Patient-Specific ACL Drill Guide for Tibial Tunnel Placement

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Solution Overview

Problem

Current ACL repair instrumentation lacks accuracy in tibial tunnel placement, often resulting in misalignment, inadequate bone integration, and potential interference with the tibial eminence due to non-custom designs that rely on surgeon judgment and bone topography matching.

Innovation Solution

Patient-specific ACL repair devices with customizable features, such as preoperatively designed drill guides that match individual patient anatomy, ensuring precise alignment and adjustment to fit specific patient dimensions and angles, facilitating accurate tibial tunnel placement and minimizing bone removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If standard or non-custom ACL repair instrumentation is used, then the device can be universally applied to different patients, but the positioning of the tibial tunnel becomes inaccurate due to reliance on surgeon judgment and bone topography matching

Engineering Contradiction:
Improveuniversal applicability of deviceVSAvoidaccuracy of tibial tunnel placement
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing preoperative CT scanning and 3D reconstruction of the patient's knee anatomy before surgery. The drill guide is custom-designed based on these preoperative images, allowing accurate positioning parameters to be determined in advance. This eliminates the need for intraoperative bone topography matching and surgeon judgment, directly resolving the accuracy problem while maintaining universal applicability through the standardized preoperative imaging workflow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by creating a patient-specific drill guide with unique geometric features tailored to the individual patient's anatomy. The guide incorporates patient-specific positioning surfaces and drill hole orientations that match the patient's unique bone structure. This localized customization ensures precise tibial tunnel placement for each patient while the overall device design remains universally applicable through the custom manufacturing process.

Inventive Principle:
Principle #3Local quality

2Device complexity

If fixed-axis devices are used, then the device structure is simple, but the positioning accuracy deteriorates because the device becomes misaligned when bone locations do not have suitable topography for mating with contact points

Engineering Contradiction:
Improvesimplicity of device structureVSAvoidalignment accuracy of tibial tunnel
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by designing the drill guide with patient-specific positioning surfaces that match the patient's unique bone topography. These localized custom features ensure precise alignment without requiring complex adjustable mechanisms. The simple overall device structure is maintained while the critical positioning interfaces are customized to the patient's anatomy, resolving the alignment accuracy problem.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies preliminary action by determining the optimal drill hole positions and orientations through preoperative 3D reconstruction of the patient's knee anatomy. The drill guide is custom-designed based on these preoperative plans, eliminating the need for intraoperative alignment adjustments. This approach maintains device simplicity while achieving high positioning accuracy through advance planning and customization.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If tibial tunnel placement is not accurately positioned, then the surgical procedure can be completed quickly, but the ACL graft experiences abnormal strains leading to plastic deformation, postoperative laxity, or failure of fixation

Engineering Contradiction:
Improvespeed of surgical procedureVSAvoidstability of ACL graft
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing comprehensive preoperative planning including CT scanning, 3D reconstruction, and determination of optimal tibial tunnel positioning parameters before surgery. The patient-specific drill guide is designed in advance with all positioning information pre-calculated. This allows the surgical procedure to proceed quickly without intraoperative trial-and-error positioning, while ensuring the ACL graft is placed at the optimal location for maximum stability and minimal abnormal strains.

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If excessive bone is removed from the femoral intercondylar roof during notchplasty, then impingement of the graft is prevented, but the amount of natural bone preserved in the knee is reduced

Engineering Contradiction:
Improveimpingement of graftVSAvoidamount of natural bone preserved
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by using preoperative 3D reconstruction to accurately measure and plan the precise amount of bone that needs to be removed from the femoral intercondylar roof. The patient-specific drill guide incorporates this pre-calculated information, allowing the surgeon to perform minimal necessary notchplasty without excessive bone removal. This ensures graft impingement is prevented while maximizing preservation of natural bone, as the positioning is determined in advance rather than through intraoperative trial-and-error.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3481312B1Patient-specific drill guide for performing anterior cruciate ligament reconstruction using
Publication Date: 2023.06.21 BIOMET SPORTS MEDICINE LLC
  • EP3481312B1 patent drawingFigure 1
  • EP3481312B1 patent drawingFigure 2
  • EP3481312B1 patent drawingFigure 3

AI summary

A guide for drilling a tunnel in a knee joint having intercondylar roof and tibial eminence. The guide can comprise a guide assembly having a positioning member including an inferior end, and a guide arm extending from the positioning member including a trochlear tip; and a drill sleeve having a body attached to the inferior end, an aperture extending along a drilling axis, and a distal end having a patient-specific surface configured to engage an anterior surface of the tibia. A method of producing a tibial tunnel can comprise inserting a trochlear tip of a guide arm between the tibial eminence and the intercondylar roof, adjusting a position of a positioning member connected to the guide arm, engaging a patient-specific tip of a drill sleeve connected to the positioning member with a surface of a tibia, and inserting a drill bit through the drill sleeve to drill a tibial tunnel.