The invention relates to a joint replacement in situ gauge system and a method of using the gauge system in a joint replacement procedure.
Joint replacement surgery frequently requires the implant of a ball component into a socket, or more generally, a convex component into a concave component. When replacing a convex and/or a concave component of a joint, proper alignment and displacement of these components with respect to each other is critical to enable a full range of motion. In an exemplary embodiment, a convex component having a convex, or curved surface such as a radiused surface including a spherical surface for example, is attached to a first bone. A concave component having a concave portion, or recessed curved surface or radiused surface, is attached to a second bone. The concave portion of the concave component is configured to nest around the convex component to reconstruct the joint. The socket, or concave portion, of the concave component and convex component must be configured with a proper amount of space or mating pressure to enable proper movement and range of motion of the joint and to prevent wear and pain. To achieve the proper spacing, a surgeon will install a concave component and, in some cases, an initial spacer for the concave component, and then test the range of motion of the joint. If there is too much pressure, the range of motion may be limited or it may be difficult to move the limb through a range of motion. If there is too much space between the convex component and concave component, the joint may be too loose and the convex component may slip out of position with respect to the concave component when the range of motion is evaluated. The surgeon will then try a different concave and/or convex component or a different sized spacer to modify the space between the convex and concave component and again, check the range of motion. This iterative method is somewhat subjective and subjects the joint to excess trauma. In addition, the iterative spacing method takes additional operating time and makes recovery more difficult.
The invention is directed to a joint replacement in situ gauge system that enables a surgeon to apply a known amount of distraction force in order to measure the appropriate spacing between the two sides of a joint, a convex component and a concave component, for example. An exemplary joint replacement in situ gauge system comprises a gauge component which may be configured in a convex component or concave component. A gauge component comprises a displacement device that displaces the mating surfaces of the joint replacement in situ gauge system with a known amount of force to determine a proper spacing. The displacement component may be a bladder that is inflated with a fluid and a gauge may measure the pressure of the bladder. A specific or specified or range of pressures may be desired for a given patient and joint being replaced to achieve a desired distraction force. In addition, a surgeon may move the joint through a range of motion with the bladder inflated to evaluate the range of motion. A scale may be configured on the gauge component to indicate the proper size of the implant component, concave or convex. The scale may indicate an amount of displacement of the gauge component and this displacement may be used to select an appropriately sized implant component. A surgeon may then remove the gauge component or assembly and implant the properly sized permanent device. This process will reduce the need for iterative trials of implant components and reduce operating time and trauma to the patient.
In an exemplary embodiment, a joint replacement in situ gauge system comprises a gauge concave assembly that comprises a concave component having a concave portion that nests around an implant convex component. A reverse shoulder replacement joint typically has this configuration. A surgeon may implant the convex component on one bone and then configure the gauge concave assembly in the mating bone. A gauge concave assembly may fit into an implant stem insert and mimic the size and dimensions of the implant concave component. A displacement device may be configured between a plate portion and the gauge concave component to displace the gauge concave component toward the implanted convex component while remaining substantially parallel to the plate. A prescribed pressure or range of pressures may be determined for a given patient and joint to deliver a desired amount of distraction force. The surgeon may displace the gauge concave component to the prescribed pressure and measure the displacement. An exemplary gauge concave assembly may comprise a scale to indicate the displacement and the surgeon may visually determine the size of the implant concave component by viewing the scale at the prescribed pressure. The gauge concave component and/or assembly may then be removed and the permanent implant concave component having the required size may then be implanted and secured.
In an exemplary embodiment, a joint replacement in situ gauge system comprises a gauge convex component or assembly that comprises a convex component configured to nest into a concave portion of an implant concave component. A shoulder replacement joint typically has this configuration. A surgeon may implant the concave component on one bone and then configure the gauge convex assembly in the mating bone. A gauge convex assembly may fit into an implant stem insert and mimic the size and dimensions of the implant convex component. A displacement device may be configured between a plate portion and the gauge convex component to displace the gauge convex component toward the implanted concave component while remaining substantially parallel to the plate. A prescribed pressure or range of pressures may be determined for a given patient and joint to deliver a desired amount of distraction force. The surgeon may displace the convex component to the prescribed pressure and measure the displacement. An exemplary gauge convex assembly may comprise a scale to indicate the displacement and the surgeon may visually determine the size of the implant convex component by viewing the scale at the prescribed pressure. The gauge convex component and/or assembly may then be removed and the permanent implant convex component having the required size may then be implanted and secured.
In an exemplary embodiment, a replacement joint may comprise mating surfaces of varying concavities and convexities. A replacement knee joint typically has this configuration. A joint replacement in situ gauge system for a knee joint may comprise two separate displacement devices to enable individual determination of spacing between each of the convex components and concave components. With the pressure or force set to a desired level for each of the displacement devices, the spacing or displacement may be non-uniform. This non-uniform displacement may be required for proper load across the joint and to reduce wear and pain. It may be desirable to have uniform pressure or loads across the joint and therefore the size of the implant from the medial to the lateral side of the joint may be different.
An exemplary displacement device may comprise a bladder and a fluid such as a non-compressible liquid, such as saline, to inflate the bladder. Any suitable fluid may be used and preferably the fluid is sterile. A fluid may be a gas, such as air or nitrogen for example. Pressure can be increased in the bladder via mechanical device such as a balloon indeflator, and a force gauge may be used to measure the pressure of the fluid in the bladder. Because the pressure is applied to known geometry, a known relationship between pressure and distraction force exists A displacement device may be a mechanical displacement device and a strain gauge or other force measurement device may be configured to measure the force. A bladder type displacement device may be preferred to an electro-mechanical device as it may be disposable, or a single-use type of device. Exemplary bladder geometries may be spherical, cylindrical, or toroidal.
An exemplary gauge convex or concave assembly may comprise a displacement gauge for determining the amount of displacement of the convex or concave component from the plate portion. A displacement gauge may be a scale that is configured on the gauge assembly and the surgeon may view the amount of displacement on the scale to determine a proper sized implant device. A displacement gauge may comprise a sensor, such as a proximity sensor or laser displacement sensor that measure the amount of displacement of the convex or concave component from the plate portion and provides a read-out. An exemplary sensor may send the displacement value wirelessly to a receiver, such as an electronic device for readout, for example.
An exemplary gauge convex assembly may mimic the actual implant convex component or assembly and have substantially the same size and shape as the implant convex assembly except for the gauge convex component being able to be displaced toward the concave component. An exemplary gauge convex assembly may fit into a convex component stem so that it is retained in substantially the same position as the implant convex component, thereby enabling a direct measurement of displacement in situ. Likewise, an exemplary gauge concave assembly may mimic the actual implant concave assembly or component and have substantially the same size and shape except for the gauge concave component being able to be displaced toward the convex component. An exemplary gauge concave assembly may fit into a concave component stem so that it is retained in substantially the same position as the implant concave component, thereby enabling a direct measurement of displacement in situ. An exemplary gauge convex or concave component may comprise a plate component that sits on the face of the bone and the stem or stem insert may extend from the plate component. The displacement device may be configured between the plate component and the convex or concave component.
The exemplary gauge convex and concave component may be made out of implantable materials, and may be sterilized. Exemplary gauge convex and/or concave components may comprise stainless steel, titanium, fluoropoymer, polyethylene, other suitable polymers and elastomers including, but not limited to fluoro-elastomer materials such as synthetic rubber and fluoropoymer elastomer compositions, and the like.
While specific concave and convex joints have been disclosed herein, it is to be understood that the joint replacement in situ gauge system may be used in any suitable joint including the knee and shoulder joints as disclosed as well as elbow shoulder, hip, and may also be used between vertebrae.
The summary of the invention is provided as a general introduction to some of the embodiments of the invention and is not intended to be limiting. Additional example embodiments including variations and alternative configurations of the invention are provided herein.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.
Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.
A convex portion of a convex component is the curved convex surface of the component and may be a radiused surface including a spherical surface; common with ball type joints.
A concave portion of a concave component is the curved concave surface of the component and may be radiused surface such as a spherically shaped recess common with socket type joints.
In situ is defined as in the natural or original position or place. The gauge component of the joint replacement system is situated in situ with respect to the joint replacement to provide an accurate measurement of the spacing requirements under a given load.
A permanent implant concave or convex component as used herein is a component that is implanted and may be implanted into a portion of the gauge concave or convex assembly after determination of the proper size for the permanent implant component.
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It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.
This application claims the benefit of priority to U.S. provisional patent application No. 62/664,253, filed on Apr. 29, 2018; the entirety of which is hereby incorporated by reference herein.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/027348 | 4/12/2019 | WO | 00 |
Number | Date | Country | |
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62664253 | Apr 2018 | US |