Expandable Reverse Shoulder Trial Liner for Soft Tension Calibration
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Solution Overview
Problem
Current reverse shoulder arthroplasty systems require extreme force for joint reduction and dislocation, risking tissue injury and using a trial-and-error approach for proper soft tissue tension, which is inefficient and potentially harmful.
Innovation Solution
An expandable trial system with a rotatable insert that engages a humeral cup, allowing for adjustable liner thickness calibration to achieve optimal deltoid tension, facilitating easier joint reduction and dislocation while minimizing tissue trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed trial liner is used for reverse shoulder arthroplasty, then the joint can be reduced, but extreme force is required and multiple trial-and-error attempts are needed to achieve proper soft tissue tension
Solution Approach 1:
The trial liner is made expandable through a rotatable insert mechanism with cam tracks, allowing the liner thickness to be dynamically adjusted during surgery. This enables the surgeon to start with a collapsed state for easy joint reduction, then expand to the optimal thickness for proper soft tissue tension without requiring extreme force or multiple attempts.
2Measurement precision
If multiple trial liners of different thicknesses are used to achieve proper soft tissue tension, then optimal deltoid tension can be found, but surgical time increases and the instrument set size and cost increase
Solution Approach 1:
The trial liner is segmented into a base liner and a rotatable insert that can be independently adjusted. The insert features cam tracks with incremental positions that allow precise control of liner thickness. This segmentation enables a single trial component to replace multiple fixed-thickness liners, providing precise soft tissue tension adjustment while reducing surgical time and instrument set requirements.
3Measurement precision
If multiple trial liners of different thicknesses are used, then optimal liner thickness can be determined, but the risk of tissue injury from repeated reduction attempts increases
Solution Approach 1:
The expandable trial liner allows the surgeon to begin with a collapsed state that facilitates easy joint reduction with minimal force, then progressively expand to the optimal thickness for proper soft tissue tension. This eliminates the need to repeatedly dislocate and reduce the joint with different fixed-thickness liners, significantly reducing the risk of tissue injury while maintaining precise liner thickness selection.
4Device complexity
If a fixed thickness trial liner is used, then the instrument set can be simple, but the surgeon must use trial and error to find the correct liner thickness
Solution Approach 1:
The expandable trial liner with rotatable insert serves multiple functions: it acts as both a collapsed trial component for easy joint reduction and an expanded trial component for precise soft tissue tension assessment. This single universal component replaces the need for multiple fixed-thickness liners, maintaining instrument set simplicity while dramatically improving the efficiency of the trialing process.
Data Source
AI summary
Described herein is an expandable shoulder trial for a reverse shoulder system including a rotatably adjustable insert housed within a humeral cup. The insert has proximal and distal ends, the proximal end having a concave recess therein adapted to receive a glenosphere prosthesis. The distal end of the insert includes a shaft, the shaft having a helical groove disposed on at least a portion thereof. A distal end of the humeral cup is inserted in a humeral stem. The humeral cup has a proximal end including a recess therein, the recess defined by a circular wall. A guide pin protrudes from the circular wall and is adapted to engage the helical groove of the insert shaft. The proximal end of the insert may rotate along an axis toward the proximal end of the humeral cup and along the same axis away from the proximal end of the humeral cup.