Microfracture Device Guide Shaft Curved Tip Stabilization
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Solution Overview
Problem
Current microfracture procedures for resurfacing damaged articular cartilage in joints, such as the ankle, knee, and hip, face challenges in creating precise channels in subchondral bone to stimulate fibrocartilage growth, often resulting in less durable fibrous cartilage with higher friction coefficients compared to hyaline cartilage.
Innovation Solution
A microfracture device comprising a guide shaft with a curved tip and stabilizing portion, along with a flexible element, is designed to create channels in subchondral bone, allowing for precise positioning and orientation to stimulate fibrocartilage growth, featuring a handle for controlled movement and rotation to enhance channel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sharp microfracture pick is driven through subchondral bone to create channels for blood supply, then fibrocartilage growth is stimulated, but the procedure lacks precision in positioning and orientation
Solution Approach 1:
A guide shaft is introduced as an intermediary device to precisely position and orient the flexible microfracture element. The guide shaft includes a stabilizing portion that contacts the bone surface and a curved tip region with an angled tip that directs the flexible element at the correct angle into the subchondral bone, ensuring accurate channel placement without requiring complex overall device structure
Solution Approach 2:
The device is divided into distinct functional segments: a stabilizing portion for positioning, a curved tip region for angulation, and a flexible element for channel creation. This segmentation allows each component to perform its specific function independently, achieving precise channel positioning while keeping the overall device structure manageable and not overly complex
2Reliability
If the damaged cartilage layer is removed to stimulate fibrocartilage growth, then pain is reduced, but the resulting fibrous cartilage has higher friction coefficient than hyaline cartilage
Solution Approach 1:
The procedure changes the physical parameters of the cartilage surface by removing damaged hyaline cartilage and stimulating regeneration. While the friction coefficient inherently increases with fibrocartilage formation, the parameter change achieves the primary goal of pain reduction and functional improvement, accepting the friction trade-off as necessary for clinical benefit
3Adaptability or versatility
If a flexible element is used to create microfracture channels, then the device can navigate curved paths, but control over channel orientation becomes difficult
Solution Approach 1:
The guide shaft acts as an intermediary that provides the missing orientation control for the flexible element. The stabilizing portion of the guide shaft contacts the bone surface to establish a reference position, while the curved tip region with its angled geometry directs the flexible element at the desired angle, mediating between the flexibility needed for navigation and the control needed for orientation
Solution Approach 2:
The curved tip region of the guide shaft is specifically designed with a radius of curvature that allows the flexible element to follow a controlled arc as it exits the guide shaft. This curvature enables the flexible element to navigate around obstacles while maintaining a predictable and controllable orientation, combining navigation flexibility with directional control
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A microfracture device comprising a guide shaft having a proximal end and a distal end and defining an internal passage between the proximal and distal ends, the distal end having a curved tip, a stabilizing portion disposed along an outer surface of the guide shaft, at least a portion of the stabilizing portion being wider than the guide shaft, and a flexible element movably positioned within the internal passage of the guide shaft, the flexible element having a distal tip configured for driving into bone.