WO2023278836A1

WO2023278836A1 - Devices and methods for microfracture

Info

Publication number: WO2023278836A1
Application number: PCT/US2022/035941
Authority: WO
Inventors: Matthew Cunningham; Timothy Young; Dennis Colleran; Ali HOSSEINI
Original assignee: Smith and Nephew Orthopaedics AG; Smith and Nephew Asia Pacific Pte Ltd; Smith and Nephew Inc
Current assignee: Smith and Nephew Orthopaedics AG; Smith and Nephew Asia Pacific Pte Ltd; Smith and Nephew Inc
Priority date: 2021-07-01
Filing date: 2022-07-01
Publication date: 2023-01-05
Anticipated expiration: 2024-01-01

Abstract

Microfracture devices include a trigger manipulable by the user and configured to cause an energy storage mechanism to release stored energy to drive a rod into a bone surface or to create a mechanical advantage. The rods include small diameter tips with minimal or no taper for easily penetrating the bone surface to a uniform depth.

Description

DEVICES AND METHODS FOR MICROFRACTURE

FIELD

The present disclosure relates to microfracture devices and, more particularly, to devices and methods for surgical repair of a defect in articular cartilage.

BACKGROUND

Articular surfaces of a joint can wear down over time and result in bone-to-bone contact, which creates a significant amount of pain and discomfort. One solution to this problem is microfracture surgery. In microfracture surgery, surgeons scrape away damaged cartilage and create holes (microfractures) in bone to stimulate blood flow and release bone marrow to the surface of the defect area.

Current microfracture devices generally use either an awl and hammer, or a drill and drill guide. Awls often have relatively large and tapered diameter tips that limit the hole density and depth for each microfracture since the density of the microfracture is dependent on the holes size at the top of the bone. Because of the tip of the awl is generally tapered, only a small diameter of the awl is able to access the deeper bone marrow area of the bone, thus limiting the amount of blood and bone marrow aspirate that can flow up to repair the damaged surface of the bone and create new cartilage. Moreover, rotation of a drill, combined with friction between the guide and drill, and/or between the drill and the bone tunnel, can create unwanted heat that a user must control to minimize necrosis of the bone. Additionally, current devices have limited curvature, thus limiting access to the defect location. Finally, these devices typically require two or more people to hold the multiple components while performing the procedure, further may generate particulate debris during use.

SUMMARY

The disclosure describes various curved microfracture devices user that solve the problems of the prior art. The devices generally include a trigger manipulable by a user and configured to cause an energy storage mechanism (such as a spring) to release stored energy to drive a rod into a bone surface. Alternatively, a surgeon can use the mechanical advantage of a lever arm to generate load multipliers by the surgeon or the device, which can then be imparted onto the bone surface to generate a microfracture. The rods advantageously include small diameter tips with minimal or no taper for easily penetrating the bone surface. The devices furthermore avoid creating unwanted heat during treatment.

Further examples of the microfracture devices of this disclosure may include one or more of the following, in any suitable combination.

In examples, a microfracture device of this disclosure includes a tube having a proximal end, a distal end, and a longitudinal axis extending therebetween. A handle couples to the proximal end of the tube. A trigger mounts on the handle. The trigger includes at least one actuatable tab. A rod extends through the tube. The rod is moveable from a first position to a second position. The distal end of the rod is configured to penetrate bone. At least one spring is disposed inside the handle and operatively coupled to the rod. The spring is configured to store energy for moving the rod from the first position to the second position. The at least one actuatable tab is operatively coupled to the spring to release the stored energy to move the rod from the first position to the second position when the tab is actuated toward the proximal end of the handle.

In further examples, the handle is T-shaped. In examples, the microfracture device further includes a hammer configured to contact a proximal end of the rod and axially moveable along the longitudinal axis. The hammer defines a bore to position the proximal end of the rod. In examples, the microfracture device further includes an intermediate contact member disposed between the proximal end of the rod and the hammer. In examples, the hammer extends through a knob disposed within the handle. A distal end of the knob is coupleable to the at least one actuatable tab and a proximal end of the knob includes a plurality of flexures. In examples, the handle defines a stop member for limiting distal axial movement of the hammer relative to the handle. In examples, the microfracture device further includes a load plate positioned proximal to the knob and slidably secured within the plurality flexures of the knob. In examples, the load plate is loaded into contact with the flexures by the at least one spring. In examples, the handle further includes a ramp element, and contact between the plurality of flexures and the ramp element causes the plurality of flexures to release contact with the load plate. In examples, the distal end of the tube is angled relative to the longitudinal axis. In examples, a diameter of a distal portion of the rod is selected to be smaller than a diameter of a proximal portion of the rod. In examples, a distal tip of the rod is pointed. In examples, the microfracture device of further includes a reset mechanism incorporated into the trigger.

Other examples of a microfracture device of this disclosure include a tube having a proximal end, a distal end, and a longitudinal axis extending therebetween. A handle couples to the proximal end of the guide tube. A trigger mounts on the handle. The trigger includes a manual lever actuatable toward a fixed portion the handle. A rod extends through the tube. The rod is moveable from a first position to a second position. A proximal end of the rod is disposed inside the handle. The distal end of the rod is configured to penetrate bone. A linkage member is disposed within the handle. A proximal end of the linkage member is operatively coupled to the manual lever. A distal end of the linkage member is rotatable about a fulcrum to slidably contact the proximal end of the rod such that actuating the manual lever causes the linkage member to move the rod from the first position to the second position. In further examples, the handle is a pistol grip handle. In examples, the distal end of the tube is angled relative to the longitudinal axis. In examples, the microfracture device further includes a spring disposed about the rod distal to the flange within the handle. In examples, a diameter of a distal portion of the rod is selected to be smaller than a diameter of a proximal portion of the rod. In examples, a distal tip of the rod is pointed. In examples, the microfracture device further includes a reset mechanism incorporated into the trigger.

Yet further examples of a microfracture device of this disclosure includes a handle and a trigger mounted on the handle. A rod couples to the handle. The rod includes a proximal end, a distal end, and a longitudinal axis extending between the proximal and distal ends. The rod is axially moveable along the longitudinal axis. The distal end of the rod configured is to penetrate bone. A compression mechanism is disposed within the handle. The compression mechanism operatively couples to the trigger such that a portion of the compression mechanism rotates about a pivot when the trigger is partially actuated. The rotation causes the compression mechanism to exert a proximal force on the rod. A spring is disposed within the handle. The spring is configured to store energy for distal movement of the rod relative to the handle. In further examples, the portion of the compression mechanism is further rotatable about the pivot when the trigger is further actuated, the further rotation causing the compression mechanism to release the proximal force on the rod. In examples, the microfracture device further includes a reset mechanism incorporated into the trigger.

A reading of the following detailed description and a review of the associated drawings will make apparent the advantages of these and other features. Both the foregoing general description and the following detailed description serve as an explanation only and do not restrict aspects of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

Reference to the detailed description, combined with the following figures, will make the disclosure more fully understood, wherein:

FIG. 1 A illustrates an example of a microfracture device of this disclosure in a perspective view;

FIG. IB illustrates the distal end of the guide tube of the device of FIG. 1A in a transparent view;

FIG. 1C illustrates the deployment of the rod of the device of FIG. 1A;

FIG. ID illustrates the components of the handle of FIG. 1 A in a transparent view;

FIGS. IE and IF illustrates the device of FIG. 1 A in an unloaded, undeployed state (FIG. IE) and a loaded, undeployed state (FIG. IF);

FIG. 1G illustrates the device of FIG. 1 A in a deployed state;

FIG. 2A illustrates another example of a microfracture device of this disclosure in a perspective view;

FIG. 2B illustrates the distal end of the guide tube of the device of FIG. 2A in a transparent view;

FIG. 2C illustrates the deployment of the rod of the device of FIG. 2 A;

FIG. 2D illustrates the handle of FIG. 2 A with the trigger in an undeployed state;

FIG. 2E is a detailed view of the handle of FIG. 2D;

FIG. 2F illustrates the handle of FIG. 2 A with the trigger in a deployed state;

FIG. 3 illustrates another example of a microfracture device of this disclosure in a transparent view;

FIGS. 4A-D illustrates another example of a microfracture device of this disclosure and a method of use thereof;

FIG. 5 illustrates another example of a microfracture device of this disclosure in a transparent view;

FIG. 6A illustrates another example of a microfracture device of this disclosure in a perspective view;

FIGS. 6B-F illustrate a method of using the device of FIG. 6 A;

FIG. 7A illustrates another example of a microfracture device of this disclosure in a schematic view;

FIGS. 7B-F illustrate a method of using the device of FIG. 7 A;

FIG. 8A illustrates another example of a microfracture device of this disclosure in a perspective view; FIG. 8B illustrates the rod of FIG. 8 A;

FIGS. 8C-F illustrate examples of accessories for use with the device of FIG. 8 A;

FIGS. 9A-D illustrate example cross-sectional views of the rod tip in the various devices disclosed herein;

FIG. 10 illustrates another alternative example of the rod tip in the various devices disclosed herein;

FIG. 11 illustrates a locking system for use with various devices disclosed herein; and

FIG. 12 illustrates a locking and reset mechanism for use with various devices disclosed herein.

DETAILED DESCRIPTION

In the following description, like components have the same reference numerals, regardless of different illustrated examples. To illustrate examples clearly and concisely, the drawings may not necessarily reflect appropriate scale and may have certain features shown in somewhat schematic form. The disclosure may describe and/or illustrate features in one example, and in the same way or in a similar way in one or more other examples, and/or combined with or instead of the features of the other examples.

In the specification and claims, for the purposes of describing and defining the invention, the terms “about” and “substantially” represent the inherent degree of uncertainty attributed to any quantitative comparison, value, measurement, or other representation. The terms “about” and “substantially” moreover represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. Open-ended terms, such as “comprise,” “include,” and/or plural forms of each, include the listed parts and can include additional parts not listed, while terms such as “and/or” include one or more of the listed parts and combinations of the listed parts.

FIG. 1A shows an example of a microfracture device 100 of this disclosure. In examples, the device 100 generally comprises a handle 101 and a guide tube 104 coupled to the handle 101 extending along a longitudinal axis A. In examples, the handle 101 has a “T” shape with an elongated first portion 102 having a first surface 102a and a second surface 102b opposite the first surface 102a. A second portion 103 extends perpendicular to the first portion 102 from an approximate center of the second surface 102b. The guide tube 104 has a proximal end 104a coupled to the second portion 103 of the handle 101 and a distal end 104b. In examples, the distal end 104b is angled relative to the longitudinal axis A. A trigger 108 mounts to the second portion 103. The trigger 108 comprises at least one manual tab 109 actuatable toward the first portion 102 of the handle 101, as further described below. The disclosure also contemplates that the tab 109 could be actuated in other directions, such as upwards.

FIG. IB shows the distal end 104b of the guide tube 104 in a transparent view. As shown in FIG. IB, the guide tube 104 defines a cannulation 112. A rod 106 extends through the cannulation 112 of the guide tube 104. In examples, the rod 106 comprises a strong yet flexible material, such as spring steel, stainless steel or Nitinol. A diameter of the distal end 106b of the rod 106 is selected to be smaller than a diameter of the proximal end 106a for ease of penetrating a bone surface. In examples, a distal tip 106c of the rod 106 is further configured to penetrate bone (e.g., pointed). The rod 106 is axially moveable relative to the guide tube 104 such that the distal end 104b is extendable from the guide tube 104 (FIG. 1C).

FIG. ID shows a transparent view of the handle 101. As shown in FIG. ID, the tabs 109 couple to a knob 110 disposed within the second portion 103 of the handle 101 such that proximal movement of the tabs 109 move the knob 110 proximally. A hammer 114 coupled to the proximal end 106a of the rod 106 extends through the knob 110 and is axially moveable along the longitudinal axis A relative to the knob 110. The hammer 114 includes a bore 115 to position the proximal end 106a of the rod 106. A load plate 116 is positioned proximal to the knob 110 and is slidably secured within a plurality of flexures 118 on a proximal end of the knob 110. The load plate 116 is loaded into contact with the flexures 118 with at least one spring 120. In examples, the spring 120 is a torsional spring. However, the disclosure also contemplates that the spring 120 is a leaf spring or a coil spring in the same or other configurations. The hammer 114 is configured to transfer stored energy from the spring 120 to the rod 106 via the load plate 116, as further described below.

FIGS. IE and IF shows the device 100 with the spring 120 in an unloaded, undeployed state (FIG. IE) and in a loaded, undeployed state (FIG. IF). As shown in FIG. IE, an intermediate contact member, such as a hardened ball bearing 122, may be used to facilitate low friction transfer of the stored energy of the spring 120 between the hammer 114 and the rod 106. As shown in FIG. IF, when the user moves the tabs 109 to their proximal-most travel position, the knob 110 moves proximally relative to the hammer 114. The knob flexures 118 contact a ramp element 124 in the handle 101. This causes the flexures 118 to bend outward until the load plate 116 is released from the knob flexures 118.

FIG. 1G shows the device 100 with the spring 120 in a deployed state. When the load plate 116 is released from the flexures 118, stored energy in the spring 120 causes the load plate 116 to move distally to strike the hammer 114. When the load plate 116 strikes the hammer 114, the energy transfer causes the hammer 114 and the rod 106 to move distally relative to the knob 110 until the hammer encounters a stop 126 defined by the handle 101. The distal movement of the rod 106 causes the distal tip 106c of the rod 106 to extend beyond the distal end of the guide tube 104 (FIG. 1C), penetrating the bone at the desired impact position.

In various alternatives (not shown) the rod 106 could have a proximal flange and a spring interposed between the flange and the handle 101 to provide a spring retraction after impact. In applications where the rod 106 extends through a curved guide tube 104, the rod 106 could be made with one or more portions have a lower flexural modulus by heating treating a portion of the rod 106 to achieve the desired flexural strength. Alternatively, the rod 106 could be multi-segmented with an intermediate diameter between the distal end 106b and the proximal end 106a. In examples, the distal tip 106c could be made from a different material (such as Nitinol or spring steel) than the rest of the rod 106 to decrease friction. In other examples, the distal tip 106c could be coated with a lubricious coating (such as PTFE) to reduce friction and improve the ease of retraction from the bone after microfracturing.

FIG. 2A shows another example of a microfracture device 200 of this disclosure.

In examples, the device 200 generally comprises a handle 201 and a guide tube 204 coupled to the handle 201 extending along a longitudinal axis A. In examples, the handle

201 has a “pistol grip” configuration with a first gripping portion 202 and a second portion 203 extending perpendicular to the first portion 202 from an end of the first portion 202. The guide tube 204 has a proximal end 204a coupled to the second portion 203 of the handle 201 and a distal end 204b. In examples, the distal end 204b is angled relative to the longitudinal axis A. A trigger 208 mounts to the gripping portion 202 in contact with the second portion 203. The trigger 208 is manually actuatable toward the gripping portion

202 of the handle 201, as further described below.

FIG. 2B shows the distal end 204b of the guide tube 204 in a transparent view. As shown in FIG. 2B, the guide tube 204 defines a cannulation 212. A rod 206 extends through the cannulation 212. In examples, the rod 206 comprises a flexible material, such as spring steel, stainless steel or Nitinol. A diameter of the distal end 206b of the rod 206 is selected to be smaller than a diameter of the proximal end 206a for ease of penetrating a bone surface. In examples, a distal tip 206c of the rod 206 is further configured to penetrate bone (e.g., pointed). The rod 206 is axially moveable relative to the guide tube 204 such that the distal end 206b is extendable from the guide tube 204 (FIG. 1C).

FIG. 2D shows a transparent view of the handle 201 with the trigger 208 in an undeployed state. As shown in FIG. 2D, a proximal end 210a of an internal force transfer linkage 210 is in slidable contact with a first cam surface 214 of the trigger 208 and rotatable about a distal fulcrum 216. The distal end 210b of the transfer linkage 210 distal to the fulcrum 216 incudes a second cam surface 218 in slidable contact with a proximal flange 220 of the rod 206. As shown in more detail in FIG. 2E, the rod 206 is slidably loaded into contact with the transfer linkage 210 with a spring 222. In examples, the spring 222 is a compression spring. However, the disclosure also contemplates that the spring 222 is a torsion spring or a leaf spring in the same or in other configurations.

FIG. 2F shows a transparent view of the handle 201 with the trigger 208 in a deployed state. As shown in FIG. 2F, when the trigger 208 is compressed towards the handle 201, the position of the distal fulcrum 216 creates a mechanical advantage that increases the force applied on the distal end 210b of the transfer linkage 210. The resulting rotation of the transfer linkage 210 causes linear displacement of the rod 206 in proportion to the degree of compression of the trigger 208. The linear displacement results in extension of the distal tip 206c of the rod 206 beyond the distal end 204b of the guide tube 204 (FIG. 2C), penetrating the bone at the desired position. The compression spring 222 retracts the transfer linkage 210 back to the undeployed position when force is removed from the trigger 208.

In various alternatives, not shown, the interface between the distal end 210b of the transfer linkage 210 and the flange 220 could include an additional linkage that would result in both controlled extension and retraction of the rod 206 with movement of the trigger 208. The trigger 208 could define a finger hole to allow the user to easily compress and extend the trigger 208. The flange 220 could be a press-on plastic cap having improved wear and low-friction properties. In applications where the rod 206 extends through a curved guide tube 204, the rod 206 could be made with one or more portions have a lower flexural modulus by heating treating a portion of the rod 206 to achieve the desired flexural strength. Alternatively, the rod 206 could be multi-segmented with an intermediate diameter between the distal end 206b and the proximal end 206a. The distal tip 206c could be made from a different material than the rest of the rod 206 to decrease friction. The distal end 206b could have portions of removed material (i.e., cuts) to increase the surface area of each hole (FIG. ID).

FIG. 3 shows another example of a microfracture device 300 of this disclosure. In examples, the device 300 generally comprises a handle 301 and a rod 306 coupled to the handle 301 extending along a longitudinal axis A. In examples, the rod 306 comprises a flexible material, such as spring steel, stainless steel or Nitinol. In examples, the handle 301 has a “pistol grip” configuration with a first gripping portion 302 and a second portion 303 extending perpendicular to the first portion 302 from an end of the first portion 302. The rod 306 has a proximal end 306a coupled to the second portion 303 of the handle 301 and a distal end 306b. In examples (not shown) the distal end 306b could be angled with respect to the longitudinal axis A. In examples (not shown), a diameter of the distal end 306b of the rod 306 is selected to be smaller than a diameter of the proximal end 306a for ease of penetrating a bone surface. In examples, a distal tip 306c of the rod 306 is further configured to penetrate bone (e.g. pointed). The rod 306 is axially moveable along the longitudinal axis A relative to the handle 301. Examples of the handle 301 can be disposable. In other examples, the handle 301 can be separable from the rod 306 to allow one handle 301 to be used with rods 306 having different tip angles as desired.

Still referring to FIG. 3, a trigger 308 mounts to the second portion 303 of the handle 301. The trigger 308 is manually actuatable toward the gripping portion 302 of the handle 301. A rotatable compression mechanism 310 is in slidable contact with a first cam surface 314 of the trigger 308. The compression mechanism 310 is configured to rotate about a pivot 316. A first projection 318 of the compression mechanism 310 is in slidable contact with a second projection 324 of a hammer 320. The hammer 320 in turn couples to the rod 306. In examples, the hammer 320 is fixedly coupled to the rod 306. In other examples, the hammer 320 is detachably coupled to the rod 306. A spring 322 in contact with the hammer 320 is disposed between the hammer 320 and an inner surface of the handle 301. In examples, the spring 322 is a compression spring. However, the disclosure also contemplates that the spring is a torsion spring or a leaf spring in the same or in other configurations. When the user partially compresses the trigger 308 towards the handle 301, the compression mechanism 310 rotates toward the first portion 302 of the handle 301. The proximal movement of the first projection 318 of the compression mechanism 310 against the second projection 324 of the hammer 320 causes the hammer 320 to move proximally to compress the spring 322. Further compression of the trigger 308 causes the first projection 318 of the compression mechanism 310 to slip out of contact with the second projection 324 of the hammer 320, removing the proximal force against the hammer 320. The stored energy of the spring 322 thus causes the hammer 320 to move distally, driving the rod 306 into bone at the desired position. Optionally, the spring 322 is configured to retract the compression mechanism 310 back to the undeployed position when force is removed from the trigger 308.

FIGS. 4A-D show another example of a microfracture device 400 of this disclosure. In examples, the device 400 generally comprises a handle 401 and a rod 406 coupled to the handle 401 extending along a longitudinal axis A. In examples, the handle 401 has a “pistol grip” configuration. The rod 406 has a proximal end 406a coupled to the handle 401 and a distal end 406b. A trigger 408 (e.g. a lever) mounts to the handle 401. The trigger 408 is manually actuatable distally toward a gripping portion of the handle 401. In examples (not shown), a diameter of the distal end 406b of the rod 406 is selected to be smaller than a diameter of the proximal end 406a for ease of penetrating a bone surface. In examples, a distal tip 406c of the rod 406 is further configured to penetrate bone (e.g. pointed). The rod 406 is axially moveable along the longitudinal axis A relative to the handle 401. The trigger 408 is operatively coupled to a compression mechanism 410 configured to rotate about a pivot 416. A projection 418 on the compression mechanism 410 is in slidable contact with a surface 424 of a hammer 420. The hammer 420 in turn couples to the rod 406. A spring 422 in contact with the hammer 420 is disposed between the hammer 220 and an inner surface of the handle 401. In examples, the spring 422 is a compression spring. However the disclosure also contemplates that the spring 422 is a torsion spring or a leaf spring in the same or in other configurations. When the user partially compresses the trigger 408 towards the gripping portion 402 of the handle 401, trigger 408 rotates toward the gripping portion 402, causing rotation of the compression mechanism 410. The proximal movement of the projection 418 of the compression mechanism 410 against the surface 424 of the hammer 420 causes the hammer 420 to move proximally to compress the spring 422. Further actuation of the trigger 408 causes the projection 418 of the compression mechanism 410 to slip out of contact with the surface 424 of the hammer 420, removing the proximal force against the hammer 420. The stored energy of the spring 422 thus causes the hammer 420 to move distally, driving the rod 406 into bone at the desired position. The disclosure also contemplates that compression of the spring 422 could be accomplished with a cam mechanism or with a four-bar mechanism (not shown). FIG. 5 shows another example of a microfracture device 500 of this disclosure. In examples, the device 500 generally comprises a handle 501 and a guide tube 504 coupled to the handle 501 extending along a longitudinal axis A. The guide tube 504 has a proximal end 504a coupled to the handle 501 and a distal end 504b. In examples (not shown), the distal end 504b may be angled relative to the longitudinal axis A. A cannulation 512 defined by the guide tube 504 extends between the proximal and distal ends 504a, b of the guide tube 504. A rod 506 extends through the cannulation 512 of the guide tube 504. In examples, the rod 506 comprises a flexible material, such as spring steel, stainless steel or Nitinol. In examples (not shown), a diameter of a distal end 506b of the rod 506 is selected to be smaller than a diameter of the proximal end 506a for ease of penetrating a bone surface. In examples, a distal tip 506c of the rod 506 is further configured to penetrate bone (e.g., pointed). The rod 506 is axially moveable along the longitudinal axis A relative to the handle 501.

Still referring to FIG. 5, in examples, the handle 501 has a “pistol grip” configuration. The rod 506 has a proximal end 506a extending through the handle 501 and defining a ratchet mechanism 520 including a plurality of teeth 524. A trigger 508 (e.g. a lever) mounts to the handle 501 and is manually actuatable toward a gripping portion 502. The trigger 508 is operatively coupled to a compression mechanism 510 within the handle 501 that comprises a spring 522. In examples, the spring 522 is a torsion spring. However, the disclosure also contemplates that the spring 522 is a coil spring or a leaf spring in the same or in other configurations. The compression mechanism 510 is configured to rotate about a pivot 516. A projection 518 on the compression mechanism 510 is in slidable contact with the plurality of teeth 524 on the rod 506. When the user partially compresses the trigger 508 towards the gripping portion 502, trigger 508 rotates toward the handle 501, causing distal movement of the projection 518 against the teeth 524 of the ratchet mechanism 520. This causes the rod 506 to move distally, driving the rod 506 into bone at the desired position. In examples, a user can measure the penetration depth of the rod 506 using a scale (such a laser marks) on the rod 506. The device 500 can include a release key (not shown) to allow the rod 506 to slide freely within the device 500 so that it can be returned to a home position and used multiple times for a given defect site.

FIG. 6A shows another example of a microfracture device 600 of this disclosure.

In examples, the device 600 is configured to attach to a power transmission mechanism 608 (for example, a shaver blade handpiece or a power drill). Alternatively, the power transmission mechanism 608 could attach to a hand-powered mechanism. The device 600 includes a rod 606 extending along a longitudinal axis A. The rod 606 has a proximal end 606a coupled to a driver 620. In examples (not shown), a diameter of the distal end 606b of the rod 606 is selected to be smaller than a diameter of the proximal end 606a for ease of penetrating a surface of a bone 10. In examples, a distal tip 606c of the rod 606 is further configured to penetrate bone (e.g., pointed). The rod 606 is axially moveable along the longitudinal axis A. An impact driving mechanism 610 includes the driver 620, a spring 622, and a cam mechanism 624. In examples, the spring 622 is a compression spring. However, the disclosure also contemplates that the spring 622 is a torsion spring or a leaf spring in the same or in other configurations. In examples, the cam mechanism 624 may or may not rotate. The device 600 can use both rotation and axial impact, or axial impact alone, depending on the design. In examples, the rod 606 can comprise a flexible wire (e.g., spring steel, stainless steel or Nitinol). In other examples, the rod 606 can be rigid and straight.

As shown in FIGS. 6B-E, the cam mechanism 624 includes an angled surface 626 that a projection 628 of the driver 620 rotates against, forcing the driver 620 to move proximally to compress the spring 622. As the driver 620 continues to rotate, the projection 628 slips off the cam mechanism 624 and the force of the spring 622 is released to create linear motion of the rod 606 into bone 10 (FIG. 6F). In examples, the driver 620 may take a single or multiple impacts to reach the full desired microfracture depth in the bone 10.

FIG. 7A shows another example of a microfracture device 700 of this disclosure.

In examples, the device 700 generally comprises a linear handle 701 and a rod 706 coupled to the handle 701 extending along a longitudinal axis A. A cannulation 712 defined by the handle 701 extends between proximal and distal ends 701a,b of the handle 701. The rod 706 has a proximal end 706a coupled to the handle 701 and a distal end 706b. In examples (not shown), a diameter of the distal end 706b of the rod 706 is selected to be smaller than a diameter of the proximal end 706a for ease of penetrating a bone. In examples, a distal tip 706c of the rod 706 is further configured to penetrate the bone (e.g., pointed). The rod 706 is axially moveable along the longitudinal axis A relative to the handle 701. The cannulation 712 defines two inwardly projecting guide members 714, 716 extending into the cannulation 712. A first drive component 710 enclosed by a first spring 722 are disposed in the cannulation 712 distal to the guide members 714, 716. In examples, the first spring 722 is a compression spring. However, the disclosure also contemplates that the first spring 722 is a torsion spring or a leaf spring in the same or in other configurations. A second drive component 718 and second spring 720 are disposed in the cannulation 712 proximal to the guide members 714, 716, with the second spring 720 proximal to the second drive component 718. The second drive component 718 includes a distal bore 724.

Still referring to FIG. 7 A, the first drive component 710 has a first conical region 710a and a second linear region 710b. In an undeployed state, as shown, the second linear region 710b extends at an angle relative to the bore 724. This initial configuration can be accomplished in a number of ways. For example, the fit between the second linear region 710b and the bore 724 may be so tight that it is unlikely that the second linear region 710b and the bore 724 will ever line up perfectly in the undeployed state. In another example (not shown), a distal face of the first drive component 710 that contacts the rod 706 may angled so that the axis of the first drive component 710 naturally is angled in the “at rest” position.

As shown in FIG. 7B, when a user exerts a downward force on the proximal end 701a of the handle 701 toward the bone 10, the rod 706 and the first drive component 710 move proximally relative to the handle 701. The first spring 722 compresses between the proximal end 706a of the rod 706 and the guide members 714, 716. The second drive component 718 also moves proximally, compressing the second compression spring 720. Notably, the relative timing and degree of compression of compression of springs 720, 722 depends on their spring constants. In one example, both springs 720, 722 have the same spring constant. In another examples, the first compression spring 722 has a substantially lower spring constant than the second compression spring 720, because the only function for the first compression spring 722 is to keep the rod 706 in an extended state in its “rest” position. As shown in FIG. 7C, at the furthest proximal movement of the first drive component 710, the guide members 714, 716 act to straighten the first drive component 710 relative to the longitudinal axis A such that the second linear region 710b aligns with a bore 724 in the second drive component 718. The second drive component 718 beings to move distally, such that the second linear region 710b enters the bore 724 (FIG. 7D). The stored energy of the first and second compression springs 720722 drive the rod 706 forward at the desired position in the bone 10 (FIG. 7E). Once the second drive component 718 reaches its furthest linear travel position, the microfracture is created. The force is then removed from the device 700 and the second linear region 710b exits the bore 724 (FIG. 7F), allowing the first drive component 710a to revert back to its native angled position (FIG. 7A). FIG. 8A shows another example of a microfracture device 800 of this disclosure.

In examples, the device 800 generally comprises a handle 801 and a guide tube 804 coupled to the handle 801 extending along a longitudinal axis A. The guide tube 804 has a proximal end 804a coupled to the handle 801 and a distal end 804b. In examples (not shown), the distal end 804b may be angled relative to the longitudinal axis A. A cannulation 812 defined by the guide tube 804 extends between the proximal and distal ends 804a, b of the guide tube 804. A rod 806 extends through the cannulation 812 of the guide tube 804. In examples, the rod 806 comprises a flexible material, such as spring steel, stainless steel or Nitinol. In other examples, the rod 806 can be rigid and straight. The rod 806 has a proximal end 806a extending from a proximal end 801a of the handle 801 and coupled to a hand crank 808. In examples (not shown), a diameter of a distal end 806b of the rod 806 is selected to be smaller than a diameter of the proximal end 806a for ease of penetrating a bone surface. In examples, a distal tip 806c of the rod 806 is further configured to penetrate bone (e.g., pointed). The rod 806 is axially moveable along the longitudinal axis A relative to the handle 801 in response to a user rotating the hand crank 808. A compression spring 822 is disposed around the rod 806 within the handle 801 and applies a consistent downward force to the rod 806. Preferably, the device 800 is coupled with a cam mechanism 624 as shown in FIGS. 6A-F, so that multiple smaller impacts are delivered during the hand cranking of the device 800 to ensure penetration of the bone with the device 800. The device 800 advantageously allows for rotation of the rod 806c at a slower rpm, which generates less friction and heat on the bone surface.

FIG. 8B shows an example of the distal end 806b of the rod 806 which could be coated with a friction reducing coating to reduce heat on the bone surface. Non-limiting examples of the coating can be PTFE based, medical grade grease, or an oxide layer. The coating can be on just the distal end 806b or along the entire rod 806. Further non-limiting examples of the distal end 806b can be a spade tip, a trocar tip, or fluted. In examples, the rod 806 could be used manually without the crank 808.

In further examples, shown in FIGS. 8C, the guide tube 804 could include an atraumatic tip 804c configured to sit on the cartilage surface during drilling. The tip 804c could be coated with a lubricant to reduce friction and heat at the cartilage surface. In examples shown in FIGS. 8D and 8E, the tip 804c could include one or more windows 826 at the distal end or just proximal to the distal end to aid in bone chip outflow during drilling. The disclosure also contemplates that the tip 804c could include ball bearings within the inner diameter to further reduce heat generated between the guide tube 804 and the rod 806. Examples of the tip 804c can be made of plastic or metal. The tip 804c may optionally be transparent. The tip 804c could also be used with any of the guide tubes 104, 204, 504 disclosed above.

FIG. 8F shows an optional attachment 820 for use with the device 800 in place of the hand crank 808. The attachment 820 includes an attachment 822 to a power drill or shaver, which has a high rpm output. A gearbox 824 reduces the rpm output and an output chuck 826 attaches to the rod 806. The attachment 820 could be a separate unit or embedded within the device 800.

FIGS. 9A-C illustrate various examples of the cross-section of the tip 906c of the rods 106, 206, 306, 406, 506, 606, 706, and 806 described above designed to increase the surface area of the microfracture hole in bone. In examples, a cross-section of the tip 906c can be a blade (FIG. 9A), an open cylinder (FIG. 9B), a “plus” sign (FIG. 9C) or a “hashtag” (FIG. 9D). The geometries of the tip 906c can be created by different means, such as mechanical impact or thermal energy. The disclosure also contemplates other geometries of the tip 906c or combinations of those disclosed herein. In alternative examples, shown in FIG. 10, the distal ends 1006b of the rods 106, 206, 306, 406, 506, 606, 706, and 806 could have portions of removed material 1028 (i.e., cuts) to increase the surface area of the microfracture hole.

FIG. 11 illustrates a locking mechanism 1100 for use with various examples of the devices disclosed above. The locking mechanism 1100 includes a slider housing 1102, a cam trigger 1104, a locking feature 1106, a sliding hammer 1114, a positive stop 1110 for the hammer 1114, and a compressed spring 1112. In this image, the microfracture needle is to the right. The spring 1112 is compressed by the user - for example, with another lever (not shown). As the spring 1112 is compressed, the locking feature 1106 slips into the opening 1118 of the slider housing 1102 when fully loaded, locking the mechanism 1100. Once the user pulls on the cam trigger 1104, the cam trigger 1104 rotates, pushing the protrusion 1120 on the locking feature 1106 up, and disengaging a ledge 1122 of the locking feature 1106 with an adjacent vertical face 1124 of the hammer 1114. This causes the hammer 1114 to be free to slide toward the positive stop 1110 and the spring exerts a force on the hammer 1114. The hammer 1114 is stopped by the positive stop 1110 and the microfracture process is complete.

FIG. 12 illustrates a locking and reset mechanism 1200 for use with various examples of the devices disclosed above - for example, devices 100, 200, 300 and 400. The reset mechanism may be incorporated into a trigger 1208 having a trigger face 1208a. The trigger 1208 is pivotally coupled to a trigger lock mechanism 1210 by pivot 1212. Pulling the trigger 1208 causes the trigger face 1208a to engage a leaf spring 1222, storing potential energy in the leaf spring 1222, which is fixed a first portion of the handle 1201a at a first end 1222a. The leaf spring 1222 is supported at its center by a second fixed portion of the handle 1201b such that, as the user compresses the trigger 1208, the leaf spring 1222 bends. The second end 1222b of the leaf spring 1222 engages a hammer 1214 in contact with the rod 1206, which is biased proximally against the leaf spring 1222. As the user continues to compress the trigger 1208, a first end 1210a of trigger lock mechanism 1210 engages another fixed area of the handle 1201c. The user then actuates a second end 1210b of the trigger lock mechanism 1210 to release the first end 1210a of the trigger lock mechanism 1210 as well as to release the stored energy in the leaf spring 1222 from the disengagement of the trigger 1208 and the leaf spring 1222. This allows the leaf spring 1222 to release its potential energy and move the hammer 1214 distally, which also moves the rod 1206 distally, exerting an impact force from the rod 1206 to the bone. Slanted surfaces 1210c, d of the trigger lock mechanism 1210 allow the trigger 1208 and the trigger lock mechanism 1210 to slide over the leaf spring 1222 to return to their initial positions.

While the disclosure particularly shows and describes preferred examples, those skilled in the art will understand that various changes in form and details may exist without departing from the spirit and scope of the present application as defined by the appended claims. The scope of this present application intends to cover such variations. As such, the foregoing description of examples of the present application does not intend to limit the full scope conveyed by the appended claims.

Claims

1. A microfracture device comprising: a tube having a proximal end, a distal end, and a longitudinal axis extending therebetween; a handle coupled to the proximal end of the tube; a trigger mounted on the handle, the trigger comprising at least one actuatable tab; a rod extending through the tube, the rod being moveable from a first position to a second position, the distal end of the rod configured to penetrate bone; at least one spring disposed inside the handle and operatively coupled to the rod, the spring configured to store energy for moving the rod from the first position to the second position; wherein the at least one actuatable tab is operatively coupled to the spring to release the stored energy to move the rod from the first position to the second position when the tab is actuated toward the proximal end of the handle.

2. The microfracture device of claim 1, wherein the handle is T-shaped.

3. The microfracture device of claim 1, further comprising a hammer configured to contact a proximal end of the rod and axially moveable along the longitudinal axis, the hammer defining a bore to position the proximal end of the rod.

4. The microfracture device of claim 3, further comprising an intermediate contact member disposed between the proximal end of the rod and the hammer.

5. The microfracture device of claim 3, wherein the hammer extends through a knob disposed within the handle, a distal end of the knob couplable to the at least one actuatable tab and a proximal end of the knob comprising a plurality of flexures.

6. The microfracture device of claim 3, wherein the handle defines a stop member for limiting distal axial movement of the hammer relative to the handle.

7. The microfracture device of claim 6, further comprising a load plate positioned proximal to the knob and is slidably secured within the plurality flexures of the knob.

8. The microfracture device of claim 7, wherein the load plate is loaded into contact with the flexures by the at least one spring.

9. The microfracture device of claim 7, wherein the handle further comprises a ramp element, and wherein contact between the plurality of flexures and the ramp element causes the plurality of flexures to release contact with the load plate.

10. The microfracture device of claim 1, wherein the distal end of the tube is angled relative to the longitudinal axis.

11. The microfracture device of claim 1, wherein a diameter of a distal portion of the rod is selected to be smaller than a diameter of a proximal portion of the rod.

12. The microfracture device of claim 1, wherein a distal tip of the rod is pointed.

13. The microfracture device of claim 1, further comprising a reset mechanism incorporated into the trigger.

14. A microfracture device comprising: a tube having a proximal end, a distal end, and a longitudinal axis extending therebetween; a handle coupled to the proximal end of the tube; a trigger mounted on the handle, the trigger comprising a manual lever actuatable toward a fixed portion the handle; a rod extending through the tube, the rod being moveable from a first position to a second position, a proximal end of the rod disposed inside the handle, the distal end of the rod configured to penetrate bone; and a linkage member disposed within the handle, a proximal end of the linkage member operatively coupled to the manual lever, a distal end of the linkage member rotatable about a fulcrum to slidably contact the proximal end of the rod such that actuating the manual lever causes the linkage member to move the rod from the first position to the second position.

15. The microfracture device of claim 14, wherein the handle is a pistol grip handle.

16. The microfracture device of claim 14, wherein the distal end of the tube is angled relative to the longitudinal axis.

17. The microfracture device of claim 14, further comprising a spring disposed about the rod distal to the flange within the handle.

18. The microfracture device of claim 14, wherein a diameter of a distal portion of the rod is selected to be smaller than a diameter of a proximal portion of the rod.

19. The microfracture device of claim 14, wherein a distal tip of the rod is pointed.

20. The microfracture device of claim 14, further comprising a reset mechanism incorporated into the trigger.

21. A microfracture device comprising: a handle; a trigger mounted on the handle; a rod coupled to the handle, the rod comprising a proximal end, a distal end, and a longitudinal axis extending between the proximal and distal ends, the rod being axially moveable along the longitudinal axis, the distal end of the rod configured to penetrate bone; and a compression mechanism disposed within the handle, the compression mechanism operatively coupled to the trigger such that a portion of the compression mechanism rotates about a pivot when the trigger is partially actuated, the rotation causing the compression mechanism to exert a proximal force on the rod; and a spring disposed within the handle, the spring configured to store energy for distal movement of the rod relative to the handle.

22. The microfracture device of claim 21, wherein the portion of the compression mechanism is further rotatable about the pivot when the trigger is further actuated, the further rotation causing the compression mechanism to release the proximal force on the rod.

23. The microfracture device of claim 21, further comprising a reset mechanism incorporated into the trigger.