Prosthetic Stem Internal Channels for BCIS Pressure Control

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Solution Overview

Problem

The use of bone cement in prosthetic implantation can lead to Bone Cement Implant Syndrome (BCIS), causing catastrophic medical complications and death due to increased intramedullary pressure during stem insertion.

Innovation Solution

A prosthetic stem with internal channels that self-regulate intramedullary pressure by allowing excess cement to flow through these channels, reducing the risk of BCIS while maintaining sufficient fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a solid stem is inserted into the intramedullary canal filled with liquid cement, then the stem is securely fixed in the bone, but intramedullary pressure increases significantly causing BCIS

Engineering Contradiction:

Improvefixation strengthVSAvoidintramedullary pressure

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The stem is divided into multiple segments along its length, with each segment containing internal channels that allow cement to flow through. This segmentation enables the stem to maintain structural integrity for fixation while simultaneously providing pressure relief pathways to prevent BCIS

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Internal channels within the stem act as intermediary pathways for cement flow. These channels mediate between the intramedullary canal and the external environment, allowing controlled cement egress that reduces intramedullary pressure while maintaining stem-bone fixation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If bone cement is used to secure the prosthetic stem, then reliable fixation is achieved, but the risk of BCIS and catastrophic complications increases

Engineering Contradiction:

Improvefixation reliabilityVSAvoidBCIS risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful effect of cement pressurization into a beneficial outcome by designing internal channels that allow controlled cement flow. The cement that would otherwise cause dangerous pressure buildup is redirected through the channels, maintaining fixation reliability while eliminating BCIS risk

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The stem design changes the physical parameters of cement flow by providing controlled pathways. This alters the pressure, flow rate, and distribution parameters of cement during insertion, achieving reliable fixation while preventing dangerous pressure accumulation

Inventive Principle:

Principle #35Parameter changes

3Strength

If the intramedullary canal is filled with liquid cement and a stem is inserted, then permanent attachment is achieved, but embolization of fat, air, cement particles, and aggregates occurs

Engineering Contradiction:

Improveattachment strengthVSAvoidembolization

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The internal channels extract excess cement and trapped air bubbles from the intramedullary canal during stem insertion. By removing these harmful elements before they can cause embolization, the design maintains secure attachment while preventing cardiovascular complications

Inventive Principle:

Principle #2Taking out (Extraction)

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 prosthetic stem effectively reduces the risk of BCIS and other harmful effects by controlling cement pressure during insertion, thereby enhancing safety and fixation in high-risk patients.

Implementation Method 1

One or more internal channels in the stem are configured to control the pressure within the prepared bone channel during insertion of the stem into the channel, particularly by forming a path through which excess cement may flow as the stem proceeds into the prepared bone channel

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS20250161059A1Prosthetic stem for a prosthetic implant

Publication Date: 2025.05.22 UNIV OF MARYLAND

AI summary

A prosthetic stem is configured to reduce the perioperative and intraoperative risk of catastrophic medical complications and death that may be caused by BCIS. The prosthetic stem includes one or more internal channels that are configured to self-regulate intramedullary pressure within a prepared bone channel as the stem is inserted into the channel, thus reducing the likelihood of BCIS without sacrificing biomechanics and maintaining a reliable and repeatable implantation process. The stem includes a head and a body, wherein the head is configured to serve as a joint replacement and the body is configured for insertion into the prepared bone channel of a patient. One or more internal channels in the stem are configured to control the pressure within the prepared bone channel during insertion of the stem into the channel, particularly by forming a path through which excess cement may flow as the stem proceeds into the prepared bone channel. By so limiting pressurization of cement during this process, the risk of BCIS complications and other potential harmful effects are reduced while still maintaining sufficient fixation of the prosthetic stem in the prepared bone channel.