US-12616460-B2 - Knee tensioner with digital force and displacement sensing

Abstract

A tensioner tool for assessing joint laxity is disclosed. The tensioner tool comprises a pair of pivotally coupled arms, each arm comprising a proximal handle portion, a distal portion, and an insertion tip selectively coupled to the distal portion. The pair of arms pivot between a compressed configuration for insertion within the joint and an expanded configuration for distraction of the joint by applying a force to the handles, thus spreading the insertion tips. The tensioner tool also comprises a force sensor configured to measure the force applied to the handle portion and a positional sensor configured to measure a separation distance between the pair of arms. The tensioner tool also comprises a processor configured to calculate a distraction force at the insertion tips based on the measured force and to calculate a tip distance between the insertion tips based on the measured separation distance.

Inventors

• Samuel C. DUMPE
• Branislav Jaramaz
• Ryan SHEEHAN
• Brian W. McKinnon
• Daniel Farley

Assignees

• SMITH & NEPHEW, INC.
• Smith & Nephew Asia Pacific Pte. Limited
• SMITH & NEPHEW ORTHOPAEDICS AG

Dates

Publication Date

20260505

Application Date

20210427

Claims (15)

1. 1 . A tensioner tool for assessing laxity of a joint including first and second bones, the tensioner tool comprising: a first component comprising: a pair of arms pivotally coupled at a pivot joint, each arm including a proximal handle portion, a distal portion, and an insertion tip selectively coupled to the distal portion, wherein the pair of arms are configured to pivot about a pivot axis between a compressed configuration for insertion between the first and second bones and an expanded configuration for distraction of the first and second bones in response to a force applied to at least one of the proximal handle portions, wherein a tip distance between the insertion tips is greater in the expanded configuration than in the compressed configuration; a force sensor coupled to one of the pair of arms and configured to collect force data related to the applied force; and a positional sensor configured to collect separation data related to a separation distance between the pair of arms; a second component comprising: an on-board processor; and an on-board non-transitory, computer-readable medium storing instructions that, when executed, cause the processor to: receive the force data from the force sensor, calculate, based on the force data, a distraction force exerted to the first and second bones by the insertion tips, receive the separation data from the positional sensor, and calculate the tip distance based on the separation data, wherein: the first component is releasably and communicatively coupled to the second component; the first component is configured for sterilization; and the second component is configured to be disposable.
2. 2 . The tensioner tool of claim 1 , wherein for each arm, the distal portion comprises a through-hole configured to mate with a shaft of the insertion tip to selectively couple the insertion tip to the distal portion.
3. 3 . The tensioner tool of claim 2 , wherein for each arm: the insertion tip is configured to be received within a first end of the through-hole and extend substantially in a first direction from the distal portion; and the insertion tip is configured to be received within a second end of the through-hole and extend substantially in a second direction, opposite the first direction, from the distal portion, wherein the first direction and the second direction are substantially parallel to the pivot axis.
4. 4 . The tensioner tool of claim 1 , wherein for each arm, the insertion tip is configured to rotate about a tip axis with respect to the distal portion when coupled to the distal portion.
5. 5 . The tensioner tool of claim 4 , wherein the tip axis is substantially parallel to the pivot axis.
6. 6 . The tensioner tool of claim 1 , wherein each insertion tip is disposable.
7. 7 . The tensioner tool of claim 1 , wherein: the insertion tip of a first arm of the pair of arms comprises a single prong; and the insertion tip of a second arm of the pair of arms comprises a pair of prongs.
8. 8 . The tensioner tool of claim 1 , wherein each insertion tip comprises a geometry configured to conform to a surface of at least one of the first and second bones.
9. 9 . The tensioner tool of claim 1 , wherein the force sensor comprises a strain gauge.
10. 10 . The tensioner tool of claim 1 , further comprising a magnet coupled to a first arm of the pair of arms, wherein the positional sensor comprises a Hall effect sensor coupled to a second arm of the pair of arms.
11. 11 . The tensioner tool of claim 1 , wherein the positional sensor comprises one or more of a rotary encoder and a rotary potentiometer.
12. 12 . The tensioner tool of claim 11 , where the positional sensor is disposed within the pivot joint.
13. 13 . The tensioner tool of claim 1 , further comprising a display configured to display one or more of the distraction force and the tip distance.
14. 14 . The tensioner tool of claim 13 , wherein one or more of the display, the processor, and the non-transitory, computer-readable medium are each disposed on the proximal handle portion of one of the pair of arms.
15. 15 . The tensioner tool of claim 1 , wherein the instructions that cause the processor to calculate the tip distance comprise instructions that, when executed, cause the processor to calculate the tip distance based on the separation distance between the pair of arms and a predetermined geometry between the positional sensor, the pivot joint, and the insertion tip of each arm.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a U.S. National Stage filing under 35 U.S.C. § 371 of International PCT Application No. PCT/US2021/029355, filed Apr. 27, 2021, which claims the benefit of priority to U.S. Provisional Application No. 63/015,907, titled “Knee Tensioner with Digital Force and Displacement Sensing,” filed Apr. 27, 2020, which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates generally to methods, systems, and apparatuses related to a computer-assisted surgical system that includes various hardware and software components that work together to enhance surgical workflows. The disclosed techniques may be applied to, for example, shoulder, hip, and knee arthroplasties, as well as other surgical interventions such as arthroscopic procedures, spinal procedures, maxillofacial procedures, rotator cuff procedures, ligament repair and replacement procedures. More particularly, the present disclosure relates to methods and systems for joint tensioning ligament balancing in a total or partial joint replacement surgical procedure. BACKGROUND Orthopaedic implants are used for resurfacing or replacing joints, such as knees, hips, shoulders, ankles, and elbows, that typically experience high levels of stress and wear or traumatic injury. Implants used to replace these joints must be strong and able to withstand the daily stress and wear at these joints, especially for weight-bearing knee and hip replacements. However, providing a sufficiently strong implant that also fits properly is challenging. Traditional orthopaedic implants are made from polymers, ceramics, metals or other appropriate materials and are formed so that they fit the patient's bone securely. In knee replacement surgeries, for example, typical approaches involve cutting the end of the tibia and/or femur, then fitting a new implant to the cut end. The size of the implant and positioning of the implant are typically determined by a surgeon based on hand measurements and visual estimates. The surgeon may assess the implant position relative to the native bony anatomy and/or the properties of the surrounding soft tissue. Medical professionals may in some cases utilize spacer blocks and/or trial implants to make assessments prior to implantation; however, the assessment may be affected by a variety of factors including the level of experience of the medical professional, and thus remains subjective and imprecise. Further, medical professionals have historically had difficulty in characterizing the properties of the surrounding soft tissues in a quantifiable manner. Further, computer assisted surgical systems allow a user to plan an implant procedure, such as a total knee arthroplasty (TKA), a total hip arthroplasty (THA), or an arthroplasty of another joint, and view a projected outcome prior to performing bone resection. For example, in order to perform virtual planning for a TKA, information regarding two physiological aspects of the patient's knee is required. Specifically, the computer assisted surgical system requires (1) anatomical information pertaining to the patient's femur and tibia, and (2) information pertaining to the soft tissue tension/laxity within the joint. Obtaining information pertaining to the patient's femur and tibia (i.e., the bony anatomy) can be reliably defined in a number of ways whether pre-operatively or intraoperatively. However, the properties of the surrounding soft tissue are much less objective. This lack of objectivity in a major system input has the potential to lead to inconsistent surgical outcomes. During an arthroplasty procedure, a force can be applied to a portion of the patient's anatomy, such as the knee during a TKA. Conventionally, the amount of force, whether applied by hand or by a tool, is applied subjectively, which can lead to inconsistent patient outcomes as a result of improperly characterizing the behavior of soft tissue in response to the applied force. Moreover, difficulties exist in designing tensioner tools having a sufficiently narrow profile to be inserted in a pre-operative joint (especially in patients with a particularly tight joint anatomy). Thus, in many conventional systems, such forces are typically applied only after one or more planar bone cuts have been made to the joint, which limits the manner in which a surgeon can adjust the joint in response to determining the behavior of the soft tissue. While some tensioner tools may facilitate pre-operative tensioning and calculation of an applied force, in many cases the bones of the joint may shift in response to distraction. Quantification of the distraction may be valuable in further characterizing the soft tissue surrounding the joint. Additionally, due to natural variations and/or abnormalities in patient anatomies, many tensioner tools are unable to make consistent and sustained contact with a particular joint surface, resulting in inconsistent joint ass