Patent Description:
In the field of orthopedics, prosthetic devices, such as artificial joints, are often implanted or seated in a patient's bone cavity. The cavity is typically formed during surgery before a prosthesis is seated or implanted. For example, a physician may remove and or compact existing bone to form the cavity. The prosthesis usually includes a stem or other protrusion that is inserted into the cavity.

To create the cavity, a physician may use a broach conforming to the shape of the stem of the prosthesis. Solutions known in the art include providing a handle with the broach for manual hammering by the physician during surgery to impel the broach into the implant area. Unfortunately, this approach is crude and notoriously imprecise, leading to unnecessary mechanical stress on the bone. The results can be unpredictable and depend on the skill of a particular physician. Historically, this approach will in many cases result in inaccuracies in the location and configuration of the cavity. Additionally, the surgeon is required to expend an unusual amount of physical force and energy to hammer the broach and to manipulate the bones and prosthesis. Most importantly, this approach carries with it the risk that the physician will cause unnecessary further trauma to the surgical area and damage otherwise healthy tissue, bone structure and the like.

Another technique for creating the prosthetic cavity is to drive the broach pneumatically, that is, by compressed air. This approach is disadvantageous in that it prevents portability of an impacting tool, for instance, because of the presence of a tethering air-line, air being exhausted from a tool into the sterile operating field and fatigue of the physician operating the tool. This approach, as exemplified in <CIT>, does not allow for precise control of the impact force or frequency and instead functions very much like a jackhammer when actuated. Again, this lack of any measure of precise control makes accurate broaching of the cavity more difficult and can lead to unnecessary patient complications and trauma. These types of tools may produce movements with wide ranges of motion perpendicular to the cutting axis, further inhibiting accuracy and precision. In some instances, such accuracy and precision, or lack thereof, may be quantified by describing the total indicator reading ("TIR") of the surgical implement connected to the tool's adapter. The TIR, for example, is a measurement describing the deviation in contour along a surface (e.g., planar, cylindrical, etc.). In a particular example, the TIR of the adapter may represent the adapter's "flatness" along an example surface.

A third technique relies on computer-controlled robotic arms for creating the cavity. While this approach overcomes the fatiguing and accuracy issues, it suffers from having a very high capital cost and removes the tactile feedback that a surgeon can get from a manual approach. Further unless the approach is by milling, an impacting means (pneumatic, electrical or manual) is still required.

Other techniques use the inventor's own work and may include a hammer throwing method which involves a linear compressor, vacuum actuation, or a mechanical or gas spring, all of which are electrically powered. With the hammer throwing method, however, the use of existing commercially available adapters to couple impact energy created by the thrown mass (hammer) or striker from within the electrically driven impactor to a surgical implement has resulted in very poor coupling of the internal energy to the surgical implement, with losses of <NUM>% or greater being typical. Document <CIT> provides a method for a regular preparation of an apparatus for a treatment of a human or animal body by mechanical shockwaves to such a treatment wherein an impact body used for shockwave production is replaced with a not-used impact body before each treatment of a further patient.

Consequently, there exists a need for improved adapters between impacting tools and surgical implements that overcome the various disadvantages of existing adapters.

The invention provides a surgical system according to claim <NUM>. Further embodiments of the invention are provided by the dependent claims.

In view of the foregoing disadvantages, adapters are provided for an electric motor-driven orthopedic impacting tool to enable coupling of surgical implements to the tool, which may be provided for orthopedic impacting in hips, knees, shoulders and the like. The adapter is capable of holding a broach, chisel, or other end effector and delivering power from the impactor to gently tap the broach, chisel or other end effector into the cavity with controlled percussive impacts, resulting in a better fit for the prosthesis or the implant. The adapter can also be used in the placement and removal of broaches, implants, cups, liners, head balls, nails, wires, pins, and other devices. Further, the adapter may enable additional control of the electrically driven orthopedic impactor by communicating or otherwise indicating impact settings based on the patient, surgical implement, or surgical procedure. The adapter further enables proper seating and, in the case of bidirectional movement, the removal of the prosthesis or the implant into or out of an implant cavity, and advantageously augments the existing surgeon's skill in guiding the electrically driven orthopedic impactor.

In order to provide context, a brief description of the electrically driven orthopedic impactor is provided. An electric motor-driven orthopedic impacting tool includes a power source (such as a battery, fuel cell, or cartridge of compressed gas), a motor assembly, a controller, a housing, a stored-energy system or mechanism such as a gas or mechanical spring capable of storing and releasing potential energy, and a striker energized by the stored-energy drive system to be operational in a forward and/or a rearward direction, where the striker is capable of generating an impact force in either a forward or a rearward direction.

In the system according to claim <NUM>, an adapter is used to communicate the force between the electrically driven impactor and the surgical implement. In a further embodiment, the adapter has two distinct surfaces which are used to communicate a forward or reverse impact from the electrically driven impactor (hereafter referred to as tool) to the surgical implement.

In the present invention, during operation of the surgical impactor, a surface communicates an impact form an anvil through the adapter to the surgical implement.

In an exemplary embodiment, the adapter communicates back to the tool whether the surgeon or robot is either pushing or pulling the adapter and surgical implement towards or away from the patient.

In a further exemplary embodiment, a surgical implement (e.g., broach, chisel or other end effector) can be rotated to a number of positions while still maintaining axial alignment, as illustrated, for example, in <FIG>, where the adapter is rotatable in four different positions, each position rotated by <NUM>°. This facilitates the use of the adapter or broach, for example, in various anatomical presentations during surgery.

In some embodiments, the adapter is configured to communicate the spatial position of the adapter in relation to the patient. For example, the adapter or the impactor may include a sensor and/or a camera that communicates the relative position and/or alignment of the tool to the patient. This may be accomplished by tracking a reference point associated with the patient and not located on the adapter or the impactor. In a further embodiment, the sensor may be configured to communicate the position of the adapter or impactor in coordination with a surgical navigation system to inform a surgeon or robot of a position in comparison to an optimal position, a planned final position, or any other desired position.

In an exemplary embodiment, the adapter of the tool includes at least one of two points of impact, a forward striking surface or first surface and a rearward striking surface or second surface.

In an exemplary embodiment, the anvil and the adapter include a single element, or one may be integral to the other.

In an exemplary embodiment, the adapter weighs less than the anvil, striker, or other thrown mass of the impactor.

In an exemplary embodiment, the adapter weighs less than half of the weight of the impactor tool, and preferably less than <NUM>% of the weight of the impactor.

In an exemplary embodiment, the adapter is substantially axially inline with the anvil, striker, or other thrown mass of the impactor. This has an unexpected benefit in that bone is an anisotropic material, which is strongest with respect to compression forces, then tension, then shear. By keeping the forces inline, operation of the tool will result in lower stress on the bone and yield better outcomes.

In an exemplary embodiment, the adapter is able to communicate force, frequency, and throw settings back to the tool based on the surgical implement or procedure.

In an exemplary embodiment, the adapter may include a dampening mechanism such as a viscoelastic material or elastomeric or mechanical spring which limits the total energy communicated from the tool to the surgical implement. The dampener may be chosen or configured to provide any desired capability, such as a particular level of dampening or dampening only in a particular direction. For example, the dampener may reduce the impact energy from the tool by <NUM>% or <NUM>%, preferably at least <NUM>%, and the dampener may only dampen energy in the forward direction, leaving a sharper impact force in the rearward direction.

In an exemplary embodiment, the adapter may include a mechanism that produces an audible or visual cue that indicates that the adapter is properly connected to the tool. For example, tabs, grooves, raised edges, and other similar features may be configured to snap into place and generate an audible cue upon proper connection of the adapter to the tool or surgical implement. A visual cue may also show that the adapter is properly connected to the tool or surgical implement. For example, a window or other designated area on the adapter, tool, or surgical implement may display a red color when the adapter is not properly connected and a green color when the adapter is properly connected.

In an exemplary embodiment, the adapter may be connected to a surgical implement having cutting teeth useful for final shaping of bone prior to placing an implant. In a still further embodiment, the pitch of the cutting teeth (spacing in the direction of impact) is determined to be less than the powered throw of the instrument. In a still further embodiment, it was found to be advantageous to have bidirectional cutting teeth, which allowed for bone shaping on both a forward impact and a rearward impact.

These, together with other aspects of the present disclosure, along with the various features of novelty that characterize the present disclosure, are pointed out with particularity in the claims annexed hereto and form a part of the present disclosure. For a better understanding of the present disclosure, its operating advantages, and the specific nonlimiting objects attained by its uses, reference should be made to the accompanying drawings and detailed description in which there are illustrated and described exemplary embodiments of the present disclosure.

The forgoing general description of the illustrative implementations and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure, and are not restrictive.

The accompanying drawings have not necessarily been drawn to scale. Any values dimensions illustrated in the accompanying graphs and figures are for illustration purposes only and may or may not represent actual or preferred values or dimensions. Where applicable, some or all features may not be illustrated to assist in the description of underlying features. In the drawings:.

The description set forth below in connection with the appended drawings is intended to be a description of various, illustrative embodiments of the disclosed subject matter. Specific features and functionalities are described in connection with each illustrative embodiment; however, it will be apparent to those skilled in the art that the disclosed embodiments may be practiced without each of those specific features and functionalities.

Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. Further, it is intended that embodiments of the disclosed subject matter cover modifications and variations thereof.

It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context expressly dictates otherwise. That is, unless expressly specified otherwise, as used herein the words "a," "an," "the," and the like carry the meaning of "one or more. " Additionally, it is to be understood that terms such as "left," "right," "top," "bottom," "front," "rear," "side," "height," "length," "width," "upper," "lower," "interior," "exterior," "inner," "outer," and the like that may be used herein merely describe points of reference and do not necessarily limit embodiments of the present disclosure to any particular orientation or configuration. Furthermore, terms such as "first," "second," "third," etc., merely identify one of a number of portions, components, steps, operations, functions, and/or points of reference as disclosed herein, and likewise do not necessarily limit embodiments of the present disclosure to any particular configuration or orientation.

Furthermore, the terms "approximately," "about," "proximate," "minor variation," and similar terms generally refer to ranges that include the identified value within a margin of <NUM>%, <NUM>% or preferably <NUM>% in certain embodiments, and any values therebetween.

All of the functionalities described in connection with one embodiment are intended to be applicable to the additional embodiments described below except where expressly stated or where the feature or function is incompatible with the additional embodiments. For example, where a given feature or function is expressly described in connection with one embodiment but not expressly mentioned in connection with an alternative embodiment, it should be understood that the inventor intends that that feature or function may be deployed, utilized or implemented in connection with the alternative embodiment unless the feature or function is incompatible with the alternative embodiment.

Describing now an exemplary tool with which the improved adapter may communicate, a motor-driven orthopedic impacting tool is provided with controlled percussive impacts. The motor may be electric, such as a brushless, autoclavable motor such as those generally available from Maxon Motor® and/or Portescap®. The motor may be battery-operated. The energy supply to the orthopedic impacting tool may provide wireless portability and communication for the orthopedic impacting tool. The tool may include the capabilities to perform single and multiple impacts, as well as impacting of variable and varying directions, forces, and frequencies. In some embodiments, the impact energy is adjustable. In certain embodiments, the impact is transferred to a surgical implement such as a broach, chisel, or other end effector connected to the tool.

In some embodiments, the tool includes a housing. The housing may securely cover and hold at least one component of the tool and may be formed of a material suitable for surgical applications, such as aluminum or Polyphenylsulfone (PPSF or PPSU), also known as Radel®. In some embodiments, the housing contains a motor assembly, at least one reducing gear, a spring element, a striker or launched mass, a control circuit or module, an anvil, a first or forward striking surface for forward impact, and a different, second or rearward striking surface for rearward impact. The motor assembly may include a linear motion converter to convert a rotary motor drive. The spring element may be a mechanical, elastomeric, or gas spring.

The tool further may include a handle portion with an optional hand grip for comfortable and secure holding of the tool, or a suitable mount interface for integrating the tool into a robotic assembly while in use, and an adapter, a battery, a positional sensor, a directional sensor, and a torsional sensor. The tool may further deliver focused illumination by way of a semiconductor light source, such as an LED or traditional incandescent light source, to provide light in the surgical work area in which a surgeon employs the tool. The anvil may be coupled to a surgical implement broach, chisel or other end effector known in the art through the use of an interfacing adapter, which adapter may have a quick connect mechanism to facilitate rapid change of different broaching sizes. The tool may further include an axially locking, but rotationally variable, feature to allow the adapter to be positioned in different spatial fashions as to gain tissue clearance for tool features such as the handle.

In some embodiments, an axis of the launched or thrown mass is aligned axially, along the direction of movement, to within <NUM> degrees of the axis of the adapter, and more preferably, to within <NUM> degrees of the axis of the adapter. Such axial alignment is significant in terms of maximizing the energy transferred to the surgical implement, as well as minimizing the generation of off-axis forces, which can contribute to adverse surgical outcomes, such as fractures. The inventor discovered that these benefits of axial alignment were, in part, a result of bone being an anisotropic material, rendering it stronger with respect to compression or tension forces than it is with respect to shear forces.

It has been determined by the inventor that the mass ratios and materials used for the launched or thrown mass, the anvil, and the adapter are significant in terms of how effectively the kinetic energy of the thrown mass is conveyed to the surgical implement. For purposes of certain embodiments, the ratio of the delivered energy to the surgical implement as a function of the kinetic energy in the thrown mass or striker is referred to as the transfer function. The transfer function is used as a measure of performance, in terms of how efficiently the tool is performing broaching, impacting, or extraction surgical procedures. For example, in one design in which the thrown mass, anvil, and adapter were all made of hardened stainless steel, the ratio of the energy conveyed to the surgical implement to the kinetic energy of the thrown mass, or the transfer function, was found to be less than <NUM>%. By increasing the mass ratio of the thrown mass to the impacted mass (the sum of the mass of the anvil, the adapter, and the surgical implement), the efficiency of the adapter and the system, in particular, the transfer function of the adapter and the system, was increased to greater than <NUM>%, and in many cases, close to <NUM>%. <FIG> shows an embodiment of the tool and illustrates the aforementioned masses, including impacted mass <NUM> and thrown mass <NUM>.

The tool, in further embodiments, includes a compliance element inserted between the striker and the adapter. Preferably, the compliance element is a resilient material that recovers well from impact and imparts minimal damping on the total energy. As an example, a urethane component could be inserted at the interface where the striker impacts the anvil. In another example, the compliance element may be inserted in such a fashion that it only reduces the impact force in the forward direction and does not affect the desire for a sharp impact force in the rearward direction. This type of compliance element can limit the peak force during impact to preclude such peaks from causing fractures in the patient's bone, yet maintain the high peak force necessary to be able to retract stuck broaches or other surgical implements.

In some embodiments, the impactor is coupled to a robot, for example, thus potentially eliminating the need for a portable power source (battery) and/or hand grip on the tool.

In some embodiments, the coupling of the adapter to the tool includes a linkage arrangement or other adjustment mechanisms known in the art such that the position of the surgical implement (broach, chisel or other end effector) can be modified without requiring the surgeon to rotate the tool.

<FIG> shows a perspective view of an example of an orthopedic impacting tool with which an improved adapter may communicate. A motor <NUM> of a mechanical spring assembly system, in combination with a linear motion converter, which includes a barrel or cylindrical cam <NUM> and a cam follower <NUM>, actuates a first spring piston 19a and/or a launched mass or striker <NUM>, in order to ultimately generate a forward impact force is provided (also provided is a second spring piston 19b to engage a second spring 2b being compressed against a second pusher plate 26b to generate a rearward impact force). It is to be noted that the piston generally refers to a thrusting or push off element and can have any of a number of shapes. The spring assembly system further includes, in some embodiments, an anvil <NUM>.

The barrel cam <NUM> can include a cylindrical portion <NUM> mounted longitudinally on a shaft <NUM> extending between the motor <NUM> and a bearing support <NUM>, and a worm <NUM> protruding radially from the cylindrical portion <NUM> and helicoidally along a length of the cylindrical portion <NUM> from a first worm end 126a to a second worm end 126b.

The bearing support <NUM> can include a housing <NUM> supported by the second pusher plate 26b and a bearing nested in the housing <NUM> to support the shaft <NUM>.

The worm <NUM> can include a backward surface 126bs, e.g. the surface facing a first pusher plate 26a, and a forward surface 126fs of the worm <NUM>, e.g. the surface facing the second pusher plate 26b, that contacts the cam follower <NUM> and forces the cam follower <NUM> to follow a rectilinear movement between the first worm end 126a and the second worm end 126b as the worm <NUM> rotates.

The cam follower <NUM> can be displaced along the worm <NUM> in the forward direction, e.g. towards the second pusher plate 26b, by having the cam follower <NUM> contacting the forward surface 126fs of the worm <NUM> and having the worm <NUM> rotating in a first direction 42a.

The cam follower <NUM> can be displaced along the worm <NUM> in the backward direction, e.g. towards the first pusher plate 26a, by having the cam follower <NUM> contacting a backward surface 126bs of the worm <NUM>, e.g. the surface facing the pusher plate 26a, and having the worm <NUM> rotating in a second direction opposite to the first direction 42a.

Bumpers 14a and 14b function as stoppers to prevent end faces of the piston 19a and 19b from impacting the striker <NUM>.

The barrel cam <NUM> can enhance efficiency of the orthopedic impacting tool by allowing the motor <NUM> to rotate with larger angles compared to a conventional linear motion converter that may rely on conventional vertical cams that hit the cam follower <NUM> through small repetitive strokes. That is, the barrel cam <NUM> allows the use of more radians of rotation for the motor to get the energy and thus, reduces the current drain on the battery significantly. Accordingly, a single primary battery could be used in certain embodiments by utilizing the advantages provided by the barrel cam <NUM> in the reduction of the current drain.

In addition, the barrel cam <NUM> can in certain cases allow for the elimination of an intermediate gear assembly, as the barrel cam <NUM> can be directly mounted onto the shaft <NUM> and thus enhance efficiency whilst reducing the cost of the orthopedic tool.

The tool, in some embodiments, facilitates controlled continuous impacting, which impacting is dependent on a position of the trigger switch <NUM> operatively coupled to the power source or motor, for example. For such continuous impacting, after the trigger switch is activated, and depending on the position of the trigger switch <NUM>, the tool may go through complete cycles at a rate proportional to the position of the trigger switch, for example. Thus, in either the single impact or continuous impacting operational modes, the creation or shaping of the surgical area may be easily controlled by the surgeon.

In some embodiments, the controlled continuous impacting is managed at least in part by a controller <NUM>. The controller <NUM>, for example, may include processing circuitry for monitoring and managing timing of the continuous impacting mode. In some examples, the controller <NUM> may include a microcontroller, system on a chip, programmable logic device, and/or microprocessor including timing circuitry for timing energy release of the surgical impacting tool. The controller may be in communication with a power source, such as a battery housed upon or within the surgical impacting device or a power connector to a separate power source.

The controller <NUM>, in certain embodiments, includes instructions stored to a non-transitory computer readable medium which, when executed, cause the controller <NUM> to manage energy storage and release to enable the repeatable continuous impacting. The controller <NUM>, in some implementations, includes one or more receivers for receiving signals from one or more communication devices or sensors, such as a positional sensor, an RFID tag, a proximity sensor, or a motion sensor. The instructions, for example, may include instructions configured to start impacting, pause impacting, and/or adapt timing of energy storage and release based upon signals received from one or more sensors or other communication devices.

The controller, in some implementations, includes one or more output elements for issuing signals to other elements of the surgical impacting device. In some embodiments, the controller includes an audio output device to issue an audible alert to an operator based upon an event, such as a low power event or a suspected mechanical failure event.

In some embodiments, as the barrel cam <NUM> assembly completes its course, e.g. the cam follower <NUM> is displaced along either the backward surface 126bs or the forward surface 126fs between the first worm end 126a and the second worm end 126b, it preferably activates the sensor <NUM> coupled operatively to the controller <NUM>. The sensor <NUM> assists in the regulation of the preferred cyclic operation of the barrel cam <NUM>. For example, the sensor <NUM> may signal the motor <NUM> to stop such that the barrel cam <NUM> is at or near a point of minimal potential energy storage. Thus, in one complete cycle, a forward or a rearward impacting force may be applied on the broach, chisel, or other end effector, or on the implant or prosthesis. In a further embodiment, it may be advantageous to insert a delay or count the number of impacts for any give procedure before starting the next cycle, making it possible to accurately control the speed of impacting, and, in turn, allowing the surgeon to accurately control the rate of energy delivery in any given operation. In a still further embodiment, it may be advantageous to stop the barrel cam <NUM> near a point of maximum potential energy storage to reduce a latency in the surgeons' hands. Latency, as defined, is the time between when the surgeon (or user) activates the orthopedic impacting tool and the tool actually delivers an impact. It has been determined by the inventor that latencies of around <NUM> milliseconds or less appear essentially as an instantaneous response. By stopping the barrel cam <NUM> at a point where at least part of the potential energy has been stored, the tool has the effect of near instantaneous release of the potential energy upon actuation of a tool trigger <NUM>.

Referring now generally to <FIG>, an orthopedic impactor is shown with various configurations of adapters for use therewith.

<FIG> illustrates a surgical impactor <NUM> and adapter <NUM> in which the adapter <NUM> can be inserted into the impactor <NUM> in any of <NUM> different rotations around an impacting axis <NUM>. For example, as illustrated in <FIG>, an impacting axis <NUM>, or the axis along which an anvil or a mass is thrown, is oriented horizontally lengthwise leftward and rightward as drawn, and the adapter <NUM> has a generally square cross-section with at least four surfaces 212a, 212b, 212c, 212d that form at least four distinct planes around the lengthwise axis of the adapter <NUM>. Those planes run parallel with the impacting or anvil axis and permit the adapter <NUM> to be inserted into the impactor <NUM> in the <NUM> different rotational orientations. Of course, while insertion via <NUM> different rotations are shown via the illustrated square interface in <FIG>, additional rotational positions would be possible. For example, an adapter with a hexagonal interface could have <NUM> different rotational configurations, and an adapter with an octagonal interface could have <NUM> different rotational configurations. The different insertion angles allow for multiple positioning of the surgical implement while maintaining the ability of the surgeon to hold the tool in a more ergonomic orientation.

In <FIG> and <FIG>, an impactor <NUM>, adapter <NUM> and surgical implement <NUM> (e.g., a broach) are shown in both an unconnected state and in a connected state.

<FIG> illustrates an embodiment in which the multiple surfaces of the adapter, such as a surface for forward impacts <NUM> and a surface for rearward impacts <NUM>, allow for both proximal and distal impacts on the adapter and consequently to the surgical implement. The ability to produce impacts proximally and distally is especially useful when implements become lodged in a cavity. By applying a direct reverse blow to the adapter, the lodged implement can easily be dislodged from the cavity. It was discovered by the inventor that the surface areas should be designed to withstand impact forces ranging from <NUM> kilonewton to <NUM> kilonewtons, and more particularly about <NUM> kilonewtons, for general durability over time as a surgical impactor. In one example, the area of contact between the impactor <NUM> and either the surface for forward impacts <NUM> or the surface for rearward impacts <NUM> should be between <NUM><NUM> and <NUM><NUM> to transfer and withstand the necessary impact forces.

<FIG> illustrates a position on the adapter where the total indicator reading ("TIR") of the adapter can be measured. As shown in the figure, the TIR of the adapter should be measured at the tip <NUM> of the adapter, and in some embodiments, the adapter should be designed such that the TIR is less than <NUM> and more preferably less than <NUM>. With a small TIR, the precision of the orthopedic impactor is increased. In use, this precision translates into minimized distortion of the cavity, less energy loss laterally, improved fitting of implants, and improved surgical outcomes. By comparison, other known surgical implements have TIRs on the order of <NUM>. A TIR of <NUM> or less is a significant improvement and produces cavities with significantly more precise forms and shapes.

<FIG> and <FIG> illustrate one embodiment of the insertion and removal procedures of the adapter connection to the impactor via a reciprocal sleeve.

In one embodiment, the reciprocal sleeve can include a release collar <NUM>, snap ring <NUM>, and retaining clips <NUM>. As shown in <FIG>, the adapter <NUM> is inserted via a single insertion motion <NUM>, towards the impactor, to secure the connection to the impactor <NUM>. During that motion, retaining clips <NUM> within a release collar <NUM> are forced apart as the adapter <NUM> moves inward. A snap ring <NUM> locks, or otherwise seats and holds, in place the retaining clips <NUM> on the adapter <NUM>. In one example, the snap ring <NUM> can be an o-ring. In other embodiments, the retaining clips <NUM> may be locked into place using a garter spring to exert inward radial force, maintaining position of the retaining clips <NUM>. In further embodiments, the snap ring <NUM> may include an elastomer ring.

As shown in <FIG>, the adapter <NUM>, in some embodiments, can be disconnected from the impactor by depressing a release collar <NUM>. The release collar <NUM> includes cam surfaces <NUM> configured to separate the retaining clips <NUM> as the release collar <NUM> slides and gradually moves from contacting the retaining clips <NUM> at the narrower section of cam surfaces <NUM> to the wider section of cam surfaces <NUM>. When the retaining clips <NUM> are separated enough to clear the adapter <NUM>, the adapter <NUM> may be moved outward away from the impactor <NUM>. In an alternative example, the reciprocal sleeve may include a pinion and rack in place of cam surfaces <NUM> to separate the retaining clips <NUM> as the adapter <NUM> is disconnected from the impactor.

As shown in <FIG>, a surgical implement for use with the adapter and an electrically driven orthopedic impactor has cutting teeth <NUM> for shaping a bone <NUM> to accept an implant. In one example, the cutting teeth <NUM> can be arranged on a surface of the impactor such that the teeth <NUM> cut linearly with an axis of the impactor. In a further embodiment, the teeth may be configured in such a fashion as to improve the fitment of a press fit implant such as a knee. In still a further embodiment, the surgical implement for use with the adapter may include features which increase the surface area available for bonding with adhesive implants.

<FIG> illustrates an example of a sensor <NUM> included on the adapter <NUM>, which communicates information to the impactor and allows the surgeon to control the impactor more accurately. The information may be used, for example, by a controller such as the controller <NUM> of <FIG> to adjust the stroke, power, or frequency of impacts, for example. For instance, if the adapter is being used in seating a head ball, where continuous impacting is not desired, the adapter sensor may be configured to communicate back to the impactor a requirement for single-shot actuation rather than repeated impacts. In this situation, surgical outcomes will be improved, as the surgeon will be less likely to cause implant subsidence during head ball impaction. The adapter may detect the surgical implement and its type or configuration information, such as in the head ball placement tool example above, by communicating with the surgical implement using the same sensor or a second sensor or other communication device. For example, the sensor may communicate an identification signal or code interpreted by the controller <NUM> and used by the controller <NUM> to adjust basic settings to those appropriate to the particular surgical implement. In a particular example, an RFID sensor on the adapter may query a passive RFID tag of the surgical implement to determine a type of the surgical implement, and provide the identification signal or code derived from the passive RFID tag to the controller <NUM>. In another example, a physical marking upon the surgical implement may be mechanically identified (e.g., "keyed" to the adapter) or electronically identified (e.g., "scanned" by a scanning sensor of the adapter) to determine a type of surgical implement connected to the adapter. The settings, in some examples, can include a frequency of impact, a force of impact, and/or a direction of impact. In some embodiments, the surgical implement is integrally formed with, and thus not detachable from, the adapter. In those embodiments, the adapter may store information relating to the surgical implement and communicate the information to the surgical impactor.

As another example, communication and control of frequency information allows the tool to precisely and consistently control the frequency of the impacting movement. By regulating the frequency of the striker, the tool may impart a greater total time-weighted percussive impact, while maintaining the same impact magnitude. This allows the surgeon better control over the cutting speed of the surgical implement. For example, the surgeon may choose cutting at a faster rate (higher frequency impacting) during the bulk of the surgical implement movement and then slow the cutting rate as the surgical implement approaches a desired depth. In fact, during testing of the tool, it was discovered that a higher frequency impacting rate, such as <NUM> impacts per second, preferably up to <NUM> impacts per second, coupled with a substantially constant energy per impact, delivering between <NUM> to <NUM> joules per second, preferably up to <NUM> joules per second, allowed the surgeon to better position certain surgical implements. This was seen, for example, in the seating of an acetabular cup, where an impact frequency of at least <NUM> impacts per second, at an energy of between <NUM> and <NUM> joules per second, resulted in far better control of the position of the acetabular cup over the prior art manual hammering technique. In a further unexpected benefit of the rapid impacting capabilities of the electric driven orthopedic impactor, the inventor discovered that the energy to perform an operation could be reduced as the movement of the surgical implement was more fluid and continuous (i.e., less of a start and stop function similar to mallet blows). This benefit of rapid impacting (e.g., at a rate greater than <NUM> times per second) finds its basis in engineering differences between static and dynamic friction. Dynamic friction is almost always less than static friction, and as such, a more continuous movement of a broach, implant, or other surgical implement allows for lower overall forces during the operation. In addition, it has been the inventor's experience in the operating room that the near continuous movement of the surgical implement not only lowers the total energy required but also results in a better surgical outcome. In a specific case of a reamed acetabulum, a reamer may leave valleys and peaks. By using a more continuous or higher frequency impacting described herein, the valleys and peaks are reduced and in effect ironed out. This has been clearly seen in numerous cadaver labs. Specifically, in the placement of the cup into the acetabulum, better fixation results from the more intimate contact between the surfaces.

Claim 1:
A surgical system, comprising:
a surgical impactor (<NUM>), the surgical impactor including an anvil (<NUM>) and being configured to produce energy to move the anvil along an anvil axis (<NUM>);
an adapter (<NUM>) configured to interface a surgical implement with the surgical impactor, the adapter comprising:
a surface for communicating an impact in a first direction (<NUM>); and
wherein the adapter comprises a sensor (<NUM>) and is configured to detect a type of surgical implement (<NUM>), wherein the sensor is configured to communicate information to the surgical impactor;
wherein, during operation of the surgical impactor, the surface communicates an impact from the anvil through the adapter to the surgical implement;
wherein the surgical impactor further comprises a controller (<NUM>), wherein the controller is configured to use the detected type of surgical implement to adjust a stroke, power or frequency of impacts.