SLEEVE ELEMENT TO BE PLACED ON A NECK OF A PROSTHETIC HIP OR SHOULDER IMPLANT

Abstract

The invention provides a sleeve element (1) to be placed on a neck (53) of a prosthetic hip (51) or shoulder implant, wherein the sleeve element is made of a biodegradable elastically deformable material comprising a medical active agent to be released from the sleeve element. The sleeve element may comprise a longitudinal channel (2) and a longitudinal slit (3) extending over the length of the longitudinal channel and between the longitudinal channel and an outer surface of the sleeve element, wherein the sleeve element is elastically deformable between a closed state and an opened state, wherein a width of the longitudinal slit in the opened state is larger than the width of the longitudinal slit in the closed state. The invention also provides a prosthetic kit, comprising a prosthetic hip or shoulder implant having a neck, and the above sleeve element.

Claims

1. A sleeve element to be placed on a neck of a prosthetic hip or shoulder implant, wherein the sleeve element is made of a biodegradable, elastically deformable material comprising one or more medical active agents.

2. The sleeve element of claim 1, wherein the elastic modulus of the biodegradable, elastically deformable material is between 1 kPa and 1 MPa.

3. The sleeve element of claim 1, wherein the sleeve element is free of fixation elements to fixate the sleeve element to the neck of the prosthesis.

4. The sleeve element of claim 1, wherein the sleeve element has a compressive strain of at least 5% at the elastic limit of the elastically deformable material in a direction in which a compressive force is exerted on the elastically deformable material.

5. The sleeve element of claim 1, wherein the biodegradable elastically deformable material comprises a main body and a coating coated on at least a part of the surface the main body, wherein the medical active agent is comprised in the main body, wherein the coating comprises a coating material and the main body comprises a main body material, wherein the coating material is stiffer than the main body material.

6. The sleeve element of claim 1, wherein the sleeve element comprises a longitudinal channel and a longitudinal slit extending over the length of the longitudinal channel and between the longitudinal channel and an outer surface of the sleeve element, wherein the sleeve element is elastically deformable between a closed state and an opened state, wherein a width of the longitudinal slit in the opened state is larger than the width of the longitudinal slit in the closed state.

7. The sleeve element of claim 6, wherein the sleeve element in the closed state is substantially non-deformed and in the opened state the sleeve element is elastically deformed.

8. The sleeve element of claim 6, wherein the sleeve element comprises a closure device to hold the sleeve element in the closed state.

9. The sleeve element according to claim 6, wherein the longitudinal slit is formed between a first longitudinal edge of the sleeve element and a second longitudinal edge of the sleeve element, wherein the closure device comprises a snap fit connection between the first longitudinal edge and the second longitudinal edge.

10. The sleeve element according to claim 9, wherein the closure device comprises a closure element that can be arranged around the sleeve element.

11. The sleeve element of claim 1, wherein the sleeve element comprises a longitudinal channel defined by a continuous ring shape around the longitudinal channel.

12. The sleeve element of claim 1, wherein the sleeve element comprises one or more stiffening elements that bias the sleeve element to the closed state.

13. The sleeve element of claim 12, wherein the one or more stiffening elements comprise one or more elastically deformable ribs arranged on or in sleeve element.

14. The sleeve element of claim 5, wherein the main body material comprises a visco-elastic material, a degradable felt material, a sponge-like material, a gelatin, a gel, in particular a hydrogel, a polymer material, or any combination thereof.

15. The sleeve element of claim 1, wherein the sleeve element comprises a shape which is designed to not hinder a range of motion of the hip or shoulder implant after implantation, or a frustro-conical outer shape.

16. (canceled)

17. The sleeve element of claim 1, wherein the medical active agent is an analgesic or an anaesthetic.

18. The sleeve element of claim 1, wherein the sleeve element comprises two or more compartments, wherein each compartment comprises one or more medical active agents.

19. A prosthetic kit, comprising: a prosthetic hip or shoulder implant having a neck, and a sleeve element according to claim 1.

20. The prosthetic kit of claim 19, wherein an inner surface of the longitudinal channel substantially mates with an outer surface of a part of the neck on which the sleeve element is placed or will be placed.

21. The prosthetic kit of claim 19, wherein the sleeve element is designed such that it can be arranged, in the closed state, in only one position on the neck of the prosthetic hip or shoulder implant.

22. The prosthetic kit of claim 19, wherein the neck is part of a femoral component of a prosthetic hip implant, the femoral component having a neck to receive a femoral head, wherein the sleeve element is designed to be placed on the neck of the femoral component.

23. The prosthetic kit of claim 22, wherein the prosthetic hip implant further comprises an acetabular component, wherein the femoral component and acetabular component are designed to facilitate, after implantation, a range of movement of the femoral component with respect to the acetabular component, wherein outer dimensions of the sleeve element are selected to prevent that relative movement of the femoral component with respect to the acetabular component is blocked by the presence of the sleeve element on the neck of the femoral component.

24. The prosthetic kit of claim 19, wherein the prosthetic kit further comprises a loader arranged to load a sleeve element on the neck of the prosthetic hip or shoulder implant.

Description

[0089] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0090] FIG. 1a shows an embodiment of a prosthetic hip implant;

[0091] FIG. 1b shows the embodiment of the prosthetic hip implant of FIG. 1a including a first embodiment of a sleeve element arranged on the neck of the femoral component of the prosthetic hip implant;

[0092] FIG. 2a shows a side view of the first embodiment of a sleeve element;

[0093] FIG. 2b shows a longitudinal sectional view B-B of the first embodiment of FIG. 1a;

[0094] FIG. 2c shows a cross sectional view A-A of the embodiment of FIG. 1a in closed state;

[0095] FIG. 2d shows a cross sectional view of the embodiment of FIG. 1a in opened state;

[0096] FIG. 3a shows a side view of a second embodiment of a sleeve element;

[0097] FIG. 3b shows a top view of the second embodiment of FIG. 3a;

[0098] FIG. 4a shows a longitudinal sectional view D-D of a third embodiment of a sleeve element;

[0099] FIG. 4b shows a cross sectional view C-C of the embodiment of FIG. 4a;

[0100] FIG. 5a shows a side view of a fourth embodiment of a sleeve element;

[0101] FIG. 5b shows a top view of the fourth embodiment of FIG. 5a;

[0102] FIG. 6 shows a longitudinal sectional view of a fifth embodiment of a sleeve element;

[0103] FIG. 7a shows a side view of a sixth embodiment of a sleeve element;

[0104] FIG. 7b shows a longitudinal sectional view E-E of the embodiment of FIG. 7a;

[0105] FIG. 7c shows a cross sectional view F-F of the embodiment of FIG. 7a;

[0106] FIG. 8 shows the embodiment of FIG. 7a mounted on a prosthetic hip implant;

[0107] FIG. 9 shows a seventh embodiment of a sleeve element mounted on a prosthetic hip implant;

[0108] FIGS. 10a and 10b show schematically a first embodiment of a loader configured to arranged the sleeve element on a neck of a prosthetic hip or shoulder implant; and

[0109] FIGS. 11a and 11b show schematically a second embodiment of a loader configured to arranged the sleeve element on a neck of a prosthetic hip or shoulder implant.

[0110] FIG. 1a shows a prosthetic hip implant generally denoted by reference numeral 50. The prosthetic hip implant 50 comprises a femoral component 51 to be connected to the femur of a patient and a acetabular component 55 to be connected to the acetabulum (hip socket) of a patient.

[0111] The femoral component 51 comprises a stem 52 to be placed into the femur, a neck 53 and a head 54 supported on the neck 53. The acetabular component 55 comprises a acetabular cup 56 that may be provided with a liner 57 arranged in the acetabular cup 56.

[0112] Prosthetic hip implants 50 are widely known in the art. Hip replacements using these types of prosthetic hip implants 50 is currently one of the most common orthopedic operations, though patient satisfaction short- and long-term varies widely. In view of the possible negative effects of a hip replacement, such as pain and infection risks, there is a need to administer one or more medical active agents to the patient after implantation of the prosthetic hip implant 50.

[0113] FIG. 1b shows the prosthetic hip implant 50 of FIG. 1 with a sleeve element 1 according to an embodiment of the invention arranged on the neck 53 of the femoral component 51. The sleeve element 1 is made of a biodegradable elastically deformable material comprising a medical active agent, for example a pain treatment drug, such as an anaesthetic or analgesic.

[0114] The sleeve element 1 is configured to release the medical active agent according to a predetermined release profile.

[0115] The sleeve element 1 is arranged to be completely degraded within 12 months, for example within 1 to 9 months. This relatively short degradation time has the advantage that the sleeve element 1 is only present on the neck of the prosthetic implant for a limited time.

[0116] FIGS. 2a, 2b, 2c and 2d show the embodiment of the sleeve element 1 as depicted in FIG. 1b in more detail.

[0117] The sleeve element 1 comprises a longitudinal channel 2 and a longitudinal slit 3. The longitudinal channel 2 is configured to receive the neck 53. In the embodiment shown in FIGS. 2a-2d, the inner dimensions of the longitudinal channel 2 are slightly larger than the outer dimensions of the neck 53 resulting in some play between the sleeve element 1 and the neck 53. In other embodiments, the inner dimensions of the longitudinal channel 2 may be substantially the same as the outer dimensions of the neck 53 resulting in a tight fit between the sleeve element 1 and the neck 53. In yet another embodiment, the inner dimensions of the longitudinal channel 2 may be smaller than the outer dimensions of the neck 53 resulting in some clamping of the sleeve element 1 on the neck 53.

[0118] The longitudinal slit 3 extends over the length of the longitudinal channel 2 between the longitudinal channel 2 and an outer surface of the sleeve element 1. As a result, the sleeve element 1 comprises two longitudinal edges 4 that may be arranged against each other to create a closed ring-shaped cross section as shown in FIG. 2c.

[0119] The sleeve element 1 is elastically deformable between a closed state, as shown in FIG. 2c, in which the width of the longitudinal slit 3 is smaller than a cross dimension of the neck 53, as shown in FIG. 2c, and an opened state in which the width of the longitudinal slit is at least the same as the cross dimension of the neck 53. In the closed state, the sleeve element 1 may be non-deformed, i.e. without any external force, the sleeve element 1 will be in the closed state shown in FIG. 2c.

[0120] The sleeve element 1 can be brought into the opened state by moving the longitudinal edges 4 away from each other, as shown in FIG. 2d by arrows K, to create a distance between the longitudinal edges 4. When the width of the slit 3, i.e. the distance between the longitudinal edges 4, is at least as large as the cross dimension of the neck 53, the sleeve element 1 can be placed on the neck 53, by movement of the sleeve element 1 in the direction L shown in FIG. 2d. When the longitudinal edges 4 are released, the sleeve element 1 will substantially deform back towards the closed state where it is held on the neck 53.

[0121] The advantage of this embodiment of the sleeve element 1 is that the sleeve element 1 can be arranged on the neck 53 even when the head 54 is already mounted on the neck 53. As a result, the sleeve element 1 may be arranged on the neck 53 at any suitable stage of the surgical procedure. For example, only after it has been concluded that the prosthetic hip implant 50 has been successfully implanted into a human or animal body, the sleeve element 1 may be arranged on the neck 53. The placement of the sleeve element 1 therefore does not have a large impact on the presently used surgical procedure for prosthetic hip or shoulder implants.

[0122] The inner surface of the sleeve element forming the longitudinal channel 2 may at least partially be provided with an adhesive layer that allows the sleeve element 1 to be adhered to the neck 53. This further reduces the chance that the sleeve element 1 inadvertently is moved from its position on the neck 53.

[0123] In another embodiment, the sleeve element is free of fixation elements to fixate the sleeve element 1 to the neck 53 of the prosthetic implant. Since the sleeve element 1 is elastically deformable, it may adapt its shape when it becomes pinched as a result of movements of the prosthetic implant, and therefore some displacement of the sleeve element 1 on the neck 53 may be accepted.

[0124] The sleeve element 1 is made of a biodegradable elastically deformable material and comprises a main body and a coating coated on at least a part of the surface the main body. The medical active agent is comprised in the main body. The medical active agent may be distributed substantially equally within the material of the main body. This has the advantage that a relatively large volume of medical active agent with a relatively low maximum concentration level of the medical active agent can be arranged in the main body of the sleeve element 1.

[0125] The coating comprises a coating material and the main body comprises a main body material. The coating material is stiffer than the main body material. The main body material may for example comprise a visco-elastic material, a degradable felt material, a sponge-like material, a gelatin, a gel, in particular a hydrogel, a polymer or any combination thereof. The sleeve element 1 may also be provided without a coating, i.e. only a main body of the same biodegradable elastically deformable material.

[0126] The elastic modulus of the biodegradable, elastically deformable material may be between 1 kPa and 1 MPa.

[0127] The sleeve element shown in FIGS. 2a, 2b, and 2c comprises a frusto-conical outer shape. This shape is selected to make maximally use of the intra articular space without hindering the range of motion of the components of the prosthetic hip implant 50. A relatively large volume of the sleeve element 1 allows to provide a relatively large amount of medical active agent with a relatively low concentration of the medical active agent.

[0128] The outer dimensions of the sleeve element are selected such that they do not overpass a virtual line between the outer dimensions of the head mounted on the neck of a prosthesis and the outer dimensions of the base of the neck, thereby ensuring no or little interference with the range of motion of the prosthesis. Some interference may be compensated by the deformability of the material of the sleeve element 1.

[0129] To compensate any interference of the sleeve element 1 with the movement of the prosthetic implant 50, the sleeve element 1 may have a compressive strain of at least 5%, for example at least 15%, at the elastic limit of the elastically deformable material in a direction in which a compressive force is exerted on the elastically deformable material. The compressive strain may be calculated as a change in dimension in a compression direction in which a compressive force is exerted on the sleeve element divided by the original dimension of the sleeve element in the compression direction.

[0130] FIGS. 3a and 3b show a second embodiment of a sleeve element 1. In this embodiment, a closure device 5 is provided to hold the sleeve element 1 in the closed state. The closure device comprises bulges 5a at one longitudinal edge 4 and corresponding recesses 5b at the opposite longitudinal edge 4 of the sleeve element 1. The bulges 5a and the recesses 5b form a snap-fit connection between the longitudinal edges 4. In the closed state of the sleeve element 1, the bulges 5a may be arranged in the recesses 5b to prevent that the longitudinal edges 4 move away from each other.

[0131] In alternative embodiments, other closure devices may be provided to hold the sleeve element 1 in the closed state. These closure devices may be integrated in the material of the sleeve element 1, such as the bulges 5a and recesses 5b, but may also be provided as separate devices that can be used to hold the sleeve element 1 in the closed state. These closure devices may for example comprise closure elements such as bands, sutures, cerclages, strips, shells or covers that can be arranged around the sleeve element to hold the sleeve element 1 in the closed state. The complete sleeve element 1 including the closure device may be made of biodegradable materials.

[0132] FIGS. 4a and 4b show a third embodiment of a sleeve element 1. On the inner surface forming the longitudinal channel 3 elastically deformable ribs 6 are arranged. The elastically deformable ribs 6 are relatively stiff with respect to the material of the main body of the sleeve element 1. The elastically deformable ribs 6 form stiffening elements that bias the sleeve element 1 to the closed state. The elastically deformable ribs 6 do however not prevent that the sleeve element 1 may be opened to the opened state to arrange the sleeve element 1 on the neck 53 of the femoral component 51. Thus, the sleeve element 1 can still be mounted on the neck 53 after the head 54 of the hip prosthesis implant 51 has been mounted on the neck 53.

[0133] The elastically deformable ribs 6 may be created by a coating material coated on the inner surface of the longitudinal channel 2. The elastically deformable ribs 6 may also be created by any other suitable material. In addition, or as an alternative, elastically deformable ribs 6 may be provided in/by the material of the main body of the sleeve element 1 or on the outer side of the sleeve element. Also, other stiffening elements, such as relatively stiff partially cylindrical elements may be provided to increase the stiffness of the sleeve element 1 in order to bias the sleeve element to the closed state. The complete sleeve element, including the stiffening elements 6 may be made of biodegradable materials.

[0134] FIGS. 5a and 5b show a fourth embodiment of a sleeve element 1. In this embodiment, the sleeve element 1 does not comprise a longitudinal slit. The cross section of the sleeve element 1 around the longitudinal channel 2 is continuous. The sleeve element 1 of FIGS. 5a and 5b can only be arranged on the neck 53 when the head 54 is not mounted on the neck 53. This requires that the sleeve element 1 is already arranged on the neck 53 during the surgical procedure before the head 54 is mounted on the neck 53, or the head 54 has to be temporarily removed from the neck 53 to place the sleeve element 1 on the neck.

[0135] FIG. 5b shows that the shape and dimensions of the cross-section of the longitudinal channel 2 are selected to substantially correspond to shape and dimensions of the cross-section of the neck 53. This provides a relative tight fit of the sleeve element 1 on the neck 53, whereby the sleeve element 53 can only be mounted in a single position on the neck 53. This single mounting position can be used advantageously to ensure that the sleeve element 1 will only occupy the intended space in the hip or should prosthesis. This may in particular be relevant when the sleeve element 1 is designed to maximally use the intra articular space, while at the same time interference with the range of motion of the hip or should prosthesis after implantation should be substantially avoided.

[0136] The adaptation of the shape and dimensions of the cross-section of the longitudinal channel 2 to substantially correspond to shape and dimensions of the cross-section of the neck 53 may also be applied in any other embodiment of a sleeve element 1, such as the sleeve elements of the embodiments shown and described in this patent application.

[0137] However, since the sleeve element 1 is made of elastically deformable material, the deformable material may also facilitate the arrangement of the sleeve element 1 on the neck of different types and sizes of the prosthetic hip or shoulder implants and facilitate the adaptation of the shape of the sleeve element 1 to the shape of the neck of the respective prosthetic hip or shoulder implant.

[0138] FIG. 6 shows a fifth embodiment of a sleeve element 1. The sleeve element 1 comprises a first compartment 7 and a second compartment 8 in the main body, wherein each of the first compartment 7 and the second compartment 8 comprises a medical active agent. The medical active agent in the first compartment 7 may be the same as the medical active agent in the second compartment 8, but the first compartment 7 and the second compartment 8 may be designed to provide different release profiles for the medical active agent. Alternatively, the medical active agent or combination of medical active agents in the first compartment 7 may be different than the medical active agent or combination of medical active agents in the second compartment 8 and having the same or different medical active agent release profiles.

[0139] For example, the first compartment 7 may comprise a medical active agent for pain treatment, such as an analgesic or anaesthetic, and the second compartment 8 may comprise an antibiotic to treat or prevent bacterial infections. These medical active agents may also be provided in a single compartment, but the use of two compartments allows to influence and control the release profiles of the two medical active agents more accurately.

[0140] In the embodiment of FIG. 6 the first compartment 7 and the second compartment 8 are separated by a separation wall 9. In an alternative embodiment, the first compartment 7 and the second compartment 8 do not have to be separated by a separation wall 9. The first compartment 7 and the second compartment 8 may for example also be distinguished by their differences in characteristics.

[0141] FIGS. 7a, 7b and 7c show a sixth embodiment of a sleeve element 1 to be arranged on the neck 53 of a prosthetic hip or shoulder implant.

[0142] FIG. 8 shows this sixth embodiment, in cross section, mounted on the neck of the prosthetic hip implant 50 of FIG. 1a.

[0143] The sleeve element 1 comprises a longitudinal slit 3 arranged between the longitudinal edges 4. The sleeve element 1 comprises a longitudinal channel 2 that tapers outwards from one side (upper side in FIG. 7b) to the opposite side (bottom side in FIG. 7b). This shape is selected such that the sleeve element 1 that is mounted on the neck 53 may have a relatively large volume, that is arranged, after implantation as shown in FIG. 8, while at the same time, a relative small length of the neck 53 is needed for mounting the sleeve element 1 on the neck 53. At the same time a relatively large amount of medical active agent in a relatively low concentration may be provided near the prosthetic hip implant 50.

[0144] In the longitudinal channel 2, the sleeve element 1 comprises a relatively stiff partially cylindrical element 10. This partially cylindrical element 10 acts as a stiffening element that improves the positioning of the sleeve element 1 on the neck 53. The partially cylindrical element 10 is also part of a closure device 5. The closure device 5 comprises two extensions 11a, 11b connected at opposite ends of the partially cylindrical element 10. Each of the two extensions 11a, 11b support ratchet teeth 12a, 12b. The ratchet teeth 12a, 12b allow the extensions 11a, 11b to be locked with respect to each other in multiple relative locking positions. Each of the multiple relative locking positions relates to a specific diameter of the partially cylindrical element 10. Thus, the closure device 5 allows the sleeve element 1 to be tightly mounted on the neck 53 of different types of prosthetic hip implants even when the necks of the different types of prosthetic hip implants may have other dimensions within the range of the relative locking positions of the two extensions 11a, 11b. This tight arrangement of the partially cylindrical element 10 on the neck 53 also reduces the risk of displacement of the sleeve element 1 on the neck 53, in particular sliding over the neck 53.

[0145] The stiffness of the partially cylindrical element 10 may be selected such that the shape of the partially cylindrical element 10 may at least partially adapt to a non-cylindrical cross section of the neck 53.

[0146] All elements of the sleeve element 1 of FIGS. 7a, 7b and 7c may be made of biodegradable materials.

[0147] FIG. 9 shows a seventh embodiment of a sleeve element 1, in cross section, mounted on the neck 53 of the prosthetic hip implant 50 of FIG. 1a. The seventh embodiment comprises generally the same shape as the embodiment of FIGS. 7a, 7b and 7c, but does not comprise the partially cylindrical element 10. The sleeve element 1 of FIG. 8 may be provided with a longitudinal slit, such the sleeve element 1 may be mounted on the neck 53 at the end of a surgical procedure, just before the wound is closed. In an alternative embodiment, the sleeve element 1 may be provided with a continuous ring shaped cross section, i.e. without a longitudinal slit. In such case the sleeve element 1 may for example be arranged on the neck 53 before the head 54 is mounted on the neck 53. When needed, the sleeve element 1 may be fixed to the neck 52, for example by gluing or by providing separate closure elements.

[0148] FIGS. 10a and 10b show a first embodiment of a loader 100. The loader 100 is arranged to load a sleeve element 1 having a longitudinal slit 3 on the neck 53 of a prosthetic hip or shoulder implant. The loader 100 comprises a body 101, a first jaw element 102 and a second jaw element 103.

[0149] The first jaw element 102 and the second jaw element 103 are movable with respect to the main body between a normal position, shown in FIG. 10a and a loading position, shown in FIG. 10b. In the normal position, the sleeve element 1 may be arranged in the closed state on the loader 100. When the first jaw element 102 and the second jaw element 103 are moved from the normal position to the loading position, the sleeve element 1 will be forced from the closed state to the opened state allowing the sleeve element 1 to be placed on a neck 53 of a hip or shoulder prosthesis. The first jaw element 102 and the second jaw element 103 may be biased towards the normal position by a biasing element. This biasing element may also be formed by the sleeve element 1 arranged on the loader 100.

[0150] The first jaw element 102 comprises a first guide surface 102a and the second jaw element 103 comprises a second guide surface 103a. By pushing the neck 53 against the first guide surface 102a and the second guide surface 103a, the first jaw element 102 and the second jaw element 103 may be moved from the normal position towards the loading position. No separate actuation mechanism is required to actuate movement of the first jaw element 102 and the second jaw element 103.

[0151] FIGS. 11a and 11b show a second embodiment of a loader 100 arranged to load a sleeve element 1 having a longitudinal slit 3 on the neck 53 of a prosthetic hip or shoulder implant. This loader 100 comprises an actuation mechanism 105 to actuate movement of the sleeve element 1 mounted on the loader 100 between the closed state, shown in FIG. 11a to the opened state, shown in FIG. 11b. The actuation mechanism 105 schematically depicted by a slider may actuate movement of a first jaw element and a second jaw element between the normal position and loading position to move the sleeve element 1 between the closed and opened state.