News Column

Patent Issued for Locking Assembly for Tibial Prosthesis Component

May 7, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Otto, Jason Karl (Plantation, FL); Abbasi, Ali Zafar (Davie, FL), filed on December 29, 2011, was published online on April 22, 2014.

The patent's assignee for patent number 8702803 is Mako Surgical Corp. (Fort Lauderdale, FL).

News editors obtained the following quote from the background information supplied by the inventors: "The knee joint comprises the interface between the distal end of the femur and the proximal end of the tibia. In a properly-functioning knee joint, medial and lateral condyles of the femur pivot smoothly along menisci attached to respective medial and lateral condyles of the tibia. When the knee joint is damaged, the natural bones and cartilage that form the joint may be unable to properly articulate, which can lead to joint pain and, in some cases, interfere with normal use of the joint.

"In some situations, surgery is required to restore normal use of the joint and reduce pain. Depending upon the severity of the damage, the surgery may involve partially or completely replacing the joint with prosthetic components. During such knee replacement procedures, a surgeon resects damaged portions of the bone and cartilage, while attempting to leave healthy tissue intact. The surgeon then fits the healthy tissue with artificial prosthetic components designed to replace the resected tissue and restore proper knee joint operation.

"Some knee replacement procedures, such as total knee arthroplasty ('TKA'), involve the resection of some or all of each of the medial and lateral condyles of both the femur and tibia and the removal of the fibro-cartilage menisci located at the femorotibial interface. A prosthetic femoral component, typically made of titanium or other strong, surgical-grade metal, is fitted and secured to the distal end of the femur to replace the resected portion of the femur. Similarly, a prosthetic tibial component, the base of which is also typically made of titanium or other suitable metal, is fitted and secured to the proximal end of the tibia to replace the resected portion of the tibia.

"The upper surface of the tibial component may include a flat or slightly concave element constructed of plastic material designed to replicate the form and function of the medial and lateral menisci located at the interface of the femur and tibia. This meniscus replacement element provides a low-friction surface upon which the femoral prosthesis can pivot smoothly at the femorotibial interface. The meniscus replacement element may be provided as part of a tibial prosthetic system, whereby a metallic tibial base component ('base' portion) is permanently secured to the tibia and the meniscus replacement element ('insert' portion) is subsequently inserted and secured to the tibial base component. Such a system allows for the insert portion to be replaced without disturbing the base portion if, for example, the insert portion becomes worn over time.

"In an effort to reduce post-operative pain and shorten recovery times, surgeons continue to develop techniques for reducing the biological impact that many surgical procedures--including knee replacement procedures--have on the human body. Such techniques, which are commonly referred to as 'minimally-invasive' techniques, are aimed at limiting the amount of tissue disturbance during the surgical procedure. For knee replacement surgery, this typically involves reducing the length of incision and limiting the amount of disturbance (e.g., cutting, stretching, etc.) of the muscles surrounding the knee joint.

"Although minimally-invasive techniques may significantly reduce the amount of pain and recovery time endured by the patient, some of these techniques may limit the ability of the surgeon to visually inspect certain areas of the surgical site. For example, as the size of the incision used to perform a knee replacement procedure decreases, the surgeon's ability to visually inspect the posterior of the completed replacement joint may also decrease. Consequently, during minimally-invasive procedures, surgeons are increasingly reliant on non-visual (e.g., tactile) methods for ensuring that the tibial prosthesis components are installed properly. Incomplete or misaligned insertion of a component (e.g., tibial implant portion within the tibial base portion) can lead to discomfort and instability of the replacement joint, thereby increasing the likelihood of the necessity of subsequent corrective surgery.

"In addition to the trend toward minimally-invasive surgical techniques, there is also a trend toward reducing manufacturing costs associated with prosthetic components. Decreasing manufacturing costs typically involves decreasing, at least to some degree, the precision with which the dimensions of the components match the specified design dimensions. In many orthopedic prosthetic systems, however, multiple components must precisely and firmly engage one another to limit movement between the components, increase stability, and reduce long-term wear. As a result, as lower cost, less precise manufacturing techniques are employed in the manufacture of prosthetic components, orthopedic prosthetic systems must be adapted to ensure that stability and function of the joint are not unduly compromised.

"For example, in a tibial prosthetic implant system, manufacturing errors at the engagement interface between the tibial insert portion and the tibial base portion can result in movement or vibration of the insert component within the base component. This movement can cause micro-abrasions on the insert component that release small fragments of plastic into the knee joint. These fragments can cause significant irritation of the joint and/or lead to premature wear of the insert component. What is needed, therefore, is a solution for controlling manufacturing costs without sacrificing implant performance due to decreased precision of the implant components.

"The presently disclosed locking assembly for a tibial base component is directed to overcoming one or more of the problems set forth above and/or other problems in the art."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "In accordance with one aspect, the present disclosure is directed to an orthopedic prosthetic system comprising a base portion and an elongated guide member protruding from a bottom surface of the base portion. The elongated guide member may extend from a posterior edge of the base portion toward an anterior edge of the base portion. The elongated guide member may comprise an overhang element and an undercut face. The orthopedic prosthetic system may also comprise an insert portion configured to slideably engage the base portion and the elongated guide member. The insert portion may comprise an underhang element configured to engage at least a portion of an undercut area defined by the overhang element and undercut face of the elongated guide member.

"According to another aspect, the present disclosure is directed to an orthopedic prosthetic system comprising an insert portion configured to slideably engage a base portion. The insert portion may comprise an underhang element configured to engage at least a portion of an undercut area defined by an overhang element of the base portion. The underhang element may comprise a stabilizer element having a different shape than the undercut area. The stabilizer element may be configured to substantially conform to the shape of the undercut area when the underhang element of the insert portion engages the base portion at the undercut area.

"In accordance with another aspect, the present disclosure is directed to an orthopedic prosthetic system comprising a base portion having a first overhang element that extends inwardly from an outer edge of the base portion and defines a first undercut area. The base portion may also comprise an elongated guide member that protrudes from a bottom surface of the base portion and extends from a posterior edge of the base portion toward an anterior edge of the base portion. The elongated guide member may comprise a second overhang element and an undercut face, the second overhang element and the undercut face defining a second undercut area. The orthopedic prosthetic system may also comprise an insert portion configured to slideably engage the base portion. The insert portion may comprise a first underhang element configured to engage at least a portion of the first undercut area and a second underhang element configured to engage at least a portion of the second undercut area.

"Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. The objects and advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

"It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims."

For additional information on this patent, see: Otto, Jason Karl; Abbasi, Ali Zafar. Locking Assembly for Tibial Prosthesis Component. U.S. Patent Number 8702803, filed December 29, 2011, and published online on April 22, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=104&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=5160&f=G&l=50&co1=AND&d=PTXT&s1=20140422.PD.&OS=ISD/20140422&RS=ISD/20140422

Keywords for this news article include: Biomedical Engineering, Biomedicine, Surgery, Prosthetics, Bioengineering, Medical Devices, Knee Replacement, Mako Surgical Corp..

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Journal of Engineering


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters