Soft tissue balancing in robotic knee surgery

Inventors

Couture, Pierre

Assignees

Advita Ortho LLC

Abstract

A system and method may be used to evaluate soft tissue. A knee arthroplasty soft tissue evaluation may use an adjustable spacer, such as varying sized physical spacers or an inflatable bladder, along with a sensor to measure force, pressure, gap distance, or the like during a range of motion test. A method may include maintaining an equal pressure or gap distance for a medial component and a lateral component of an adjustable spacer during a range of motion test. Information, including, for example a maximum or minimum gap distance or pressure may be determined during the range of motion test. The determined information may be output for display or used to update a surgical plan.

Core Innovation

The invention provides a robotic surgical system for robotically-assisted total knee arthroplasty in which a three-dimensional plan is initiated using a user interface. A tibia resection is performed to produce a resected surface, and an adjustable spacer is inserted between the resected surface of the tibia and a femur. The spacer includes independently adjustable components on a medial side and a lateral side, which are inflated using one or more integral pumps of the robotic surgical system.

During a range of motion test, the system tracks a degree of flexion or extension using an optical tracking system operatively coupled to the robotic surgical system. The system maintains medial and lateral symmetry by maintaining an equal gap distance or maintaining an equal pressure between the medial and lateral gaps or pressures, by increasing or decreasing pressure or by increasing or decreasing gap distance using the integral pumps. A force sensor device is inserted between the resected surface of the tibia and the femur.

The system determines a maximum force or a maximum gap distance during the range of motion test using the force sensor device, and displays the maximum force or the maximum gap distance on a display coupled to the robotic surgical system. The determined maximum force or maximum gap distance can be used to adjust the three-dimensional plan and can be used to determine and display an implant indication on the display. The workflow supports alternative control modes of fixed pressure versus fixed gap to maintain medial/lateral balance while performing and evaluating the range of motion test.

Claims Coverage

The document contains two independent claims. Together they define a robotically-assisted total knee arthroplasty workflow with an adjustable spacer having independently adjustable medial and lateral components driven by integral pumps, optical tracking of flexion or extension during a range of motion test, and force-sensor-based determination of maximum force or maximum gap distance for display.

The core coverage centers on robotically-assisted total knee arthroplasty using a spacer with independently adjustable medial and lateral components driven by one or more integral pumps, optical tracking of flexion or extension during a range of motion test, medial/lateral symmetry maintained as either equal gap distance or equal pressure, and sensor-based determination of a maximum measurement that is displayed to the user.

Stated Advantages

Documented Applications