US 5,961,474 AGranted

Non-invasive measurement of joint translation and range of motion

OwnerMark T. Reisinventor

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Abstract

Electromagnetic position sensors are placed on the skin of a patient to electronically measure joint translation and range of motion. Non-invasive monitoring is provided during a joint translation examination by placing one position sensor on the skin of the patient to measure the position of a first bone in the vicinity of the joint and another position sensor on the skin of the patient to measure the position of a second bone in the vicinity of the joint. The translation examination is then conducted by the attending physician, and the amount of joint translation is determined objectively by determining the difference in the relative position between the sensors from an initial position for the exam to a clinical end point for the exam. In a glenohumeral translation examination, one sensor is preferably placed on the skin over the scapular spine while the other sensor is preferably placed over the bicipital groove. In a shoulder range of motion examination, the sensor over the bicipital groove is moved to cover the biceps. Again, the range of motion is determined objectively by determining the difference in the relative position between the sensors from an initial position for the exam to a clinical end point for the exam. The invention can be used to objectively monitor translation and range of motion of other joints as well.

Claims29

Dependent claims

In a patient having a first bone and a second bone which are articulated at a joint, a non-invasive method of objectively measuring joint translation at the joint in a clinical setting comprising the steps of

a) placing a first position sensor on the surface of the skin of a patient to measure the position of the first bone in the vicinity of the joint;
b) generating a first position signal in response to the position of the first position sensor;
c) placing a second position sensor on the surface of the skin of the patient to measure the position of the second bone in the vicinity of the joint;
d) generating a second position signal in response to the position of the second position sensor;
e) positioning the first bone and the second bone with respect to each other in a clinical neutral position at the joint and storing the value of the first and second position signals when the first and second bones are positioned in the clinical neutral position;
f) using the stored value of the first and second position signals when the first and second bones are positioned in the clinical neutral position to determine the relative position between the first and second electromagnetic position sensors when the first and second bones are positioned in the clinical neutral position;
g) applying force to move the first bone in the vicinity of the joint with respect to the second bone in the vicinity of the joint to a clinical end point and storing the value of the first and second position signals when the first and second bones are positioned at the clinical end point;
h) using the stored values of the first and second position signals when the first and second bones are positioned at the clinical end point to determine the relative position between the first and second position sensors when the first bone in the vicinity of the joint is positioned at the clinical end point with respect to the second bone in the vicinity of the joint;
and
i) determining the translation of the joint by comparing the relative position between the first and second position sensors when the first and second bones are in the clinical neutral position to the relative position between the first and second position sensors when the first bone is positioned at the clinical end point with respect to the second bone.

7 more elements

A non-invasive system for objectively measuring joint translation in a joint of a patient comprising:

an electromagnetic transmitter that produces a magnetic field in an examination area;
a first electromagnetic position sensor that generates a first position signal in response to the position of the first electromagnetic position sensor in the magnetic field, where the first electromagnetic position sensor is configured for placement on the surface of the skin of the patient over a first bone in the vicinity of the joint;
a second electromagnetic position sensor that generates a second position signal in response to the position of the second electromagnetic position sensor in the magnetic field, wherein the second electromagnetic position sensor is part of a sensor assembly that includes means for mounting the second sensor on the surface of the skin of the patient over a second bone in the vicinity of the joint;
and
a programmed computer that receives the first and second position signals, the programmed computer including means for objectively determining joint translation of the joint when the patient undergoes a joint translation examination with the first electromagnetic position signal placed on the surface of the skin of the patient over the first bone in the vicinity of the joint and the second electromagnetic position sensor placed on the surface of the skin of the patient over the second bone in the vicinity of the joint.

2 more elements

A non-invasive method of objectively measuring glenohumeral translation in a patient in a clinical setting comprising the steps of:

a) placing a scapula position sensor on the surface of the skin of a patient over the patient's scapula;
b) generating a scapula position signal in response to the position of the scapular position sensor;
c) placing a humeral head position sensor on the surface of the skin of the patient at a location corresponding to the humeral head of the patient;
d) generating a humeral head position signal in response to the position of the humeral head position sensor;
e) centering the humeral head within a glenoid of the scapula, and storing the values of the scapula position signal and the humeral head position signal when the humeral head is centered within the glenoid of the scapula;
f) using the stored values of the scapula position signal and the humeral head position signal to determine the relative position between the scapula position sensor and the humeral head position sensor when the humeral head is centered within the glenoid of the scapula;
g) applying force to move the humeral head with respect to the glenoid of the scapula to a clinical end point, and storing the values of the scapula position signal and the humeral head position signal when the humeral head is positioned at the clinical end point with respect to the glenoid of the scapula;
h) using the stored values of the scapula position signal and the humeral head position signal to determine the relative position between the scapula position sensor and the humeral head position sensor when the humeral head of the patient is positioned at the clinical end point with respect to the glenoid of the scapula;
i) determining glenohumeral translation by comparing the relative distance between the scapula position sensor and the humeral head position sensor when the humeral head is centered in the glenoid to the relative distance between the scapular position sensor and the humeral head position sensor when the humeral head is positioned at the clinical end point with respect to the glenoid.

6 more elements

In a patient having a first bone and a second bone articulated at a joint, a non-invasive method of objectively measuring range of motion of the joint in a clinical setting comprising the steps of:

a) placing a first position sensor on the surface of the skin of the patient to measure the position of the first bone in the vicinity of the joint;
b) generating a first position signal in response to the position of the first position sensor;
c) placing a second position sensor on the surface of the skin of the patient to measure the position of the second bone;
d) generating a second position signal in response to the position of the second position sensor;
e) placing the second bone at an initial position and storing the value of the first and second position signals when the second bone is in the initial position;
f) actively or passively moving the second bone through a clinical range of motion examination to a clinical end point and storing the value of the first and second position signals when the second bone is positioned at the clinical end point;
and
g) objectively determining the range of motion of the joint by comparing the relative position of the first and second position sensors when the second bone of the patient is in the initial position to the relative position of the first and second sensors when the second bone of the patient is positioned at the range of motion clinical end point.

5 more elements

For use with a patient having a first bone and a second bone which are articulated at a joint, a non-invasive electromagnetic monitoring system for objectively measuring range of motion of the joint comprising:

an electromagnetic transmitter that produces a magnetic field in an examination area;
a first electromagnetic position sensor that generates a first position signal in response to the position of the first electromagnetic position sensor in the magnetic field, wherein the first electromagnetic position sensor is configured for placement on the surface of the skin of the patient over the second bone articulated at the joint;
a second electromagnetic position sensor that generates a second position signal in response to the position of the second electromagnetic position sensor in the magnetic field, wherein the second electromagnetic position sensor is configured for placement on the surface of the skin of the patient over the second bone articulated at the joint;
and
a programmed computer that receives the first and second position signals, the programmed computer including means for objectively determining joint range of motion when the patient undergoes a range of motion examination with the first electromagnetic position sensor placed on the surface of the skin of the patient over the first bone in the vicinity of the joint and the second electromagnetic position sensor placed on the surface of the skin of the patient over the second bone.

2 more elements

Dependencies are inferred from the claim text.