Hammering Insertion Instrument for ACL Tendon Fixation

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Solution Overview

Problem

Existing methods for fixing tendon replacements in cruciate ligament reconstruction, such as using interference screws, risk damaging the tendon implant during insertion and can hinder its growth due to twisting or lateral movement within the drilled canal, especially when fixed close to the joint.

Innovation Solution

An insertion instrument with an arcuate body and a striking head, allowing the locking element to be hammered into the drilled channel along its length, reducing the risk of twisting and enabling precise, gentle fixation close to the joint without the need for screwing, thus minimizing damage and promoting proper integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an interference screw is screwed into the drilled channel from the outside, then fixation close to the joint is achieved, but the tendon implant may twist and be damaged during the turning operation

Engineering Contradiction:

Improvefixation position precisionVSAvoidtendon implant damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the rotational screwing mechanism with a linear hammering mechanism. The insertion instrument delivers axial impact forces to drive the locking element straight into the drilled channel, eliminating the rotational motion that causes tendon twisting and damage while achieving precise fixation near the joint.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of screwing the locking element from the outside (extra-articular) direction, the patent inserts the locking element from the inside (intra-articular) direction through the knee joint. This inversion of the insertion direction allows fixation close to the joint without requiring extensive rotation that would damage the tendon.

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If an interference screw is advanced through a relatively long tibial or femoral drill channel from the outside, then fixation close to the joint is achieved, but multiple turning operations are required which can injure the tendon replacement

Engineering Contradiction:

Improvefixation position precisionVSAvoidinsertion time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the time-consuming rotational screwing operation with a rapid linear hammering operation. The impact-driven insertion mechanism drives the locking element through the drill channel in a single straightforward motion, eliminating multiple turning operations and significantly reducing insertion time while maintaining precise fixation positioning.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If a locking element is screwed in using a screwdriver, then the tendon implant is pressed against the inner wall of the bore, but the implant may twist under the turning motion

Engineering Contradiction:

Improvefixation strengthVSAvoidtendon implant integrity

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent replaces the rotational screwing action with a linear impact action. The hammering mechanism delivers axial forces that press the locking element and tendon implant against the bore wall without introducing rotational torque, thereby maintaining fixation strength while preserving tendon implant integrity and preventing twisting damage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 instrument allows for safe and precise insertion of the locking element into the drilled channel, reducing the risk of tendon damage and facilitating proper integration of the tendon replacement by eliminating twisting and ensuring correct positioning close to the joint.

Implementation Method 1

hitting the impact head causes the interlocking element to be driven in along the line of impact

Methodology Applied

Scientific EffectImpact force: Impact Force

Data Source

PatentEP2345389B1Insertion instrument for hammering a blocking element

Publication Date: 2014.08.06 KARL STORZ SE & CO KG

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AI summary

The instrument (10) has a striking head (20) arranged on a proximal end of a C-shaped curved body (12), and a blocking element (30) whose feeding device is arranged on a distal end of the curved body. A fixing screw and a groove are provided for holding the blocking element, and the striking head and the feeding device are aligned along a drive line (28). A deepening on the striking head operates driving of the blocking element along the drive line. End sections (16) are provided on the ends of the curved body and extended parallel to each other.