Patent Application
20190314043
The present invention relates to tools and equipment for drilling holes more particularly to such tools capable of use, but not exclusively in orthopaedic surgery. The invention further relates to an assembly including a cutting tool and cooperating guide which allow a first cut using the cutting tool and a second cut using the cutting guide. Although the invention is particularly suited to bone cutting in at least orthopaedic surgery, it will be appreciated that the tools can be adapted for use in cutting hard materials other than bone. The invention will primarily be described with reference to its application in orthopaedic surgery and with particular reference to use in repair of the anterior cruciate ligament in the human knee. The invention further relates to an assembly which enables formation of a tapered cut using a first cutter and a co-operating guide which enables and provides alignment for a secondary cut by a second cutting tool. The assembly allows the creation of a cut profile in which the opening has a narrow region and a wide region resulting in a wedge shaped component.
Cruciate ligaments occur in the knee of humans and other bipedal animals and in the neck, fingers, and foot. The cruciate ligaments of the knee are the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). These ligaments are two, strong, generally rounded, bands of varying cross sections along their length that extend from the head of the tibia to the intercondyloid notch of the femur. The ACL femoral attachment is lateral and the PCL is medial. Due to a twist or rotation along the length of the ligament the proximal and distal ends are disposed so they cross each other like the limbs of an X. In other words their respective anchorages are in a sense out of phase. This makes the cruciate ligament a complex structure with a complex anatomical geometry. The ACL and PCL remain distinct throughout and each has its own partial synovial sheath. Relative to the femur, the ACL keeps the tibia from slipping forward and the PCL keeps the tibia from slipping backward. It is a critical ligament for posterior/anterior knee stability. ACL injuries are among the most common knee injuries suffered by sports people. A ruptured ACL can occur by a movement as benign as a sudden change of direction or in more traumatic impact such as falling awkwardly in a tackle and abnormal knee extensions. Anatomical characteristics of a particular individual may predispose one individual to an ACL rupture more so than another individual engaged in the same knee extension, trauma, impact etc. After an ACL reconstruction patients have varying degrees of successful results in that some can return to high level sports whereas others must be content with retirement from sports. Prognosis post-surgery can depend upon the quality of the ligament repair and the method of repair or reconstruction used in surgical treatment. After surgery patients are concerned about the risk of repeating the injury particularly if attempting a return to high level sports, in which the knee is loaded and stressed. The incidence of Anterior Cruciate Ligament (ACL) tears requiring surgery is about 50 per 100,000 in the general population in Australia. Males are more likely than females to rupture an ACL as a result of sports injuries. Prognostic factors in determining outcomes of ACL repairs include age, gender, timing of surgeries and other concomitant injuries such as cartilage and meniscal injuries.
One of the difficulties faced by surgeons in ACL or PCL repair is the loss of natural cruciate ligament tissue when ruptured. Each individual has a cruciate of finite length. If ruptured, the tissue at opposing ends at the rupture becomes frayed. In a case where the elected surgical method requires the frayed ends to be sewn together the loss of tissue length can inhibit an optimal result and inevitably results in failure of the ligament to heal compromising knee stability and the development of instability. In cases where the cruciate ligament cannot be sewn back together grafts can be employed as a substitute for the ruptured cruciate ligament.
A knee reconstruction can involve repair of the cruciate ligament or use of grafts. A graft for example may be harvested from the patella tendon in the knee—a bone patellar tendon bone autograft,—or from the hamstring—autogenous hamstring tendons. Surgical outcomes can be dependent upon the type of graft used for the repair, age and gender of the patient, durability of the graft. In high level sports a patellar tendon graft may be the preferred selection but a hamstring graft can work just as well in male or female patients. In a graft repair the ends of the graft must be anchored to femoral and tibial bone to simulate as far as is anatomically possible the natural anchorage of the cruciate ligament to bone. Screws and rods are used to effect an anchorage of the new graft but a graft is not usually as strong as the natural anatomy of the cruciate ligament. As the cruciate ligament has a complex structure and a unique geometry a tendon harvested from another site although very often effective in a repair is not ideal.
An ideal repair method is to re-join if possible the anterior cruciate ligament in the knee if there is sufficient length of the ligament left after the rupture. It can be very difficult to re-join ruptured cruciate ends due to the loss of length on rupture indicated earlier. If possible, the ends are stitched together but they must be stretched to a tension beyond the cruciate ligament's normal rest tension. Post-operative physiotherapy is then used in an attempt to regain as much of the original knee function and range of movement existing before the ACL rupture.
The current gold standard treatment option for mid-substance ACL tear is reconstruction with patellar or hamstring tendon autografts. The operation generally yields good results in many patients, although it carries an approximately 3% revision rate at 5 years. The reported rates of patients returning to pre-injury activity levels range widely from 26% to 90%. That means 10-74% patients did not have excellent results after the operation, indicating that there is still room for improvements in regards to ACL repair procedures.
There are two intrinsic surgical difficulties encountered with the current standard surgical treatment of ACL rupture. Firstly, the human ACL is not a simple cylindrical structure but has a complex anatomy consisting of at least 2 rotary bundles which are difficult to replicate. Secondly, the ACL tibial and especially femoral attachment sites have an ellipsoid rather than a circular footprint which has not been successfully reproduced by the single, double or four stranded ACL graft repairs that are currently used.
Primary repair of the ACL trialled in the past encountered the problem of non-union and subsequent failure of the ligament. The reason that many intra articular tissues fail to heal has been attributed to the lack of blood supply and fibroblastic proliferation. However, histological studies of ruptured ACL revealed that the proliferation of fibroblasts and angiogenesis does occur in ruptured ACLs and therefore ACL should have the healing potential similar to other ligamentous tissues.
There are histological reasons which may explain why repaired ligaments fail.
1. The expression of actin-containing smooth muscle cells in the synovial tissue results in the retraction and the formation of a gap between the ACL ends which prevents the healing process;
2. The subsequent formation of synovial tissue over the discontinuous ruptured ACL ends has been postulated to further impede the ACL healing process. It is hypothesised that the overlay of the two ruptured ACL ends could potentially overcome the problem of the gap formation and non-union in primary ACL repair.
In mid-substance Achilles tendon ruptures, a primary repair yields excellent results as the frayed ends are sutured together in an overlaying manner. A significant outcome-modifying measure in the primary repair of an Achilles tendon is the ability to overlay the two ends by plantar-flexing the ankle joint. The same significant outcome-modifying measure has not been possible in the past with the primary repair of the ACL as the frayed ends could not be overlayed due to loss of length from rupture.
There is an ongoing need to constantly explore ways to improve the apparatus and equipment for Cruciate and other ligament repairs and to increase the success rate of surgical repair of ligaments. More generally there is an ongoing need to constantly improve tooling and cutting devices including, but not limited to, those used in orthopaedic surgery.
The present invention provides a tool assembly for cutting an opening relatively hard materials such as bone and includes a cutter which forms an opening for a co -operating cutting guide having an opening which receives a second cutter which completes cutting of the opening. The invention also provides a cutting tool and guide assembly for creating holes including such holes required in bone surgery. The invention further provides an assembly including a cutting tool providing a first cut and co-operating guide which allows a second cut using a second cutting blade. Although the invention is particularly suited to bone cutting in at least orthopaedic surgery, it will be appreciated that the tools can be adapted for use in cutting hard materials other than bone. The invention will primarily be described with reference to use in repair of the anterior cruciate ligament in the human knee. The invention further relates to an assembly which enables formation of a tapered cut using a first cutter and a cooperating guide which enables and provides alignment for a secondary cut by a second cutting tool thereby creating a tapered wedge from the cut profiles. The assembly allows the creation of a cut profile in which the opening formed has a narrow region and a wide region resulting in a wedge shaped component.
With this in mind the present invention provides a surgical tool assembly including a tool which enables tapered cutting to allow advancement and retraction of a bone core with or without ligament or tendon attached during a surgical procedure for repair of a ligament or tendon. More particularly the invention provides a cutting tool and associated cutting guide, the tool capable of drilling out a bone core from surrounding bone to enable advancement and retraction of the core so that the distance between ends of a soft tissue structure such as a ligament can be adjusted to allow either abutment or overlap of ends during repair. The invention further provides an assembly which includes a tool which allows repair of a ruptured tendon without using a graft.
More particularly the invention provides a cutting tool and guide which enables the creation of a tapered bone core which can be freed from surrounding bone to enable advancement and retraction of the tapered core. The invention further relates to a surgical kit including a cutting tool and cutting guide tool which allows a user to fashion a tapered core of bone (with or without tendon or ligament attached) and which can move relative to surrounding bone for altering the distance between a soft tissue anchored to the core for repair of ruptured soft tissues such as ligaments and the like.
Outlined broadly below are embodiments and features of the invention to enable the invention to be better understood, and in order that the present contribution to and improvement over the current the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways in various anatomical sites including in veterinary applications. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other variations on the tool assembly, structures, methods and systems for carrying out the purposes of the present invention.
It is one an object of the present invention to provide a new and improved cutting tool which removes the practical disadvantages encountered in surgical repair of an ACL and other cruciate ligaments. It is a further object of the present invention to provide a new and improved tool assembly including the cutting tool and guide for the above purpose and which is of a durable and reliable construction. A further object of the invention is to provide tooling which enables an alternative to autographing a torn ACL, and enables end-to-end repair of the ACL itself. In the past, it has not been possible to primarily repair a torn ACL, as both ends are anchored to the bone, and the central body ligament shred cannot be over-lapped and repaired. By using a cutting tool and associated guide a tapered cut is created which allows advancing a tibia core of bone with the attached ACL stump, say 0.5-1.0 cm, it is then possible to arthroscopically (or open) repair the tear with overlap. By cutting a tapered cut (preferably trapezoidal or tapering cone shaped bone plug (with the ACL still attached)), it is possible to advance and lock the bone in its canal, fix it solidly, and repair the ligament while maintaining alignment of the natural complex orientation of the ACL bundles.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
In one broad form the present invention comprises:
According to a preferred embodiment, the cutting tool comprises a generally arcuate body with a wide proximal portion tapering to a narrow distal portion. The body includes cutting edges extending from the proximal to the distal end with a cutting profile there along formed by an array of cutting teeth.
In another broad form the present invention comprises:
In another broad form the present invention comprises:
According to a preferred embodiment the cutting tool creates a profiled cut which cut receives a cutting guide. The cutting guide comprises a curved tapered body and at one end an opening which receives extending therethrough a second cutting blade which completes the tapered cut formed by the cutting tool.
Preferably the power tool induces a reciprocating rotational cutting action in the cutting tool thereby creating an arcuate cut in the material. According to one embodiment the material cut by the cutting tool is bone.
Preferably the cutting tool at least partially curved having a first end which engages a powered activation tool and a second tapered end which includes a cutting edge profile. The cutting edge profile is formed by a continuous array of teeth extending from a proximal region on the tool to a distal end and then from the distal end to a second proximal region. The guide which co-operates with the cutting tool has a similar profile and is insertable into a first cut made by the cutting tool. The guide includes an opening which receives and guides a second cutting implement which makes a secondary cut in the bone, the first and second cuts creating a tapered bone portion releasable from the surrounding bone.
In another broad form the present invention comprises:
According to one embodiment the hard material is bone.
In another broad form the present invention comprises:
an assembly for cutting bone during a ligament reconstruction procedure, the assembly comprising: a guide for insertion of a pilot wire;
a bone cutting tool operable by a power tool to effect a tapered cut in the bone;
a guide member insertable in the tapered cut made by the cutting tool; the guide member having an opening which receives a cutting blade which completes the tapered cut.
The cutting tool is adapted for cutting bone which retains part of a ligament. The invention described herein is adaptable for the repair/reattachment of a variety of ligaments when shortened on rupture.
The cutting tool and associated guide form a variety of prismic shapes including cylindrical or trapezoidal sections of bone isolated from a bone site. Preferably, the cut section of bone is one that has a ligament attached to one face so that the cut bone can advance in the direction of the ligament. According to a preferred embodiment the ligament is the cruciate ligament.
The present invention provides an alternative to the known prior art and the shortcomings identified. The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying representations, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying illustrations, like reference characters designate the same or similar parts throughout the several views. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
The present invention will now be described in more detail according to a preferred embodiment but non limiting embodiment and with reference to the accompanying illustrations. The examples referred to herein are illustrative and are not to be regarded as limiting the scope of the invention. While various embodiments of the invention have been described herein, it will be appreciated that these are capable of modification, and therefore the disclosures herein are not to be construed as limiting of the precise details set forth, but to avail such changes and alterations as fall within the purview of the description. Although the assembly incorporating the cutting tool and cutting guide will be described with reference to its use in anterior cruciate ligament repair it will be appreciated that the assembly has other applications where tapered cuts and tapered cores are required.
One of the difficulties faced by surgeons in ACL or PCL repair is the loss of natural cruciate ligament tissue when ruptured. Each individual has a cruciate of finite length. If ruptured, the tissue at opposing ends of the rupture becomes frayed. In a case where surgical treatment requires the frayed ends to be sewn together the loss of tissue length can inhibit an optimal result and inevitably results in failure of the ligament to heal which compromises joint stability leaving the joint unstable. In cases where the cruciate ligament cannot be sewn back together grafts can be employed as a substitute for the ruptured cruciate ligament.
Referring to
As shown in
The steps below highlight a preferred technique adopted using the cutting assembly. The surgeon arthroscopes the knee, then performs a mini open medial arthrotomy with a mini medial upper tibia incision. Using a standard Anterior Cruciate Ligament alignment jig, the length of the trapezoidal cone shaped piece of bone is measured from the length of wire internal exit point to the external tibia entry point. Using the ACL alignment jig (+/− computer guidance), the guide wire is drilled into the centre of the tibia attachment of the ACL. The ACL alignment jig, is removed leaving in the guide wire.
Using the guide wire the cannulated ˜300° rotating cutting tool 30 employs its cutting edges 39, 40 and 41 is advanced up to the inner tibial cortex, cutting an approximately 300° curved channel in the tibia. At this stage, the cutting is partially complete. A separate and secondary cut is required to complete release of the tapered bone core. Prior to the secondary cut a guide 50 is inserted into the curved cut made by cutting tool 30.
The cut formed by cutting tool 30 defines at its proximal end an arc greater than 180 degrees and at its distal end an arc less than 180 degrees. This naturally forms a tapered cut. Once guide 50 is in position, a known flat straight saw blade 62 cuts an oblique angled track accurately (−5 degree angle) into the bone. This secondary cut releases the cut bone core 80 (which is preferably in the form of a tapered cone) from its surrounding bone and enables the tapered bone component to advance in the direction of the anterior cruciate ligament. As a result of the secondary cut a flat region on the bone core prevents unwanted rotation of the cut bone core 80. It is desirable to prevent rotation of the freed bone segment 80 to avoid misalignment between the severed ends of the ACL. Bone core 80 is close to a cone shape and becomes wedged when it advances along the cut. The male cone shaped bone is advanced proximally after being advanced ˜0.5 cms. It then locks into the female similar shaped cone and is locked by an interference screw.
With cutting tool 30 and guide 50 an angled track is cut to create the trapezoidal cone shaped bone (with the ACL attached) within the tibia. The trapezoid/cone of bone (with its attached ACL distal stump) is now free within its similarly shaped bone canal to be advanced in the direction of the ACL to allow an overlap which can then be repaired. The tapering bone+ACL stump is advanced about ˜½-1 cm to lock bone core 80 into the corresponding tapering tunnel in the tibia formed by the cut. The angle of the trapezoidal/cone shape has been calculated so that the bone+ACL stump does advance the required amount.
The two torn components of the ACL are now overlapped, ready for suturing. Optimally, bone anchors are implanted into the femur just adjacent to the proximal ACL footprint. The ACL is repaired with Bunnell type sutures, tied off at the base of the ACL footprint of the tibia. The sutures are optionally then passed down the sides of the trapezoidal tibial bone. The sutures are tied over an EndoButton after applying traction to tighten the ACL repair & the tibial bone segment.
One method of performing an ACL repair using the assembly and associated jig is described below. A minimally invasive mini medial arthrotomy incision is made approximately 3 cm in size. An ACL alignment jig is used to guide and drill a say 1.5 mm Kirschner wire into the centre of the proposed tibial bone core 80 exiting the centre of the distal ACL tibial attachment 7a. The bone core 80 containing the distal ACL segment 7a is cut in the tibia with the cutter tool 30 guided by the alignment of the pilot wire. The diameter of the tibial bone core cut by the crown saw would vary depending upon patient size but the size of core 80 would be in the region of 12, 14 or 16 mm depending on patient size.
Using a round punch, the tibial bone core is advanced up its tunnel for approximately 5 mm to allow overlap and end 7a-to-end 7b repair of the central body ACL rupture. A bone anchor is then inserted over each side of the proximal attachment of the ACL to the femur. Using a say Bunnell type suture, the two ends of the torn ACL 7a and 7b will be repaired via a medial arthrotomy. This may be performed using an arthroscopic procedure.
The bone core is then retrieved down its tunnel by either
a.) traction on the suture which is tied firmly over the tibia with an endobutton or similar apparatus; or
b.) pushing the tibial bone core down via access from the medial arthrotomy, leaving mild tension only at the repair site. The bone core is anchored onto the tibia with cross wires. The wounds are closed in the standard manner using sutures. The knee is immobilized in a hinge brace with the same postoperative program as that used for contemporary anterior cruciate repair (ACLR).
Using the core advancement technique the tibial bone core containing the distal ACL stump can be mobilized 3 to 5 mm proximally. An overlay repair of the two ruptured ACL ends 7a and 7b can be achieved The tibial bone tunnel containing the distal ACL stump can be fixed distally. The repaired ACL can be kept intact throughout the surgical procedure.
The following description sets out a series of preferred but non limiting steps which a surgeon may adopt when using the tooling described herein to create a bone prism whose free movement over a selected distance enables repair of a ruptured anterior cruciate ligament (ACL). A standard C Guide is used to set an alignment between a ruptured ACL and an axis which will indicate a path for a guide wire 71. The guide wire 71 traverses a path between the tibia and the ruptured ACL as described. This allows the surgeon to measure a distance a between an entry point in the tibia for the guide wire and the distal side of the ruptured ACL. A Computer guidance transmitter may be used to find an optimal angle of a block or wedge of bone to be drilled free of tibial bone. Distance a is a length between an entry point in the proximal tibia and a footprint centroid of ruptured ACL component anchored on the tibia. In a second step a guide wire 71 is inserted between the entry point and the centroid of the ACL component. The guide wire left in situ may have 0.5 mm laser markings or a depth gauge can be used to measure distance. The wire would have a known length. In a third step a slotted cutting block is urged against the tibial bone with its centre aligned with the path of the guide wire. Spikes are included on the plate spaced for centralizing the plate. For example four equally spaced spikes about 3 mm in length are provided. In a fourth step a cutting block is cut down on four sides of the block using a reciprocating saw using a 1 mm blade×5mm.
Once a cut has been formed in the bone the cutting device 30 is removed but the guide wire 71 is kept in situ. Secondary cutting guide 50 is inserted and a final flat cut is made with a known blade 62. The cut piece of bone which according to one embodiment is wedge shaped or a trapezoidal bone section advances proximally along the female passage preferably about 4 mm but within a range of 1-20 mm. When the bone section is advanced proximally, a transfixation wire is inserted transversely to lock the bone section from further movement relative to the tibia once ruptured ends of the cruciate ligament have been stitched together. Since the cut bone section is preferably wedge shaped—in that it has a wider distal end and a narrow proximal end. Since an inner wall of the tibia form which the bone section has been removed, is also tapered, movement of the bone section in the proximal direction will cause wedging of the section after it has advanced about 4 mm within the available range of movement. The cutting tool can be selected to release a bone section which achieves a desired limit of travel within the through passage.
The angle of an outer surface of the bone section will dictate the length of the travel within the passage formed. Selecting a cutting angle for the outer surface contour of the bone section will impact on the limit of travel. For example if a 2 cm block of bone cut from the tibia and having an apex of 8×6 mm, a taper angle of 27.5 would be required achieved by a 1 mm saw width and a 4mm advancement to interlock the bone section in the wedge shaped or trapezoidal shaped channel. Likewise, if a 3 cm block of bone cut from the tibia and having an apex of 8×6 mm, a taper angle of 27 would be required and achieved by a 1 mm saw width and a 4 mm advancement to interlock the bone section in the wedge shaped or trapezoidal shaped channel. If a 2.5 cm block of bone cut from the tibia and having an apex of 8×6 mm, a taper angle of 27 would be required and achieved by a 1 mm saw width and a 4 mm advancement to interlock the bone section in the wedge shaped or trapezoidal shaped channel. An acute taper angle would be about 27 degrees.
A surgeon would select an appropriate cutting guide based on the cutting angle required. Guides are provided at different angles and cut widths to control the extent of axial travel of the bone section cut. In the case of a cruciate ligament the footprint on the tibial bone can vary from patient to patient with typical cruciate base sizes in the range of 8-12 mm. Sizes outside this range are also contemplated. As well as selection of the angle of cutting guide the thickness of cutting blades also impact on the extent of axial advancement of the bone section cut. The thicker the cutting blade the longer the travel distance. 1mm wide cut may allow a 5-12 mm advance of the bone section. A preferred distance for advance of the bone section would be in the order of 5 mm at an angle of about 73-75 degrees. Also as bone has a certain elasticity this will also contribute to the overall extent of axial movement and can be allowed for in selection of cutting angles and thickness of cutting blades. Thus, it is proposed that a primary ACL repair using the research technique would bypass these intrinsic surgical difficulties as it does not require the surgeon to reproduce the ACL's complex multi strand spiral anatomy or ellipsoid attachment sites.
It will be appreciated by those skilled in the art that numerous variations and modifications may be made to the invention without departing from the overall spirit and scope of the invention broadly described herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 3013901899 | May 2013 | AU | national |
This is a continuation-in-part of U.S. patent application Ser. No. 14/894,409, a § 371 national stage of PCT/AU2014/000554 filed May 28, 2014, both herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14894409 | Nov 2015 | US |
| Child | 16457105 | US |
