Pivotable Cut Guide Alignment for Knee Arthroplasty
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Solution Overview
Problem
Existing extramedullary cut guide alignment systems for knee arthroplasty face challenges in adjusting the angular orientation of the cut guide without introducing bending stresses in the assembly, limiting flexibility and precision during surgical procedures.
Innovation Solution
The extramedullary cut guide alignment assembly features a pivotably mounted proximal fixation arm, allowing for adjustments in the angular orientation of the cut guide relative to the tibia without forcing spikes deeper into the bone, thus avoiding bending stresses. This is achieved through a flexible coupling assembly that maintains the angular orientation of the fixation arm while allowing the cut guide to be adjusted freely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the angular orientation of the cut guide is adjusted during surgery, then flexibility and precision of alignment are improved, but bending stresses are introduced in the assembly
Solution Approach 1:
The fixation arm is made pivotably mounted to the body instead of being rigidly fixed, allowing dynamic adjustment of angular orientation. The pivotable coupling enables the fixation arm to rotate relative to the body, accommodating changes in angular orientation without transmitting bending stresses through the entire assembly.
Solution Approach 2:
A pivotable coupling mechanism acts as an intermediary between the fixation arm and the body. This coupling allows relative rotation and accommodates angular adjustments while preventing the transmission of bending stresses from the cut guide adjustments to the fixation spikes in the bone.
2Measurement precision
If the cut guide angular orientation is changed, then alignment precision is improved, but spikes are forced deeper into the bone
Solution Approach 1:
The pivotable fixation arm allows the system to dynamically adjust during the alignment process. When the cut guide angular orientation is changed, the fixation arm can pivot independently, preventing the transmission of forcing forces to the spikes already embedded in the bone.
Solution Approach 2:
The pivotable coupling serves as a mechanical intermediary that decouples the adjustment movements from the fixation points. It allows angular orientation changes to be accommodated through controlled rotation at the pivot joint rather than forcing the spikes deeper into the bone.
3Stability of the object's composition
If a rigid fixation arm is used, then structural stability is improved, but adjustment flexibility is reduced
Solution Approach 1:
The system transitions from a rigid fixation arm to a pivotable fixation arm that combines structural stability with rotational flexibility. The pivotable coupling maintains structural integrity while enabling angular adjustments, allowing the fixation arm to remain stable during use but flexible during alignment adjustments.
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
The solution enables precise and flexible alignment of the cut guide, reducing bending stresses and facilitating smooth, precise resections by maintaining the original angular orientation of the fixation arm during adjustments, thereby improving the accuracy and efficiency of the surgical process.
Implementation Method 1
The pivotable coupling allows for adjustments in the angular orientation of the cut guide relative to the tibia without forcing spikes deeper into the bone
Data Source
AI summary
An extramedullary cut guide alignment assembly allows various adjustments to the cut guide without introducing bending stresses in the rest of the assembly. More particularly, the angular orientation of the cut guide with respect to the tibia may be freely changed during use, while maintaining the angular orientation of the proximal fixation arm of the alignment assembly with respect to the proximal tibial surface to which the arm is affixed. To achieve this decoupling of the angular orientations of the fixation arm and cut guide, the proximal fixation arm is pivotably mounted to the cut guide alignment assembly. Thus, the alignment assembly may be adjusted as necessary to achieve a desired angular orientation of the cut guide mounted thereto, while the pivotable junction between the alignment assembly and the proximal fixation arm automatically adjusts to accommodate the changing angular arrangement.