Adjustable Hip Trial Head for Precise Femoral Offset Selection
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Solution Overview
Problem
The current method of determining the desired offset between the femoral head and femoral stem in hip arthroplasty involves multiple trials, leading to complex, time-consuming procedures that disrupt tissue and require frequent relocation of the hip joint.
Innovation Solution
A hip arthroplasty trial system comprising a head member, spacer, shaft, and locking member, allowing for adjustable positioning and secure attachment to achieve the desired offset without repeated assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple head length options are individually trialed to determine the desired offset, then the desired offset can be accurately determined, but the procedure becomes complex and time-consuming with repeated hip relocation
Solution Approach 1:
The trial system is divided into modular components: a femoral stem, a trial head with adjustable neck, and an offset indicator mechanism. The neck can be segmented into different length positions, allowing precise adjustment of the head-to-stem offset without requiring multiple complete trial assemblies. The offset indicator separates the measurement function from the structural components.
Solution Approach 2:
The trial head assembly serves multiple functions: it provides structural support for the hip joint, allows adjustment of neck length to achieve different offsets, and incorporates an offset indicator mechanism. This multi-functional design eliminates the need for separate trial instruments for each head length option, reducing procedural complexity while maintaining measurement precision.
2Measurement precision
If multiple head length options are individually trialed, then the desired offset can be determined, but the procedure time increases significantly
Solution Approach 1:
The offset indicator mechanism is pre-configured on the trial head assembly, allowing the surgeon to visually determine the offset measurement before finalizing the head-to-stem configuration. This preliminary indication eliminates the need for time-consuming measurements and calculations after each trial assembly, enabling faster decision-making while maintaining precision.
Solution Approach 2:
The trial neck is designed with dynamic adjustability, allowing the surgeon to change neck length positions during a single trial procedure. This dynamic adjustment capability replaces the static, time-consuming process of assembling and disassembling multiple trial heads with different fixed lengths, significantly reducing trial procedure time while maintaining the ability to determine the desired offset accurately.
3Measurement precision
If multiple head length options are individually trialed with repeated assembly and disassembly, then the desired offset can be determined, but tissue disruption increases
Solution Approach 1:
The trial system allows the surgeon to perform a partial trial by adjusting the neck length position on a single assembled trial head, rather than requiring complete disassembly and reassembly for each head length option. This partial adjustment approach minimizes the number of times the hip joint must be fully relocated and repositioned, reducing tissue disruption while maintaining the ability to determine the desired offset through the offset indicator.
4Productivity
If a single trial system is used with adjustable positioning, then procedural complexity and time are reduced, but the mechanism becomes more complex
Solution Approach 1:
The offset indicator mechanism is nested within the trial head assembly, with the indicator components integrated into the existing structural elements. The neck adjustment mechanism is nested within the trial head, allowing multiple functions (structural support, length adjustment, offset indication) to be combined in a compact configuration. This nesting reduces the overall number of separate components and simplifies the assembly process, improving productivity without excessive increase in device complexity.
Data Source
AI summary
Hip arthroplasty trial systems and associated medical devices, methods, and kits are described that can be utilized in situ to complete a femoral head trial. An example embodiment of a hip arthroplasty trial system includes a medical device and a femoral stem. The medical device has a head member, a spacer, a shaft, and a locking member. The spacer is disposed within the head member and is moveable from a first position to a second position. The shaft is disposed within the head member and contacts the femoral stem. The shaft is moveable from a first position to a second position. Movement of the shaft from the first position to the second position moves the spacer from its first position to its second position. The locking member is disposed within the head member and releasably attaches the shaft to the head member.