Dynamic ligament balancing system

• US 10,722,385 B2
• Filed: 01/11/2017
• Issued: 07/28/2020
• Est. Priority Date: 04/28/2016
• Status: Active Grant

• Current Assignee: MIT Entwicklungs-GmbH
• Original Assignee: Medfit Beratungs-Und Beteiligungsges mbH
• Inventors: Paszicsnyek, Thomas
• Primary Examiner(s): Abouelela, May A
• Application Number:
  US15/403,624
• Publication Number:
  US 20170312099A1
• Time in Patent Office: 1,294 Days
• Field of Search: 600300, 600587, 600595, 606102, 623 1314, 707758
• 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 joint 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 spring, and wherein each of the platforms are configured to variably depress the spring through a range of motion of a joint when the prosthetic inlay device is placed in situ;

a force sensing sensor configured beneath each spring, the force sensing sensor detecting pressures from depressing the spring at each of the at least two platform structures; and

a communication interface coupled to the force sensing sensors, the communication interface transmitting data corresponding to the detected pressures to a computing device that is configured to generate a set of heights representing displacement of the at least two platform structures and corresponding to medial and lateral tension on the joint tissue based on the detected pressures at a plurality of reference angles of the joint.

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 configured to conform to a patient'"'"'s femur.

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

7. The system of claim 1, wherein the set of heights comprises a first set of heights representing displacement of the at least two platforms pre-prosthesis and a second set of heights representing displacement of the at least two platforms post-prosthesis.

8. The system of claim 7, the computing device further configured to determine differences between the first and second sets of heights and display an indication for one or more of the plurality of reference angles of the joint.

9. A method, in a data processing system comprising

a processor and a memory, for measuring tension, pressure, and distance of knee tissue, the method comprising:

receiving, by a computing device, a first set of signals from a ligament balancing device including at least two platform structures, wherein each of the platform structures are supported on a scissor arm structure and a spring, and force sensing sensors that measure force applied to each of the at least two platform structures that variably displace each of the springs through a range of motion of a knee when the ligament balancing device is placed in situ, 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, by the computing device, a first set of medial and lateral forces at the one or more knee flexion angles from the first set of signals;

receiving, by the computing device, 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, by the computing device, a second set of medial and lateral forces at the one or more knee flexion angles from the second set of signals;

determining, by the computing device, a first set of heights represent displacement of the at least two platforms structures based on the first set of medial and lateral forces and a second set of heights correspond to displacement of the at least two platforms based on and the second set of medial and lateral forces;

determining, by the computing device, an amount of difference between the first set of heights and the second set of heights at each of the one or more knee flexion angles;

and displaying, by the computing device, an indication for the one or more knee flexion angles based on the determined amount of difference between the first set of heights and the second set of heights.

10. The method of claim 9, wherein the first set of heights are determined pre-prosthesis and the second set of heights are determined post prosthesis.