Universal Positioning Block for Knee Surgery
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Solution Overview
Problem
Current surgical guide blocks used in total knee replacement surgery face challenges in sterilization due to complex mechanisms that prevent easy cleaning, and they lack sufficient flexibility for precise adjustments, particularly in computer-assisted surgery (CAS) systems.
Innovation Solution
A universal positioning block with five degrees of freedom, featuring a rotatable mounting element and adjustable translation mechanisms, along with a disengageable pawl mechanism for easy cleaning and autoclaving, allowing precise alignment and movement relative to the bone element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex mechanisms are used in surgical guide blocks to enable precise adjustments, then positioning precision is improved, but ease of cleaning and sterilization deteriorates
Solution Approach 1:
The surgical guide block is divided into multiple independent components including a positioning body, a mounting element, and a disengageable pawl mechanism. This segmentation allows each component to be cleaned separately and facilitates complete disassembly for sterilization, while maintaining precise positioning capabilities through the coordinated function of these separated elements.
Solution Approach 2:
The guide block incorporates dynamic elements such as the disengageable pawl mechanism that can be moved between engaged and disengaged states. This dynamic design allows the mechanism to transition from a locked precise positioning state during surgery to an unlocked easily cleanable state for sterilization, resolving the contradiction between precision and ease of cleaning.
2Reliability
If fixed mechanisms are used in guide blocks to ensure stability, then reliability is improved, but adaptability to different implant types and surgical steps deteriorates
Solution Approach 1:
The guide block is designed with universal features including multiple degrees of freedom (five degrees of freedom through rotational mounting and translational adjustment) that allow it to accommodate various implant types and surgical procedures. The disengageable pawl mechanism enables the same guide block to be used across different surgical steps by allowing repositioning and reconfiguration, maintaining reliability while achieving versatility.
Solution Approach 2:
The guide block transitions from a fixed rigid structure to a dynamic adjustable system that can be positioned and oriented in multiple configurations. The disengageable pawl allows the mechanism to be locked in specific positions for stability during use, yet easily repositioned for different implant types and surgical steps, resolving the contradiction between reliability and adaptability.
3Reliability
If complex mechanisms are used to prevent bacterial buildup, then reliability is improved, but ease of cleaning deteriorates
Solution Approach 1:
By segmenting the guide block into separable components with the disengageable pawl mechanism, each part can be thoroughly cleaned and sterilized independently. This segmentation eliminates hidden crevices and complex internal mechanisms where bacteria could accumulate, maintaining reliability while significantly improving ease of cleaning compared to integrated fixed designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances surgical precision and simplifies procedures by enabling easy cleaning and adjustment, reducing the risk of bacterial buildup while accommodating various implant types and surgical steps in total knee replacement surgeries.
Implementation Method 1
an elastically deflectable blade spring, the blade spring biasing one of the rack and the pawl such that they are normally engaged together
Data Source
AI summary
A positioning block (10) for use in total knee replacement surgery, permitting five degrees-of-freedom movement relative to a bone element (39) to which it is fixed. The positioning block (10) comprises a rotational mounting element (14) that is removably engaged to the bone element such that the mounting element (14) is selectively rotatable relative to the bone element, about three substantially perpendicular axes of rotation. A guide body portion (12) is engaged with the mounting element (14) such that it is translatable relative thereto along a proximal-distal axis (43) and an anterior-posterior axis (47), while being rotationally fixed relative to the mounting element (14) such that the guide body portion (12) and the mounting element (14) rotate together relative to the bone element (39).