Dynamic Ligament Balancing System

• US 20170312099A1
• Filed: 01/11/2017
• Published: 11/02/2017
• Est. Priority Date: 04/28/2016
• Status: Active Grant

• Current Assignee: MIT Entwicklungs-GmbH
• Original Assignee: Medfit Beratungs-Und Beteiligungsges mbH
• Inventors: Paszicsnyek, Thomas
• Granted Patent: US 10,722,385 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 2017/0268 for the knee
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/4585 Evaluating the knee
• CPC Class Codes: A61B 5/4851 Prosthesis assessment or monitoring
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/4668 for measuring angles

Abstract

A method and system for measuring tension, pressure, and distance of knee tissue, the system comprising a prosthetic inlay device comprising at least two platform structures, wherein each of the platforms are supported on a scissor arm structure and a coil spring, a force sensing sensor configured beneath each coil spring, and a connector cable coupled to the force sensing sensors.

Claims

1. A system for measuring tension, pressure and distance of knee tissue, the system comprising:

a prosthetic inlay device comprising;

at least two platform structures, wherein each of the platforms are supported on a scissor arm structure and a coil spring;

a force sensing sensor configured beneath each coil spring; and

a connector cable coupled to the force sensing sensors.

2. The system of claim 1 further comprising a sliding surface beneath the scissor arm structures.

3. The system of claim 2 wherein the scissor arm structure includes a fixed leg and a sliding leg.

4. The system of claim 3 wherein the sliding leg is operable to move along the sliding surface.

5. The system of claim 1 wherein the at least two platform structures include indentations suitable for conforming to a femur bone element.

6. The system of claim 1 wherein the prosthetic inlay device comprises biocompatible material.

7. A method for measuring tension, pressure, and distance of knee tissue, the method comprising:

receiving a first set of signals from a ligament balancing device including force sensing sensors that measure force applied to at least two platform structures, the first set of signals representative of force applied to each of the at least two platform structures by a femur at one or more knee flexion angles prior to a prosthetic operation;

identifying a first set of medial and lateral forces at the one or more knee flexion angles from the first set of signals;

receiving a second set of signals from the ligament balancing device, the second set of signals representative of force applied to each of the at least two platform structures by the femur at the one or more knee flexion angles subsequent to the prosthetic operation;

identifying a second set of medial and lateral forces at the one or more knee flexion angles from the second set of signals;

displaying the first set of medial and lateral forces and the second set of medial and lateral forces on a display device;

determining an amount of difference between medial and lateral forces at each of the one or more knee flexion angles; and

displaying an indication for the one or more knee flexion angles based on the determined amount of difference between the medial and lateral forces in the second set of medial and lateral forces.

8. Non-transitory computer readable media comprising program code that when executed by a programmable processor causes execution of a method for measuring tension, pressure, and distance of knee tissue, the computer readable media comprising:

computer program code for receiving a first set of signals from a ligament balancing device including force sensing sensors that measure force applied to at least two platform structures, the first set of signals representative of force applied to each of the at least two platform structures by a femur at one or more knee flexion angles prior to a prosthetic operation;

computer program code for identifying a first set of medial and lateral forces at the one or more knee flexion angles from the first set of signals;

computer program code for receiving a second set of signals from the ligament balancing device, the second set of signals representative of force applied to each of the at least two platform structures by the femur at the one or more knee flexion angles subsequent to the prosthetic operation;

computer program code for identifying a second set of medial and lateral forces at the one or more knee flexion angles from the second set of signals;

computer program code for displaying the first set of medial and lateral forces and the second set of medial and lateral forces on a display device;

computer program code for determining an amount of difference between medial and lateral forces at each of the one or more knee flexion angles; and

computer program code for displaying an indication for the one or more knee flexion angles based on the determined amount of difference between the medial and lateral forces in the second set of medial and lateral forces.