Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION: SYSTEM FOR ASSEMBLING PROSTHETIC COMPONENTS
2. APPLICANT:
Meril Corporation (I) Private Limited, an Indian company of the address Survey No. 135/139, Muktanand Marg, Bilakhia House, Pardi, Vapi, Valsad-396191 Gujarat, India.

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[1] The present disclosure relates to a press instrument. More particularly, the present disclosure relates to a bipolar cup press instrument for assembling prosthetic components.
BACKGROUND OF INVENTION
[2] Hip replacement is a surgical procedure involving replacement of a damaged hip joint with artificial implants. An artificial implant includes a femoral component and a socket component. Further, for assembling a head (of the femoral component) and a cup (of the socket component) of an orthopedic hip prosthesis, an assembling instrument is required. The assembling instrument can be a (bipolar) cup press.
[3] Conventionally, a cup press requires human intervention for assembling the components of an implant. Typically, a conventional cup press includes a combination of springs, handles, rods, etc. Due to compression of springs, a controlled and directed pressure is generated, thereby assembling a bipolar cup. The surgeon uses the cup press to apply a controlled and directed pressure to a specific area of the bipolar cup to assemble the same.
[4] Conventional cup press is prone to human errors as it achieves the press function using human intervention and relies on manually controlled components. This can lead to improper alignment of the implant increasing the probability of misdiagnosis.
[5] Therefore, there arises a need for an automated bipolar cup press instrument to overcome the problems associated with a conventional cup press.
SUMMARY OF INVENTION
[6] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are mere examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[7] The present disclosure relates to a system for assembling components of a prosthetic implants. The system includes a first prosthesis holder and a second prosthesis holder. At least one of the first prosthesis holder and the second prosthesis holder is coupled to a hydraulic actuator. The hydraulic actuator is configured to move the first prosthesis holder relative to the second prosthesis holder. The system includes one or more sensors to measure parameters of one or more actuators. The actuators parameters include pressure, position, displacement and acceleration related to the hydraulic actuator. The system includes a control unit. The control unit controls at least one of a pressure, position, displacement, acceleration, velocity or a travelling direction of the hydraulic actuator. The parameters are controlled based on the measured actuator parameters.
BRIEF DESCRIPTION OF DRAWINGS
[8] The summary above and the detailed description of descriptive embodiments, is better understood when read in conjunction with the apportioned drawings. For illustration of the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[9] FIG. 1 depicts a schematic view of a system 100, according to an exemplary embodiment;
[10] FIG. 2 depicts a housing 110 of the system 100, according to an exemplary embodiment;
[11] FIG. 3 depicts a hydraulic circuit 120, according to an exemplary embodiment;
[12] FIG. 4 depicts a hydraulic actuator 330, according to an exemplary embodiment;
[13] FIG. 5 depicts a block diagram of a control unit 130, according to an exemplary embodiment;
[14] FIG. 6 depicts an isometric view of a head and a socket component of an orthopedic implant, according to an exemplary embodiment; and
[15] FIG. 7A – 7D depicts schematics corresponding to the operational steps or working of the system 100, according to an exemplary embodiment.
DETAILED DESCRIPTION OF DRAWINGS
[16] Prior to describing the disclosure in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like. Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[17] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[18] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[19] Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.
[20] The present disclosure relates to a bipolar cup press system for assembling at least two components of an orthopedic prosthesis with minimal human intervention in a substantially automated manner. The bipolar cup press system employs hydraulics to generate a required force to assemble the prosthetic components of the orthopedic prosthesis. The orthopedic prosthesis includes in an exemplary embodiment, a head and a socket component. Such a construction is typical of joints of the human body, for example, the hip joint, and the shoulder joint. Advantageously, the system does not require human power/force for assembling the prosthetic components. Consequently, the bipolar cup press system facilitates swift, accurate, and repeatably precise alignment of the prosthetic components, ultimately improving the overall safety, success, and/or effectiveness of orthopedic replacement surgeries.
[21] The bipolar cup press system described herein comprises a plurality of sensors including but not limited to a pressure sensor, a position sensor, a displacement sensor, an accelerometer, an ultrasonic sensor, a PIR sensor, a strain gauge sensor, or a combination thereof. The plurality of sensors is configured to reduce the human effort and error to minimum and ensure proper assembling of the prosthetic implant components.
[22] Referring now to the figures, FIG. 1 depicts a system 100 for a bipolar prosthesis assembly, according to one exemplary embodiment. The system 100 includes at least a housing 110, a hydraulic circuit 120, a control unit 130, and a pair of prosthesis holders, a first prosthesis holder 150a and the second prosthesis holder 150b.
[23] The housing 110 is configured to contain the other subsystems of the system 100, thereby protecting them at least partially, from the external environment, shocks and/or dust and debris. The housing 110 is described in greater detail in conjunction with FIG. 2.
[24] The hydraulic circuit 120 is configured to provide the seating or fitting force for assembling two prosthetic components, such as a head prosthetic component, and an acetabular prosthetic component. In some embodiments, the head prosthetic component may be a femoral head, and the acetabular prosthetic component may be a hip acetabulum. In some other embodiments, the head prosthetic component may be a humeral head, and the acetabular prosthetic component may be a glenoid cavity. The hydraulic circuit 120 allows a substantially smooth application of force for seating the head component into the socket component, devoid of percussive forces. Further, the hydraulic circuit 120 enables the seating force to be applied accurately, and repeatably precisely, without the need for human application of force. The hydraulic circuit 120 and the various subcomponents therein are described in greater detail in conjunction with FIG. 3. In various embodiments, the hydraulic circuit 120 is configured to operate under the control of the control unit 130.
[25] The control unit 130 is configured to control the operation of the hydraulic circuit 120. The control unit 130 is configured to receive one or more actuator parameters from one or more sensors, and responsively, control the operation of the hydraulic circuit 120. Exemplary actuator parameters include, without limitation, a pressure applied by the hydraulic circuit 120, a position of a hydraulic actuator of the hydraulic circuit 120, a displacement of the hydraulic actuator 330, and an acceleration of the hydraulic actuator 330.
[26] In various embodiments, the control unit 130 may control the operation of the hydraulic actuator 330 within the hydraulic circuit 120. In an embodiment, based upon the measured actuator parameters, the control unit 130 is configured to control at least one of the parameters such as a pressure, a position, a displacement, a velocity, an acceleration, a direction etc. of the hydraulic actuator 330. In some embodiments, the control unit 130 may control the operation of a hydraulic pump 320 within the hydraulic circuit 120. In some other embodiments, the control unit 130 may control the operation of one or more valves within the hydraulic circuit 120.
[27] In various embodiments, the control unit 130 may further include, a microprocessor, a microcontroller, a driver circuitry, or any combination thereof.
[28] The microprocessor or microcontroller is configured to generate control signals based on the received sensor inputs (i.e. the actuator parameters). In some embodiments, the microprocessor or microcontroller may generate the control signals using a logical operation (Boolean, and/or fuzzy), or using a look-up table, or using any known programming constructs and algorithms, or a combination thereof. Once generated, the control signals are communicated to the driver circuitry.
[29] The driver circuitry is configured to drive the subcomponents of the hydraulic circuit 120. The control signals generated by the microprocessor or microcontroller are low level signals, with sufficient power to trigger the drive equipment such as motors and electro-mechanical valves (solenoid valves, ball valves, etc.). The driver circuitry is essentially configured to convert these low-level control signals into driving signals. The driver circuitry may do so by employing solid state switches, power amplifiers, electromagnetic relays, and so forth.
[30] The first prosthesis holder 150a and the second prosthesis holder 150b, are particularly designed for a close fit with a respective prosthesis component, such that the prosthesis components do not move during assembly, thus minimizing the change for misalignment, and taking the guesswork out of positioning the prosthesis components within the system 100. In an embodiment, the first prosthesis holder 150a is configured to hold a socket component (610) of the prosthetic implant and the second prosthesis holder (150b) is configured to hold a head component (620) of the prosthetic implant. Further, the first prosthesis 150a and the second prosthesis holder 150b can include one or more sensors configured to provide continuous data during the assembling of the prosthesis implant explained in details later.
[31] FIG. 2 illustrates the housing 110, according to one embodiment. The housing 110 may be configured to contain the various subcomponents of the hydraulic circuit 120, and the control unit 130. The housing 110 may be configured to protect the components from external environmental elements such as dust, humidity etc. The housing 110 may have one or more closable openings (not illustrated), to permit maintenance and repairs of the system 100. The housing 110 can be made from any suitable material such as stainless steel, aluminum, carbon fiber, HDPE, etc. The housing 110 may be shaped according to the assembly of components to be housed. In one embodiment, the housing 110 is C-shaped as illustrated.
[32] The housing 110 may further include a top portion 210, and a base portion 220. The base portion 220 may further include a platform 222, and the first prosthesis holder 150a. The top portion 210 is configured to mechanically couple with a linear hydraulic actuator, in a substantially rigid, immovable manner. The base portion 220 may be constructed to provide a substantially rigid base for the system 100. The base portion 220 may be attached to the housing 100 in a manner that substantially inhibits any flexure, bending, or movement of the platform 222 with respect to the housing 110. To this end, in various embodiments, the housing 110 may further include a substantially rigid frame (not illustrated), either internal or external to the housing 100, on which various subcomponents of the system 100 may be mounted. In particular, the substantially rigid frame may be used to mount the platform 222, and the barrel of the linear hydraulic actuator, in a manner such that there is only a permissibly small or no relative movement between the platform 222 and the barrel of the hydraulic actuator. In other words, the base portion 220 withstands the force applied by the hydraulic circuit 120, without moving or deforming.
[33] In various embodiments, the base portion 220 may further include the first prosthesis holder 150a. The first prosthesis holder 150a may be in the form of a protruding stud, according to various embodiments. The first prosthesis holder 150a is configured to position a head component of a two-part orthopedic implant. The first prosthesis holder 150a ensures proper alignment of the head portion of the orthopedic implant by restricting the movement of the placed implant component.
[34] In various embodiments, the base portion 220 may further include one or more sensors (referred to hereinafter collectively and individually, as base sensors). The base sensors (not illustrated) may be configured to measure the force acting on the first prosthesis holder 150a. Such base sensors may include force sensors, load sensors, pressure sensors, and so forth. The base sensors may be any suitable sensor capable of measuring force, pressure, or load, for example, but not limited to, strain gauge sensor, load cell, extensometer sensor, photo-elastic sensor, Fiber Bragg Grating (FBG) sensor, and the like. Multiple such base sensors may be arranged in an axial symmetry around the first prosthesis holder150a. Alternatively, a single base sensor may be used, and arranged coaxially with the first prosthesis holder 150a. The base sensors may be placed within the platform 222, in some embodiments. In other embodiments, the base sensors may be placed within the first prosthesis holder 150a. In still other embodiments, the base sensors may be placed elsewhere within the base portion 220, still capable of measuring the force, load, or pressure acting on the first prosthesis holder 150a.
[35] In various embodiments, the housing 110 may also include one or more sensors (hereinafter, collectively and individually referred to as operator sensors), for detecting the position and movement of the operator using the system 100. In particular, operator sensors may be deployed to confirm that the operator’s hands or other body parts are clear of the system 100, while the system 100 is performing a press-fit assembly. Exemplary operator sensors may include, without limitation, ultrasonic sensors, PIR sensors, imaging sensors, etc. The operator sensors provide continuous signals to the control unit 130 providing clearance to proceed or to hold off the assembling process/procedure.
[36] Fig. 3 illustrates in greater detail, the hydraulic circuit 120, according to various exemplary embodiments. The hydraulic circuit 120 includes a reservoir 310, a hydraulic pump 320, a hydraulic actuator 330, hoses 340, and valves 350. The reservoir 310, the hydraulic pump 320, and the hydraulic actuator 330 may be in fluid communication with one another through hoses 340 and valves 350.
[37] The hydraulic pump 320, and hydraulic actuator 330 may be specified based on the mating/fitting requirements of the bipolar cup assembly system 100. In one exemplary embodiment, the bipolar cup assembly system 100 requires a peak force about 2 kN +/- 50 N applied with a displacement control at a rate of about 0.04 mm/s or force control at a rate of about 1 kN/s or less.
[38] The reservoir 310 is an essential component of the hydraulic circuit 120 for holding the hydraulic fluid. In various embodiments, the hydraulic fluid may be an incompressible biocompatible material, such as, but not limited to, silicone fluids, polyethylene glycol (PEG) solutions, hydrogels, and so forth. In an alternate embodiment, the hydraulic fluid is a regular hydraulic fluid such as oil, water etc. The reservoir 310 may include one or more ports (not illustrated) to allow inlet and outlet flow of the hydraulic fluid. The reservoir 310 may be of any suitable shape, such as a cube, cuboid, sphere, cylinder, prism etc. The reservoir 310 may be constructed from any suitable material such as stainless steel, aluminum, HDPE, LDPE, carbon fiber and so forth.
[39] The hydraulic pump 320 is configured to generate suction and/or generate a gauge pressure to draw and supply the hydraulic fluid to and from the reservoir 310, and to and from the hydraulic actuator 330. The hydraulic pump 320 may further include a pump head 322, and a prime mover 324. The hydraulic pump 320 may include fluid ports (not illustrated) configured to receive and discharge the hydraulic fluid.
[40] The pump head 322 may include one of a gear pump, a vane pump, a gerotor pump, a piston pump, a screw pump, a scroll pump, or any other suitable positive displacement pump.
[41] The prime mover 324 may be an AC motor, or a DC motor. In one embodiment, the prime mover may be a brushless DC (BLDC) motor. The prime mover 324 converts supplied electrical energy into a rotational mechanical energy required to operate the pump 320, to generate suction and/or discharge pressure. The prime mover 324 is in electrical communication with the control unit 130 and is under the control of the control unit 130. In particular, the starting, stopping, rotational speed, torque, acceleration, or any combination thereof, of the prime mover 324 may be controlled by the control unit 130. The control of the prime mover 324 results in the control of the pressure and suction generated by the pump 320 in the hydraulic circuit 120.
[42] The hydraulic actuator 330 is configured to move linearly to apply a mating/fitting force to assemble the components of an orthopedic implant. The hydraulic actuator 330 may be a linear hydraulic actuator that is configured to extend and retract under applied hydraulic pressure and/or suction. Functionally, the hydraulic actuator 330 is configured to press-fit two components of the orthopedic implant. The hydraulic actuator 330 is described in greater detail in conjunction with FIG. 4.
[43] The reservoir 310, the hydraulic pump 320, and the hydraulic actuator 330 may be in fluid communication with one another through hoses 340 and/or valves 350. The hoses 340 are configured to provide the fluid pathway between the components. The valves 350 are configured to control the flow of the hydraulic fluid between the reservoir 310, the hydraulic pump 320, and the hydraulic actuator 330. The valves 350 may be configured to change the direction of flow, the rate of flow, and/or starting and stopping the flow of the hydraulic fluid in the various portions of the hydraulic circuit 120. In various embodiments, the valves 350 may be electro-mechanical or electro-magnetic valves, such as solenoid valves, motorized ball valves, motorized multi-way (3-way or 4-way) valves, and so forth. The valves 350 may operate under the control of the control unit 130.
[44] In various embodiments, any conventionally known arrangements of hoses 340 and valves 350 may be employed. The exact arrangement of hoses 340 and valves 350 may vary, and various arrangements are within the scope of the present disclosure, as long as the arrangement of hoses 340 and valves 350 serve the intended operation of the hydraulic circuit 120 and thus achieve the purpose of the system 100 i.e. for assembling components of an orthopedic implant, via a press fitting or mating operation. An exemplary operation of the assembling components of the orthopedic implant is described in greater detail, in conjunction with FIG. 6 and FIG. 7.
[45] The hydraulic circuit 120 may further include on or more sensors (hereinafter, collectively and individually referred to as hydraulic sensors). The hydraulic sensors may be configured to measure various actuator parameters such as, but not limited to, a pressure applied by the hydraulic actuator (330), a position of the hydraulic actuator (330), a displacement of the hydraulic actuator (330), and an acceleration of the hydraulic actuator (330). Such sensors may be positioned within the hydraulic actuator 330, or in direct fluid communication or mechanically coupled with the hydraulic actuator 330.
[46] Some other examples of hydraulic sensors may include pressure sensors, flow rate sensors, and flow velocity sensors. Such hydraulic sensors may be positioned in, or in direct fluid communication with, for example, the hydraulic pump 320. Still other examples of hydraulic sensors may include sensors for the prime mover 324, such as, but not limited to, shaft speed sensors, shaft position sensors, current and voltage sensors, and the like, to monitor the operation of the prime mover 324, and ensure accurate and precise control of the hydraulic output of the hydraulic pump 320.
[47] It should be appreciated that various arrangements and positions of sensors are possible, to measure various parameters of the hydraulic circuit 120. All such positions and arrangements of sensors are within the scope of the embodiments described herein.
[48] FIG. 4 illustrates a hydraulic actuator 330, according to various embodiments. The hydraulic actuator 330 includes a cylinder 410, a piston 420, a piston rod 430, and ports 440. The hydraulic actuator 330 is coupled to at least one of the first prosthesis holder 150a and a second prosthesis holder 150b. In an embodiment, the hydraulic actuator 330 is coupled to the second prosthesis holder 150b. Further, the hydraulic actuator 330 is configured to move the second prosthesis holder 150b towards the first prosthesis holder 150a explained in details later.
[49] The cylinder 410 is the outer shell of the hydraulic actuator 330, and houses the piston 420. The cylinder 410 is configured to be fixed to the housing 110, or a structural frame thereof. In an embodiment, the cylinder 410 of the hydraulic actuator 330 is configured to include the incompressible biocompatible fluid.
[50] The piston 420 may further include sealing rings around its circumference to make it fluid tight against the walls of the cylinder 410. The piston 420 is in turn connected to the piston rod 430. In various embodiments, the piston 420 and the piston rod 430 may be manufactured as a single unit. In other embodiments, the piston 420 may be a separate component, mechanically attached to the piston rod 430, by, for example, a screw connection or a connecting pin.
[51] The end of the piston rod 430 opposite to the piston 420, is mechanically coupled to the second prosthesis holder 150b. Such a mechanical coupling may be configured to have no relative movement or flexure in the axial direction. This ensures accurate tracking and positioning of the second prosthesis holder 150b.
[52] The hydraulic actuator 330 may further include the ports 440. The ports 440 allow flow of hydraulic fluid into and out of the cylinder 410. In various embodiments, the ports 440 may be on opposite axial ends of the cylinder 410, for example, if the hydraulic actuator 330 is a double acting type actuator. In other embodiments, the ports 440 may be on the same axial end of the cylinder 410, for example, if the hydraulic actuator 330 is a single acting type actuator.
[53] As discussed above, in connection with FIG. 3, the hydraulic actuator 330 may further include on or more hydraulic sensors. The hydraulic sensors may be configured to measure various actuator parameters such as, but not limited to, a pressure applied by the hydraulic actuator 330, a position of the hydraulic actuator 330, a displacement of the hydraulic actuator 330, and an acceleration of the hydraulic actuator 330. Such sensors may be positioned within the hydraulic actuator 330, or in direct fluid communication or mechanically coupled with the hydraulic actuator 330.
[54] Some exemplary sensors for measuring position, displacement, and/or acceleration of the hydraulic actuator 330 may include, without limitation, ultrasonic sensors, IR sensor, Laser range finders, time-of-flight sensors, capacitive sensors, photoelectric sensors, inductive sensors, Hall effect sensors, linear encoders, and the like.
[55] FIG. 5 illustrates a block diagram of an electronic control system 500 for operating various subcomponents of the system 100. Electronic control system 500 includes the control unit 130 that includes the intelligence, logic, and saved parameters for operating the hydraulic circuit 120. The electronic control system 500 is electrically coupled to an external power source (not shown) such as a mains AC power, or a battery. The electronic control system 500 may further include the necessary circuitry to draw power from any of the connected power source.
[56] The control unit 130 communicates with and receives input signals from the base sensors 510 and housing sensors (described in conjunction with FIG. 2), and the hydraulic sensors 520 (described in conjunction with FIG. 3). Exemplary communication between the sensors, the valves, and the control unit 130 will now be described in detail.
[57] One operation of the electronic control system 500 is to retract the hydraulic actuator 330. The control unit 130 may receive input signals from the hydraulic sensors to enable precise retraction of the hydraulic actuator 330, within the design specifications of speed, and travel of the piston rod 430. The control unit 130 may measure the position of the piston rod 430 using one of the position sensors or the displacement sensors of the hydraulic actuator 330. The control unit 130 may control the hydraulic pump 320 and one or more valves 350 to induce a net hydraulic pressure in the cylinder 410 to cause the piston 420 to move in an upward direction, thus retracting the piston rod 430, and consequently the second prosthesis holder 150b.
[58] In embodiments where the hydraulic actuator 330 is a single acting type, the control unit 130 causes the hydraulic pump 320 and/or the valves 350 to induce a net suction (i.e. a net negative hydraulic pressure) in the cylinder 410. In embodiments where the hydraulic actuator 330 is a double acting type, the control unit 130 causes the hydraulic pump 320 and/or the valves 350 to induce in the cylinder 410, a relative pressure differential above and below the piston 420 (i.e. higher pressure below the piston 420, and lower pressure above the piston 420), thus retracting the piston rod 430.
[59] The control unit 130 may also detect the end of travel of the piston 420, based on the position sensors or displacement sensors within the cylinder 410, to halt the retraction of the piston rod 430.
[60] A second operation of the electronic control system 500 is to extend the hydraulic actuator 330. The control unit 130 may receive input signals from the hydraulic sensors to enable precise extension of the hydraulic actuator 330, within the design specifications of speed, and travel of the piston rod 430. The control unit 130 may measure the position of the piston rod 430 using one of the position sensors or the displacement sensors of the hydraulic actuator 330. The control unit 130 may control the hydraulic pump 320 and one or more valves 350 to induce a net hydraulic pressure in the cylinder 410 to cause the piston 420 to move in a downward direction, thus extending the piston rod 430, and consequently the second prosthesis holder 150b.
[61] In embodiments where the hydraulic actuator 330 is a single acting type, the control unit 130 causes the hydraulic pump 320 and/or the valves 350 to induce a net positive hydraulic pressure in the cylinder 410. In embodiments where the hydraulic actuator 330 is a double acting type, the control unit 130 causes the hydraulic pump 320 and/or the valves 350 to induce in the cylinder 410, a relative pressure differential above and below the piston 420 (i.e. higher pressure above the piston 420, and lower pressure below the piston 420), thus extending the piston rod 430.
[62] The control unit 130 may also detect the end of travel of the piston 420, based on the position sensors or displacement sensors within the cylinder 410, to halt the retraction of the piston rod 430. In addition, and particularly when the system 100 is being used to assemble prosthesis components, the sensors will not signal the end of travel, or maximum extension of the piston rod 430, due to the prosthesis components being placed between the first prosthesis holders 150a and the second prosthesis holder 150b. In such a case, the control unit 130 is configured to measure a pressure within the cylinder 410. If the pressure within the cylinder 410 meets or exceeds a preconfigured prosthesis seating/mating/fitting optimal pressure, the control unit 130 signals a proper fitting of the prosthesis components, and halts further extension or force application by the piston rod 430, to avoid damaging the newly assembled orthopedic prosthesis. In some embodiments, the base portion 220 may further include a threshold trigger, that generates a signal when a preset force or pressure threshold is reached, to signal the control unit 130 to halt further force application or extension of the piston rod 430.
[63] A third operation of the electronic control system 500 is to maintain position of the piston rod 430. The control unit 130 may achieve this by signaling the hydraulic pump 320 to stop. Alternatively, the control unit 130 may achieve this by signaling the valves 350 to divert the hydraulic fluid from the cylinder 410 to the reservoir 310, in an amount equal to that being delivered by the hydraulic pump 320 to the cylinder 410. In other words, the control unit 130 uses the valves 350 to balance the hydraulic pressure entering and leaving the cylinder 410, thus causing net zero movement of the piston rod 430.
[64] In various embodiments, control unit 130 operates in a continuous closed loop control – meaning the control unit 130 continuously monitors the hydraulic sensors, the base sensors, and the housing sensors, to control the hydraulic circuit 120.
[65] A fourth operation of the electronic control system 500 is to check if the prosthesis is well seated or not. The electronic control system 500 communicates with the at least one strain gauge present in the platform 222. If a difference in strain gauge reading is obtained, the control unit 130 terminates the action of the piston rod 430.
[66] In an embodiment, the system 100 may include a feedback unit configured to provide feedback on assembling components of the prosthetic implant. The feedback unit can include a visual feedback such as on a display or via notification lights, or an audio feedback such as a buzzer with optimized sounds for different events or a combination of both visual feedback and audio feedback system. In an embodiment, the system 100 includes a display 700 for both visual feedback and audio feedback configured to provide both visual feedback and audio-visual feedback on assembling components of the prosthetic implant. The display 700 is electrically coupled to the control unit 130. The control unit 130 upon completion of the assembling operation of the prosthetic components dictates the display 700 to provide feedback based on proper or improper outcomes of the assembling of the prosthetic components.
[67] FIG. 6 illustrates two components, a head component 620 and a socket component 610 type of an orthopedic implant, according to various embodiments. FIG. 6A illustrates the socket component 610 and the head component 620. The head component 620 is designed to be press-fit into, or mechanically mated with the socket component 610. In one exemplary embodiment, the orthopedic implant may be a hip joint, and the socket component 610 may be a complete or partial acetabulum, and the head component 620 may be a femoral head. In another exemplary embodiment, the orthopedic implant may be a shoulder joint, and the socket component 610 may be a partial or complete glenoid cavity, and the head component 620 may be a humeral head. The system 100 is employed to assemble the socket component 610 and the head component 620 using hydraulic pressure. An exemplary process of such an assembly operation will now be described in further detail, in conjunction with FIG. 7A-7D.
[68] Referring now to FIGS. 7A – 7D, an exemplary process flow of orthopedic implant assembly is illustrated, as performed by the system 100. In particular FIGS. 7A – 7D illustrate the process of press-fitting the two-part orthopedic implant illustrated in FIG. 6.
[69] In the first step (FIG. 7A), upon initial power on, the system 100 is in a ready state. The control unit 130 operates the hydraulic circuit 120, to move the hydraulic actuator 330 in a fully retracted position. This position allows an operator sufficient space to position the two parts of the orthopedic implant in the system 100, for assembly.
[70] In the next step (FIG. 7B), the operator positions the head component 620 of the orthopedic implant on the first prosthesis holder 150a, and the socket component 610 of the orthopedic implant on top of the head component 620. The first prosthesis holder 150a restricts movements of the cup socket component 610 during the assembly process. The hydraulic actuator 330 remains in the fully retracted position, till the operator issues a command to hold the implants. Once the operator issues the command to hold the implants, the control unit 130 extends the hydraulic actuator 330 till the actuator is lightly holding the socket component 610 against the head component 620. At this point, there is no coupling between the head component 620 and the socket component 610, rather only final positioning. At this point, the control unit 130 awaits the operator instruction to commence press-fitting. In some embodiments, the control unit 130 may also await determination that the operator’s hands are clear of the assembly, to prevent any injuries.
[71] In the next step (FIG. 7C), the control unit 130 commences the press-fit assembly. The control unit 130 causes the hydraulic actuator 330 to apply pressure to the head component 620 and the socket component 610. The control unit 130 may progressively increase the force on the prosthesis components (via pressure in the hydraulic actuator 330). In various embodiments the control unit 130 may increase the force progressively in a step-less manner, so as to impart minimal to zero percussive forces to the prosthesis components.
[72] The control unit 130 monitors the base sensors and the hydraulic actuator 330 sensors to monitor the force being delivered to the head component 620 and socket component 610, and the position of the hydraulic actuator 330, for closed loop feedback. When the control unit 130 determines that the head component 620 is fully and properly seated within the socket component 610, the control unit 130 indicates the completion of the assembly process. The control unit 130 may determine the proper assembly of the prosthesis components, for example, by comparing the applied force, with preconfigured fitting parameters, such as preset assembly force, or prosthesis thickness.
[73] The system 100 generates enough power to meet for example, the standards of ASTM required for the assembly of the orthopedic implant. The head component 620 and the socket component 610 are assembled with a peak force ranging from 2 kN +/- 50 N. The force is applied with displacement control at a rate of 0.04 mm/s or force control at a rate of 1 kN/s or less as guidance according to ASTM.
[74] Subsequently the control unit 130 fully retracts the hydraulic actuator 330 (FIG. 7D), allowing the operator to remove the assembled orthopedic implant from the assembly system 100.
[75] The system 100 presents several advantages over conventional devices. Due to the automatic operation and delivery of precise amount of the force to the implant components for assembly, the system 100 minimizes the chances of misalignment, and provides repeatably precise, and accurate assembly of prosthesis components.
[76] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. , Claims:WE CLAIM:
1. A system (100) for assembling components of a prosthetic implant, the system comprising:
a first prosthesis holder (150a), and a second prosthesis holder (150b);
a hydraulic actuator (330) coupled to at least one of the first prosthesis holder (150a) and the second prosthesis holder (150b), the hydraulic actuator (330) being configured to move the second prosthesis (150b) holder relative to the first prosthesis holder (150a);
one or more sensors configured to measure one or more actuator parameters, the actuator parameters comprise a pressure applied by the hydraulic actuator (330), a position of the hydraulic actuator (330), a displacement of the hydraulic actuator (330), and an acceleration of the hydraulic actuator (330); and
a control unit (130) configured to control at least one of a pressure, a position, a displacement, a velocity, an acceleration, or a direction of travel of the hydraulic actuator (330), based on the measured actuator parameters.
2. The system (100) as claimed in claim 1, wherein the first prosthesis holder (150a) is configured to hold a socket component (610) of the prosthetic implant, and the second prosthesis holder (150b) is configured to hold a head component (620) of the prosthetic implant.
3. The system (100) as claimed in claim 1, wherein the hydraulic actuator (330) includes a biocompatible hydraulic fluid.
4. The system (100) as claimed in claim 1, wherein the control unit (130) comprises a microprocessor, a microcontroller, driver circuitry, or a combination thereof.
5. The system (100) as claimed in claim 1, wherein the control unit (130) is configured to halt a fitting operation based on the measured actuator parameters.
6. The system (100) as claimed in claim 1, wherein the control unit (130) is further configured to receive or predetermine the fitting parameters as a configuration input.
7. The system (100) as claimed in claim 6, wherein the control unit (130) is configured to control at least one of a pressure, a position, a displacement, a velocity, an acceleration, or a direction of travel of the hydraulic actuator (330), based on the measured actuator parameters, and the received fitting parameters.
8. The system (100) as claimed in claim 1 comprising:
a hydraulic pump (320); and
one or more valves,
wherein the control unit (130) is configured to control the hydraulic pump (320), the one or more valves, or a combination thereof.
9. The system (100) as claimed in claim 1, comprising:
a feedback unit configured to provide feedback on assembling components of the prosthetic implant, wherein the feedback comprises one or more of a visual feedback, an audio feedback, or a combination thereof.
10. The system (100) as claimed in claim 1, wherein the one or more sensors comprise a pressure sensor, a position sensor, a displacement sensor, an accelerometer, an ultrasonic sensor, a PIR sensor, a strain gauge sensor, or a combination thereof.
11. The system (100) as claimed in claim 1, wherein the one or more sensors are positioned on the hydraulic actuator (330), the first prosthesis holder (150a), the second prosthesis holder (150b), or a combination thereof.