Patent Description:
Current solutions are based on a set of burrs limited by graded, fixed diameters and a wide range of equipment used during procedures. The drawback of these solutions is a large number of elements used in the surgical set, which frequently remain unused during the procedure. The currently used tools do not allow for a controlled removal of the products of cutting out of the operating field. patent No. <CIT>, an expandable acetabular reaming system for use in hip replacement surgery comprises a reamer head having a convex forward surface attached to a base plate that defines an interior space therebetween. The forward surface includes a plurality of apertures therethrough. The base plate includes a central aperture over which a flexible bladder is mounted within the interior space. The reaming system further includes a plurality of cutting blades mounted to the bladder and positioned so as to correspond with respective apertures. An air cylinder is coupled to the underside of the base plate and includes an open top in communication with the bladder through the central aperture of the base plate. A threaded shaft extends through a threaded aperture in a bottom wall of the air cylinder and is coupled to a thimble-type knob. As a user turns the knob, the shaft rotates to force air through the base plate aperture so as to inflate the bladder. Turning the knob in an opposite direction deflates the bladder in like manner. The blades are projected through respective apertures as the bladder is inflated and are retracted as the bladder is deflated. It is known from U. patent application No. <CIT>, a surgical trabecular tool for manipulating or removing bone tissue includes a tool body and at least one cutting element provided on the tool body. The cutting element includes a number of cutting edges arranged thereon, and the tool body is formed at least in part by a trabecular internal structure including a plurality of material struts forming a regular or irregular lattice structure which supports and connects the cutting elements.

Units are known for the reaming of internal surfaces of joints, in particular of the hip joint, and so: in the US patent description <CIT> an improved spring-loaded expandable acetabular reamer is described, which comprises a number of convex reaming segments symmetrically located by pair around a central core of the Reamer tool. It is also a goal of the present invention to provide and improve a spring-loaded reaming segment, which expands faster and requires less manipulation by the operating surgeon and staff, therefore minimizing the risk of infection and of tissue damage. Furthermore, introducing large size conventional acetabular reamers with rough and sharp edges through small surgical incisions will undoubtedly cause damage to the edge of the incision and to the surrounding soft tissues, which may ultimately result in delayed wound healing.

The <CIT> patent demonstrates an acetabular reamer including a reaming head having arcuately-shaped segments generally symmetrically distributed about a center point. The arcuately-shaped segments are extendable or retractable about the center point to create a variable dimensioned recess in an acetabular region. The reamer may also include an actuator for selectively extending or retracting the segments so that the segments remain generally symmetrically distributed about the center point as the segments are expanded or retracted. The segments may further include cutting surfaces having a shape corresponding to a portion of a surface of a hemisphere. In one form, the segments may be configured in a narrow symmetrical "slice" of a hemispherical surface that provides an adjustable hemispherically shaped cutting arc, whereas the <CIT> patent describes reamer for reaming of a acetabulum during a minimally invasive procedure. Generally, the reamer, particularly the reamer head, can be inserted and removed through a substantially small incision without trauma to the tissue surrounding the incision. The reamer, generally includes a reaming or scraping portion, which are aligned substantially along a single meridian of a hemisphere. The reamer further includes stabilizing portions to assist in ensuring a selected reaming orientation.

In the <CIT>/<CIT> patent the use of a surgical reamer for the cutting of cartilaginous and bone tissue is demonstrated. The reamer further includes a fixed support portion aligned with the drive axis and having at least one radial cutting blade, a pivoting portion aligned with the drive axis and pivotable about this axis, the pivoting portion supporting at least one radial cutting blade and a pivoting joint wherein the pivoting portion may be pivoted toward and away from the fixed portion so as to expand or contract the reamer in relative overall size.

In the <CIT>) patent an acetabular reamer was described with a cutting structure rotatable about a longitudinal axis with a domed shell portion. The shell has an outer surface presenting multiple cutting sites and an inner surface for accumulation of debris. The tool shape is defined by a pair of first curved portions generated about a first radius with a center that lies on the axis and a pair of second curved portions generated about a center that is spaced apart from the axis.

In the <CIT> (A1) patent discusses an expanding reamer for reaming or cutting a concave surface, for example, for reaming an acetabulum in preparation for implanting a prosthetic component, such as an acetabular cup or socket, during a hip arthroplasty. The reamer includes a rotating shaft cooperating with a surgical drill or other power source at one end and rotating a reamer head at the other end, and a system adapted to expand one or more blades on the reamer head. In a preferred version, the reamer head comprises a plurality of generally circular, preferably substantially flat and parallel blades, the outer blades of which are radially expandable as segments of a cutting sphere to enlarge the effective diameter of the reamer head. The <CIT>) patent discusses an expanding reamer for reaming or cutting a concave surface, for example, for reaming an acetabulum in preparation for implanting a prosthetic component during a hip arthroplasty. A rotating shaft cooperates with a surgical drill or other power source at one end and rotates a reamer head at the other end, and an actuation system expands one or more blades on the reamer head. The reamer head comprises one or more cutting blades, which act as segments of a cutting sphere, wherein the blades are expandable in directions non-parallel to the plane of the respective blades in order to enlarge the cutting sphere. Upon rotation of the reamer head, the blade(s) form a portion of an effective cutting sphere that is preferably greater-than-<NUM>-degrees; this allows greater flexibility in placement of the shaft of the reamer relative to the surface being reamed, for example, relative to the center of axis of the acetabulum. In the <CIT>) patent a disposable acetabular reamer designed to improve tissue removal efficiency is described. The reamer device comprises a reamer cutting shell and a reamer driver interface. The reamer cutting shell has a hemispherical structure with a plurality of spaced apart rib portions that extend from a central region located about an apex of the shell.

The essence of the invention is a unit, as defined in the claims, for reaming of the surface of joint cartilage and of periarticular bone of an acetabulum or a femoral head, wherein it has at least two burrs with a slanting end of the cutting blade and an arc shape, wherein each of the burrs is placed in a channel of a shaped body, wherein the body is connected by a joint with the unit's drive mechanism. A unit for reaming characterized in that the burrs and with a ball-shaped pivot placed in the guides of a matrix, whereas the matrix is placed on a shank, which is connected with the shaft by a threaded connection with a lock, and the body has a threaded joint to the shaft, moreover each of the burrs has the duct with an outlet opening used to clean the inside of the burr.

It is advantageous when the body has a chamber for the placement of the head of the rfemur to be reamed.

It is advantageous when the body has an external supporting surface for inserting into the acetabulum of the reamed bone and protecting the bone tissue against damage.

It is also advantageous when each of the burrs is placed at the same angular distance from a circular plane perpendicular to its lengthwise axis.

It is also advantageous when the burrs are bevelled at an angle β <NUM>-<NUM>° advantageously <NUM>°.

It is also advantageous when the angle of application α of the burr blades to the surface being reamed is within a range of <NUM>-<NUM><NUM> advantageously <NUM>°.

It is especially advantageous when the cutting edge of the burr has a cutting tongue.

Moreover it is advantageous when the burr is a tube. or an open element, or a partially open element.

The use of the solution presented in the invention enables the following technical and utility effects:.

The subject of the invention, in the example implementation, which is not limiting, was presented on drawings, where <FIG> presents the cross-section of the unit on a plane passing through its axis of rotation for the machining of the femoral head in the first version, <FIG> presents the cross-section of the body on a plane passing through its axis of rotation for the machining of the femoral head in the first version, <FIG> presents the cross-section of the unit on a plane through its axis of rotation for the machining of the acetabulum in the second version, <FIG> presents the cross-section on a plane through its axis of rotation for the machining of the acetabulum in the second version, <FIG> presents a view of the matrix, <FIG> presents a cross-section of the matrix on a plane perpendicular to its lengthwise axis, <FIG> presents a view of the matrix on a plane through its lengthwise axis, <FIG> presents a view of the shaft, <FIG> presents a partial cross-section through the matrix on a plane through the axis of the channel with the blade, <FIG> presents a view of the blade being partially open, <FIG> presents detail A from <FIG>, whereas <FIG> presents the placement of the burr blade against the machined surface.

A unit for the machining of external surfaces of joint bones, being the head, has at least two burrs <NUM> with a slanting end of the cutting blade <NUM> and an arc shape, ending with a ball-shaped pivot <NUM>, placed in the guides <NUM> of a matrix <NUM>. Each of the burrs <NUM> is placed in a channel <NUM> of the shaped body <NUM>. The body <NUM> is connected by a joint with a drive mechanism <NUM> of the unit, whereas the matrix <NUM> is placed on a shank <NUM> having a threaded connection <NUM> with a stop <NUM> to the shaft <NUM>, and the body <NUM> has a threaded joint <NUM> to the shaft <NUM>. Each of the burrs <NUM> is placed at the same angular distance from a circular plane perpendicular to its lengthwise axis. Burrs <NUM> are bevelled at an angle β <NUM>°, whereas the α angle of application of the cutting blades <NUM> of the burrs <NUM> to the machined surface <NUM> has a value of <NUM>°. The cutting blade <NUM> of the burr <NUM> has a cutting tongue <NUM> for breaking the matter being cut. There are versions where the burr <NUM> is a tube, there are also versions where the burr <NUM> is an open element, there are also versions where the burr <NUM> is a partially open element. Each of the burrs <NUM> in the first version has an outlet opening <NUM> of the burr duct <NUM> used to clean the inside of the burr <NUM>.

The drive mechanism <NUM> is permanently connected with the matrix <NUM> by the shaft <NUM> which transfers the rotational drive. The matrix <NUM> is moved in a reciprocating and rotational manner by a threaded connection <NUM> with the shaft <NUM>. In the matrix <NUM> the burrs <NUM> with the cutting blades <NUM> move inside the ducts <NUM> of the body <NUM>. Each of the burrs <NUM> moves through the ducts <NUM>, which force it to move solely over a specific trajectory. The cutting blades <NUM> of the burr <NUM> are connected to the matrix <NUM> using a movable connection through a ball-shaped pivot <NUM> and guide <NUM> which ensure their minimal movement in relation to the matrix <NUM> and body <NUM>.

The drive mechanism <NUM> is connected to an external rotating drive. By connecting the drive mechanism <NUM> with the shaft <NUM> the rotating movement is transferred to the entire tool. During work the tool is rotating around the axis of the shaft <NUM> - a stipulated axis of symmetry of the tool. The movement is either clockwise or counterclockwise, depending on the angular setting of cutting blades <NUM>. The shaft <NUM> is connected by the threaded connection <NUM> to the body <NUM>. Both connections with the body <NUM> and the drive mechanism <NUM> have a thread that is in agreement with the tool's direction of rotation, which prevents the possible disconnection of the parts. On the shaft <NUM> the matrix <NUM> is screwed on, moving over a thread with a high pitch, which ensures high linear displacement and low angular displacement. The movement of the matrix <NUM> is locked by the stop <NUM> - wedge <NUM> system. After setting the matrix <NUM> to the dimension of the cutting area <NUM> of the joint by turning it around the tool's axis of symmetry with the widened part of the shaft <NUM> with incisions facilitating gripping, its movement is locked by screwing in the stop <NUM> into the threaded hole <NUM> located in the matrix <NUM>. Screwing in the stop <NUM> results in the gradual driving of the bottom surface of the wedge <NUM> into the non-threaded surface of the shaft <NUM>. Gradual screwing in of the stop <NUM> at some point becomes impossible, which means that the wedge <NUM> resting against the surface of the shaft <NUM> has completely locked the movement of the system of the stop <NUM> with the matrix <NUM> In order to release the movement of the matrix <NUM> the stop <NUM> should be screwed out of it. The matrix <NUM> moves within the chamber of the body <NUM> limited by the walls of the body <NUM> and two parts of the cover <NUM> of the body <NUM>. The cover <NUM> of the body <NUM> restricts the maximum external protraction of the matrix <NUM>, additionally stabilising the position of the matrix <NUM> in relation to the tool's axis of symmetry. The cover <NUM> of the body <NUM> is bolted to the body <NUM> with a set of four mounting bolts <NUM>. The rotational and linear movement of the matrix <NUM> in relation to the shaft <NUM> causes the head of the matrix <NUM> to press on the spherical ends of the cutting blades <NUM> of the burr <NUM>. The ends of the cutting blades <NUM> of the burr <NUM> in the shape of the ball-shaped pivot <NUM> set on the threader rod and screwed into the body <NUM> move within the channels <NUM> cut in the surface of the head of the matrix <NUM>. The guides <NUM> are cut symmetrically or asymmetrically in relation to the tool's axis of rotation - this depends, among others, on the number of cutting blades <NUM>. The guides <NUM> restrict the movement of the cutting blades <NUM>. Screwing the matrix <NUM> out of the body <NUM> in relation to the shaft <NUM> results in the cutting blades <NUM> of the burr <NUM> sliding into the closed chamber of the body <NUM> at an angle of <NUM>°. Screwing the matrix <NUM> in has a reverse effect. The cutting blades <NUM> of the burr <NUM> slide out, making the cutting edges closer to each other, which results in the decrease of the final diameter of the machined spherical surface. The movement of the cutting blades <NUM> of the burr <NUM> outside of the guides <NUM> cut in the head of the matrix <NUM> takes place within the space restricted by the openings <NUM> in the body <NUM>. Channels <NUM> ensure the movement of the cutting blades <NUM> of the burr <NUM> over an arc-shape trajectory with a defined radius. After establishing an appropriate diameter of machining - that is, the position of the cutting blades <NUM> of the burr <NUM> and locking the movement of the matrix <NUM> with the stop <NUM>, the drive mechanism <NUM> is used to provide rotational movement from an external drive. The angle of application α of the cutting blade <NUM> of the matrix <NUM> has a value of <NUM><NUM>, and the angle of attack β <NUM><NUM>. The cuttings fall into the ducts <NUM> of the burr <NUM>, falling out between the internal chamber <NUM> and the external chamber <NUM> of the body <NUM> through the outlet opening <NUM> of the duct <NUM> used to clean the inside of the burr <NUM>. Along the shaft <NUM> and through the drive mechanism <NUM> a duct for a medium <NUM> (e.g. water) passes, which enables the delivery of a medium to the internal space of the body <NUM>, diluting the cuttings and aiding in their removal.

After establishing the position (cutting diameter) of the matrix <NUM>, the matrix <NUM> is locked by screwing in the stop <NUM> with the wedge <NUM>, after which the drive is started. Afterwards, the tool is applied to the machined surface, e.g. the hip joint, and the medium is fed through the duct <NUM> located along the shaft <NUM> and in the drive mechanism <NUM>, after which the surface is cut with the cutting blades <NUM> of the burr <NUM>. The cuttings with the medium fall out through the outlet openings <NUM> of the burr ducts <NUM>. Bigger pieces of the cuttings are broken by the cutting tongue <NUM>. After removing a specified amount of matter from the hip joint the position of the matrix <NUM> is corrected by unlocking the clamp of the drive mechanism <NUM>. After making the changes, inspecting the machined surface, e.g. the hip joint after removing another layer of the hip joint tissue, the matrix <NUM> is locked again and the material is again removed until required hip joint surface is obtained. The cutting area is limited by the external edges of the tool.

A unit for the machining of external surfaces of joint bones, being the acetabulum, has at least two burrs <NUM> with a slanting end of the cutting blade <NUM> and an arc shape, ending with a ball-shaped pivot <NUM>, placed in the guides <NUM> of a matrix <NUM>. Each of the burrs <NUM> is placed in a channel <NUM> of the shaped body <NUM>. The body <NUM> is connected by a joint with a drive mechanism <NUM> of the unit, whereas the matrix <NUM> is placed on a shank <NUM> having a threaded connection <NUM> with a stop <NUM> to the shaft <NUM>, and the body <NUM> has a threaded joint <NUM> to the shaft <NUM>. Each of the burrs <NUM> is placed at the same angular distance from a circular plane perpendicular to its lengthwise axis. Burrs <NUM> are bevelled at an angle β <NUM><NUM>, whereas the angle of application α of the cutting blades <NUM> of the burrs <NUM> to the machined surface <NUM> has a value of <NUM><NUM>. The cutting blade <NUM> of the burr <NUM> has a cutting tongue <NUM> for breaking the matter being cut. There are versions where the burr <NUM> is a tube, there are also versions where the burr <NUM> is an open element, there are also versions where the burr <NUM> is a partially open element. Each of the burrs <NUM> in the first version has an outlet opening <NUM> of the burr duct <NUM> used to clean the inside of the burr <NUM>.

The drive mechanism <NUM> is permanently connected with the matrix <NUM> by the shaft <NUM> which transfers the rotational drive. The matrix <NUM> is moved in a reciprocating and rotational manner by a threaded connection <NUM> with the shaft <NUM>. In the matrix <NUM> the burrs <NUM> with the cutting blades <NUM> move inside the channels <NUM> of the body <NUM>. Each of the burrs <NUM> moves through the channels <NUM>, which force it to move solely over a specific trajectory. The cutting blades <NUM> of the burr <NUM> are connected to the matrix <NUM> using a movable connection through a ball-shaped pivot <NUM> and guide <NUM> which ensure their minimal movement in relation to the matrix <NUM> and body <NUM>.

The drive mechanism <NUM> is connected to an external rotating drive. By connecting the drive mechanism <NUM> with the shaft <NUM> the rotating movement is transferred to the entire tool. During work the tool is rotating around the axis of the shaft <NUM> - a stipulated axis of symmetry of the tool. The movement is either clockwise or counterclockwise, depending on the angular setting of cutting blades <NUM>. The shaft <NUM> is connected by the threaded connection <NUM> to the body <NUM>. Both connections with the body <NUM> and the drive mechanism <NUM> have a thread that is in agreement with the tool's direction of rotation, which prevents the possible disconnection of the parts. On the shaft <NUM> the matrix <NUM> is screwed on, moving over a thread with a high pitch, which ensures high linear displacement and low angular displacement. The movement of the matrix <NUM> is locked by the stop <NUM> - wedge <NUM> system. After setting the matrix <NUM> to the dimension of the cutting area <NUM> of the joint by turning it around the tool's axis of symmetry with the widened part of the shaft <NUM> with incisions facilitating gripping, its movement is locked by screwing in the stop <NUM> into the threaded hole <NUM> located in the matrix <NUM>. Screwing in the stop <NUM> results in the gradual driving of the bottom surface of the wedge <NUM> into the non-threaded surface of the shaft <NUM>. Gradual screwing in of the stop <NUM> at some point becomes impossible, which means that the wedge <NUM> resting against the surface of the shaft <NUM> has completely locked the movement of the system of the stop <NUM> with the matrix <NUM> In order to release the movement of the matrix <NUM> the stop <NUM> should be screwed out of it. The matrix <NUM> moves within the chamber of the body <NUM> limited by the walls of the body <NUM> and two parts of the cover <NUM> of the body <NUM>. The cover <NUM> of the body <NUM> restricts the maximum external protraction of the matrix <NUM>, additionally stabilising the position of the matrix <NUM> in relation to the tool's axis of symmetry. The cover <NUM> of the body <NUM> is bolted to the body <NUM> with a set of four mounting bolts <NUM>. The rotational and linear movement of the matrix <NUM> in relation to the shaft <NUM> causes the head of the matrix <NUM> to press on the spherical ends of the cutting blades <NUM> of the burr <NUM>. The ends of the cutting blades <NUM> of the burr <NUM> in the shape of the ball-shaped pivot <NUM> set on the threader rod and screwed into the body <NUM> move within the channels <NUM> cut in the surface of the head of the matrix <NUM>. The guides <NUM> are cut symmetrically or asymmetrically in relation to the tool's axis of rotation - this depends, among others, on the number of cutting blades <NUM>. The guides <NUM> restrict the movement of the cutting blades <NUM>. Screwing the matrix <NUM> out of the body <NUM> in relation to the shaft <NUM> results in the cutting blades <NUM> of the burr <NUM> sliding into the closed chamber of the body <NUM> at an angle of <NUM>°. Screwing the matrix <NUM> in has a reverse effect. The cutting blades <NUM> of the burr <NUM> slide out, making the cutting blades <NUM> closer to each other, which results in the decrease of the final diameter of the machined spherical surface <NUM>. The movement of the cutting blades <NUM> of the burr <NUM> outside of the guides <NUM> cut in the head of the matrix <NUM> takes place within the space restricted by the openings <NUM> in the body <NUM>. Channels <NUM> ensure the movement of the cutting blades <NUM> of the burr <NUM> over an arc-shape trajectory with a defined radius. After establishing an appropriate diameter of machining - that is, the position of the cutting blades <NUM> of the burr <NUM> and locking the movement of the matrix <NUM> with the stop <NUM>, the drive mechanism <NUM> is used to provide rotational movement from an external drive. The cutting edges <NUM> of the burr <NUM> penetrate the material to the set diameter. The angle of application α of the cutting surface <NUM> of the cutting blades <NUM> of the matrix <NUM> has a value of <NUM><NUM>, and the bevel angle β <NUM><NUM>. The cuttings fall into the ducts <NUM> of the burr, falling out between the internal chamber <NUM> and the supporting surface <NUM> of the body <NUM> through the outlet opening <NUM> used to clean the inside of the burr <NUM>. Along the shaft <NUM> and through the drive mechanism <NUM> a duct for a medium <NUM> (e.g. water) passes, which enables the delivery of a medium to the internal space of the body <NUM>, diluting the cuttings and aiding in their removal.

Claim 1:
A unit for reaming of the surface of joint cartilage and of periarticular bone of an acetabulum or of a femoral head, the unit comprising:
a shaped body (<NUM>);
a matrix (<NUM>) having guides (<NUM>);
a drive mechanism (<NUM>);
a shank (<NUM>);
a shaft (<NUM>); and
at least two burrs (<NUM>) having an arc shape and a slanting end forming a cutting blade (<NUM>);
wherein each of the burrs (<NUM>) is placed in a channel (<NUM>) of the shaped body (<NUM>), wherein the shaped body (<NUM>) is connected by a joint with the unit's drive mechanism (<NUM>), wherein the burrs (<NUM>) end with a ball-shaped pivot (<NUM>) placed in the guides (<NUM>) of the matrix (<NUM>), wherein the matrix (<NUM>) is placed on the shank (<NUM>), which is connected with the shaft (<NUM>) by a threaded connection (<NUM>) with a lock (<NUM>), wherein the shaped body (<NUM>) has a threaded joint (<NUM>) to the shaft (<NUM>), and wherein each of the burrs (<NUM>) has a duct (<NUM>) with an outlet opening (<NUM>) configured to be used to clean the inside of the burr (<NUM>).