# US 10,864,044 B2 · Systems and methods for measuring bone joint laxity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,044 B2 - Document ID: US10864044B2 - Status: Granted - Kind: B2 - Application number: 16/493,188 - Filed: 2018-03-14 - Published: 2020-01-09 - Granted: 2020-12-15 - Earliest claimed: 2017-03-14 - Assignees: Smith & Nephew, Inc. - Applicants: Smith & Nephew, Inc. - Inventors: Constantinos Nikou; Branislav Jaramaz - Web page: https://patentgrep.com/patent/US10864044B2 ## CPC - A61B 34/10: Computer-aided planning, simulation or modelling of surgical operations - A61B 5/4504: {Bones (A61B5/4547 takes precedence)} - A61B 5/4528: {Joints (A61B5/4533, A61B5/4538 take precedence)} - A61B 34/20: Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis - A61B 34/25: {User interfaces for surgical systems} - A61F 2/4657: {Measuring instruments used for implanting artificial joints (for surgical instruments A61B90/06)} - A61F 2/4684: {Trial or dummy prostheses} - A61B 2034/102: {Modelling of surgical devices, implants or prosthesis} - A61B 2034/104: {Modelling the effect of the tool, e.g. the effect of an implanted prosthesis or for predicting the effect of ablation or burring} - A61B 2034/105: {Modelling of the patient, e.g. for ligaments or bones} - A61B 2034/108: {Computer aided selection or customisation of medical implants or cutting guides} - A61B 2034/2048: {using an accelerometer or inertia sensor} - A61B 2034/2055: {Optical tracking systems} - A61B 2034/2057: {Details of tracking cameras} - A61B 2034/2068: {using pointers, e.g. pointers having reference marks for determining coordinates of body points} - A61B 2034/254: {being adapted depending on the stage of the surgical procedure} - A61B 2034/256: {having a database of accessory information, e.g. including context sensitive help or scientific articles} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) ## Abstract A system and device (110) for determining bone laxity. For example, the system includes a tracked probe (300) comprising at least one probe marker (310) and a computer assisted surgical (CAS) system (100). The CAS system includes a navigation system (130) and a processing device (110) operably connected to the navigation system and a computer readable medium configured to store one or more instructions that, when executed, cause the processing device to receive location information from the navigation system, generate (820) a surgical plan comprising a post-operative laxity assumption (720), collect (850) first motion information related to movement of the joint through a first range of motion, collect (860) second motion information related to movement of the joint through a second range of motion, determine (870) a post-operative laxity (710), and compare the post-operative laxity and the post-operative laxity assumption to determine laxity results. ## Claims ### Claim 1 A system for determining bone laxity during a surgical procedure to replace at least part of a joint with an implant, the system comprising: a tracked probe comprising at least one probe marker, the tracked probe configured to provide an indication of at least one anatomical landmark on a bone during the surgical procedure; and a computer assisted surgical system comprising: a navigation system configured to track the tracked probe and at least one bone marker during the surgical procedure, and a processing device operably connected to the navigation system and a computer readable medium configured to store one or more instructions that, when executed, cause the processing device to: receive location information related to a position of the tracked probe and the at least one bone marker from the navigation system, pre-operatively generate a surgical plan comprising a post-operative laxity assumption based on one or more of standard gap information and statistical gap information, collect first motion information related to movement of the joint through a first range of motion, wherein the first motion information is collected while a first portion of the joint is in a first position with respect to a second portion of the joint, collect second motion information related to movement of the joint through a second range of motion, wherein the second motion information is collected while the first portion of the joint is in a second position, different from the first position, with respect to the second portion of the joint, determine a post-operative laxity for the joint based on a difference between the first motion information and the second motion information, compare the post-operative laxity for the joint and the post-operative laxity assumption to determine laxity results for the surgical procedure, and cause the laxity results to be displayed on a display operably connected to the processing device. ### Claim 2 (depends on 1) The system of claim 1, wherein the first motion information comprises baseline information collected while the joint is moved through the first range of motion wherein the first portion of the joint is touching the second portion of the joint. ### Claim 3 (depends on 2) The system of claim 2, wherein the first portion of the joint comprises a tibial implant and the second portion of the joint comprises a femoral implant. ### Claim 4 (depends on 2) The system of claim 2, wherein the second motion information comprises distracted motion information collected while the joint is moved through the second range of motion wherein the first portion of the joint is in a distracted position from the second portion of the joint. ### Claim 5 (depends on 1) The system of claim 1, wherein determining the post-operative laxity for the joint comprises determining spatial differences in the first motion information and the second motion information for the at least one bone marker. ### Claim 6 (depends on 1) The system of claim 1, wherein determining the laxity results comprises: plotting distance information associated with the post-operative laxity assumption to obtain a first laxity curve; plotting distance information associated with the post-operative laxity to obtain a second laxity curve; and comparing the first laxity curve and the second laxity curve. ### Claim 7 (depends on 1) The system of claim 1, wherein the computer readable medium is configured to store one or more additional instructions that, when executed, cause the processing device to update the surgical plan based upon the laxity results. ### Claim 8 (depends on 1) The system of claim 1, wherein the post-operative laxity assumption is based upon implant size information, preservation of an original joint line for the joint, and ensuring sufficient space in the joint for full range of motion. ### Claim 9 (depends on 8) The system of claim 8, wherein the sufficient space in the joint for full range of motion is determined based upon the standard gap information for the joint. ### Claim 10 (depends on 1) The system of claim 1, wherein the joint comprises a knee. ### Claim 11 (depends on 1) The system of claim 1, wherein the at least one bone marker comprises an optical navigation marker mounted on a patient's tibia. ### Claim 12 A device for determining bone laxity during a surgical procedure to replace at least part of a joint with an implant, the device comprising: a processing device operably connected to a navigation system and a computer readable medium configured to store one or more instructions that, when executed, cause the processing device to: receive location information related to a position of a tracked probe and at least one bone marker from the navigation system, pre-operatively generate a surgical plan comprising a post-operative laxity assumption based on one or more of standard gap information and statistical gap information, track movement of the joint through a first range of motion and collect first motion information related to movement of the joint through the first range of motion while a first portion of the joint is in a first position with respect to a second portion of the joint, track movement of the joint through a second range of motion and collect second motion information related to movement of the joint through the second range of motion while the first portion of the joint is in a second position, different from the first position, with respect to the second portion of the joint, determine a post-operative laxity for the joint based on a difference between the first motion information and the second motion information, compare the post-operative laxity for the joint and the post-operative laxity assumption to determine laxity results for the surgical procedure, and cause the laxity results to be displayed on a display operably connected to the processing device. ### Claim 13 (depends on 12) The device of claim 12, wherein the first motion information comprises baseline information collected while the joint is moved through the first range of motion wherein the first portion of the joint is touching the second portion of the joint. ### Claim 14 (depends on 13) The device of claim 13, wherein the first portion of the joint comprises a tibial implant and the second portion of the joint comprises a femoral implant. ### Claim 15 (depends on 13) The device of claim 13, wherein the second motion information comprises distracted motion information collected while the joint is moved through the second range of motion wherein the first portion of the joint is in a distracted position from the second portion of the joint. ### Claim 16 (depends on 12) The device of claim 12, wherein determining the post-operative laxity for the joint comprises determining spatial differences in the first motion information and the second motion information for the at least one bone marker. ### Claim 17 (depends on 12) The device of claim 12, wherein determining the laxity results comprises: plotting distance information associated with the post-operative laxity assumption to obtain a first laxity curve; plotting distance information associated with the post-operative laxity to obtain a second laxity curve; and comparing the first laxity curve and the second laxity curve. ### Claim 18 (depends on 12) The device of claim 12, wherein the computer readable medium is configured to store one or more additional instructions that, when executed, cause the processing device to update the surgical plan based upon the laxity results. ### Claim 19 (depends on 12) The device of claim 12, wherein the post-operative laxity assumption is based upon implant size information, preservation of an original joint line for the joint, and ensuring sufficient space in the joint for full range of motion. ### Claim 20 (depends on 19) The device of claim 19, wherein the sufficient space in the joint for full range of motion is determined based upon the standard gap information for the joint. ### Claim 21 (depends on 12) The device of claim 12, wherein the joint comprises a knee. ### Claim 22 (depends on 12) The device of claim 12, wherein the at least one bone marker comprises an optical navigation marker mounted on a patient's tibia.