Surgical reaming instrument for shaping a bone cavity

CROSS-REFERENCE TO RELATED

id="REI-00001" date="20181204"

APPLICATION

id="REI-00001"

id="REI-00002" date="20181204"

APPLICATIONS

id="REI-00002"

0001This application is an application for reissue of U.S. Pat. No. 9,011,444, which claims the benefit of the filing date of U.S. Provisional Patent Application No. 61/568,808, filed Dec. 9, 2011, the disclosure of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

0002The present invention relates to surgical instruments for preparing a bone to receive a joint prosthesis system, and in particular relates to fully guided surgical reaming instruments for use in total knee replacement revision procedures.

BACKGROUND OF THE INVENTION

0003Joint replacement surgery is a common orthopedic procedure for joint such as the shoulder, hip, knee, ankle and wrist. Prior to implanting prosthetic components in a joint of a patient, a surgeon generally has to resect at least a portion of the patient's native bone in order to create a recess or cavity for receiving at least a portion of the prosthetic components being implanted. During the process of resecting bone, a surgeon generally only resects the amount of bone that is needed in order to implant the prosthetic components in the joint replacement surgery properly. Once native bone is resected from a joint, it generally can no longer be used in the joint. Thus, the surgeon attempts to maintain as much native structural integrity of the joint as he or she can during the resection process.

0004When prosthetic components fail for any one of a variety of reasons, a revision procedure is often necessary. An issue generally encountered by surgeons replacing joints during a revision procedure is the loss of native bone near the joint being replaced. Defects in a bone adjacent a joint, such as the hip or knee, may occur due to wear and arthritis of the joint, congenital deformity, and following the removal of a failed prosthetic component. When the failed prosthetic component or components are removed from the joint during a revision procedure, it is common for there to have been further native bone loss in the area adjacent the original implant position of the prosthetic component or components. This bone loss is typically due to movement of the component or components after implantation or even degeneration or further degeneration of the bone, which can form bone voids that have unpredictable and non-uniform shapes.

0005When bone voids are observed in either the proximal tibia or distal femur, or both, it is standard surgical practice to fill those voids as part of the surgical procedure. The preferred practice is to fill those voids with weight bearing void fillers, typically made of an implant-grade metal such as titanium. These void fillers may be referred to as metaphyseal reconstruction devices (MRD). The name MRD more accurately reflects functions such as weight bearing that these devices provide.

0006Because the bone voids are typically irregular in shape, preparation of the bone void area is typically required prior to implantation of the MRD. This preparation (typically by reaming, broaching or milling) ensures there is sufficient room in the bone cavity for the MRD. An accurate fit between the shaped bone cavity and the MRD is important for establishing joint line, and allowing for weight bearing and bone remodeling during the recovery process.

0007Different methods are commonly used to attempt to prepare the bone void area to create an accurate fit between the shaped bone cavity and the MRD. One method is to ream along the intramedullary (IM) axis, followed by broaching. Another method is to ream on the IM axis, followed by freehand burr or rongeur bone removal, which may also be followed by broaching. Problems with these methods include that reaming is performed on the IM axis only, so that void areas at a distance from the IM axis, which commonly occur, can only be resected using manual methods. Moreover, broaching generally has at least two problems. First, a manual operation can be time consuming, particularly in cases of sclerotic bone, which exposes the patient to an increased risk of infection and a longer recovery. Second, in the case of large bone voids, broaching generally needs to be performed in a multi-step process because attempting to remove high volumes of bone in a single broaching step generally requires high impact forces to the bone. Also, freehand bone removal, either powered or unpowered, such as by burr or rongeur, often does not produce accurate cavity shapes to receive predefined prosthetic components. A typical result is that areas remain where the outer walls of the MRD do not contact the cavity, which may lead to undesirable stress distribution and possible loss of bone regrowth. Also typical is the time consuming requirement of iterative bone removal, with multiple checks against the MRD, to obtain a correct fit.

0008Thus, there is a need for a surgical reaming instrument that creates accurate bone cavity geometries in minimal time and that minimizes the necessity for freehand bone removal. There is also a need for enabling surgeons to create bone cavities with a fully guided system.

BRIEF SUMMARY OF THE INVENTION

0009According to one aspect of the present invention, a surgical system for preparing a bone. The surgical system comprises a reaming guide assembly, which includes a trial stem having a proximal end and a longitudinal axis. The trial stem is configured to fit into an intramedullary canal in the bone. The reaming guide assembly also comprises a guide tube assembly, which has a distal end portion and a guide tube that is angled with respect to the distal end portion, wherein the distal end portion of the guide tube is coupled to the proximal end of the trial stem such that a longitudinal axis of the guide tube is angled with respect to the longitudinal axis of the trial stem. The surgical system further comprises a cannulated reamer assembly for shaping a bone cavity. The cannulated reamer assembly has a proximal end, a reaming head coupled at a distal end and a cannulation extending through the reaming head and distal end thereof, wherein a longitudinal axis of the cannulated reamer assembly is angled with respect to the longitudinal axis of the trial stem when at least a portion of the guide tube is housed within the cannulation of the cannulated reamer assembly.

0010In one embodiment, the proximal end of the cannulated reamer assembly is configured to engage a torque applying device, for example a drill or manual device.

0011According to another embodiment, the cannulated reamer assembly further comprises a quick connect mechanism, which has a ball detent engaged to a distal end of a reamer shaft. The ball detent selectively engages a notch in a proximally protruding extension of the reaming head in order to couple the reamer shaft to the reamer head.

0012According to another aspect of the present invention, the reaming guide assembly further comprises a handle assembly for manipulating the reaming guide assembly. The handle assembly is coupled to the proximal end of the trial stem such that a surgeon can manipulate the reaming guide assembly while the trial stem is located in the intramedullary canal.

0013Yet another aspect of the current invention the surgical system further comprises an insertion/removal tool for efficient removal of the reaming guide assembly from the bone canal. The insertion/removal tool has a distal end configured for selective engagement to the proximal end of the trial stem.

0014In one embodiment, the guide tube assembly and the handle assembly are fixed with respect to each other and are rotatably mounted to the proximal end of the trial stem such that a surgeon may rotate the guide tube assembly and the handle assembly about the longitudinal axis of the trial stem while the guide tube assembly and the handle assembly partially reside within a central pocket in the bone.

0015According to another aspect of the current invention, the surgical system further comprises a tibial implant for implantation into the reamed bone void created by the reaming guide and cannulated reamer assemblies. The tibial implant is shaped to match contours of the bone cavity and has a central opening defined therethrough, wherein the central opening is configured to permit the passage of the trial stem or a stem boss of a tibial baseplate into the intramedullary canal.

0016The shape of the tibial implant may be realized in the form of at least two outer surfaces being blended tapered conical surfaces that substantially match the contours of the bone cavity.

0017In one embodiment, the tibial implant further comprises a proximal surface, a lateral wall, a medial wall and a fin clearance for positional adjustment of the tibial baseplate. The fin clearance defines a groove that extends from the lateral wall through the medial wall and extends through the proximal surface.

0018According to another embodiment of the present invention, the surgical system further comprises a femoral implant for implantation into the bone cavity. The femoral implant is shaped to match contours of the bone cavity and having a central opening defined therethrough, wherein the central opening is configured to permit the passage of a femoral stem into the intrameduallry canal.

0019The shape of the femoral implant may be realized in the form of at least two outer surfaces being tapered conical surfaces that substantially match the contours of the bone cavity.

0020In one embodiment, the femoral implant further comprises a posterior wall, an anterior wall and a first and second clearance space, wherein the first clearance space defines a recess in the posterior wall shaped to accommodate a femoral cam box, and the second clearance space defines a cut in anterior wall shaped to accommodate an anterior chamfer of a femoral implant.

0021Another aspect of the present invention is a surgical method for preparing bone. The method comprises placing a reaming guide assembly at least partially into an already formed intramedullary canal and an already formed central pocket. The central pocket is in fluid communication with the intramedullary canal. The reaming guide assembly comprises a trial stem and guide tube assembly. The trial stem has a proximal end configured to be received in the intramedullary canal, and the guide tube assembly has a distal end portion coupled to the proximal end of the trial stem and a guide tube angled with respect to the distal end portion. The guide tube assembly at least partially resides in the central pocket when the trial stem is fully seated in the intraumeddulary canal. The method further comprises coupling a cannulated reamer assembly to the guide tube assembly such that the proximal end of the guide tube assembly is housed within a cannulation of the cannulated reamer assembly, and the reaming head contacts bone at a first position. Further, there is a step of driving the cannulated reamer to a predetermined depth into the bone, thereby forming a first bone cavity adjacent to the central pocket.

0022In one embodiment, the reaming guide assembly further comprises a handle assembly. The handle assembly being fixed at the proximal end of the trial stem such that the handle assembly at least partially resides in the central pocket when the trial stem is fully seated in the intramedullary canal.

0023A further aspect of the method comprises the step of manipulating the handle assembly, thereby placing the reaming guide assembly in an optimum angular position.

0024In yet another embodiment, the guide tube assembly and the handle assembly are fixed with respect to each other and are rotatably mounted to the proximal end of the trial stem.

0025According to an additional aspect of the method, the method further comprises the step of rotating the handle assembly and guide tube assembly to a second position while partially residing within the central pocket.

0026In one embodiment, the method includes a step of reaming bone at the second position with the cannulated reamer assembly placed over the guide tube assembly, thereby forming a second bone cavity adjacent to the central pocket.

0027According to another embodiment, is a method for preparing bone to receive a revision prosthesis, which comprises the step of reaming bone generally along an intramedullary canal with an intramedullary reamer having a proximal end. Another step of the method is placing a cannulated reamer assembly having a reaming head over the proximal end of the intramedullary reamer such that the reaming head contacts bone. Further, the method includes driving the cannulated reamer into bone to a predetermined depth, thereby forming a central bone pocket. The method further comprising removing the intramedullary reamer and cannulated reamer assembly from the intramedullary canal and central bone pocket. Additionally, there is a step of placing a reaming guide assembly at least partially into the intramedullary canal and central bone pocket. The reaming guide assembly comprises a trial stem, a guide tube assembly, and a handle assembly. The trial stem has a proximal end and is configured to fit into the intramedullary canal. Further, the guide tube assembly has a proximal end and distal end that is rotatably fixed to the proximal end of the trial stem at an oblique angle such that the guide tube assembly at least partially resides in the central bone pocket when the trial stem is fully seated in the intramedullary canal. The handle assembly is fixed at the proximal end of the trial stem such that the handle assembly at least partially resides in the central bone pocket when the trial stem is fully seated in the intramedullary canal. Also included is the step of placing the cannulated reamer assembly over the proximal end of the guide tube assembly such that the reaming head contacts bone at a first position. The method further comprises the step of driving the cannulated reamer into bone to a predetermined depth, thereby forming a first bone cavity adjacent to the central bone pocket.

0028In one embodiment, the method further comprises the step of rotating the handle assembly and guide tube assembly with respect to the trial stem while partially residing within the central pocket to a second position.

0029According to another aspect of the invention, the method further comprises the step of reaming bone at the second position with the cannulated reamer assembly placed over the guide tube assembly, thereby forming a second bone cavity adjacent to the central pocket.

BRIEF DESCRIPTION OF THE FIGURES

0030<figref idref="DRAWINGS">FIG. 1A</figref> shows an assembled perspective view of one embodiment of a surgical reaming instrument of the present invention.

0031<figref idref="DRAWINGS">FIG. 1B</figref> shows a partially exploded perspective view of the surgical reaming instrument shown in <figref idref="DRAWINGS">FIG. 1A</figref> with a trial stem separated therefrom.

0032<figref idref="DRAWINGS">FIG. 2A</figref> shows an exploded perspective view of a reaming guide the surgical reaming instrument shown in <figref idref="DRAWINGS">FIG. 1A</figref>.

0033<figref idref="DRAWINGS">FIG. 2B</figref> shows a partially assembled perspective view of a spring detent of the reaming guide shown in <figref idref="DRAWINGS">FIG. 2A</figref> with a spring detent thereof being visible.

0034<figref idref="DRAWINGS">FIG. 2C</figref> shows an assembled perspective view of the reaming guide shown in <figref idref="DRAWINGS">FIG. 2A</figref>.

0035<figref idref="DRAWINGS">FIG. 3A</figref> shows a side view of a reaming guide assembly and a guide tube assembly.

0036<figref idref="DRAWINGS">FIG. 3B</figref> shows a cross section view of the reaming guide assembly and the guide tube assembly taken along line <b>3</b>B-<b>3</b>B of <figref idref="DRAWINGS">FIG. 3A</figref>.

0037<figref idref="DRAWINGS">FIG. 3C</figref> shows an enlarged view of an attachment mechanism shown in <figref idref="DRAWINGS">FIG. 3B</figref>.

0038<figref idref="DRAWINGS">FIG. 4A</figref> shows a side view of a reaming guide assembly and a guide tube assembly with a locking rod.

0039<figref idref="DRAWINGS">FIG. 4B</figref> shows a cross section view of the reaming guide assembly and the guide tube assembly with locking rod taken along line <b>4</b>B-<b>4</b>B of <figref idref="DRAWINGS">FIG. 4A</figref>.

0040<figref idref="DRAWINGS">FIG. 5A</figref> shows an exploded perspective view of a handle assembly of one embodiment of the surgical reaming instrument of the present invention.

0041<figref idref="DRAWINGS">FIG. 5B</figref> shows a side view of the handle assembly of <figref idref="DRAWINGS">FIG. 5A</figref>.

0042<figref idref="DRAWINGS">FIG. 5C</figref> shows a cross section view of the handle assembly taken along line <b>5</b>C-<b>5</b>C of <figref idref="DRAWINGS">FIG. 5B</figref>.

0043<figref idref="DRAWINGS">FIG. 5D</figref> shows a perspective view of a handle assembly detached from a guide body assembly and guide tube assembly.

0044<figref idref="DRAWINGS">FIG. 6A</figref> shows an exploded perspective view of an insertion/removal tool for use with a surgical reaming instrument.

0045<figref idref="DRAWINGS">FIG. 6B</figref> shows a perspective view of an assembled insertion/removal tool for use with a surgical reaming instrument.

0046<figref idref="DRAWINGS">FIG. 6C</figref> shows a perspective view of an insertion/removal tool connected to a surgical reaming instrument.

0047<figref idref="DRAWINGS">FIG. 6D</figref> shows a side view of an insertion/removal tool connected to a surgical reaming instrument.

0048<figref idref="DRAWINGS">FIG. 6E</figref> shows a cross section view of an insertion/removal tool connected to a surgical reaming instrument taken along line <b>6</b>E-<b>6</b>E of <figref idref="DRAWINGS">FIG. 6D</figref>.

0049<figref idref="DRAWINGS">FIG. 7A</figref> shows a side view of a cannulated reamer assembly.

0050<figref idref="DRAWINGS">FIG. 7B</figref> shows a cross section view of a cannulated reamer assembly taken along line <b>7</b>B-<b>7</b>B of <figref idref="DRAWINGS">FIG. 7A</figref>.

0051<figref idref="DRAWINGS">FIG. 7C</figref> shows an exploded perspective view of one embodiment of a cannulated reamer assembly of the present invention.

0052<figref idref="DRAWINGS">FIG. 7D</figref> shows an assembled perspective view of the cannulated reamer assembly of <figref idref="DRAWINGS">FIG. 7C</figref>.

0053<figref idref="DRAWINGS">FIG. 8A</figref> shows a perspective view of a preparatory reaming step in a tibial bone.

0054<figref idref="DRAWINGS">FIG. 8B</figref> shows a side view of a preparatory reaming step in a tibial bone.

0055<figref idref="DRAWINGS">FIG. 8C</figref> shows a cross section view of the preparatory reaming step in a tibial bone taken along line <b>8</b>C-<b>8</b>C of <figref idref="DRAWINGS">FIG. 8B</figref>.

0056<figref idref="DRAWINGS">FIG. 9A</figref> shows a perspective view of a first reaming step in a tibial bone using a cannulated reamer assembly.

0057<figref idref="DRAWINGS">FIG. 9B</figref> shows a side view of a tibial bone after a first reaming step has been completed.

0058<figref idref="DRAWINGS">FIG. 9C</figref> shows a cross section view of a tibial bone after a first reaming step has been completed with a cannulated reaming assembly taken along line <b>9</b>C-<b>9</b>C of <figref idref="DRAWINGS">FIG. 9B</figref>.

0059<figref idref="DRAWINGS">FIG. 10A</figref> shows a perspective view of a surgical reaming instrument and tibial bone being prepared for a second reaming step.

0060<figref idref="DRAWINGS">FIG. 10B</figref> shows a perspective view of a surgical reaming instrument and tibial bone after the second reaming step has been completed.

0061<figref idref="DRAWINGS">FIG. 10C</figref> shows a side view of a surgical reaming instrument and tibial bone after the second reaming step has been completed.

0062<figref idref="DRAWINGS">FIG. 10D</figref> shows a cross section view of a surgical reaming instrument and tibial bone after the second reaming step has been completed taken along line <b>10</b>D-<b>10</b>D of <figref idref="DRAWINGS">FIG. 10C</figref>.

0063<figref idref="DRAWINGS">FIG. 11A</figref> shows a side view of a tibial bone after the second reaming step has been completed.

0064<figref idref="DRAWINGS">FIG. 11B</figref> shows a cross section view of a tibial bone after the second reaming step has been completed taken along line <b>11</b>B-<b>11</b>B of <figref idref="DRAWINGS">FIG. 11A</figref>.

0065<figref idref="DRAWINGS">FIG. 11C</figref> shows a side view of a tibial bone after the third reaming step has been completed.

0066<figref idref="DRAWINGS">FIG. 11D</figref> shows a cross section view of a tibial bone after the third reaming step has been completed taken along lien <b>11</b>-D-<b>11</b>D of <figref idref="DRAWINGS">FIG. 11C</figref>.

0067<figref idref="DRAWINGS">FIG. 11E</figref> shows a top view of a tibial bone after the third reaming step has been completed.

0068<figref idref="DRAWINGS">FIGS. 12A-D</figref> show different views of one embodiment of a tibial metaphyseal reconstruction device of the present invention.

0069<figref idref="DRAWINGS">FIG. 13A</figref> shows a perspective view of the tibial metaphyseal reconstruction device shown in <figref idref="DRAWINGS">FIGS. 12A-D</figref> prior to implantation into a tibial bone.

0070<figref idref="DRAWINGS">FIG. 13B</figref> shows a side view of the tibial bone after a metaphyseal reconstruction device has been implanted.

0071<figref idref="DRAWINGS">FIG. 13C</figref> shows a cross section view of the tibial bone after a metaphyseal reconstruction device has been implanted, taken along line <b>13</b>C-<b>13</b>C of <figref idref="DRAWINGS">FIG. 13B</figref>.

0072<figref idref="DRAWINGS">FIGS. 14A-D</figref> show different views of one embodiment of a femoral metaphyseal reconstruction device of the present invention.

0073<figref idref="DRAWINGS">FIG. 14E</figref> shows a perspective view of the femoral metaphyseal reconstruction device shown in <figref idref="DRAWINGS">FIGS. 14A-D</figref> prior to attachment to a femoral implant.

0074<figref idref="DRAWINGS">FIG. 14F</figref> shows a perspective view of the femoral metaphyseal reconstruction device after attachment to a femoral implant.

DETAILED DESCRIPTION

0075As used herein, when referring to the surgical reaming instrument of the present invention, the term “proximal” means closer to the surgeon or in a direction toward the surgeon and the term “distal” means more distant from the surgeon or in a direction away from the surgeon. The term “anterior” means towards the front part of the body or the face and the term “posterior” means towards the back of the body. The term “medial” means toward the midline of the body and the term “lateral” means away from the midline of the body.

0076<figref idref="DRAWINGS">FIG. 1A</figref> shows a surgical reaming instrument <b>10</b>. The surgical reaming instrument <b>10</b> generally includes a reaming guide assembly <b>100</b>, a guide tube assembly <b>200</b>, a handle assembly <b>300</b>, and a trial stem <b>400</b>, each of which will be described in further detail below. <figref idref="DRAWINGS">FIG. 1B</figref> shows the surgical reaming instrument <b>10</b> with the trial stem <b>400</b> removed from the reaming guide assembly <b>100</b>.

0077<figref idref="DRAWINGS">FIGS. 2A-C</figref> show the reaming guide assembly <b>100</b> in detail. <figref idref="DRAWINGS">FIG. 2A</figref> shows an exploded view of the components of the reaming guide assembly <b>100</b>. Reaming guide assembly <b>100</b> generally includes a reaming guide <b>102</b>, a reaming guide collar <b>104</b>, and a spring detent <b>116</b>. The reaming guide <b>102</b> includes a handle receiving portion <b>118</b> and a guide tube receiving portion <b>124</b>. Reaming guide <b>102</b> further includes a distally projecting extension <b>106</b>, which is configured to fit within a hollow proximal portion of the reaming guide collar <b>104</b>. When the distally projecting extension <b>106</b> is within the hollow proximal portion of the reaming guide collar <b>104</b>, collar apertures <b>114</b> align with a notch <b>108</b> in the distally projecting extension <b>106</b>. This allows for reaming guide locking pins <b>112</b> to be placed through collar apertures <b>114</b> and sit within the notch <b>108</b> in the distally projecting extension <b>106</b>. When the locking pins <b>112</b> are in place, the reaming guide <b>102</b> and the reaming guide collar <b>104</b> are restricted from moving distally or proximally with respect to each other.

0078<figref idref="DRAWINGS">FIG. 2B</figref> shows a detailed view of spring detent <b>116</b> located between partially assembled reaming guide <b>102</b> and reaming guide collar <b>104</b>. Referring to <figref idref="DRAWINGS">FIGS. 2A-B</figref>, spring detent <b>116</b> includes ridges <b>128</b> and a protrusion <b>126</b>. Spring detent <b>116</b> is generally horseshoe shaped and surrounds a portion of the distally projecting extension <b>106</b> proximal to the notch <b>108</b> when the distally projecting extension <b>106</b> is within the reaming guide collar <b>104</b>. The spring detent protrusion <b>126</b> fits into one of apertures <b>130</b>, <b>132</b> on the underside of the reaming guide <b>102</b>. Additionally, each ridge <b>128</b> in the spring detent <b>116</b> sits within a respective collar notch <b>110</b> in the reaming guide collar <b>104</b>. When a surgeon or other operating room personnel inserts the reaming guide <b>102</b> into the reaming guide collar <b>104</b>, the spring detent protrusion <b>126</b> preferably engages the aperture <b>130</b>, for instance, and both the spring detent <b>116</b> and reaming guide <b>102</b> can be rotated until the ridges <b>128</b> engage their respective collar notches <b>110</b>. When the ridges <b>128</b> engage the collar notches <b>110</b>, this engagement can be felt and feedback is provided to ensure that the reaming guide <b>102</b> is in a position such that locking pin aperture <b>132</b> is aligned with another of the collar notches <b>110</b>. <figref idref="DRAWINGS">FIG. 2C</figref> shows the reaming guide assembly <b>100</b> when reaming guide <b>102</b>, reaming guide collar <b>104</b> and spring detent <b>116</b> are all assembled.

0079<figref idref="DRAWINGS">FIGS. 3A-C</figref> show detailed views of the guide tube assembly <b>200</b> together with the reaming guide assembly <b>100</b>. <figref idref="DRAWINGS">FIG. 3A</figref> shows a side view of the reaming assembly <b>100</b> and the guide tube assembly <b>200</b>, along with section origin <b>3</b>B.

0080<figref idref="DRAWINGS">FIG. 3B</figref> shows a cross section of the reaming guide assembly <b>100</b> and guide tube assembly <b>200</b> along section origin <b>3</b>B. <figref idref="DRAWINGS">FIG. 3C</figref> shows an enlarged view of circular section D from <figref idref="DRAWINGS">FIG. 3B</figref>. Referring to <figref idref="DRAWINGS">FIGS. 3B-C</figref>, a locking pin <b>204</b> is seated partially within the guide tube receiving portion <b>124</b> and further through one of locking pin apertures <b>130</b>, <b>132</b>. The locking pin <b>204</b> is surrounded by a coil spring <b>206</b> dimensioned such that the head of locking pin <b>204</b> cannot pass through coil spring <b>206</b>, and coil spring <b>206</b> cannot pass through locking pin aperture <b>132</b>. The coil spring <b>206</b> and locking pin <b>204</b> are further dimensioned so that when the head of locking pin <b>204</b> is resting on the coil spring <b>206</b> with no additional force applied, the distal end of the locking pin <b>204</b> does not enter any portion of a collar notch <b>110</b>. Although in <figref idref="DRAWINGS">FIGS. 3B-C</figref> there is no force being applied to the locking pin <b>204</b> other than the weight of the locking pin <b>204</b> itself, the locking pin <b>204</b> is shown in the locked position for purposes of illustration (i.e. the distal end of the locking pin <b>204</b> is within a collar notch <b>110</b>). The locking pin <b>204</b>, when in the locked position, prevents relative rotation between the reaming guide <b>102</b> and the reaming guide collar <b>104</b> since the locking pin <b>204</b> rests in one of collar notches <b>110</b> of reaming guide collar <b>104</b>.

0081Guide tube receiving portion <b>124</b> of the reaming guide <b>102</b> may include one or more rinse holes <b>209</b> to improve the ability to clean the surgical reaming instrument <b>10</b>. Once the locking pin <b>204</b> is seated within the guide tube receiving portion <b>124</b> and further through locking pin aperture <b>132</b>, a guide tube <b>202</b> may be inserted into the guide tube receiving portion <b>124</b>. The guide tube <b>202</b> may be permanently fixed within the guide tube receiving portion <b>124</b>, for example, by welding. As will be explained in more detail below, guide tube <b>202</b> is used to act as a guide for a cannulated reamer assembly <b>600</b> when reaming a bone.

0082<figref idref="DRAWINGS">FIGS. 4A-4B</figref> show detailed views of the guide tube assembly <b>200</b> and the reaming guide assembly <b>100</b> with locking rod <b>208</b> inserted into guide tube <b>202</b>. <figref idref="DRAWINGS">FIG. 4A</figref> shows a side view of the reaming assembly <b>100</b> and the guide tube assembly <b>200</b>, along with section origin <b>4</b>B. <figref idref="DRAWINGS">FIG. 4B</figref> shows a cross section of the reaming guide assembly <b>100</b> and guide tube assembly <b>200</b> along section origin <b>4</b>B. Locking rod <b>208</b> is inserted into guide tube <b>202</b> and can be fixed, for example, by threading the locking rod <b>208</b> into corresponding threads on the inside of guide tube <b>202</b>. When the locking rod <b>208</b> is fully or nearly fully inserted into the guide tube <b>202</b>, a proximal portion of the locking rod <b>208</b> clears the guide tube <b>202</b> and provides a handle <b>210</b> for the surgeon to manipulate reaming guide <b>102</b>. By rotating the locking rod handle <b>210</b>, and thus the locking rod <b>208</b>, the distal end of the locking rod <b>208</b> makes contact with, and applies force to, the head of the locking pin <b>204</b>. This rotation can be continued until the locking pin <b>204</b> is fully driven into a collar notch <b>110</b>. Once fully driven into the collar notch <b>110</b>, the system is in the locked position and the reaming guide <b>102</b> is prevented from rotating relative to the reaming guide collar <b>104</b>.

0083<figref idref="DRAWINGS">FIG. 5A</figref> shows an exploded view of the handle assembly <b>300</b>. <figref idref="DRAWINGS">FIG. 5B</figref> shows a side view of the handle assembly <b>300</b> with section origin <b>5</b>C. <figref idref="DRAWINGS">FIG. 5C</figref> shows a cross section of the handle assembly <b>300</b> along section origin <b>5</b>C. <figref idref="DRAWINGS">FIG. 5D</figref> shows the handle assembly <b>300</b> fully assembled and exploded from the remainder of the surgical reaming instrument <b>10</b>. Referring now to <figref idref="DRAWINGS">FIGS. 5A-D</figref>, handle assembly <b>300</b> generally includes a handle <b>302</b>, to allow the surgeon to grip the surgical reaming instrument <b>10</b>, and an attachment screw <b>304</b>, to attach the handle assembly <b>300</b> to the reaming guide <b>102</b>. Alignment pins <b>303</b> are inserted into their respective flanking apertures <b>122</b> of the handle receiving portion <b>118</b> of the reaming guide <b>102</b>. These alignment pins <b>303</b> align the screw aperture <b>306</b> of the handle assembly <b>300</b> with the center aperture <b>120</b> of the handle receiving portion <b>118</b> of the reaming guide <b>102</b>. Once aligned, the surgeon can insert the attachment screw <b>304</b> into the screw aperture <b>306</b> and further into the center aperture <b>120</b> by gripping and rotating the screw handle <b>308</b> so that the attachment screw <b>304</b> threads fully through the screw aperture <b>306</b>. Once the attachment screw <b>306</b> is fully inserted into the screw aperture <b>306</b>, the screw collar <b>315</b> sits distal to the retaining pin aperture <b>312</b>. At this point, the surgeon can insert the screw retaining pin <b>310</b> into the retaining pin aperture <b>312</b> such that the screw retaining pin <b>310</b> sits proximal the screw collar <b>314</b>. This ensures that the attachment screw <b>304</b> is locked into place and cannot exit the screw aperture <b>306</b>.

0084<figref idref="DRAWINGS">FIG. 6A</figref> shows an exploded view of an optional insertion/removal tool <b>500</b>. <figref idref="DRAWINGS">FIG. 6B</figref> shows a view of the assembled insertion/removal tool <b>500</b>. The insertion/removal tool <b>500</b> is optionally used to insert or remove the surgical reaming instrument <b>10</b>. Referring to <figref idref="DRAWINGS">FIGS. 6A-B</figref>, an insertion/removal tool <b>500</b> generally includes a tool body <b>502</b> and a locking lever <b>504</b>. Tool body <b>502</b> includes a slot <b>518</b> into which the locking lever <b>504</b> is installed. Locking lever <b>504</b> includes an aperture <b>516</b> that aligns with pivot pin apertures <b>514</b> on each side of the tool body <b>502</b>. Pivot pin <b>506</b> can be inserted through locking lever aperture <b>516</b> and both pivot pin apertures <b>514</b> on the tool body <b>502</b>. The pivot pin <b>506</b> allows the locking lever <b>504</b> to pivot about the pivot pin <b>506</b>. Additionally, the proximal end of the body slot <b>518</b> includes a preload spring <b>508</b>. The preload spring <b>508</b> contacts the locking lever actuator <b>520</b>. When the locking lever actuator <b>520</b> is pressed, the preload spring <b>508</b> compresses and the locking lever <b>504</b> pivots about pivot pin <b>506</b>, ultimately causing the lever hook <b>510</b> to move away form the body <b>502</b> of the insertion/removal tool <b>500</b>. The end of the tool <b>512</b> may optionally be configured to match a universal instrument handle.

0085<figref idref="DRAWINGS">FIG. 6C</figref> shows the insertion/removal tool <b>500</b> assembled with the reaming guide assembly <b>100</b>, the guide tube assembly <b>200</b>, and the handle assembly <b>300</b>. <figref idref="DRAWINGS">FIG. 6D</figref> shows a side view of the illustration in <figref idref="DRAWINGS">FIG. 6C</figref> along with section origin <b>6</b>E. <figref idref="DRAWINGS">FIG. 6E</figref> shows a cross section view of the illustration in <figref idref="DRAWINGS">FIG. 6D</figref> along section origin <b>6</b>E. Referring to <figref idref="DRAWINGS">FIGS. 6C-E</figref>, the insertion/removal tool <b>500</b> can be slid distally toward the guide body receiving portion <b>124</b> of the reaming guide assembly <b>100</b> until the lever hook <b>510</b> snaps into a hook receiving portion <b>150</b> of the guide body receiving portion <b>124</b> of the reaming guide assembly <b>100</b>. The preload spring <b>508</b> provides enough force on the proximal end of the locking lever <b>504</b> to keep the insertion/removal tool <b>500</b> engaged with the reaming guide assembly <b>100</b>. If a surgeon, for instance, desires to detach the insertion/removal tool <b>500</b> from the reaming guide assembly <b>100</b>, he simply applies pressure to the locking lever actuator <b>520</b> such that the locking lever <b>504</b> pivots about pivot pin <b>506</b> and the lever hook <b>510</b> disengaged from the reaming guide assembly <b>100</b>.

0086<figref idref="DRAWINGS">FIG. 7A</figref> shows a side view of a cannulated reamer assembly <b>600</b> with section origin <b>7</b>B. Cannulated reamer assembly <b>600</b> generally includes reaming head <b>602</b> and reamer shaft assembly <b>604</b>. Reamer shaft assembly includes quick connect mechanism <b>606</b>, shaft handle <b>607</b> and drill attachment end <b>608</b>. The surgeon can grip the quick connect mechanism <b>606</b> and insert the reaming head <b>602</b> into the distal end of the reamer shaft assembly <b>604</b> to connect the reaming head <b>602</b> to the reamer shaft assembly <b>604</b>. To disconnect the reaming head <b>602</b> from the reamer shaft assembly <b>604</b>, the surgeon can grip the shaft handle <b>607</b> and pull the reamer shaft assembly <b>604</b> proximally away from the reaming head <b>602</b>. The reamer shaft assembly <b>604</b> further includes a drill attachment end <b>608</b> on the proximal end of the reamer shaft assembly <b>604</b>. The drill attachment end <b>608</b> can be attached to a drill, such as an electric or pneumatic drill, in order to drive the cannulated reamer assembly <b>600</b>. Reaming head <b>602</b> may include a depth indicator <b>605</b>, such as a groove in the reaming head <b>602</b>, that gives feedback to the surgeon, such as visual feedback, to notify the surgeon that the reaming head <b>602</b> has traveled a predetermined distance. Reaming head <b>602</b> can also contain a tapered distal end <b>603</b>.

0087<figref idref="DRAWINGS">FIG. 7B</figref> shows a cross section of the cannulated reamer assembly <b>600</b> along the section origin <b>7</b>B. Reaming head <b>602</b> and reamer shaft assembly <b>604</b> both include cannulations <b>612</b> that allow the cannulated reamer assembly <b>600</b> to slide over a rod, such as the guide tube <b>202</b> of the guide tube assembly <b>200</b> or over the rod of a traditional intramedullary (IM) reamer. The reaming head <b>602</b> also includes a counterbore <b>610</b> to allow the reaming head <b>602</b> to clear the guide tube receiving portion <b>124</b> of the reaming guide assembly <b>100</b>. Additionally, the reamer shaft assembly <b>604</b> may include a viewing port <b>614</b> located at the proximal end of the cannulation <b>612</b> to give the surgeon visual feedback regarding whether or not the cannulated reamer assembly <b>600</b> has “bottomed out.” Essentially, as long as the rod over which the cannulated reamer assembly <b>600</b> is placed cannot be seen through the view port <b>614</b>, there is no danger of “bottoming out.” Once the rod can be seen through the view port <b>614</b>, the surgeon, for instance, can view whether the cannulated reamer assembly <b>600</b> is close to travelling the full distance of which it is capable before the rod makes contact with the proximal closed end of the cannulation <b>612</b> of the reamer shaft assembly <b>604</b>. <figref idref="DRAWINGS">FIG. 7C</figref> shows an exploded view of the cannulated reamer assembly <b>604</b> with the reaming head <b>602</b> separated from the reamer shaft assembly <b>604</b>. <figref idref="DRAWINGS">FIG. 7D</figref> shows the cannulated reamer assembly <b>604</b> fully assembled.

0088An example of one method of use of the invention will now be described. Referring now to <figref idref="DRAWINGS">FIGS. 8A-C</figref>, the beginning of one method of a revision procedure is shown. For example, in a revision procedure of a total knee replacement surgery, the initial step is to ream the bone <b>700</b> generally along the IM canal. Although the IM reamer <b>704</b> is illustrated here as distally reaming the tibia beginning at the tibial plateau <b>702</b>, this is merely an example. The IM reamer <b>704</b> could also proximally ream the femur beginning at the distal end of the femur in substantially the same manner. <figref idref="DRAWINGS">FIG. 8B</figref> shows the initial step along with section origin <b>14</b>C, and <figref idref="DRAWINGS">FIG. 8C</figref> shows a cross section of the initial step along section origin <b>14</b>C. As can be seen, the IM reamer <b>704</b> enters through the initial bone void <b>706</b> that was originally created during a previous knee replacement surgery, for example.

0089<figref idref="DRAWINGS">FIG. 9A</figref> shows the first step following the initial tibial or femoral IM canal preparation. The IM reamer <b>704</b> used to initially prepare the IM canal is left in place and the cannulation <b>612</b> of the cannulated reaming assembly <b>600</b> is placed over the proximal end of the IM reamer <b>704</b>. The surgeon then reams over the stem of the IM reamer <b>704</b> using the cannulated reaming assembly <b>600</b>. The reaming head <b>602</b> is driven distally into the tibial bone until the surgeon, optionally using the depth indicator <b>605</b> as a guide, determines that the proper depth has been reached based on the dimensions of a MRD to be implanted into the bone. <figref idref="DRAWINGS">FIG. 9B</figref> shows a side view of the bone <b>700</b> after this reaming step has been performed, along with section origin <b>9</b>C. <figref idref="DRAWINGS">FIG. 9C</figref> shows a cross section of the bone following this reaming step along section origin <b>9</b>C. As can be seen, one void space in the bone <b>700</b> is the generally cylindrical preparatory IM reaming void <b>708</b> created by the initial preparation step with the IM reamer <b>704</b>. A central pocket <b>710</b> created in the initial reaming step corresponds in shape to the tapered distal end <b>603</b> of the reaming head <b>602</b>.

0090<figref idref="DRAWINGS">FIG. 10A</figref> shows the reaming guide setup for the second reaming step. The cannulated reaming assembly <b>600</b> first is removed from the IM reamer <b>704</b>. Then, the fully assembled reaming guide assembly <b>100</b>, guide tube assembly <b>200</b>, handle assembly <b>300</b>, and optional insertion/removal tool <b>500</b> are placed near bone <b>700</b>. <figref idref="DRAWINGS">FIG. 10B</figref> shows the surgical reaming instrument <b>10</b> inserted in the central pocket <b>710</b> in the bone after the second reaming step has been completed. <figref idref="DRAWINGS">FIG. 10C</figref> shows a side view of <figref idref="DRAWINGS">FIG. 10B</figref> along with section origin <b>10</b>D. <figref idref="DRAWINGS">FIG. 10D</figref> shows a cross section of <figref idref="DRAWINGS">FIG. 10C</figref> along section origin <b>10</b>D. Once inserted, as seen in <figref idref="DRAWINGS">FIG. 10D</figref>, the reaming guide <b>102</b> makes contact with a portion of the bone <b>700</b> surrounding central pocket <b>710</b>. The cannulated reaming assembly <b>600</b> is then preferably inserted over the guide tube <b>202</b> of the guide tube assembly <b>200</b>. The surgeon may use the handle <b>302</b> of the handle assembly <b>300</b> for optimum angular positioning of the reaming guide <b>102</b>. The reaming head <b>602</b> of the reaming assembly <b>600</b> is then driven, either manually or with a drill, distally along the guide tube <b>202</b> to ream the bone <b>700</b>. The reaming guide assembly <b>100</b> acts as a depth stop to ensure that reaming head <b>602</b> can only travel a predetermined distance. Although the counterbore <b>610</b> of the reaming head <b>602</b> will pass over the guide tube receiving portion <b>124</b> of the reaming guide assembly <b>100</b>, the remainder of the reaming guide assembly <b>100</b> will act as a stop for the distal end of the reaming head <b>602</b>.

0091<figref idref="DRAWINGS">FIG. 11A</figref> shows a side view of the bone <b>700</b> after the second reaming step is completed, along with section origin <b>11</b>B. <figref idref="DRAWINGS">FIG. 11B</figref> shows a cross section of the bone <b>700</b> along section origin <b>11</b>B. In addition to the central pocket <b>710</b>, a medial reaming void <b>712</b> preferably exists along the path taken by the reaming head <b>602</b> in the second reaming step. If necessary, depending on the size and the shape of the bone void, a third reaming step can be undertaken. With the surgical reaming instrument <b>10</b> in the bone void, the reaming head <b>602</b> is moved proximally along the guide tube <b>202</b> until it clears the bone <b>700</b>. The locking rod handle <b>210</b> of the locking rod <b>208</b> is preferably rotated to release the force on the locking pin <b>204</b>. The coil spring <b>206</b> will cause the locking pin <b>204</b> to move proximally and clear that collar notch <b>110</b>. Once the locking pin <b>204</b> clears the collar notch <b>110</b>, the system is in what may be referred to as an unlocked position and the reaming guide <b>102</b> can rotate in relation to the reaming guide collar <b>104</b>. One in the unlocked position, the surgeon can use the handle <b>302</b> to rotate the reaming guide <b>102</b> into the desired position for a further reaming step. Angular stops may be provided in the handle <b>302</b> so that angular rotation between reaming steps can be accurately controlled. Once in place, the locking rod <b>208</b> is manipulated to force the locking pin <b>204</b> back into the locking position so that the third reaming step can be performed. The third reaming step is preferably completed in substantially the same manner as the second reaming step, with the only difference being the portion of the bone <b>700</b> being reamed. <figref idref="DRAWINGS">FIG. 11C</figref> shows a side view of the bone <b>700</b> after the third reaming step has been performed, along with section origin <b>11</b>D. <figref idref="DRAWINGS">FIG. 11D</figref> shows a cross section of the bone <b>700</b> along section origin <b>11</b>D after the third reaming step has been performed. As can be seen, in addition to central pocket <b>710</b> and medial reaming void <b>712</b>, there is now a lateral reaming void <b>714</b> created as a result of the third reaming step. <figref idref="DRAWINGS">FIG. 11E</figref> shows a top view of bone <b>700</b> after the third reaming step. The IM axis <b>720</b> corresponds to the center of the central pocket <b>710</b> and preparatory IM reaming void <b>708</b>. The medial reaming axis <b>722</b> corresponds to the center of the medial reaming void <b>712</b>, and the lateral reaming axis <b>724</b> corresponds to the center of the lateral reaming void <b>714</b>. When the reaming is complete, the bone <b>700</b> is ready to receive a void filler prosthetic component, such as an MRD, for example. In certain embodiments, the three aforementioned reaming steps do not have to be performed in any particular order, and in other embodiments, not all three of the reaming steps are performed.

0092<figref idref="DRAWINGS">FIGS. 12A-D</figref> show different views of a MRD. In this illustrative embodiment, the MRD is a tibial MRD <b>800</b>. The tibial MRD <b>800</b> is placed within the one or more reaming voids <b>710</b>, <b>712</b> and <b>714</b> in the bone <b>700</b>. The tibial MRD <b>800</b> includes a central opening <b>802</b> to allow insertion of a trial stem <b>400</b>, in this case a tibial stem. The central opening <b>802</b> also allows for insertion of the stem boss of a tibial baseplate (not shown), the tibial baseplate being engaged to the proximal side of the tibial MRD <b>800</b>. The tibial MRD <b>800</b> can also include fin clearances <b>804</b> to permit rotation and position adjustment of the tibial baseplate. The outer surfaces <b>806</b> of the tibial MRD <b>800</b> are configured to match the dimensions of surfaces of the bone <b>700</b> created by a particular cannulated reamer assembly <b>600</b>. In this illustrative embodiment, outer surfaces <b>806</b> include three blended tapered conical surfaces that match the surface in the bone <b>700</b> created by the three reaming steps described above.

0093<figref idref="DRAWINGS">FIG. 13A</figref> shows the tibial MRD <b>800</b> prior to insertion into the void in the bone <b>700</b> consisting of the central pocket <b>710</b>, the medial reaming void <b>712</b> and the lateral reaming void <b>714</b>. <figref idref="DRAWINGS">FIG. 13B</figref> shows a side view of the bone <b>700</b> with the tibial MRD <b>800</b> inserted, along with section origin <b>13</b>C. <figref idref="DRAWINGS">FIG. 13C</figref> shows a cross section along section origin <b>13</b>C of the bone <b>700</b> with tibial MRD <b>800</b> inserted.

0094<figref idref="DRAWINGS">FIGS. 14A-D</figref> show, respectively, superior, isometric, anterior, and lateral views of an MRD. In this illustrative embodiment, the MRD is a femoral MRD <b>900</b>. The femoral MRD <b>900</b> is generally similar to the tibial MRD <b>800</b>, with the main difference being that the femoral MRD <b>900</b> is inserted into the bone void created by a reaming process on the distal end of the femur. The femoral MRD <b>900</b> includes a central opening <b>902</b> to allow for passage of a femoral stem. The femoral MRD <b>900</b> also can include tapered conical surfaces <b>904</b> to correspond to the particular shape of the bone voids created in the reaming process. Additionally, the femoral MRD <b>900</b> can include a first clearance space <b>906</b> for a femoral cam box, if needed, and a second clearance space <b>908</b> for the anterior chamfer of a femoral implant. <figref idref="DRAWINGS">FIGS. 14E and 14F</figref> show the femoral MRD <b>900</b> before and after attachment to the femoral implant <b>910</b>, respectively. In this illustration, the femoral stem is omitted from the femoral stem attachment site <b>912</b> for clarity. The present invention can be used for multiple types of MRD implantation. For example, cemented MRDs can be used within the scope of this invention, in which there is a gap between the MRD and the balance of the implant construct, which is filled with bone cement during the procedure. Additionally, locked MRDs can be used within the scope of this invention, in which a mechanical connection, such as a taper lock, is made between the MRD and the balance of the implant construct.

0095There are many benefits of performing a revision procedure with the surgical reaming instrument of the present invention. For example, all bone removal steps may be fully guided without the need for any freehand bone removal. Additionally, the present invention provides a surgeon with the option of performing a guided ream of the bone either by hand or by using a powered source, such as a drill. Further, the instruments generally anatomically match typical bone voids observed in surgery. For example, the prepared cavity can be wider in the medial/lateral direction than in the anterior/posterior direction. Another related benefit is that the instrument has the capability to prepare asymmetric cavities, such as larger cavities on the medial side than the lateral side, which is often seen in cases of tibial bone voids. Importantly, because of the precision of control allowed when using this instrument, the shape of the cavity can be precisely controlled which allows for stock MRDs to accurately fit into the bone void without dependence on the technique of the particular surgeon performing the surgery. Related to this is that the symmetric, geometrically defined shape of the MRD simplifies the setup and machining of void fillers. Yet another benefit of an embodiment of this invention is that it allows a cannulated reamer set to consist of differently sized modular reaming heads and a single shaft to fit all reaming head sizes. This results in a reduced cost and size of the instrument set. The MRDs described herein can be made of any biocompatible material such as polymer and stainless steel, for example.

0096Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention.