EP-4734880-A1 - SYSTEM AND METHOD

EP4734880A1EP 4734880 A1EP4734880 A1EP 4734880A1EP-4734880-A1

Abstract

An aspect of the disclosure provides a bone implant system for stimulating growth in bone tissue cells of a human or animal patient, the system comprising: a bone implant (530); and an apparatus configured to be carried by the bone implant, the apparatus comprising: an energy provider (512), comprising an electromagnetic coupler configured to obtain electromagnetic energy via an electromagnetic field from an energy source disposed outside a body of the patient, wherein the electromagnetic coupler is carried by an external surface of the bone implant system; and a stimulator (517) configured to provide, based on energy from the energy provider, at least one of electrical or mechanical stimulus to a bone into which the bone implant is implanted.

Inventors

HALL, Thomas Ainsley Grant
ARKEL, Richard Jan van
CEGLA, Frederic

Assignees

IMPERIAL COLLEGE INNOVATIONS LIMITED

Dates

Publication Date: 20260506
Application Date: 20240628

Claims (20)

1. A bone implant system for stimulating growth in bone tissue cells of a human or animal patient, the system comprising: a bone implant; and an apparatus configured to be carried by the bone implant, the apparatus comprising: an energy provider, comprising an electromagnetic coupler configured to obtain electromagnetic energy via an electromagnetic field from an energy source disposed outside a body of the patient, wherein the electromagnetic coupler is carried by an external surface of the bone implant system; and a stimulator configured to provide, based on energy from the energy provider, at least one of electrical or mechanical stimulus to a bone into which the bone implant is implanted.
2. The bone implant system of claim 1 wherein the stimulator comprises an electromechanical element configured to provide a mechanical stimulus
3. The bone implant system of claim 2 wherein the electromechanical element comprises a piezoelectric transducer.
4. The bone implant system of claim 1 , 2, or 3, wherein an electrode of the electromechanical element comprises at least a portion of the exterior conductive surface and/or wherein the electromechanical element is provided on the exterior surface of the bone implant or wherein the electromechanical element is provided in the body of the bone implant and is mechanically coupled to the body of the bone implant and/or wherein the electromechanical element is at least partially encapsulated in the body of the bone implant.
5. The bone implant system of claim 4, wherein the electromechanical element comprises a plurality of piezoelectric transducers arranged such that each of the plurality of piezoelectric transducers is configured to provide a mechanical stimulus to the bone tissue at a location corresponding to the location of each piezoelectric transducer.
6. The bone implant system of any preceding claim wherein the electromagnetic coupler is at least partially encapsulated in a polymer casing, for example wherein the polymer casing provides a spacing between the electromagnetic coupler and all conductive parts of the bone implant system for example, wherein the electromagnetic coupler extends from the body of the implant.
7. The bone implant system of claim 6, wherein the polymer casing is at least partially transparent to radio frequency signals in the range 3 Hz to 9 GHz.
8. The bone implant system of any preceding claim wherein the electromagnetic coupler comprises at least one of an inductive coupler and a capacitive coupler, such as an antenna.
9. The bone implant of any preceding claim, wherein the stimulator is configured to provide a return signal via the energy provider, wherein the return signal is indicative of fixation of the bone implant to said bone.
10. A bone implant system for stimulating growth in bone tissue cells of a human or animal patient, the system comprising: a bone implant; and an apparatus configured to be carried by the bone implant, the apparatus comprising: an energy provider, configured to obtain energy from an energy source disposed outside a body of the patient; and a stimulator configured to provide, based on energy from the energy provider, stimulus to a bone into which the bone implant is implanted, wherein the stimulator is configured to provide a return signal via the energy provider, wherein the return signal indicates the fixation of the bone implant to said bone.
11. The bone implant system of claim 10, wherein the energy provider is configured to transmit the return signal provided by the stimulator and/or wherein the stimulator comprises an electromechanical element and an electrical response of the electromechanical element to an electrical signal is indicative of fixation of the bone implant, for example wherein the electrical response comprises an apparent impedance for example, wherein the electromechanical element comprises a piezoelectric transducer for example wherein the electromechanical element comprises a plurality of piezoelectric transducers arranged such that each of the plurality of piezoelectric transducers provide a return signal indicative of fixation of the bone implant at a location corresponding to the location of said each piezoelectric transducer.
12. The bone implant system of claim 11 , wherein the stimulator is configured to provide an alternating electrical stimulus to the bone and wherein an electrical coupling of the stimulator to said bone is indicative of fixation of the bone implant for example, wherein the stimulator comprises an exterior conductive surface for providing the alternating electrical stimulus to said bone and an electrical coupling between the exterior conductive surface and said bone is indicative of fixation of the bone implant.
13. The bone implant or bone implant system of any of claims 9 to 12, wherein the stimulator comprises at least two conductive elements for providing an alternating electric field.
14. The bone implant or bone implant system of any of claims 9 to 13, wherein the apparatus comprises a logic element configured to control the stimulator to provide stimulus to a bone into which the bone implant is implanted based on at least one of: energy from the energy provider; and the return signal.
15. The bone implant or bone implant system of any preceding claim wherein the stimulator is configured to provide oscillating stimulus of said bone tissue cells.
16. The bone implant or bone implant system of any preceding claim wherein the stimulator is configured to produce a mechanical stimulus that oscillates a bone facing surface of the bone implant system with an amplitude in a range of 1 pm to 1 urn leading to a corresponding displacement of the bone tissue cells and/or wherein the stimulator is configured to produce an electrical stimulus comprising an oscillating electrical charge with an amplitude in a range of in the range 1 pC/m 2 to 1 C/m 2 and/or wherein the mechanical stimulus and/or wherein the electrical stimulus is produced with a frequency in the range of 0.1 Hz to 500 MHz.
17. A bone implant system of any preceding claim, wherein the apparatus is at least partially positioned on the exterior surface of the bone implant optionally wherein the apparatus is at least partially encapsulated in the body of the bone implant.
18. A bone implant system of any preceding claim, wherein the apparatus protects the energy provider and stimulator from damage for example wherein the apparatus comprises a casing, wherein the energy provider and stimulator are at least partially embedded in the casing for example wherein the energy provider and stimulator are provided in the apparatus out of a wear path of the bone implant.
19. The bone implant system of any preceding claim further comprising an energy source, configured to be disposed outside the body for supplying energy to the energy provider of the apparatus.
20. An energy source for use with a bone implant system for stimulating growth in bone tissue cells of a human or animal patient wherein the energy source comprises: an electromagnetic coupler for coupling with an energy provider of the bone implant system, said bone implant system comprising said energy provider and a stimulator; the energy source further comprising: a controller, configured to: control the electromagnetic coupler to interrogate said bone implant system using an interrogation signal thereby also to cause the stimulator to provide a stimulus to a bone into which the bone implant is implanted, and to determine, based on a response to the interrogation signal, an indication of the fixation of the bone implant.

Description

System and Method Field of Invention The present invention relates to systems and methods and more particularly systems and methods for stimulating bone tissue growth in the proximity of bone implants. Background Bone-anchored implants are widely used in orthopaedic and orthodontic reconstructions for procedures including joint replacement (arthroplasty) , joint fusion (arthrodesis) , bone realignment (osteotomy) , and dental implants. Such implants require strong fixation to withstand the biomechanical loads of activities of daily life, with current fixation methods delineated as cemented versus cementless. In cementless fixation, implants are initially stabilised using design features, such as keels and pegs, or adjunct devices, such as screws or compressive anchors. Long-term fixation is then dependent on harnessing the innate regenerative properties of bone to establish direct structural and functional connections to the host tissue - osseointegration. It takes more than three months for biological fixation to reach peak strength, during which time patients are advised to moderate their activities of daily living. Successful osseointegration is ultimately dependent on the mechanical loading environment in the periprosthetic bone via mechanotransduction pathways. Excessive micromotion, mechanical displacements of the implant surface leading to motion between the implant and bone, causes the formation of a fibrous capsule and deprivation from mechanical load results in resorption of periprosthetic bone. Both complications pose a loosening risk for patients: the most common complication associated with cementless arthroplasty . Cementless fixation is preferable due to shorter operation times, which improves procedural efficiency for clinicians and reduces perioperative infection risk for patients, and ongoing biological maintenance of the implant-bone interface, which avoids the progressive and irreparable degradation of a cement layer. However, cementless fixation is not recommended for all patients, and is often contraindicated in patients with low bone density or low metabolism, such as osteoporotic or elderly patients. Survivorship of cementless implants is also lower in joints with less suitable bone stock for anchoring and restraint, such as glenoid components in anatomical total shoulder arthroplasty and tibial components in total knee arthroplasty. Research and development in this technical field has so far focused on passive measures, such as stiffness-matched implants, hydroxyapatite coatings, or piezoelectric implants. Others have sought to influence cellular pathways using orthobiologics, such as recombinant human bone morphogenetic protein 2 (rhBMP-2) , though use has been limited by problems with heterotopic ossification. External stimulation using ultrasound and electromagnetic fields have also been investigated as standalone treatments. US2006047283 describes a device for providing in vivo diagnostics of loads, wear, and infection in orthopaedic implants. US2021378841 describes an implantable electronic device and an endoprosthesis activity monitoring system. W014057077 describes a device and method for measuring the anchorage status of implants. DE102014109683 describes a device for detecting loosening and/or wear of an endoprosthesis. US5496256 describes an ultrasonic bone healing device for dental application . US2004038180 describes a dental implant, that comprises surface regions of a first type which have osseointegrative, inflammation- inhibiting, infection-combating and/or growth-promoting properties , and surface regions of a second type which consi st of a material which is liquefiable by mechanical oscillations . US2006052782 describes an orthopaedic implant , such as a bone plate , for the fixation of bone where the implant also has at least one microchip and at least one sensor connected to the microchip . US2019159725 describes a device for inductive heating of a foreign metallic implant are di sclosed . The present di sclosure describes systems and methods for providing enhanced os seointegration in patients with bone implants . Summary Aspects and examples of the invention are set out in the claims and aim to addres s at least a part of the above described technical problem, and other problems . Embodiments of the di sclosure may be useful in prosthetics which restore the function of a j oint , such as in prostheses for arthroplasty, for example artificial j oints and other prosthetics which may be used in hip arthroplasty, knee arthroplasty and so forth . Embodiments may be employed to improve cementles s fixation by enhanced os seointegration . Thi s may return patients to activity faster and more safely than current technologies , with as sociated societal and economic benefits . Enhancing os seointegration could also widen suitability for cementles s fixation to older patients , who are currently contraindicated for cementless procedures due to reduced activity level