Bone Screw Reverse-Conical Head for Angled Bone Fixation

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Solution Overview

Problem

Existing bone screws often protrude beyond the bone surface when implanted at an angle, leading to potential complications and reduced stability, and require pilot holes for insertion, which can complicate surgical procedures.

Innovation Solution

A bone screw design featuring a reverse frustoconical head with a tapered lateral surface and angled bevel, allowing for secure implantation without protrusion and eliminating the need for pilot holes through integrated cutting flutes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional frustoconical head with wide base at proximal end is used, then the screw can be easily driven and has good drive feature access, but the screw protrudes beyond the bone surface and cannot achieve secure implantation at extreme angles

Engineering Contradiction:

Improvedrive feature accessVSAvoidsecure implantation at extreme angles

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent inverts the conventional frustoconical head design by placing the narrow base at the proximal end and the wide base at the distal end. This reverse conical configuration allows the screw to engage with bone at extreme angles without protruding, while the narrow proximal end provides adequate drive feature access for implantation.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If a conventional frustoconical head design is used, then the screw structure is simple and easy to manufacture, but the thread surface area is insufficient leading to incomplete bone contact

Engineering Contradiction:

Improvescrew structure simplicityVSAvoidthread surface area

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent transitions from a conventional two-dimensional frustoconical head to a three-dimensional curved lateral surface that wraps around the shank. This curved surface configuration increases the thread surface area and enhances bone contact while maintaining manufacturing simplicity through the continuous surface geometry.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the head is designed with a flat top surface for drive access, then driver insertion is easy, but the screw cannot be implanted at extreme angles without protrusion

Engineering Contradiction:

Improvedriver insertionVSAvoidimplantation angle range

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent employs an asymmetric head configuration where the proximal end is narrower than the distal end, creating a reverse conical shape. This asymmetric design allows the screw to accommodate extreme implantation angles while maintaining a functional drive recess for driver insertion, eliminating the need for a flat top surface.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS12611239B2Orthopedic bone screw

Publication Date: 2026.04.28 VOOM MEDICAL DEVICES INC

AI summary

The present disclosure describes a bone screw for use in orthopedic procedures. The bone screw includes a shank portion having a helical thread and a head portion also having a helical thread. The shank also includes a first purchase zone having a first thread pitch configured for purchase in cancellous bone and a second purchase zone having a second thread pitch configured for purchase in cortical bone, the first purchase zone extending proximally from the distal end of the screw, and the second purchase zone extending proximally from an interface with the first purchase zone; wherein the first thread pitch and the second thread pitch are compression neutral.