Method and apparatus for determining osseous implant fixation integrity

Claim 1

A method for determining, without the utilization of base line information, the integrity of a heterogeneous composite substrate of an implant fixation in a bone of a limb of a patient, the substrate including a bone to cement interface and a cement to implant fixation interface, comprising: using a vibrator having a smoothly contoured member; compressing firmly with the contoured member, the flesh of the limb to the bone and to the implant fixation, of the substrate, over a large outer surface area of the limb, to enable vibrations to be imparted through the compressed flesh and through said heterogeneous composite substrate, to the bone, with little discomfort or damage to the limb; supplying to said vibrator an input energizing electrical signal having a predetermined recurring pattern of a single non-resonant frequency; vibrating the heterogeneous composite substrate, including each one of the interfaces thereof in response to the vibrator being energized by said input signal; using a single pick-up device; pressing the pick-up device into engagement with the outer surface of the limb spaced from the vibrator at the same bone, for detecting the vibratory motion of the bone implant heterogeneous composite substrate, to generate a single output electrical signal; analyzing said input energizing electrical signal relative to the recurring pattern only of the single output electrical signal transmitted through the bone implant heterogeneous composite substrate and each one of said interfaces, without the utilization of base line information; and determining implant loosening when said recurring pattern of said output signal is persistently distorted.

Claim 2

A method for determining, without the utilization of base line information, the integrity of a heterogeneous composite substrate of an implant fixation in a bone of a limb of a patient, the substrate including a bone to cement interface and a cement to implant fixation interface, comprising: using a vibrator having a smoothly contoured member; compressing firmly with the contoured member, the flesh of the limb to the bone and to the implant fixation, of the substrate, over a large outer surface area of the limb, to enable vibrations to be imparted through the compressed flesh and through said heterogeneous composite substrate, to the bone, with little discomfort or damage to the limb; supplying to said vibrator an input energizing electrical signal having a predetermined recurring pattern of a single non-resonant frequency; vibrating the heterogeneous composite substrate, including each one of the interfaces thereof in response to the vibrator being energized by said input signal; using a single pick-up device; pressing the pick-up device into engagement with the outer surface of the limb spaced from the vibrator at the same bone, for detecting the vibratory motion of the bone implant heterogeneous composite substrate, to generate a single output electrical signal; analyzing said input energizing electrical signal relative to the recurring pattern only of the single output electrical signal transmitted through the bone implant heterogeneous composite substrate and each one of said interfaces, without the utilization of base line information; and determining implant loosening when said recurring pattern of said output signal is persistently distorted.

Claim 3

An apparatus for determining, without the utilization of base line information, the integrity of a heterogeneous composite substrate of an implant fixation in a bone of a limb of a patient, the substrate including a bone to cement interface, and a cement to implant fixation interface, comprising: vibrator means for imparting to the heterogeneous composite substrate, including each one of the interfaces thereof, vibratory motion having a predetermined recurring pattern, said vibrator means including a smoothly contoured member adopted to compress firmly the flesh of the limb to the bone and to the implant fixation, of the substrate, over a large outer surface area of the limb, to enable vibrations to be imparted through the compressed flesh and through said heterogeneous composite substrate, to the bone, with little discomfort or damage to the limb; means for generating a vibrator energizing electrical signal having a predetermined recurring pattern of single non-resonant frequency; single pick-up means adapted to be pressed into engagement with the outer surface of limb spaced from said vibrator means for detecting the vibratory motion of said bone implant heterogeneous composite substrate, to generate a recurring single output electrical signal; and means for analyzing said input energizing electrical signal relative to the pattern of said single output electrical signal only transmitted through the bone implant heterogeneous composite substrate and each one of said interface, without the utilization of base line information, to determine implant fixation loosening when said single input recurring pattern is persistently distorted; wherein said means for analyzing includes means for detecting subharmonic frequencies of said signal output signal to indicate a lack of implant fixation integrity.

Claim 4

An apparatus for determining, without the utilization of base line information, the integrity of a heterogeneous composite substrate of an implant fixation in a bone of a limb of a patient, the substrate including a bone to cement interface, and a cement to implant fixation interface, comprising: vibrator means for imparting to the heterogeneous composite substrate, including each one of the interfaces thereof, vibratory motion having a predetermined recurring pattern, said vibrator means including a smoothly contoured member adopted to compress firmly the flesh of the limb to the bone and to the implant fixation, of the substrate, over a large outer surface area of the limb, to enable vibrations to be imparted through the compressed flesh and through said heterogeneous composite substrate, to the bone, with little discomfort or damage to the limb; means for generating a vibrator energizing electrical signal having a predetermined recurring pattern of single non-resonant frequency; single pick-up means adapted to be pressed into engagement with the outer surface of limb spaced from said vibrator means for detecting the vibratory motion of said bone implant heterogeneous composite substrate, to generate a recurring single output electrical signal; and means for analyzing said input energizing electrical signal relative to the pattern of said single output electrical signal only transmitted through the bone implant heterogeneous composite substrate and each one of said interface, without the utilization of base line information, to determine implant fixation loosening when said single input recurring pattern is persistently distorted; wherein said means for analyzing includes means for detecting subharmonic frequencies of said signal output signal to indicate a lack of implant fixation integrity.