FreshPatents.com Logo
stats FreshPatents Stats
2 views for this patent on FreshPatents.com
2013: 1 views
2012: 1 views
Updated: July 21 2014
newTOP 200 Companies filing patents this week


    Free Services  

  • MONITOR KEYWORDS
  • Enter keywords & we'll notify you when a new patent matches your request (weekly update).

  • ORGANIZER
  • Save & organize patents so you can view them later.

  • RSS rss
  • Create custom RSS feeds. Track keywords without receiving email.

  • ARCHIVE
  • View the last few months of your Keyword emails.

  • COMPANY DIRECTORY
  • Patents sorted by company.

Follow us on Twitter
twitter icon@FreshPatents

System and method for prosthetic fitting and balancing in joints

last patentdownload pdfdownload imgimage previewnext patent


20120290088 patent thumbnailZoom

System and method for prosthetic fitting and balancing in joints


A device for intraoperative use in balancing joint forces and verifying the placement of the tibial component in total knee arthroplasty includes a spacer defining an enclosure; the spacer is sized to engage a top portion of the tibial component. A sensor array is embedded in the spacer, the sensor array measures forces on the spacer. A wireless transceiver is embedded in the spacer and forwards the output to a processor. The processor is analyzes the output and creates a pressure distribution graph indicative of the forces on the spacer, thereby assisting a surgeon in performing selective soft tissue release or component positioning in connection with surgical implantation of an orthopedic knee prosthesis.
Related Terms: Intraoperative

Browse recent The Board Of Trustees Of The University Of Illinois patents - Urbana, IL, US
Inventors: Farid Amirouche, Mark H. Gonzalez
USPTO Applicaton #: #20120290088 - Class: 623 1412 (USPTO) - 11/15/12 - Class 623 
Prosthesis (i.e., Artificial Body Members), Parts Thereof, Or Aids And Accessories Therefor > Implantable Prosthesis >Meniscus

view organizer monitor keywords


The Patent Description & Claims data below is from USPTO Patent Application 20120290088, System and method for prosthetic fitting and balancing in joints.

last patentpdficondownload pdfimage previewnext patent

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 12/539,283, filed Aug. 11, 2009 (now U.S. Pat. No. 8,197,549), which is a divisional of U.S. patent application Ser. No. 10/393,243, filed Mar. 19, 2003 (now U.S. Pat. No. 7,575,602), which is a non-provisional application claiming priority from Provisional Application Ser. Number 60/365,678, filed Mar. 19, 2002. The disclosures of U.S. patent application Ser. Nos. 12/539,283; 10/393,243, and 60/365,678 are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to joint replacement and, more particularly, to a system and method for prosthesis fitting and balancing in joints.

BACKGROUND OF THE INVENTION

Some medical conditions can result in the degeneration of a human joint, causing a patient to consider and ultimately undergo joint replacement surgery. While joint replacement surgery is well known in the art, the decision to undergo such a procedure may be a difficult one, as the long-term success of the surgery oftentimes relies upon the skill of the surgeon and may involve a long, difficult recovery process.

The materials used in a joint replacement surgery are designed to enable the joint to move just like a normal joint. The prosthesis is generally composed of a metal piece that fits closely into and bears on a corresponding plastic component. The plastic component is typically supported on another metal piece. Several metals are typically used, including stainless steel, alloys of cobalt and chrome, and titanium, while the plastic material is typically constructed of a durable and wear resistant polyethylene. Plastic bone cement may be used to anchor the prosthesis into the bone, however, the prosthesis may be implanted without cement when the prosthesis and the bone are designed to fit and lock together directly.

To undergo the operation, the patient is given an anesthetic while the surgeon replaces the damaged parts of the joint. For example, in knee replacement surgery, the damaged ends of the bones (i.e., the femur and the tibia) and the cartilage are replaced with metal and plastic surfaces that are shaped to restore knee movement and function. In another example, to replace a hip joint, the damaged ball (the upper end of the femur) is replaced by a metal ball attached to a metal stem fitted into the femur, and a plastic socket is implanted into the pelvis, replacing the damaged socket. Although hip and knee replacements are the most common, joint replacement can be performed on other joints, including the ankle, foot, shoulder, elbow and fingers.

As with all major surgical procedures, complications can occur. Some of the most common complications are typically thrombophlebitis, infection, stiffness, and loosening. While thrombophlebitis (i.e., vein inflammation related to a blood clot) and infection are oftentimes treated medically, stiffness and loosening may require additional surgeries. One technique utilized to reduce the likelihood of stiffness and loosening relies upon the skill of the surgeon to align and balance the replacement joint along with ligaments and soft tissue during surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a computer system illustrating an example environment of use for the disclosed system;

FIG. 2 is a block diagram of a joint prosthesis fitting and balancing system;

FIG. 3 is a front perspective view of an embodiment of a prosthesis fitted within a human knee;

FIG. 4 is a top perspective view of an embodiment of a spacer of the system of FIG. 2;

FIG. 5 is a bottom perspective view of the spacer of FIG. 4;

FIG. 6 is a side perspective view of an embodiment of a portion of the system of FIG. 2;

FIG. 7 is a front perspective view of an embodiment of a portion of the system of FIG. 2;

FIG. 8 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at zero degrees;

FIG. 8A is a graph plotting pressure readings in the prosthesis of FIG. 8;

FIG. 9 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at thirty degrees;

FIG. 9A is a graph plotting pressure readings in the prosthesis of FIG. 9;

FIG. 10 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at sixty degrees;

FIG. 10A is a graph plotting pressure readings in the prosthesis of FIG. 10;

FIG. 11 is a graph plotting pressure readings as a function of joint angle of a prosthesis of FIG. 2 during flexion of the prosthesis;

FIG. 12 is a graph plotting pressure readings as a function of joint angle of a prosthesis of FIG. 2 during extension of the prosthesis;

FIG. 13 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2;

FIG. 14 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2;

FIG. 15 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2;

FIG. 16 is a top perspective view of an embodiment of a jig which may be used in conjunction with the system of FIG. 2;

FIG. 17 is a diagrammatic view of a wireless graphical hand-held output display in accordance with one possible form of the present invention; and

FIG. 18 is a block diagram of an exemplary data collection modeling/analysis display scheme.

DETAILED DESCRIPTION

OF THE PREFERRED EMBODIMENT

A block diagram of an example computer system 10 is illustrated in FIG. 1. The computer system 10 may be a personal computer (PC) or any other computing device capable of executing a software program. In an example, the computer system 10 includes a main processing unit 12 powered by a power supply 13. The main processing unit 12 illustrated in FIG. 1 includes one or more processors 14 electrically coupled by a system interconnect 16 to one or more memory device(s) 18 and one or more interface circuits 20. In an example, the system interconnect 16 is an address/data bus. Of course, a person of ordinary skill in the art will readily appreciate that interconnects other than busses may be used to connect the processor(s) 14 to the memory device(s) 18. For example, one or more dedicated lines and/or a crossbar may be used to connect the processor(s) 14 to the memory device(s) 18.

The processor(s) 14 may include any type of well known microprocessor, such as a microprocessor from the Intel Pentium™ family of microprocessors. The illustrated main memory device 18 includes random access memory such as, for example, dynamic random access memory (DRAM), or static random access memory (SRAM), but may also include non-volatile memory. In an example, the memory device(s) 18 store a software program which is executed by one or more of the processors(s) 14 in a well known manner.

The interface circuit(s) 20 are implemented using any type of well known interface standard, such as an Ethernet interface and/or a Universal Serial Bus (USB) interface. In the illustrated example, one or more input devices 22 are connected to the interface circuits 20 for entering data and commands into the main processing unit 12. For example, an input device 22 may be a keyboard, mouse, touch screen, track pad, track ball, isopoint, and/or a voice recognition system.

In the illustrated example, one or more displays, printers, speakers, and/or other output devices 24 are also connected to the main processing unit 12 via one or more of the interface circuits 20. The display 24 may be a cathode ray tube (CRT), a liquid crystal display (LCD), or any other type of display, such as a hand-held display 500 as shown in FIG. 17. The display 24 may generate visual indications of data generated during operation of the main processing unit 12. For example, the visual indications may include prompts for human operator input, calculated values, detected data, etc.

The illustrated computer system 10 also includes one or more storage devices 26. For example, the computer system 10 may include one or more hard drives, a compact disk (CD) drive, a digital versatile disk drive (DVD), and/or other computer media input/output (I/O) devices.

The illustrated computer system 10 may also exchange data with other devices via a connection to a network 118. The network connection may be any type of network connection, such as an Ethernet connection, digital subscriber line (DSL), telephone line, coaxial cable, etc. The network 118 may be any type of network, such as the Internet, a telephone network, a cable network, and/or a wireless network.

An example system for prosthesis fitting and balancing in joints is illustrated in FIG. 2. In one embodiment, the system includes a prosthesis 30, a joint angle sensor 36, a ligament tension sensor 38, an analysis program 40, the main unit 12, the one or more storage devices 26, and the display 24. As will be described in detail below, the artificial joint may comprise a femoral component 32, a tibial tray 58, and a spacer 34 with one or more imbedded sensors 35. Any or all of the sensors 35, 36, 38 may be implemented by conventional sensor technology, including commercially available pressure sensors, tension sensors, and angle sensors. Furthermore, any or all of the storage device 26, and the analysis program 40 may be implemented by conventional electronic circuitry, firmware, and/or by a microprocessor executing software instructions in a well known manner. However, in the illustrated example, the analysis program 40 is implemented by software stored on the memory 18 and executed by the processor 14, while the storage device 26 may be implemented by database server software stored on the memory 18, and executed by the processor 14 to physically store data on a hard drive. In addition, a person of ordinary skill in the art will readily appreciate that certain modules in the apparatus shown in FIG. 2 may be combined or divided according to customary design constraints. Still further, one or more of the modules may be located external to the main processing unit 12.

Turning to FIG. 3, there is shown an example of the prosthesis 30 as used in conjunction with the replacement of a human knee 50. In general, the human knee 50 comprises a femur 52, a patella 53, a tibia 54, a plurality of ligaments (not shown), and a plurality of muscles (not shown). The prosthesis 30 generally comprises two parts, the femoral component 32 and a tibial component 56. Additionally, the tibial component 56 is typically made up of two parts, the metal tibial tray 58 that is attached directly to the tibia 54 and the spacer 34 that provides the bearing surface. It will be understood that the while in the disclosed embodiment the tibial component 56 is comprised of separate components, the spacer 34 and the metal tibial tray 58 may be integrally formed. The materials used in a joint replacement surgery are designed to enable the joint to mimic the behavior or a normal knee joint.

In the illustrated embodiment, the femoral component 32 is a metal piece, shaped similar to the end of the femur and fitting closely into a corresponding plastic spacer 34. Several metals are typically used, including stainless steel, alloys of cobalt and chrome, and titanium, while the plastic material is typically constructed of a durable and wear resistant polyethylene. Other suitable materials may now exist or may be developed in the future. Plastic bone cement may be used to anchor the prosthesis 30 into the bones 52, 54, however, the prosthesis 30 may be implanted without cement when the prosthesis 30 and the bones 52, 54 are designed to fit and lock together directly. A cemented prosthesis 30 is held in place by a type of epoxy cement that attaches the metal to the bones 52, 54. An uncemented prosthesis 30 has a fine mesh of holes on the surface that allows the bones 52, 54 to grow into the mesh and attach the prosthesis 30 to the bones 52, 54.

Referring now to FIGS. 4 and 5, there is illustrated an example spacer 34 which may be used in conjunction with an embodiment of the system of FIG. 2. The spacer 34 includes a pair of opposed faces 60, 62 and an elongated side edge 64. The face 60 comprises a pair of condyle recesses 68, 66, shaped to closely match or otherwise accommodate the shaped end of the femoral component 32. The face 60 may also comprise an extension 70 which may slidably engage a groove 71 in the femoral component 32 and prevent lateral movement between the spacer 34 and the femoral component 32, while allowing the two pieces to rotate relative to each other in a predefined range of motion similar to a biological knee, for example, between zero degrees (0°), i.e., extension, and ninety degrees (90°), i.e., flexion. The contact between the femoral component 32 and the spacer 34 will produce deformations in the two surfaces in contact, which may be measured by the sensors 35 embedded in the spacer 34. The sensed deformation may cause an output to be created by the sensors 35.

The opposite face 62 includes an elevated face 72. The elevated face 72 and the face 62 cooperate to form a snap-fit connection with the tibial tray 58 as is well known in the art. It will be noted that connection between the tibial tray 58 and the spacer 34 may vary according to known design variations. For instance, the elevated face 72 and the face 62 may be substantially coplanar and may be cemented onto the tibial tray 58.

In the illustrated embodiment of FIG. 5, the elevated face 72 is illustrated with a plurality of recesses 74. The recesses 74 are milled in the face 72 of the polyethylene and have a cross section sized to accept sensors 35, thereby enabling the sensors 35 embedded in the spacer 34. Since the sensors 35 are responsive to the deformation of the spacer 34, the depth of the recesses 74 may be chosen to minimize the impact on the deformation characteristics of the spacer 34, as well as to ensure an accurate reading based on the sensitivity of the sensor 35.

For example, in the illustrated embodiment, the recesses 74 have a cross section of appropriately dimensioned to accept a strain sensor marketed by Omega Engineering, Inc., of Stanford, Conn. In one embodiment, the recesses are arranged in an array and include a bar-shaped micro miniature strain gage (sensor 35) of approximate dimension 1 mm×0.5 mm×0.15 mm. The strain gage is responsive to the deformation of curvature with a maximum strain of 3000μ. Furthermore, the strain gage may provide data in a real-time, or near real-time fashion, allowing for intraoperative analysis of the data. A person of ordinary skill in the art will readily appreciate that other sensors may be used to sense the deformation of the spacer 34. For example, a single sensor, or an array of sensors may be used to sense the deformation of the spacer 34.

Once the sensor 35 is placed in the recesses 74, the recesses may be filled with a plug of the same, or similar, material as the spacer 34, to further minimize the impact on the deformation characteristics of the spacer 34. The recess plug may be, for example, glued in place, or held by an interference fit. Of course, a person of ordinary skill in the art will readily appreciate that any number of recesses 74 and sensors 35 may be utilized. Moreover, the dimensions of the recesses may vary greatly, depending upon the characteristics of the spacer 34, the sensor 35, and/or the desired sensitivity. Still further, it will be appreciated that the sensors 35 may be embedded within the spacer 34 utilizing any known or yet to be developed manufacturing method, including direct insertion during the molding process, as well as insertion utilizing a transverse cut in the spacer 34.

The spacer 34 illustrated in FIG. 5 includes a plurality of sensors 35 electrically coupled by a system interconnect (not shown) to one or more transceiver device(s) 76. In the example, the system interconnect is a plurality of wires (not shown) transversely carried through the spacer 34 to the transceiver device(s) 76. Of course, a person of ordinary skill in the art will readily appreciate that interconnects other than wires may be used to connect the sensors 35 to the transceiver devices(s) 76. For example, one or more wireless connections may be used to connect the sensors 35 to the transceiver device(s) 76. In the illustrated embodiment, the transceiver device(s) 76 is embedded within another recess 77 within the elevated face 72 of the spacer 34, however, it will be understood that the transceiver may be located in any location, including external to the spacer 34.

In one embodiment, the transceiver device(s) 76 is a self powered, 5 channel input transceiver having approximate dimensions of 1.46 cm×3.05 cm×0.65 cm. The transceiver has a sample rate of 150 samples per second and is powered by a 3.1 volt minimum, 7 volt maximum, 13.8 DC battery. Additionally, the transceiver may contain a memory for storing sensor data. In operation, the transceiver device 76 is adapted to receive, as an input, multiple sensor outputs created by each of the sensors 35 in response to the deformation of the spacer 34. The transceiver device 76 is further adapted to convert the multiple sensor inputs to a serial data stream and transmit the data stream, via wired or wireless connection, to the main unit 12. The transceiver devices 76 is preferably a single battery powered transceiver capable of wireless transmission, however, it may be any type of transceiver known or yet to be developed, such as a magnetically powered transceiver. Furthermore, it will be appreciated by one of ordinary skill in the art that the transceiver device(s) 76 and the sensors 35 may be combined or divided according to customary design constraints. Still further, the spacer 34 with embedded sensors 35 may be designed to be substantially permanently attached to the tibial tray 58, i.e., bioengineered to remain in the prosthesis 30 after surgery, or it may be temporarily attached to the tibial tray 58, i.e., to be used only during the actual replacement surgery to gather data and replaced by a substantially permanent spacer. In the disclosed example, this is aided by the fact that the sensors 35, etc. are fully encapsulated in the spacer 34.

Referring now to FIGS. 6 and 7, there is illustrated a human knee exposed for surgery with the prosthesis 30 and sensors 35, 36, 38 in place. Specifically, the femoral component 32 is attached to the femur 52, and the tibial component 56 is attached to the tibia 54. The spacer 34 and embedded sensors 35 are in place between the femoral component 32 and the tibial tray 58. In the illustrated embodiment, a plurality of ligament tension sensors 38 are attached to external knee ligaments, such as, for example, the medial cruciate ligament and the lateral cruciate ligament. Additionally, the joint angle sensor 36 may be attached to the surface of the human knee 50.

The ligament tension sensors 38 may be any commercially available tension sensors such as one marketed by Omega Engineering, Inc., of Stanford, Conn. The ligament tension sensor 38 is responsive to the tension of the ligament to which it is attached, and is adapted to produce an output in response to the sensed tension. The ligament tension sensor 38 may also comprise a transceiver (not shown) similar to the above-described transceiver device 76. The data output from the ligament tension sensor 38 may thereby be transmitted to the main unit 12.



Download full PDF for full patent description/claims.

Advertise on FreshPatents.com - Rates & Info


You can also Monitor Keywords and Search for tracking patents relating to this System and method for prosthetic fitting and balancing in joints patent application.
###
monitor keywords



Keyword Monitor How KEYWORD MONITOR works... a FREE service from FreshPatents
1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored.
3. Each week you receive an email with patent applications related to your keywords.  
Start now! - Receive info on patent apps like System and method for prosthetic fitting and balancing in joints or other areas of interest.
###


Previous Patent Application:
Incus replacement partial ossicular replacement prosthesis
Next Patent Application:
Expandable fusion device and method of installation thereof
Industry Class:
Prosthesis (i.e., artificial body members), parts thereof, or aids and accessories therefor
Thank you for viewing the System and method for prosthetic fitting and balancing in joints patent info.
- - - Apple patents, Boeing patents, Google patents, IBM patents, Jabil patents, Coca Cola patents, Motorola patents

Results in 0.54956 seconds


Other interesting Freshpatents.com categories:
Amazon , Microsoft , IBM , Boeing Facebook

###

All patent applications have been filed with the United States Patent Office (USPTO) and are published as made available for research, educational and public information purposes. FreshPatents is not affiliated with the USPTO, assignee companies, inventors, law firms or other assignees. Patent applications, documents and images may contain trademarks of the respective companies/authors. FreshPatents is not affiliated with the authors/assignees, and is not responsible for the accuracy, validity or otherwise contents of these public document patent application filings. When possible a complete PDF is provided, however, in some cases the presented document/images is an abstract or sampling of the full patent application. FreshPatents.com Terms/Support
-g2-0.1358
     SHARE
  
           

FreshNews promo


stats Patent Info
Application #
US 20120290088 A1
Publish Date
11/15/2012
Document #
13489333
File Date
06/05/2012
USPTO Class
623 1412
Other USPTO Classes
International Class
61F2/08
Drawings
17


Intraoperative


Follow us on Twitter
twitter icon@FreshPatents