Polymer cutting block

An orthopaedic surgical instrument includes an all-polymer 4-in-1 cutting block having a number of polymer cutting guides. In some embodiments, the all-polymer cutting block is be embodied as a multi-piece cutting block, while in other embodiments the all-polymer cutting block is embodied as a single, monolith cutting block. Several methods for fabricating the different all-polymer 4-in-1 cutting blocks are also disclosed.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgical instruments and, more particularly, to cutting blocks used to resect a patient's bone.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged natural joint is replaced by a prosthetic joint. Typical artificial joints include knee prostheses, hip prostheses, shoulder prostheses, ankle prostheses, and wrist prostheses, among others. For example, in a total knee arthroplasty surgical procedure, a patient's natural knee joint is partially or totally replaced by a prosthetic knee joint or knee prosthesis. A typical knee prosthesis includes a tibial tray, a femoral component, and a polymer insert or bearing positioned between the tibial tray and the femoral component. In a hip replacement surgical procedure, a patient's natural acetabulum is replaced by a prosthetic cup and a patient's natural femoral head is partially or totally replaced by a prosthetic stem and femoral ball.

To facilitate the replacement of the natural joint with a prosthesis, orthopaedic surgeons use a variety of orthopaedic surgical instruments such as, for example, cutting blocks, drill guides, milling guides, and other surgical instruments. Typically, the orthopaedic surgical instruments are reusable and generic with respect to the patient such that the same orthopaedic surgical instrument may be used on a number of different patients during similar orthopaedic surgical procedures.

SUMMARY

According to an aspect of the present disclosure, a polymer 4-in-1 cutting block for performing an orthopedic surgical procedure on a distal end of a patient's femur includes a first polymer half-block and a second polymer half-block. The first polymer half-block may have a plurality of first cutting slots and a plurality of alignment receptacles formed in an inner sidewall of the first polymer half-block. The second polymer half-block separate from the first polymer half-block and configured to be coupled to the first polymer half-block to form an assembled polymer 4-in-1 cutting block. The second polymer half-block may include a plurality of second cutting slots and a plurality of alignment protrusions formed in an inner sidewall of the second polymer half-block. Additionally, when the second polymer half-block is coupled to the first polymer half-block, each of the first cutting slot cooperates with a corresponding second cutting slot to define a respective polymer cutting guide and each alignment protrusion is received in a corresponding alignment receptacle.

In some embodiments, the inner sidewall of the first polymer half-block may confront the inner sidewall of the second polymer half-block when the second polymer half-block is coupled to the first polymer half-block. Additionally, in some embodiments, when the second polymer half-block is coupled to the first polymer half-block, the plurality of first cutting slots and the plurality of second cutting slots cooperate to define an anterior polymer cutting guide and two polymer chamfer cutting guides. Furthermore, in some embodiments, the each respective polymer cutting guide is devoid of any metal inserts. Additionally, in some embodiments, an anterior edge of the inner sidewall of the first polymer half-block and an anterior edge of the inner sidewall of the second polymer half-block are both chamfered inwardly.

According to another aspect of the present disclosure, a method for fabricating a polymer cutting block for performing an orthopedic surgical procedure on a distal end of a patient's femur may include injection molding a first polymer half-block having a plurality of first cutting slots and a plurality of alignment receptacles formed in an inner sidewall of the first polymer half-block using a first injection mold and injection molding a second polymer half-block configured to be coupled to the first polymer half-block using a second injection mold. The second polymer half-block may include a plurality of second cutting slots and a plurality of alignment protrusions formed in an inner sidewall of the second polymer half-block. Additionally, each alignment protrusion may be configured to be received in a corresponding alignment receptacle of the first polymer half-block. The method may also include coupling the second polymer half-block to the first polymer half-block such that the inner sidewall of the first polymer half-block confronts the inner sidewall of the second polymer half-block.

In some embodiments, coupling the second polymer half-block to the first polymer half-block may include inserting each alignment protrusion of the second polymer half-block into a corresponding alignment receptacle of the first polymer half-block. Additionally, the method may also include securing the second polymer half-block and the first polymer half-block to each other. For example, the second polymer half-block and the first polymer half-block may be secured to each other using a metal securing device. The method may also include cleaning the first polymer half-block and the second polymer half-block prior to coupling the second polymer half-block to the first polymer half-block.

According to a further aspect of the present disclosure, a fabrication kit for fabricating a polymer 4-in-1 cutting block via an injection molding fabrication process may include an anterior cutting guide core, a first chamfer cutting guide core, and a second chamfer cutting guide core. The anterior cutting guide core may include a planar body including an anterior cutting guide molding end and a handle end opposite the anterior cutting guide molding end. The handle end may have a greater width than the anterior cutting guide molding end and the anterior cutting guide molding end may be configured to form an anterior polymer cutting guide of the polymer 4-in-1 cutting block during the injection molding fabrication process. The first chamfer cutting guide core may have a planar body including a first chamfer cutting guide molding end, a handle end opposite the first chamfer cutting guide molding end, and a slot defined through the first chamfer cutting guide molding end. The first chamfer cutting guide molding end may be configured to form a first chamfer cutting guide of the polymer 4-in-1 cutting block during the injection molding fabrication process. The second chamfer cutting guide core may have a planar body including a second chamfer cutting guide molding end and a handle end opposite the second chamfer cutting guide molding end. The second chamfer cutting guide molding end may be configured to be received through the slot of the planar body of the first chamfer cutting guide core and may form a second chamfer cutting guide of the polymer 4-in-1 cutting block during the injection molding fabrication process.

In some embodiments, the first chamfer cutting guide core may further include a medial side-rail attached to a medial side of the planar body of the first chamfer cutting guide core and a lateral side-rail attached to a lateral side of the planar body of the first chamfer cutting guide core. In such embodiments, the first chamfer cutting guide core may further include a medial stop flange attached to the medial side-rail toward the handle end of the planar body of the first chamfer cutting guide core and a lateral stop flange attached to the lateral side-rail toward the handle end of the planar body of the first chamfer cutting guide core.

In some embodiments, the second chamfer cutting guide core may further include a medial side-rail attached to a medial side of the planar body of the second chamfer cutting guide core and a lateral side-rail attached to a lateral side of the planar body of the second chamfer cutting guide core. The second chamfer cutting guide core may further include a medial stop flange attached to the medial side-rail toward the handle end of the planar body of the second chamfer cutting guide core, and a lateral stop flange attached to the lateral side-rail toward the handle end of the planar body of the second chamfer cutting guide core. Additionally, in some embodiments, each of the anterior cutting guide, the first chamfer cutting guide, and the second chamfer cutting guide may be formed from a metallic material.

According to yet a further aspect of the present disclosure, a method for fabricating a polymer 4-in-1 cutting block for performing an orthopedic surgical procedure on a distal end of a patient's femur may include coupling a first chamfer cutting guide core to a second chamfer cutting guide core to form an assembled chamfer cutting guide core, positioning an anterior cutting guide core into an injection mold of the polymer 4-in-1 cutting block, positioning the assembled chamfer cutting guide core into the injection mold; and performing an injection molding process to form the polymer 4-in-1 cutting block using the injection mold, the anterior cutting guide core, and the assembled chamfer cutting guide core. Each of the first and second chamfer cutting guide cores may include a planar body having a chamfer cutting guide molding end and a handle end opposite the chamfer cutting guide molding end. Additionally, the anterior cutting guide core may include a planar body having an anterior cutting guide molding end and a handle end opposite the anterior cutting guide molding end.

In some embodiments, the anterior cutting guide core molding end may form a polymer anterior cutting guide of the polymer 4-in-1 cutting block during the injection molding process. Additionally, each chamfer cutting guide molding end of the first and second chamfer cutting guide cores may form a polymer chamfer cutting guide of the polymer 4-in-1 cutting block during the injection molding process.

Additionally, in some embodiments, coupling the first chamfer cutting guide core to the second chamfer cutting guide core may include inserting the chamfer cutting guide molding end of the first chamfer cutting guide core through a slot defined in the chamfer cutting guide molding end of the second chamfer cutting guide core. In such embodiments, the method may further include removing the anterior cutting guide core molding end from the polymer 4-in-1 cutting block, removing the first chamfer cutting guide core from the polymer 4-in-1 cutting block by sliding the chamfer cutting guide molding end of the first chamfer cutting guide core from the slot defined in the chamfer cutting guide molding end of the second chamfer cutting guide core, and removing the second chamfer cutting guide core from the polymer 4-in-1 cutting block subsequent to the removal of the first chamfer cutting guide core.

According to an additional aspect of the present disclosure, a polymer 4-in-1 cutting block for performing an orthopedic surgical procedure on a distal end of a patient's femur may include a polymer body and a polymer chamfer cutting guide insert. The polymer body may include a bone-engaging side, an outer side opposite the bone engaging side, a polymer anterior cutting guide defined through the body, a polymer posterior cutting guide, and a chamfer cutting guide recess defined through the polymer body. The chamfer cutting guide recess may include a first opening defined on the outer side and a second opening, larger than the first opening, defined on the bone-engaging side. Additionally, the polymer chamfer cutting guide insert may be configured to be received in the chamfer cutting guide recess via the second opening to define a polymer chamfer cutting guide of the polymer 4-in-1 cutting block.

In some embodiments, the polymer body may further include a medial guide track defined on a medial side of the polymer body and a lateral guide track defined on a lateral side of the polymer body opposite the medial side. Additionally, the polymer chamfer cutting guide insert may further include a medial guide arm extending from a medial side of the polymer chamfer cutting guide insert and a lateral guide arm extending from a lateral side of the polymer chamfer cutting guide insert. In such embodiments, the medial guide arm may be configured to be received in the medial guide track and the lateral guide arm may be configured to be received in the lateral guide track when the polymer chamfer cutting guide insert is received in the chamfer cutting guide recess of the polymer body.

Additionally, in some embodiments, the polymer body may include a pair of threaded apertures and the polymer chamfer cutting guide insert may include a pair of non-threaded apertures defined therethough. In such embodiments, the polymer 4-in-1 cutting block may further include a pair of securing devices configured to be received into the non-threaded apertures of the polymer chamfer cutting guide insert and threaded into the threaded apertures of the polymer body to secure the polymer chamfer cutting guide insert to the polymer body.

In some embodiments, the polymer chamfer cutting guide insert may have a triangular cross-section. Additionally, in some embodiments, the polymer chamfer cutting guide insert and the polymer body may cooperate to define an anteriorly-angled polymer chamfer cutting guide and a posteriorly-angled polymer chamfer cutting guide when the polymer chamfer cutting guide insert is received in the chamfer cutting guide recess of the polymer body.

According to yet another aspect of the present disclosure, a method for performing an orthopaedic surgical procedure on a distal end of a patient's femur may include assembling a polymer 4-in-1 cutting block by inserting a polymer chamfer cutting guide insert into a chamfer cutting guide recess of a polymer body, securing the assembled polymer 4-in-1 cutting block to a surgically prepared distal end of the patient's femur, and performing a femoral resection procedure on the patient's femur using the assembled polymer 4-in-1 cutting block. In some embodiments, the polymer body may include a polymer anterior cutting guide and a polymer posterior cutting guide.

In some embodiments, the chamfer cutting guide recess may include a first opening defined on an outer side of the polymer body and a second opening, larger than the first opening, defined on a bone-engaging side of the polymer body. In such embodiments, assembling the polymer 4-in-1 cutting block may include inserting the polymer chamfer cutting guide insert into chamfer cutting guide recess of the polymer body via the second opening. Additionally, in such embodiments, securing the assembled polymer 4-in-1 cutting block may include abutting the bone-engaging side of the polymer body to the surgically prepared distal end of the patient's femur such that the polymer chamfer cutting guide insert is in contact with the patient's femur.

In some embodiments, assembling the polymer 4-in-1 cutting block may include inserting a pair of guide arms of the polymer chamfer cutting guide insert into a corresponding pair of guide tracks of the polymer body. In such embodiments, the method may further include securing the polymer chamfer cutting guide insert to the polymer body using a plurality of securing devices.

According to a further aspect of the present disclosure, a fabrication kit for fabricating a polymer 4-in-1 cutting block via an injection molding fabrication process may include a sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core. The sacrificial anterior cutting guide core may be configured to form an anterior polymer cutting guide of the polymer 4-in-1 cutting block during the injection molding fabrication process. The sacrificial chamfer cutting guide core may include a first cutting guide core and a second cutting guide core. The first and second cutting guide cores may extend through each other at an oblique angle relative to each other. Additionally, the sacrificial chamfer cutting guide core may be configured to form a polymer chamfer cutting guide of the polymer 4-in-1 cutting block during the injection molding fabrication process. In some embodiments, the sacrificial anterior cutting guide core and the sacrificial chamfer cutting guide core may be formed from a metal material having a melting point lower than a polymer from which the polymer 4-in-1 cutting block is formed.

Additionally, in some embodiments, the sacrificial anterior cutting guide core and the sacrificial chamfer cutting guide core may be formed from a metal alloy having a melting point of 550 degrees Fahrenheit or less. Furthermore, in some embodiments, the sacrificial anterior cutting guide core may include an elongated body having a first end, a second end opposite the first end, and a cutting guide molding section defined between the first end and the second end. The cutting guide molding section may have a thickness that is greater than a thickness of each of the first and second ends.

In some embodiments, the cutting guide molding section may have a shorter width than the each of the first and second ends. Additionally, in some embodiments, the first and second cutting guide cores of the sacrificial chamfer cutting guide core may include an elongated body having a first end, a second end opposite the first end, and a cutting guide molding section defined between the first end and the second end. In such embodiments, each cutting guide molding section may have a thickness that is greater than a thickness of the corresponding first and second ends.

According to yet a further aspect of the present disclosure, a method for fabricating a polymer 4-in-1 cutting block for performing an orthopedic surgical procedure on a distal end of a patient's femur may include positioning a sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core into a polymer 4-in-1 cutting block mold, injecting a polymer into the mold to form the polymer 4-in-1 cutting block, and melting the sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core to produce the polymer 4-in-1 cutting block. Each of the sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core has a melting point lower than the polymer.

In some embodiments, injecting the polymer into the mold may include forming a polymer anterior cutting guide of the polymer 4-in-1 cutting block using the sacrificial anterior cutting guide core and forming a polymer chamfer cutting guide using the sacrificial chamfer cutting guide core. Additionally, in some embodiments, melting the sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core may include subjecting the polymer 4-in-1 cutting block including the sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core to a temperature of at least 550 degrees Fahrenheit.

Furthermore, in some embodiments, melting the sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core may include immersing the polymer 4-in-1 cutting block into a liquid bath having a temperature of at least 550 degrees Fahrenheit. Additionally, in some embodiments, each of the sacrificial anterior cutting guide core and the sacrificial chamfer cutting guide core is formed from a metal alloy having a melting point of 550 degrees Fahrenheit or less. In such embodiments, the method may further include reclaiming the metal alloy subsequent to melting the sacrificial anterior cutting guide core and a sacrificial chamfer cutting guide core.

DETAILED DESCRIPTION OF THE DRAWINGS

Terms representing anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etcetera, may be used throughout the specification in reference to the orthopaedic implants and surgical instruments described herein as well as in reference to the patient's natural anatomy. Such terms have well-understood meanings in both the study of anatomy and the field of orthopaedics. Use of such anatomical reference terms in the written description and claims is intended to be consistent with their well-understood meanings unless noted otherwise.

Referring initially to the figures in general, various embodiments of a single use orthopaedic surgical instrument are described below. As its name implies, the described single use orthopaedic surgical instrument is intended to be disposed of after use in a single orthopaedic surgical procedure. In the illustrative embodiments described herein, the orthopaedic surgical instrument is embodied as a single use all-polymer 4-in-1 cutting block for use in the surgical preparation of the patient's distal femur during a knee replacement procedure. As described in more detail below, each of the described embodiments of the single use all-polymer 4-in-1 cutting block may be used to perform various cuts of the distal end of the patient's femur, including an anterior cut, a posterior cut, and two chamfer cuts.

In each of the embodiments described below, the single use all-polymer 4-in-1 cutting block is formed using a corresponding injection molding procedure. As such, each of the described all-polymer 4-in-1 cutting blocks is formed from a polymer material. However, because the described 4-in-1 cutting blocks are designed to be all-polymer, certain design features are considered to facilitate the fabrication of the all-polymer 4-in-1 cutting blocks. An initial consideration is the particular polymer material used to form the all-polymer 4-in-1 cutting blocks. The polymer material may be selected so as to have a suitable rigidity and resistance to wear and debris production during the bone cutting procedures. For example, in some embodiments, the described all-polymer 4-in-1 cutting blocks may be formed from a polyetherimide-based resin that has been alloyed with a lubricant to minimize wear and with carbon fiber to increase strength and dimensional stability. However, in other embodiments, other types of polymers may be used to form the described all-polymer 4-in-1 cutting blocks. Another consideration is the geometrical design of each component of the various embodiments of the all-polymer 4-in-1 cutting block. That is, the particular shape and size of each component is selected to ensure each component can be properly fabricated from an injection molding procedure, while also properly coupling with other components to produce an assembled all-polymer 4-in-1 cutting block as described in more detail below.

It should be appreciated that each of the described embodiments of the all-polymer 4-in-1 cutting block differ from typical polymer cutting blocks in that they are devoid of any metal inserts, which are typically used to form the metal cutting guides. For example, a typical polymer 4-in-1 cutting block4700is shown inFIGS.47and48. The polymer 4-in-1 cutting block4700includes a body4702having an outer surface4704and a bone-engaging surface4706opposite the outer surface4704. The polymer 4-in-1 cutting block4700also includes a number of cutting guides, each formed from a corresponding metallic insert. For example, the polymer 4-in-1 cutting block4700includes an anterior cutting slot4720defined in the body4702toward an anterior end4710of the body4702. The anterior cutting slot4720is embodied as an elongated slot that extends in the medial/lateral direction and extends completely through the body4702(i.e., from the outer surface4704to the bone-engaging surface4706). A metallic anterior cutting guide4722is secured within the anterior cutting slot4720. The metallic anterior cutting guide4722is embodied as a captured cutting guide (i.e., it is closed on the anterior, posterior, medial, and lateral sides so as to capture a saw blade therein).

The polymer 4-in-1 cutting block4700also includes a posterior cutting surface4730formed on the body4702toward a posterior end4712of the body4702. The posterior cutting surface4730is embodied as an elongated surface that extends in the medial/lateral direction and extends completely across the body4702(i.e., from the outer surface4704to the bone-engaging surface4706). A metallic posterior cutting guide4732is secured to the posterior cutting surface4730. The metallic posterior cutting guide4732is embodied as a non-captured cutting guide, but may be embodied as a captured cutting guide in some embodiments.

Additionally, the polymer 4-in-1 cutting block4700includes a chamfer cutting slot4740defined in the body4702toward its middle section, between the anterior cutting slot4720and the posterior cutting surface4730. The chamfer cutting slot4740is embodied as an elongated slot that extends in the medial/lateral direction and extends completely through the body4702(i.e., from the outer surface4704to the bone-engaging surface4706). The chamfer cutting slot4740includes an anteriorly angled cutting slot4750and a posteriorly angled cutting slot4760, which extend away from each other as shown best inFIG.48. A metallic chamfer cutting guide4752is secured within the anteriorly angled cutting slot4750, and a metallic chamfer cutting guide4762is secured within the posteriorly angled cutting slot4760. Each of the metallic chamfer cutting guides4752,4762is embodied as a capture cutting guide, but may be embodied as a non-captured cutting guide in other embodiments.

Each of the metallic cutting guides4722,4732,4752,4762is sized and shaped to receive, or otherwise support, a surgical saw or other cutting instrument and properly orient the cutting blade to resect the corresponding area of the patient's femur during an orthopaedic surgical procedure. The metallic cutting guides4722,4732,4752,4762protect the polymer body4702of the polymer 4-in-1 cutting block4700, which is typically formed from a soft polymer material, from the saw blade during the orthopaedic surgical procedure. However, the inclusion of the metallic cutting guides4722,4732,4752,4762can increase the overall fabrication cost and complexity of the polymer 4-in-1 cutting block4700and limit or restrict the use of injection molding techniques to form the polymer 4-in-1 cutting block4700.

Referring now toFIGS.1-9, in an illustrative embodiment, an orthopaedic surgical instrument10is embodied as an all-polymer 4-in-1 cutting block100. The illustrative all-polymer 4-in-1 cutting block100includes a “plug” polymer half-block102and a “jack” polymer half-block202, which are sized and shaped to couple to each other as described in more detail below. Each of the plug polymer half-block102and the jack polymer half-block202form roughly one half of the all-polymer 4-in-1 cutting block100. As such, the plug polymer half-block102and the jack polymer half-block202have a similar size and shape in the illustrative embodiment, but may be differently sized and/or shaped in other embodiments.

The plug polymer half-block102includes a polymer body110having an outer surface112and a bone-engaging surface114opposite the outer surface112. The plug polymer half-block102also includes an anterior end116, a posterior end118opposite the anterior end116, and an inner sidewall120as shown inFIG.5. Similarly, the jack polymer half-block202includes a polymer body210having an outer surface212and a bone-engaging surface214opposite the outer surface212. The jack polymer half-block202also includes an anterior end216, a posterior end218opposite the anterior end216, and an inner sidewall220as shown inFIG.6. Additionally, each of the polymer bodies110,210includes a number of mounting apertures122,222, respectively, defined therethrough and configured to facilitate the attachment of the all-polymer 4-in-1 cutting block100to a distal end of the patient's surgically-prepared femur using corresponding securing devices, such as bone screws.

Each polymer half-block102,202includes a number of cutting slots, which cooperate to define cutting guides when the polymer half-blocks102,202are coupled together as discussed below. For example, the plug polymer half-block102includes an anterior cutting slot130defined in the polymer body110toward the anterior end116of the polymer body110. The anterior cutting slot130is embodied as an open-ended, elongated slot that extends in the medial/lateral direction and includes an opened end132defined on the inner sidewall120of the polymer body110as best shown inFIG.5. The anterior cutting slot130extends completely through the polymer body110(i.e., from the outer surface112to the bone-engaging surface114).

Additionally, the plug polymer half-block102includes a posterior cutting surface140formed on the polymer body110toward the posterior end118of the polymer body110. The posterior cutting surface140is embodied as an elongated surface that extends in the medial/lateral direction, ending at the inner sidewall120as shown inFIG.5. The posterior cutting surface140also extends completely through the polymer body110(i.e., from the outer surface112to the bone-engaging surface114).

The plug polymer half-block102also includes a chamfer cutting slot150defined in the polymer body110toward its middle section, between the anterior cutting slot130and the posterior cutting surface140. The chamfer cutting slot150is embodied as an open-ended, elongated slot that extends in the medial/lateral direction and includes an opened end152defined on the inner sidewall120of the polymer body110as best shown inFIG.5. Similar to the anterior cutting slot130, the chamfer cutting slot150extends completely through the polymer body110(i.e., from the outer surface112to the bone-engaging surface114). The chamfer cutting slot150includes an anteriorly angled cutting slot154and a posteriorly angled cutting slot156, which extend away from each other as shown best inFIG.5.

Similar to the plug polymer half-block102, the jack polymer half-block202includes an anterior cutting slot230defined in the polymer body210toward the anterior end216of the polymer body210. Similar to the anterior cutting slot130of the plug polymer half-block102, the anterior cutting slot230is embodied as an open-ended, elongated slot that extends in the medial/lateral direction and includes an opened end232defined on the inner sidewall220of the polymer body210as best shown inFIG.6. The anterior cutting slot230extends completely through the polymer body210(i.e., from the outer surface212to the bone-engaging surface214).

Additionally, the jack polymer half-block202includes a posterior cutting surface240formed on the polymer body210toward the posterior end218of the polymer body210. Similar to the posterior cutting surface140of the plug polymer half-block102, the posterior cutting surface240is embodied as an elongated surface that extends in the medial/lateral direction, ending at the inner sidewall220as shown inFIG.6. The posterior cutting surface240also extends completely through the polymer body210(i.e., from the outer surface212to the bone-engaging surface214).

The jack polymer half-block202also includes a chamfer cutting slot250defined in the polymer body210toward its middle section, between the anterior cutting slot230and the posterior cutting surface240. Again, similar to the anterior cutting slot130of the plug polymer half-block102, the chamfer cutting slot250is embodied as an open-ended, elongated slot that extends in the medial/lateral direction and includes an opened end252defined on the inner sidewall220of the polymer body210as best shown inFIG.6. The chamfer cutting slot250extends completely through the polymer body210(i.e., from the outer surface212to the bone-engaging surface214). The chamfer cutting slot250includes an anteriorly angled cutting slot254and a posteriorly angled cutting slot256, which extend away from each other as shown best inFIG.6.

When the jack polymer half-block202is coupled to the plug polymer half-block102, the various cutting slots of the polymer half-blocks102,202cooperate to define corresponding polymer cutting guides. For example, the anterior cutting slot130of the plug polymer half-block102is brought into fluid communication with the anterior cutting slot230of the jack polymer half-block202, and the anterior cutting slots130,230cooperate to define a polymer anterior cutting guide330, when the polymer half-blocks102,202are coupled together as best shown inFIG.8. Similarly, the posterior cutting surface140of the plug polymer half-block102is abutted to the posterior cutting surface240of the jack polymer half-block202, and the posterior cutting surfaces140,240cooperate to define a polymer posterior cutting guide340, when the polymer half-blocks102,202are coupled together as best shown inFIG.8. Additionally, the chamfer cutting slot150of the plug polymer half-block102is brought into fluid communication with the chamfer cutting slot250of the jack polymer half-block202, and the chamfer cutting slots150,250cooperate to define polymer chamfer cutting guide350, when the polymer half-blocks102,202are coupled together as best shown inFIG.8.

It should be appreciated that the polymer cutting guides330,340,350are devoid of any metallic cutting inserts or guides as used in typical polymer cutting blocks. Rather, each of the polymer cutting guides330,340,350is sized and shaped to receive, or otherwise support, a surgical saw or other cutting instrument, without the use of a metallic cutting insert, and properly orient the cutting blade to resect the corresponding area of the patient's femur during an orthopaedic surgical procedure. To reduce the likelihood of the saw blade catching at the seam of the polymer half-blocks102,202, the edge of each cutting slot/surface130,140,150,230,240,250at the corresponding inner sidewall120,220may be chamfered inwardly as illustratively shown via area800inFIG.8.

To facilitate the coupling of the plug polymer half-block102and the jack polymer half-block202, each of the polymer half-blocks102,202includes alignment features defined on/in their respective inner sidewalls120,220. For example, as shown inFIG.5, the plug polymer half-block102includes a number of alignment receptacles160defined in the inner sidewall120. Some of the alignment receptacles160may have simple geometric shape such as the cylindrical-shaped alignment receptacles160located toward the anterior end116of the polymer body110, while other alignment receptacles160may have complex geometric shapes. For example, some of the alignment receptacles160have a complex shape defined by the anterior cutting slot130, the posterior cutting surface140, and the chamfer cutting slot150as shown inFIG.5.

Conversely, as shown inFIG.6, the jack polymer half-block202includes a number of alignment protrusions260that extend from the inner sidewall220. Some of the alignment protrusions260may have simple geometric shape such as the cylindrical-shaped alignment protrusions260located toward the anterior end216of the polymer body210, while other alignment protrusions260may have complex geometric shapes. For example, some of the alignment protrusions260have a complex shape defined by the anterior cutting slot230, the posterior cutting surface240, and the chamfer cutting slot250as shown inFIG.6.

As shown inFIG.7, the plug polymer half-block102and the jack polymer half-block202may be coupled together by inserting the alignment protrusions260of the jack polymer half-block202into the corresponding alignment receptacles160of the plug polymer half-block102. When the polymer half-blocks102,202are coupled in this manner, the inner sidewall120of the plug polymer half-block102confronts the inner sidewall220of the jack polymer half-block202. The polymer half-blocks102,202may be subsequently secured to each other via use of one or more securing devices700, which may be formed from a metallic material such as, for example, steel, titanium alloy, or cobalt chromium alloy.

Referring now toFIG.9, each of the plug polymer half-block102and the jack polymer half-block202may be fabricated via an injection molding process. To do so, a corresponding molding core900for each polymer half-block102,202may be used. The molding core900may be formed any suitable material capable of withstanding the temperatures associated with the injection molding process. For example, in the illustrative embodiment, the molding core900is formed from a metallic material such as, for example, steel or a titanium alloy.

Each molding core900includes a number of negative mold features902, each of which extends from a base904. The negative mold features902include body features910, which are sized, shaped, and position to define the various walls of the polymer bodies110,210. Additionally, the negative mold features902include cutting slot features912, which are sized, shaped, and position to define the anterior cutting slots130,230and the chamfer cutting slots150,250.

Referring now toFIG.10, a method1000may be used to fabricate the all-polymer 4-in-1 cutting block100. The method1000begins with block1002in which each of the plug polymer half-block102and the jack polymer half-block202are fabricated. For example, in block1004, the plug polymer half-block102may be injection molded using a plug molding core900as described above. Similarly, in block1006, the jack polymer half-block202may be injection molded using a jack molding core900as described above. The particular injection molding process used (e.g., the temperature and length of the molding process) may depend on various factors including, for example, the particular type of polymer used.

After the polymer half-blocks102,202have been formed, the polymer half-block102,202are cleaned in block1008. The cleaning process removes any extraneous polymer pieces from the polymer half-blocks102,202. Additionally, fine detailing of the polymer half-blocks102,202may be performed in block1008. For example, the various cutting slots130,230,140,240,150,250may be cleaned or further machined to ensure a cleaned and planar cutting guide.

Subsequently, in block1010, the plug polymer half-block102and the jack polymer half-block202are coupled together. To do so, in block1012, the alignment protrusions260of the jack polymer half-block202are received in the alignment receptacles160of the plug polymer half-block102as discussed above. The polymer half-blocks102,202may then be secured together in block1014. For example, as discussed above, the polymer half-blocks102,202may be secured to each other via use of the securing devices700as discussed above in regard toFIG.7.

Referring now toFIGS.11-23, in another illustrative embodiment, the orthopaedic surgical instrument10is embodied as an all-polymer 4-in-1 cutting block1100. The illustrative all-polymer 4-in-1 cutting block1100includes a polymer body1110having an outer surface1112and a bone-engaging surface1114opposite the outer surface1112. The polymer body1110also includes an anterior end1116and a posterior end1118opposite the anterior end1116. Additionally, the polymer body1110includes a number of mounting apertures1120defined therethrough and configured to facilitate the attachment of the all-polymer 4-in-1 cutting block1100to a distal end of the patient's surgically-prepared femur using corresponding securing devices, such as bone screws.

The polymer body1110of the all-polymer 4-in-1 cutting block1100also includes a polymer anterior cutting guide1130, a polymer posterior cutting guide1140, and a polymer chamfer cutting guide1150. As best shown inFIG.14, the anterior cutting guide1130is embodied as a captured cutting slot1132that extends from the outer surface1112to the bone-engaging surface1114of the polymer body1110. The polymer posterior cutting guide1140is embodied as a posterior cutting surface1142that also extends from the outer surface1112to the bone-engaging surface1114of the polymer body1110. The polymer chamfer cutting guide1150is formed from a captured anteriorly-angled cutting slot1152and a captured posteriorly-angled cutting slot1154, which intersect each other and extend from the outer surface1112to the bone-engaging surface1114of the polymer body1110.

As shown inFIGS.15-23and described in more detail below, each of the polymer anterior cutting guide1130and the polymer chamfer cutting guide1150is formed during an injection molding process using an anterior cutting guide core1500, an anterior chamfer cutting guide core1600, and a posterior chamfer cutting guide core1700. Each of the cores1500,1600,1700are formed from a metallic material, such as steel or a titanium alloy, having a melting point high enough to withstand the temperatures of the injection molding process.

As shown inFIGS.17and18, the anterior cutting guide core1500is used during the injection molding process to define the captured cutting slot1132, which defines the polymer anterior cutting guide1130. The anterior cutting guide core1500includes a planar body1502having an anterior cutting guide molding end1504and a handle end1506opposite the anterior cutting guide molding end1504. The handle end1506may be used to properly position the anterior cutting guide core1500, and the anterior cutting guide molding end1504is configured to form the captured cutting slot1132during the injection molding process. As shown inFIG.18, the handle end1506has width1510that is greater than a width1512of the anterior cutting guide molding end1504.

As shown inFIGS.19-23, the anterior chamfer cutting guide core1600and the posterior chamfer cutting guide core1700are configured to couple to each other and used during the injection molding process to define the captured anteriorly-angled cutting slot1152and the captured posteriorly-angled cutting slot1154, which cooperate to define the polymer chamfer cutting guide1150.

As shown best inFIG.20, the illustrative posterior chamfer cutting guide core1700includes a planar body1702having a chamfer cutting guide molding end1704and a handle end1706opposite the chamfer cutting guide molding end1704. Similar to the anterior cutting guide core1500, the handle end1706of the posterior chamfer cutting guide core1700may be used to properly position the posterior chamfer cutting guide core1700. The chamfer cutting guide molding end1704is configured to form the posteriorly-angled cutting slot1154during the injection molding process.

The planar body1702of the posterior chamfer cutting guide core1700also includes a medial side1710and a lateral side1714opposite the medial side1710. A medial side-rail1712is attached to the medial side1710of the planar body1702, and a lateral side-rail1716is attached to the lateral side1714. The side-rails1712,1716improve the rigidity of the planar body1702, which may allow the planar body1702to have a smaller thickness than otherwise would be obtainable without the additional support provided by the side-rails1712,1716. The posterior chamfer cutting guide core1700also includes a medial stop flange1722and a lateral stop flange1726. The medial stop flange1722is attached to the medial side-rail1712and extends outwardly therefrom, and the lateral stop flange1726is attached to the lateral side-rail1716and extends outwardly therefrom. As such, the stop flanges1722,1726define a width1730of the handle end1706that is greater than a width1732of the chamfer cutting guide molding end1704as shown inFIG.20. The planar body1702also includes a slot1750defined therethrough. As shown inFIG.19and described in more detail below, the slot1750is shaped and sized so as to allow the anterior chamfer cutting guide core1600to be inserted through the planar body1702of the posterior chamfer cutting guide core1700.

The anterior chamfer cutting guide core1600is substantially similar to the posterior chamfer cutting guide core1700. For example, as shown best inFIG.22, the illustrative anterior chamfer cutting guide core1600includes a planar body1602having a chamfer cutting guide molding end1604and a handle end1606opposite the chamfer cutting guide molding end1604. Again, similar to the anterior cutting guide core1500, the handle end1606of the anterior chamfer cutting guide core1600may be used to properly position the anterior chamfer cutting guide core1600. The chamfer cutting guide molding end1604is configured to form the anteriorly-angled cutting slot1152during the injection molding process.

The planar body1602of the anterior chamfer cutting guide core1600also includes a medial side1610and a lateral side1614opposite the medial side1610. A medial side-rail1612is attached to the medial side1610of the planar body1602, and a lateral side-rail1616is attached to the lateral side1614. The side-rails1612,1616improve the rigidity of the planar body1602, which may allow the planar body1602to have a smaller thickness than otherwise would be obtainable without the additional support provided by the side-rails1612,1616as discussed above. The anterior chamfer cutting guide core1600also includes a medial stop flange1622and a lateral stop flange1626. The medial stop flange1622is attached to the medial side-rail1612and extends outwardly therefrom, and the lateral stop flange1626is attached to the lateral side-rail1616and extends outwardly therefrom. As such, the stop flanges1622,1626define a width1630of the handle end1606that is greater than a width1632of the chamfer cutting guide molding end1604as shown inFIG.22.

Referring now toFIG.24, in use, a method2400may be executed for fabricating the all-polymer 4-in-1 cutting block1100. The method2400begins with block2402in which the anterior chamfer cutting guide core1600and the posterior chamfer cutting guide core1700are coupled together. To do so and depending on the particular embodiment, the anterior chamfer cutting guide core1600may be inserted into the slot1750of the planar body1702of the posterior chamfer cutting guide core1700in block2404. Alternatively, in other embodiments, the posterior chamfer cutting guide core1700may be inserted into a slot defined in the planar body1602of the anterior chamfer cutting guide core1600in block2406.

Regardless, after the chamfer cutting guide cores1600,1700have been coupled to each other, the anterior cutting guide core1500and the chamfer cutting guide cores1600,1700are positioned and aligned into the injection mold in block2408. In block2410, the all-polymer 4-in-1 cutting block1100is formed via an injection modeling process and using the cutting guide cores1500,1600,1700. In doing so, in block2412, the anterior cutting guide core1500forms the polymer anterior cutting guide1130and the chamfer cutting guide cores1600,1700cooperate to define the polymer chamfer cutting guide1150.

After the all-polymer 4-in-1 cutting block1100has been fabricated in block2410, the method2400advances to block2414. In block2414, the cutting guide cores1500,1600,1700are removed from the all-polymer 4-in-1 cutting block1100. To do so, the anterior chamfer cutting guide core1600may be initially removed from the all-polymer 4-in-1 cutting block1100by sliding the anterior chamfer cutting guide core1600through the slot1750of the planar body1702of the posterior chamfer cutting guide core1700and from the all-polymer 4-in-1 cutting block1100. After the anterior chamfer cutting guide core1600has been so removed, the posterior chamfer cutting guide core1700may be subsequently removed from the all-polymer 4-in-1 cutting block1100.

Referring now toFIGS.25-33, in another illustrative embodiment, the orthopaedic surgical instrument10is embodied as an all-polymer 4-in-1 cutting block2500. The illustrative all-polymer 4-in-1 cutting block2500includes a polymer body2510and a polymer chamfer cutting guide insert2570configured to be coupled to the polymer body2510as discussed in more detail below. The polymer body2510includes an outer surface2512and a bone-engaging surface2514opposite the outer surface2512. The polymer body2510also includes an anterior end2516, a posterior end2518opposite the anterior end2516, a medial side2522, and a lateral side2524opposite the medial side2522. Additionally, the polymer body2510includes a number of mounting apertures2520defined therethrough and configured to facilitate the attachment of the all-polymer 4-in-1 cutting block2500to a distal end of the patient's surgically-prepared femur using corresponding securing devices, such as bone screws.

The polymer body2510of the all-polymer 4-in-1 cutting block2500also includes a polymer anterior cutting guide2530and a polymer posterior cutting guide2540. As best shown inFIG.33, the anterior cutting guide2530is embodied as a captured cutting slot2532that extends from the outer surface2512to the bone-engaging surface2514of the polymer body2510. The polymer posterior cutting guide2540is embodied as a posterior cutting surface2542that also extends from the outer surface2512to the bone-engaging surface2514of the polymer body2510.

The polymer body2510also includes a chamfer cutting guide recess2560positioned between the polymer anterior cutting guide2530and the polymer posterior cutting guide2540. The chamfer cutting guide recess2560is embodied as an elongated recess that extends from the outer surface2512to the bone-engaging surface2514of the polymer body2510. In particular, the chamfer cutting guide recess2560includes an opening2562located on the outer surface2512and an opening2564located on the bone-engaging surface2514that is larger than the opening2562. The opening2564of the chamfer cutting guide recess2560is shaped and sized to receive the polymer chamfer cutting guide insert2570as best shown inFIG.27. When the polymer chamfer cutting guide insert2570is received in the chamfer cutting guide recess2560, the polymer chamfer cutting guide insert2570and the polymer body2510cooperate to define a polymer chamfer cutting guide2550. Illustratively, the polymer chamfer cutting guide insert2570and the opening2564each have a corresponding triangular cross-sectional shape that defines an anteriorly-angled cutting slot2552and posteriorly angled cutting slot2554, which extend away from each other as shown best inFIG.33.

To facilitate the attachment of the polymer chamfer cutting guide insert2570to the polymer body2510, the polymer body2510and the polymer chamfer cutting guide insert2570include features arranged to mate with each other. For example, the illustrative polymer body2510includes a medial guide track2582defined on the medial side2522and a lateral guide track2584defined on the lateral side2524. And, the illustrative polymer chamfer cutting guide insert2570includes a medial guide arm2572extending from a medial side2576and a lateral guide arm2574extending from a lateral side2578. As shown inFIGS.26and27, the medial guide arm2572is configured to be received in the medial guide track2582and the lateral guide arm2574is configured to be received in the lateral guide track2584when the polymer chamfer cutting guide insert2570is coupled to the polymer body2510. The polymer chamfer cutting guide insert2570may be secured to the polymer body2510via use of pair of securing devices2590, which may be received through corresponding non-threaded apertures2592of the polymer chamfer cutting guide insert2570and threaded into threaded apertures2594of the polymer body2510.

Referring now toFIG.34, the above-described all-polymer 4-in-1 cutting block2500may be used in a method3400for performing an orthopaedic surgical procedure. The method3400begins with block3402in which the all-polymer 4-in-1 cutting block2500is assembled. To do so, in block3404, the polymer chamfer cutting guide insert2570is attached to the polymer body2510. As discussed above, the polymer chamfer cutting guide insert2570may be received in the chamfer cutting guide recess2560of the polymer body2510. In doing so, the guide arms2572,2574of the polymer chamfer cutting guide insert2570are received in the guide tracks2582,2584of the polymer body in block3406. In block3408, the polymer chamfer cutting guide insert2570is secured to the polymer body2510via the securing devices2590.

In block3410, the assembled all-polymer 4-in-1 cutting block2500is secured to a surgically-prepared distal end of the patient's femur. For example, the all-polymer 4-in-1 cutting block2500may be secured to the patient's femur using bone screws and/or pins, similar to a typical 4-in-1 cutting block. In block3412, an orthopaedic surgeon may perform a femoral resectioning procedure using the assembled all-polymer 4-in-1 cutting block2500. For example, the orthopaedic surgeon may perform an anterior femoral cut using the polymer anterior cutting guide2530, a posterior femoral cut using the polymer posterior cutting guide2540, and a pair of chamfer cuts using the polymer chamfer cutting guide2550.

Referring now toFIGS.35-45, in another illustrative embodiment, the orthopaedic surgical instrument10is embodied as an all-polymer 4-in-1 cutting block3500. The illustrative all-polymer 4-in-1 cutting block23500includes a polymer body3510having an outer surface3512and a bone-engaging surface3514opposite the outer surface3512. The polymer body3510also includes an anterior end3516and a posterior end3518opposite the anterior end3516, a medial side2522, and a lateral side2524opposite the medial side2522. Although not shown in the illustrative figures, the polymer body3510may also a number of mounting apertures defined therethrough and configured to facilitate the attachment of the all-polymer 4-in-1 cutting block3500to a distal end of the patient's surgically-prepared femur using corresponding securing devices, such as bone screws.

The polymer body3510of the all-polymer 4-in-1 cutting block3500also includes a polymer anterior cutting guide3530, a polymer posterior cutting guide2540, and a polymer chamfer cutting guide3550. As best shown inFIG.45, the anterior cutting guide3530is embodied as a captured cutting slot3532that extends from the outer surface3512to the bone-engaging surface3514of the polymer body3510. The polymer posterior cutting guide3540is embodied as a posterior cutting surface3542that also extends from the outer surface3512to the bone-engaging surface3514of the polymer body3510. The polymer chamfer cutting guide3550is formed from a captured anteriorly-angled cutting slot3552and a captured posteriorly-angled cutting slot3554, which intersect each other and extend from the outer surface3512to the bone-engaging surface3514of the polymer body3510.

As shown inFIGS.38-45and described in more detail below, each of the polymer anterior cutting guide3530and the polymer chamfer cutting guide3550is formed during an injection molding process using a sacrificial anterior cutting guide core3800and a sacrificial chamfer cutting guide core3900, respectively. The cutting guide cores3800,3900are “sacrificial” in that they melted away from the polymer body3510after the polymer body3510has been formed via an injection molding process as described in more detail below. To facilitate such sacrificial removing, each of the cutting guide cores3800,3900is formed from a metal material (e.g., a metal alloy) having a melting point that is lower than the polymer used to form the polymer body3510. For example, in the illustrative embodiment, the cutting guide cores3800,3900are formed from a metal material having a melting point of 550 degrees Fahrenheit or less, such as a tin bismuth alloy.

As shown inFIGS.39-45, the sacrificial anterior cutting guide core3800is used during the injection molding process to define the captured cutting slot3532, which defines the polymer anterior cutting guide3530. The anterior cutting guide core3800includes an elongated body3802having a first end3804, a second end3806opposite the first end3804, and a cutting guide molding section3808defined between the first end3804and the second end3806. As best shown inFIG.42, the cutting guide molding section3808has a thickness that is greater than the thickness of the first end3804and the second end3806.

Similar to the sacrificial anterior cutting guide core3800, the sacrificial chamfer cutting guide core3900is used during the injection molding process to define the captured anteriorly-angled cutting slot3552and the captured posteriorly-angled cutting slot3554, which cooperate to define the polymer chamfer cutting guide3550. The illustrative sacrificial chamfer cutting guide core3900includes an anteriorly-angled cutting guide core3902and a posteriorly angled cutting guide core3904, which extend through each other as best shown inFIG.43. The anteriorly-angled cutting guide core3902and the posteriorly angled cutting guide core3904extend away from each other at an oblique angle. Each of the anteriorly-angled cutting guide core3902and the posteriorly angled cutting guide core3904includes an elongated body4002having a first end4004, a second end4006opposite the first end4004, and a cutting guide molding section4008defined between the first end4004and the second end4006. As best shown inFIG.44, each cutting guide molding section4008has a thickness that is greater than the thickness of the corresponding first end4004and the second end4006.

Referring now toFIG.46, a method4600for fabricating the all-polymer 4-in-1 cutting block3500is shown. The method4600begins with block4602in which the sacrificial anterior cutting guide core3800and the sacrificial chamfer cutting guide core3900are formed or otherwise obtained. As discussed above, each of the cutting guide cores3800,3900is formed from a metal alloy or material having a relatively low melting point (i.e., a melting point that is less than the melting point of the polymer used to form the all-polymer 4-in-1 cutting block3500).

In block4604, the cutting guide cores3800,3900are positioned in an injection mold of the all-polymer 4-in-1 cutting block3500. The injection mold is subsequently sealed and injected with a polymer in block4606to form the all-polymer 4-in-1 cutting block3500.

After the all-polymer 4-in-1 cutting block3500has been formed in block4606, the method4600advances to block4608in which the cutting guide cores3800,3900are removed from the all-polymer 4-in-1 cutting block3500. To do so, in the illustrative embodiment, the cutting guide cores3800,3900are melted away from the all-polymer 4-in-1 cutting block3500. For example, in block4610, the all-polymer 4-in-1 cutting block3500with the cutting guide cores3800,3900installed therein may be immersed in a liquid bath having a temperature greater than the melting temperature of the cutting guide cores3800,3900, which causes the cutting guide cores3800,3900to melt away from the all-polymer 4-in-1 cutting block3500.

In block4612, the resulting all-polymer 4-in-1 cutting block3500may be cleaned. The cleaning process may remove any extraneous polymer pieces from the all-polymer 4-in-1 cutting block3500. Subsequently, in block4614, the melted metal or metal alloy may be reclaimed from the liquid bath and reused in a subsequent polymer cutting block fabrication process.