Modular Humeral Arthroplasty System for Glenoid Access

Solution Overview

Problem

Current prostheses for total shoulder arthroplasty, such as stemmed and resurfacing prostheses, face challenges in accurately matching the patient's anatomy, especially in cases of deformity, and in providing adequate access to the glenoid during surgery.

Innovation Solution

A humeral arthroplasty system comprising small, medium, and large size prostheses with overlapping circles of a sphere articular surface, allowing for bone preservation and anatomically accurate surgical operations. The system includes a bone-facing side with multiple planar surfaces and anchoring elements, requiring minimal bone removal and allowing for precise placement based on individual anatomy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stemmed prosthesis is used to anchor the humeral head, then the prosthesis provides stable anchoring in the humeral shaft, but it requires removal of the entire humeral head bone and extensive drilling into the shaft, resulting in loss of bone stock and difficulty in accessing the glenoid during total shoulder arthroplasty

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The prosthesis is divided into separate functional components: a modular humeral head component that can be detached from the stem, allowing the head to be removed while preserving the stem and bone. This segmentation enables selective replacement of the articular surface while maintaining anchoring stability through the stem.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The prosthesis incorporates adjustable and detachable features that allow dynamic reconfiguration. The modular design permits the humeral head to be separated from the stem during surgery, and the stem can be adjusted or removed as needed, providing flexibility in surgical approaches while maintaining stability.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a stemmed prosthesis with modular adjustable connection mechanisms is used, then the prosthesis allows partial adjustment of the humeral head position, but the adjustments are limited and constrained by the stem, failing to match the actual anatomy of patients with deformity

Engineering Contradiction:

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The prosthesis allows for可变 changes in geometric parameters such as offset, neck-shaft angle, and retroversion through modular components. The detachable design enables surgeons to adjust these parameters post-operatively or intra-operatively to match the patient's actual anatomy, overcoming the constraints of fixed or limited-adjustment stems.

Inventive Principle:

Principle #35Parameter changes

3Loss of substance

If a resurfacing prosthesis is used to preserve bone in the upper humerus, then the prosthesis rests directly on the humeral bone without extending into the shaft, but this preserves bone that blocks access to the glenoid and makes placement of the glenoid prosthesis challenging

Engineering Contradiction:

Core Design Contradiction:

Loss of substanceVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The humeral head component can be extracted or removed from the stem during surgery, allowing the surgeon to access the glenoid area without the obstruction of the humeral head. This extraction capability provides surgical access while preserving the stem and underlying bone for future needs.

Inventive Principle:

Principle #2Taking out (Extraction)

4Strength

If a solid metal hemispherical head component is used in stemmed prostheses, then the prosthesis provides robust structural strength, but the component is of considerable weight, potentially affecting shoulder mechanics

Engineering Contradiction:

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The prosthesis utilizes composite construction with a metal stem for structural strength and anchoring, combined with a separate humeral head component that can be made from lighter materials or different compositions. This composite approach maintains the necessary strength while reducing overall weight compared to a solid metal hemispherical head.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentEP3679900B1Humeral arthroplasty

Publication Date: 2025.06.04

Figure 1A~1F
Figure 2A~2F
Figure 3A~3F

AI summary

Arthroplasty components (600, 600', 600'') include an articular surface (602, 602', 602'') and a bone-facing surface (604). The bone-facing surface includes a concave arrangement of planar surfaces (620, 622, 624, 626) which converge as they approach a middle portion of the articular surface. Instruments and implantation methods are also disclosed.