry (10-20 inches radius) provides a lever arm that distributes forces, enabling the knee to flex appropriately (15-45 degrees) during loading response, thereby maintaining blood flow through controlled movement while still providing protective offloading
3Object-affected harmful factors
If a subject adopts a stiffening strategy with knee flexion angle under 15 degrees during loading response phase, then pain and discomfort are reduced, but muscle atrophy and joint stiffness occur
Solution Approach 1:
The device changes the mechanical parameters by introducing a curved shaft with radius of curvature between 10-20 inches, which creates an optimal moment arm for knee flexion. This parameter change enables the knee to achieve and maintain flexion angles of 15-45 degrees during loading response, transforming the stiffening strategy into a controlled flexion pattern that maintains joint flexibility while managing pain
Solution Approach 2:
The curved portion of the main shaft (10-20 inches radius) mimics the natural arc of knee flexion during loading response. This curvature provides a mechanical guide that encourages proper knee bending geometry, replacing the straight-legged stiffening gait with a more natural, joint-friendly movement pattern that maintains flexibility
Data Source
AI summary
Disclosed herein is an orthopedic device and methods to aid in reducing weight or pressure on a portion of a subject's knee while maintaining stability and normal gait patterns following injury or surgery. Certain embodiments include a main shaft for use in an orthopedic device, wherein the main shaft includes a curved portion. In embodiments, the curved portion cures outwardly in the walking direction. The curvature can comprise a curvature that is consistent with the maximum knee flexion angle that is observed during the loading phase of the normal gait cycle. In embodiments, the device further comprises a handle portion and a foot, wherein the main shaft is disposed between the handle portion and the foot. Additional aspects include a method of promoting the healing or recovery in a subject following injury or surgery of the knee using any one or more of the orthopedic devices disclosed herein.