Glenosphere Guide Tool for Shoulder Implant Alignment
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Solution Overview
Problem
In shoulder implant surgeries, particularly with reverse shoulder systems, accurately positioning and securing the glenoid implant on the scapula is challenging due to the presence of soft tissues and the thinness of the scapula, requiring precise alignment and depth of screws without damaging surrounding nerves, ligaments, or tendons.
Innovation Solution
A glenosphere helper device is introduced, which facilitates the alignment and secure mounting of the glenosphere on a baseplate using a guide pin and flange system, ensuring proper engagement with the glenoid liner component, and includes patient-specific instrumentation for precise positioning and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If screws are made deep enough within the bone material to solidly secure the implant to the scapula, then the fixation strength is improved, but the risk of piercing through the bone surface and damaging soft tissue increases
Solution Approach 1:
The guide tool serves as an intermediary device that enables precise control of screw depth and trajectory. It mediates between the need for deep fixation and the risk of soft tissue damage by providing a physical stop and alignment reference, allowing surgeons to achieve adequate fixation strength without penetrating the thin scapula and damaging surrounding nerves, ligaments, or tendons.
Solution Approach 2:
The guide tool is installed preliminarily on the glenoid implant before screw insertion. It establishes the correct screw trajectory and depth limits in advance, preventing errors during the actual fixation process. This preliminary positioning ensures that screws achieve sufficient purchase in the bone while stopping before piercing through the scapular surface.
2Reliability
If the implant is positioned to replicate normal bio-mechanical movements of the humerus relative to the scapula, then the bio-mechanical function is improved, but the difficulty of precise positioning increases due to the presence of ligaments and soft tissue
Solution Approach 1:
The guide tool replaces complex manual positioning techniques with a standardized mechanical system. Instead of relying on surgeon skill to navigate soft tissue obstacles and achieve correct orientation, the guide tool provides predetermined alignment features and positioning references that mechanically ensure proper implant orientation for replicating natural bio-mechanical movements.
3Measurement precision
If patient specific instrumentation is used to create instruments made specifically for the patient from imagery data, then the positioning precision is improved, but the device complexity and manufacturing requirements increase
Solution Approach 1:
The patient specific guide tool incorporates local quality by customizing only the patient-specific positioning interface and alignment features, while using standardized components for the glenoid implant interface and screw guide features. This approach achieves precise patient-specific positioning without requiring complete customization of the entire instrument system, thereby reducing manufacturing complexity compared to fully custom solutions.
Data Source
AI summary
Methods and systems include a patient specific instrument for installing a glenosphere within a joint. For example, a method for implanting a glenosphere includes installing first and second pins in a glenoid cavity using a patient specific instrument that sets a distance between the guide pins, installing an implant at the location of the second guide pin, and guiding a glenosphere onto the implant using a helper connected to the first pin. In another example, a glenosphere helper includes a cup shaped body having an interior surface for engaging at least a portion of an outer surface of the glenosphere, and a flange extending from the cup to receive a guide pin at a point, the flange extending from the cup shaped body such that the point is positioned outside a periphery of the glenosphere.