EP-4391910-B1 - SYSTEMS FOR DETERMINING TIBIA CORONAL ALIGNMENT

EP4391910B1EP 4391910 B1EP4391910 B1EP 4391910B1EP-4391910-B1

Inventors

HAZIN, Wael
LIGHTCAP, CHRISTOPHER
TROUSDALE, Jonathan
ROCHE, MARTIN

Dates

Publication Date: 20260506
Application Date: 20220819

Claims (10)

A system for measuring a tibia varus or valgus angle of a patient, comprising: a prosthetic knee component (70) configured to couple to a bone of the patient, the prosthetic knee component comprising: a measurement device comprising: an inertial measurement unit (82) including: an accelerometer; and a gyroscope, wherein the inertial measurement unit (82) is configured to record a plurality of measurements using the accelerometer and the gyroscope; and a transmitter configured to output the plurality of measurements.
The system of claim 1, further comprising: a display (260); and a computing device for determining the tibia varus or valgus angle of the patient, the computing device including: at least one processor (252); a communication component operatively connected to the processor (252); and a memory (254, 256) operatively connected to the processor (252), and storing instructions (274) that are executable by the processor (252) to perform operations, including: receiving first data from the measurement device that includes a plurality of measurements from each of the accelerometer and the gyroscope; receiving a first measurement of a length of a tibia of the patient; determining the tibia varus or valgus angle based on the first data and the first measurement; and causing the display (260) to output the determined tibia varus or valgus angle.
The system of claim 2, wherein the operations further include: causing the display (260) to output instructions for moving or posing a musculoskeletal system of the patient that, when executed, cause the accelerometer and the gyroscope to generate the first data.
The system of claim 3, wherein: different portions of the first data correspond to respective movements or poses of the musculoskeletal system of the patient; and causing the display (260) to output the instructions for moving or posing the musculoskeletal system of the patient includes iteratively causing the display to output respective instruction for each of the respective movement or pose, iteration between a current respective movement or pose and a next respective movement or pose being based on receiving a portion of the first data corresponding to the current respective movement.
The system of claim 2, wherein: the measurement device further includes a memory storing calibration data for the inertial measurement unit (82); and the operations further include: obtaining the calibration data for the inertial measurement unit (82); and prior to determining the tibia varus or valgus angle, modifying the plurality of measurements based on the calibration data.
The system of claim 2, wherein the operations further include: preprocessing the first data by at least removing one or more of the plurality of measurements that exceeds a predetermined maximum angular acceleration.
The system of claim 2, wherein determining the tibia varus or valgus angle includes: computing an orientation of the inertial measurement unit for each of the plurality of measurements by performing a time-integration of angular rates for each of the plurality of measurements; modifying the first data by removing gravity acceleration for each acceleration in the plurality of measurements; determining, based on the plurality of measurements, a vector that connects a point on an axis of rotation of the musculoskeletal system of the patient to a center point of the inertial measurement unit; determining a mean axis of rotation for the plurality of measurements by unionizing a result of averaging angular rate measurements of the plurality of measurements that are above a predetermined minimum threshold; modifying the plurality of measurements based on a reference frame of the inertial measurement unit relative to a reference frame of a tibia of the patient; modifying the plurality of measurements based on an offset vector between a heel of the patient and an ankle of the patient; determining a pose of the measurement system based on the plurality of measurements; decomposing the pose of the measurement system into tri-axial rotations in a frame of reference of the tibia of the patient; and determining the tibia varus or valgus angle based on the tri-axial rotations.
A non-transitory computer-readable medium storing instructions that are executable by a processor to perform operations, including: receiving first data from a measurement system, wherein: a prosthetic knee component (70) comprising the measurement system is coupled to a bone of a patient; and the first data includes a plurality of measurements from each of an accelerometer and a gyroscope included with an inertial measurement unit (82) of the measurement system; receiving a first measurement of a length of a tibia (44) of the patient; determining a tibia varus or valgus angle based on the first data and the first measurement; and causing a display (260) to output the determined tibia varus or valgus angle.
The non-transitory computer-readable medium of claim 8, wherein the operations further include: causing the display (260) to output instructions for moving or posing the musculoskeletal system of the patient that, when executed, cause the accelerometer and the gyroscope to generate the first data.
The system of claim 1, wherein the measurement device is configured to removably couple to the prosthetic knee component.

Description

TECHNICAL FIELD The present disclosure relates generally to measurement of physical parameters, and particularly to, but not exclusively, medical electronic devices for high precision orthopedic alignment. BACKGROUND The skeletal system of a mammal is subject to variations among species. Further changes can occur due to environmental factors, degradation through use, and aging. An orthopedic joint of the skeletal system typically comprises two or more bones that move in relation to one another. Movement is enabled by muscle tissue and tendons attached to the skeletal system of the joint. Ligaments hold and stabilize the one or more joint bones positionally. Cartilage is a wear surface that prevents bone-to-bone contact, distributes load, and lowers friction. There has been substantial growth in the repair of the human skeletal system. In general, orthopedic joints have evolved using information from simulations, mechanical prototypes, and patient data that is collected and used to initiate improved designs. Similarly, the tools being used for orthopedic surgery have been refined over the years, but have not changed substantially. Thus, the basic procedure for replacement of an orthopedic joint has been standardized to meet the general needs of a wide distribution of the population. Although the tools, procedure, and artificial joint meet a general need, each replacement procedure is subject to significant variation from patient to patient. The correction of these individual variations relies on the skill of the surgeon to adapt and fit the replacement joint using the available tools to the specific circumstance. The solution of this disclosure resolves these and other issues of the art. US 2015/272484 A1 discloses apparatus for monitoring, measuring and/or estimating deviation of a body part of a vertebral mammal. The disclosed apparatus includes at least one sensor for measuring rotation of the body part relative to a first frame of reference and for providing data indicative of the rotation. The apparatus also includes a memory device adapted for storing the data and a processor adapted for processing the data to evaluate a deviation of the body part that correlates to the data. The apparatus may include rotation sensors such as gyroscopes and optionally one or more inertial sensors such as accelerometers and/or magnetometers to ascertain medio-lateral deviation. In one form of apparatus the sensors are placed along or in-line with tibial axes of the left and right legs of a human subject. US 2017/252187 A1 discloses an orthopedic measurement system to measure leg alignment. The measurement system includes a tri-axial gyroscope configured to measure movement of a leg. The gyroscope is coupled to a tibia of the leg. For example, the gyroscope can be placed in an insert or tibial prosthetic component that couples to the tibia. The gyroscope is used to measure alignment relative to the mechanical axis of the leg. The leg alignment measurement is performed by putting the leg through a first leg movement and a second leg movement. The gyroscope outputs angular velocities on the axes the sensor is rotated about. The gyroscope is coupled to a computer that calculates the alignment of the leg relative to the mechanical axis from the gyroscope measurement data. SUMMARY OF THE INVENTION The scope of the present invention is set out in the appended set of claims. SUMMARY OF THE DISCLOSURE In accordance with certain embodiments of the present disclosure, a system for measuring one or more parameters of the muscular-skeletal system is disclosed. The system may include a measurement device. The measurement device may include: a housing that is configured to couple to a musculoskeletal system of the patient; an inertial measurement unit disposed within the housing, and a transmitter configured to output the plurality of measurements. The inertial measurement unit may include: an accelerometer; and a gyroscope. The inertial measurement unit may be configured to record a plurality of measurements using the accelerometer and the gyroscope. The system may further include a prosthetic knee joint including a tibial prosthetic component coupled to a proximal end of a tibia of the patient. The housing of the measurement device may be configured to removably couple to the tibial prosthetic component. The system may further include a display; and a computing device for determining the tibia varus or valgus angle of the patient. The computing device may include: at least one processor; a communication component operatively connected to the processor; and a memory operatively connected to the processor, and storing instructions that are executable by the processor to perform operations. The operations may include: receiving first data from the measurement device that includes a plurality of measurements from each of the accelerometer and the gyroscope; receiving a first measurement of a length of a tibia of the patient; determining