Patent Description:
A tibial plateau leveling osteotomy (TPLO) plate is used in veterinary surgery to stabilize a stifle joint in an animal after a torn cranial cruciate ligament. Current TPLO plates, when applied at an angle in a plane deviating from parallel to the long axis of the tibia, often result in abnormal angulation of the plate and screws, with the ensuing risk that a fixed angle screw could engage or enter structures such as joints, bones, or soft-tissue. Where the tibial plateau is translated during TPLO and the plate becomes offset from the bone surface, there can be increased bending stress placed on the screws, leading to cyclical loading to failure at far fewer cycles. Variations of anatomy, such as a mediolateral flared "trumpet-like" proximal tibia, can also lead to similar issues of plate offset from bone surface and angulation, even if the tibial plateau is rotated (leveled) without intentionally or unintentionally inducing translation in the mediolateral plane. Due to this unusual anatomy, an out-of-parallel plate application can result using the standard angle-stable TPLO plate.

<CIT> relates to a bone plate dimensioned for securing the rotated cut segment of an upper tibia to the lower portion of the tibia as part of a tibial leveling osteotomy procedure for an animal. The bone plate includes an elongated shaft, a head portion pre-bent with respect to the elongated shaft, and a transition between the elongated shaft and head portion including opposing concave sidewalls. The elongated shaft has a centerline and the pre-bent head portion has a centerline angled with respect to the centerline of the elongated shaft to dispose the elongated shaft collinear or approximately collinear with respect to the lower portion of the tibia and to better fit the head portion to the rotated cut segment of the upper tibia. Further examples of bone plates are known from <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

The present invention is defined by the appended independent claim. The dependent claims describe optional features and preferred embodiments. The present disclosure relates to a tibial osteotomy leveling plateau (TPLO) plate with offset. The TPLO plate with offset includes distal portion, an offset portion, and a proximate portion. The distal portion includes attachment apertures to secure the TPLO plate with offset to the body of the tibia. The proximal portion includes attachment apertures to secure the TPLO plate to an upper portion of a tibia or the osteotomized section of a tibia. The offset portion connects the proximal portion and the distal portion in an offset relation. The offset portion, or step or jog is generally perpendicular to both the distal portion and the proximal portion, such that the distal portion and the proximal portion are in parallel planes offset from each other. However, a section of the distal portion may be twisted, rotated or inclined with respect to the plane of the remaining section of the distal portion.

The TPLO plate typically allows mediolateral translation of the tibial plateau segment during TPLO and further typically allows the concurrent treatment of cranial cruciate ligament rupture and medial patella luxation. The TPLO plate is typically adapted to patients with trumpet-shaped or markedly flared proximal tibial anatomy or to patients with profound medial buttress (without necessitating extensive buttress elevation). The TPLO plate further is typically designed to facilitate TPLO plate placement parallel to the tibial long-axis and TPLO screw placement parallel to the joint surface. By providing multiple plates with different offsets, the surgeon is allowed to choose the preferred tibial plateau (tuberosity) translation or adapt to variable anatomy.

The foregoing features will be apparent from the following Detailed Description, taken in connection with the accompanying drawings, in which:.

The present disclosure relates to a tibial plateau leveling osteotomy (TPLO) plate with offset for a tibial plateau leveling osteotomy. The offset allows for translation of the osteotomized segment medially or laterally for alignment of the tibia, patella and quadriceps. This plate can be used for an apparatus in veterinary surgery for orthopedic surgical translation of an osteotomized segment in canines, felines, and other quadruped animal species, both domestic and exotic. The plate can be used to repair a torn cranial cruciate ligament while concurrently repairing a chronic pre-existing patella luxation.

The TPLO plate with offset allows translation of a proximal tibial segment while maintaining plate alignment parallel to a tibial long axis and screw alignment parallel a joint surface to minimize the risk of unacceptable screw impingement. The TPLO with offset minimizes plate-to-bone distance to minimize a risk of screw failure, and allows a surgeon to adapt to abnormal anatomy while maintaining a plate parallel to the tibial long axis to reduce risk of complications.

The present disclosure relates to a tibial osteotomy leveling plateau (TPLO) plate with an offset. The TPLO plate with offset includes distal portion, an offset portion, and a proximate portion. The distal portion includes attachment apertures to secure the TPLO plate with offset to the body of the tibia. The proximal portion includes attachment apertures to secure the TPLO plate to an upper portion of a tibia or the osteotomized section of a tibia. The offset portion connects the proximal portion and the distal portion in an offset relation. The offset portion can be at <NUM>° with respect to both the distal portion and the proximal portion such that the distal portion and the proximal portion are in parallel planes offset from each other. The length of the offset portion can be varied.

Referring now to the drawings in detail wherein like numerals refer to like elements throughout the several views, one see that <FIG> show the TPLO plate with offset, indicated generally at <NUM>. Specifically, <FIG> shows a perspective view, <FIG> shows a top view, and <FIG> shows a side view of the TPLO plate <NUM> with offset. The TPLO plate with offset <NUM> comprises three portions: a distal portion <NUM>, an offset portion <NUM>, and a proximal portion <NUM>.

The distal portion <NUM> includes one or more dual attachment apertures such as the illustrated dual-attachment apertures <NUM>, <NUM>. A one single attachment aperture <NUM> can also be included to secure the plate <NUM> to the body of the tibia. Apertures <NUM>, <NUM>, <NUM> include respective chamfered entrances 22a, 24a, 26a to capture an attachment device (see elements <NUM>, <FIG> and <FIG>), and can have threaded portions 22b, 24b, and 26b for locking / threaded fixation hardware. Furthermore, dual attachment apertures <NUM>, <NUM> are formed with two axes of rotation, offset from one another, 22c, 22d and 24c, 24d, respectively, each axis of which can have threaded portions. A pilot aperture <NUM>, illustrated as configured as a hemispherical blind aperture, can be used for preliminary attachment. Any suitable type of attachment aperture can be used such as a single position aperture <NUM> or multiple position apertures <NUM> and <NUM>. The apertures can be locking, as shown, with threading at lower portions thereof, or non-locking. The apertures can also be compression apertures. The attachment apertures <NUM>, <NUM>, <NUM> can be positioned linearly along a center or longitudinal axis of the distal portion <NUM> for proper attachment to a bone. However, the attachment apertures <NUM>, <NUM>, <NUM> can also be offset from the center axis of the distal portion <NUM> if desired. An end <NUM> of the distal portion <NUM> can be contoured to be elevated away from the bone of the distal tibia so as not to impede tibial soft tissues. For example, a clearance of <NUM>-<NUM> may be provided.

The proximal portion <NUM> includes attachment apertures <NUM>, <NUM>, <NUM>, formed along the edge of proximal portion in a semi-circular configuration, which are used to secure the proximal portion <NUM> of the plate <NUM> to an upper portion of a bone, such as an osteotomized section of a tibia. Similar to attachment apertures <NUM>, <NUM>, <NUM>, attachment apertures <NUM>, <NUM>, <NUM> include respective chamfered entrances 42a, 44a, 46a to capture an attachment device (see elements <NUM>, <FIG> and <FIG>), and can have threaded portions 42b, 44b, and 46b for locking / threaded fixation hardware. A pilot aperture <NUM>, illustrated as configured as a hemispherical blind aperture, can be used for preliminary attachment.

The proximal portion <NUM> can take on any suitable shape, such as linear, triangular, etc. As shown in the Figures, the proximal portion <NUM> could have a general triangular shape with first and second bulges <NUM> and <NUM> corresponding to attachment apertures <NUM> and <NUM>, a generally straight edge <NUM>, leading to a curved edge <NUM>, around attachment aperture <NUM>, and an edge <NUM> with a scalloped indentation between attachment apertures <NUM> and <NUM>.

The attachment apertures <NUM>, <NUM>, <NUM> can be positioned in any location on the proximal portion <NUM> for proper attachment to an osteotomized segment of a bone. For example, attachment aperture <NUM> can be positioned at the apex of the plate <NUM> with its center being at a center plane running the length of the plate <NUM>, attachment aperture <NUM> can be positioned towards the offset portion, flanking attachment aperture <NUM>. An end <NUM> of the proximal portion <NUM> can be contoured to be elevated away from the bone of the distal tibia so as not to impede tibial soft tissues. For example, a clearance of <NUM>-<NUM> can be provided. Each attachment aperture <NUM>, <NUM>, <NUM> can comprise a fully or partially rounded exterior surface. It should be understood that the proximal portion <NUM> can contain any number of attachment apertures, such as two or more.

Each of the attachment apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can be designed to receive a fastener, such as a bolt, a screw, or any other applicable fastening device (see element <NUM>, <FIG> and <FIG>) Accordingly, these apertures can be threaded, tapered, rounded, etc. In the case of the dual attachment apertures <NUM>, <NUM>, these apertures can have multiple locations (e.g., apertures) for receiving a fastener, such as a screw. Each of the attachment apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can be aligned and extend through the front and back of generally planar faces. The diameter of the attachment apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> (including each dual aperture within attachment apertures <NUM>, <NUM>) can vary such that they can accept appropriate sized screw, or other fastener. For example, the attachment apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> could be <NUM> in diameter, to allow for the placement of a <NUM> cortical bone screw. These apertures can be sized to have a sufficient diameter such that the head of the screw, such as a <NUM> cortical screw, fits flush with the distal and proximal portions <NUM> and <NUM>. Other sized bone screws, such as <NUM>, <NUM>, or <NUM> cortical bone screws can also be used, and the apertures could be sized accordingly to the given application.

As shown in the Figures, the apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can have a round or oblong profile to act as compression type holes. The overlapping holes include angled surfaces that create a compression effect as the TPLO plate <NUM> is attached to the bone <NUM>, such that while the plate <NUM> is connected to a bone <NUM> via screws <NUM> mounted through the apertures a compressive force is imparted to the bone sections which causes the bone sections to move towards the center of the plate <NUM>.

The apertures <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are shown with locking screw holes are threaded and designed to work with different designs of locking screws <NUM>. Locking screws <NUM> thread into the plate <NUM> as well as into the bone <NUM>.

The offset portion <NUM> links the distal portion <NUM> and the proximal portion <NUM> such that the proximal portion <NUM> is situated on a plane offset from the distal portion <NUM> but generally parallel thereto. The offset portion <NUM> can be oriented at angle A of <NUM>° with respect to the distal and proximal portions <NUM> and <NUM>. Accordingly, there is a first angle between the distal portion <NUM> and the offset portion <NUM>, and a second angle between the offset portion <NUM> and the proximal portion <NUM>. The offset portion <NUM> is generally perpendicular to the distal and proximal portions <NUM> and <NUM>. The length of the offset portion <NUM> can be varied as suitable to the given application.

Different offsets can be used for different sized implants intended for various sized animals, and can be scaled in accordance to the average needs of a patient group. For example, a <NUM> plate can be designed with different offsets to allow for a range of accommodations. Any amount of offset could be engineered into the TPLO plate <NUM>, such as a range of, for example, between <NUM> and <NUM> or more or less. Additionally, the proximal portion <NUM> may optionally include a bend <NUM> thereby causing an angle or curvature <NUM> (see <FIG>), where the proximal portion <NUM> has a twist or a bend <NUM> to better attach to a osteotomized section of bone and further causing a portion of the proximal portion <NUM> to be on a plane which is twisted, rotated or inclined with respect to the plane of the remaining portion of the proximal portion <NUM>. This twist, rotation or inclination is illustrated by a rotation C about axis B, or an inclination of axis B as indicated by arrow D in <FIG>. As such, the proximal portion can be angled or turned about a long axis of the plate <NUM> so that a contact face of the proximal portion <NUM> is at an angle with respect to a contact face of the distal portion <NUM>. Typically, however, the portion of proximal portion <NUM> immediately adjacent to offset portion <NUM> is in a plane parallel with that of distal portion <NUM>. Other embodiments may include a proximal portion <NUM> which is entirely in a plane parallel to that of distal portion <NUM>.

As further illustrated in <FIG>, the lower surface of distal portion <NUM> can include undercuts <NUM>, <NUM> (some embodiments includes similar undercuts on the opposite unillustrated side of distal portion <NUM>).

The TPLO plate <NUM> with offset can be formed from any number of biocompatible, implantable materials. These materials include, but are not limited to, <NUM> stainless steel, titanium, or ultra-high-molecular-weight polyethylene. Exposed edges of the plate <NUM> can be rounded and smooth. The length of the plate <NUM> can vary with the size of the patient. Similarly, the thickness of the plate <NUM> can vary with the size of the patient.

Claim 1:
A tibial plateau leveling osteotomy plate (<NUM>), including:
a proximal portion (<NUM>) including at least one first attachment aperture (<NUM> ,<NUM>, <NUM>);
a distal portion (<NUM>) including at least one second attachment aperture (<NUM>, <NUM>, <NUM>); and
an offset portion (<NUM>) extending generally perpendicularly from the proximal portion (<NUM>) and the distal portion (<NUM>) thereby joining the proximal portion (<NUM>) to the distal portion (<NUM>) wherein the proximal portion (<NUM>) is in a different plane from the distal portion (<NUM>).