Patent Application
20070010818
The present invention relates to a surgical fastening system for treatment of a joint. More particularly, certain embodiments of the present invention relate to a surgical fastening system for inserting an implant to treat joint pain and specifically, bunions. The surgical fastening system includes a surgical guide, an implant, and a fastener.
Some joints in the human body carry extreme loads caused by such things as body weight, gait impact, lifting heavy objects, or choice of apparel. In the event these joints are structurally deficient, chronic and progressive subluxation of the joint can occur. A subluxation is a partial dislocation of a bone in a joint. This movement can result in deformity, pain, embarrassment, or other undesirable conditions. There are numerous conditions that are related to such movements at joints.
One of the most common subluxations is Hallux Abducto Valgus (HAV). HAV is a very common and painful foot disorder resulting in the formation of a bunion, recognized as a bony bulge, on the inside of the base of the big toe. HAV occurs when, for complex reasons, the first metatarsophalangeal joint (or MPJ) subluxes the first metatarsal bone medially and the base of the big toe (or Hallux) laterally. This joint movement results in a pronounced and painful bunion that is often embarrassing to the patient, and can lead to other complications and afflictions. There are many contributing factors to HAV. The joint may be deficient in transmitting and distributing the tremendous forces generated by a person's body weight while standing and moving. The condition may be exacerbated by the design of footwear, especially women's high heeled shoes and shoes that form a pointed toe. These types of footwear can shift more of the weight forward onto the ball of the foot, and thus provide even higher lateral forces for the foot's structure to carry. People with flat feet are also more prone to form bunions than those with high arches. Some forms of arthritis can contribute to bunion formation as well. The hereditary condition that predisposes persons to HAV leads to chronic worsening of the condition over time.
A physician measures the severity of HAV by measuring several angles of the foot's bone structure. These angles are seen using an X-ray. The first angle measured is the intermetatarsal (or IM) angle created by lines bisecting the central portions of the first and second metatarsal shafts of the foot. The second angle measured is the Hallux Abductus Angle (or HAA) created by the intersection of lines bisecting the central portions of the first metatarsal and the proximal phalanx of the hallux.
Two other angles (not shown) are useful in the evaluation of HAV. The Proximal Articular Set Angle (P.A.S.A.) is the angular relationship of the bisection of a line through the central portion of the first metatarsal 14 and a line which parallels the articular cartilage of the first metatarsal head. The Distal Articular Set Angle (D.A.S.A.) is the angular relationship of the bisection of a line through the central portion of the proximal phalanx of the hallux 22 and a line perpendicular to the articular cartilage of the base of the proximal phalanx of the hallux.
The IM angle is considered normal from 0-8 degrees. In individuals prone to bunion formation, this angle increases to between 9 and 35 degrees. The normal range for the HAA angle is less than 15 degrees. During bunion formation, the HAA angle can increase to greater than 30 degrees. HAV worsens as the IM and HAA angles increase. Normal P.A.S.A. and D.A.S.A. angles are 0-8 degrees. Every degree of increase of these angles is accompanied by more pain. Conventional treatments of HAV include externally applying pads and cushions to the foot to relieve the growing pain. In addition, anti-inflammatory and pain reducing medications may be used. These methods are only useful at mitigating symptoms and have no affect on the root cause of the condition. For many patients, surgery is required to correct HAV. Hundreds of surgical procedures have been described for correction of HAV. They include simple bunion removal, distal first metatarsal osteotomies, proximal first metatarsal osteotomies, metatarsal-cuneiform joint procedures, and hallux osteotomies. Many of the surgical procedures for HAV attach implants or plates to the bones to limit the movements of bones and joints and allow for healing in the treated area.
There are numerous simple bunions surgeries used to treat HAV. A Silver bunionectomy may be performed when the first MPJ is rectus and there is a normal or low IM. This procedure involves the simple removal of a prominent medial or dorso-medial prominence 34 of bone at the head of the first metatarsal 14 as shown in
Hallux osteotomies (known as an Akin or modified Akin procedure) are adjunctive procedures. An Akin is performed when the D.A.S.A. is increased. The procedure involves taking a wedge of bone to re-align the long axis of the proximal phalanx of the hallux. An Akin osteotomy can help re-align the long axis of the EHL tendon more medially to reduce lateral movement of the hallux. The osteotomy can result in slow-healing, especially if the lateral hinge is fractured. This osteotomy is more difficult to fixate especially when a transverse osteotomy line is left. Oblique Akin cuts can be fixated with screws, pins, wires, or staples.
Several types of distal first metatarsal osteotomies have also been developed. These osteotomies are performed when the IM angle is up to 15 degrees. Modifications of these osteotomies, which include wedging and angulating, can correct bi-plane and tri-plane deformities. The most commonly employed osteotomies are the Austin, Modified Austin, Reverdin with modifications, Scarf, Mitchell, and Hohman.
Alternatively, proximal first osteotomies are performed when the IM angle is greater than 15 degrees. These procedures include Opening and Closing base wedge, crescentic, and transverse oblique osteotomies.
Metatarsal-cuneiform procedures are performed when the IM is greater than 15 degrees, a hypermobile first ray is present, and significant metatarsus adductus is present. Such procedures include a Lapidus fusion and cuneiform osteotomies.
Besides HAV, Hallux Limitus (HL) and Hallux Rigidus (HR) are other common conditions of the big toe joint. These conditions are characterized by limited Sagittal plane motion of the MPJ with associated joint compression causing pain, stiffness, and arthritis. Hallux Limitus refers to the earlier stages of first MPJ arthritis where joint motion is “limited”. Hallux Rigidus refers to end stage arthritis where joint motion is “rigid”. These conditions are commonly caused from trauma, a long first metatarsal, and a flexible pes piano valgus deformity with a hypermobile first ray. Surgical procedures for HL and HR can be divided into joint salvage versus joint destructive procedures.
Joint salvage procedures have several goals including reduction in joint tension and mobilization of the plantar joint structures. The most commonly performed procedure for HL is a cheilectomy which involves removal of joint osteophytes with resection of the dorsal portion of the first metatarsal head. Distal metatarsal osteotomies are employed in an attempt to decompress the first MPJ by shortening and/or plantarflexing the first metatarsal head. Joint decompression increases joint motion and improves the structural mechanics of the first MPJ. These procedures include wedge, plantarflexory, and decompression osteotomies. Proximal first metatarsal osteotomies are employed for the more significant metatarsus primus elevatus. These osteotomies attempt to plantarflex the first ray and relax the plantar first MPJ structures. Additionally, decompression osteotomies of the hallux have been attempted in the past without great success.
Joint destructive procedures are purely for salvage of the joint to relieve pain. These include Keller arthroplasty with and without implant, Valenti arthroplasty, and first MPJ fusion.
While all the available surgical techniques provide an immediate correction for HAV, HL/HR, and other joint conditions, none of the surgical techniques presently employed prevents these conditions from reoccurring. At least one in every ten adult bunions recur (Mann R. A., Coughlin M. J. Adult hallux valgus. Surgery of the foot and ankle, vol. 1, 6th ed., St. Louis, CV Mosby, 1992). In fact, bunion recurrence in children can be over 50%. (Gerbert. Complication of Austin Bunionectomy, Journal of Foot Surgery, 1978). While this is a significant number of reoccurrences, it is believed the actual number is much higher. For example, many patients who have had surgery believe that surgery was the last chance for resolving their bunion. Because of this belief, they fail to seek additional treatment and simply live with the recurrent bunion. Also, the patients may choose not to return to the same medical discipline since that discipline did not resolve their bunions with surgery. Instead, the patients seek treatment from other non-conventional practitioners and thereby avoid being counted as a reoccurrence.
Furthermore, bunion surgery often includes the use of surgical fasteners which provide other problems for treating bunions. Surgical fasteners are pins and screws used in bunion surgery, and other forms of surgery, that are made from biocompatible materials. Surgical fasteners are used to affix broken or surgically separated bones together to cause healing to occur in a desired configuration. Also, surgical fasteners may be used to hold surgical implants in place so that the implant can perform its desired function. Surgical fasteners are designed to be inserted into the body during surgeries by either a press fit into a hole that was drilled into the bone or a self-tapping threaded screw. In some cases, a surgically approved adhesive is employed to add more strength to the engagement of the fastener with the bone. Surgical fasteners have to be able to withstand pull-out forces and avoid loosening or walking out during normal patient movements. Depending on the application, pull-out forces can be quite high, resulting in the use of larger diameter fasteners and surgical adhesives to prevent pull-out from occurring. Patients often are required to adjust their lifestyles in order to reduce the pull-out forces on the fasteners and/or implant. When these measures fail and the fasteners still pull out or walk out, revision surgery is required to fix the fasteners or to reset them.
With conventional non-surgical fasteners, pull-out is prevented by capturing the distal end of the fasteners with at least one nut that is larger than the hole the fastener goes through. Surgical fasteners, however, cannot employ a nut on the end of the fastener because the physician would need to make an additional incision in order to capture the end of the fastener. Even if the patient and physician were so inclined to try to capture the distal end of the fastener, there may not be functional space available within the body for the addition of a nut to the end of the fastener. Therefore, surgical fasteners typically use threads, surgical adhesives or a press fit to prevent pull-out. The length of the fastener is chosen so that the distal end of it does not protrude beyond the other side of the bone. When pull-out occurs, another incision for revision surgery is necessary to correct the fastener issue.
Therefore, a need exists for a joint treatment system that reduces the need for repeat surgeries and addresses fastener pull-out and walk out.
Certain embodiments of the present invention include a fastener for use during surgical procedures having a first member having a first shaft, a second member having a second shaft, and an elastomeric component positioned about at least one of the first and second members. The first shaft of the first member engages and secures the second shaft of the second member thereabout within a bore such that the elastomeric component is compressed between the first and second members and expands to retain the first and second members within the bore.
Certain embodiments of the invention include a surgical implant for attachment to two bones at a joint. The implant includes a first member having a first hole and that is connected to a first bone by a fastener at the first hole. The implant includes a second member having a second hole and that is connected to a second bone by a fastener at the second hole. The second member is configured to receive at least a portion of the first member therein such that the first member slidably moves within the second member as the bones of the joint go through a range of motions.
Certain embodiments of the invention include a surgical guide system for drilling at a surgical site for installation of an implant. The surgical guide includes a base member, at least one clamp for connecting the base member to a surgical site, a first guide member configured to be moved about the base member and including a first drill pilot hole, and a second guide member configured to be moved about the first guide member and including a second drill pilot hole. The first guide member is moved about the base member and secured to a position such that the first drill pilot hole is aligned with a first point at the surgical site and the second guide member is moved about the first guide member to a position such that the second drill pilot hole is aligned with a second point at the surgical site in order to guide a drill into the first and second points.
Certain embodiments of the present invention include a surgical kit for treatment of a joint. The kit includes a surgical guide system for drilling bones at the joint. The surgical guide system includes a base member configured to be connected at the joint, a first guide member configured to be moved about the base member and including a first drill pilot hole, and a second guide member configured to be moved about the first guide member and including a second drill pilot hole. The first and second guide members are moved such that the first and second drill pilot holes are aligned with a first bone and a second bone at the joint, respectively, to guide a drill into the first and second bones. The kit includes a surgical implant for attachment to the two bones at the joint. The implant includes a first implant member connected to the first bone and a second implant member connected to the second bone, the second implant member being configured to receive at least a portion of the first implant member therein such that the first implant member slidably moves within the second implant member as the first and second bones go through a range of motions. The kit includes a fastener for connecting the implant to the joint. The fastener includes a first member having a first shaft and a second member having a second shaft, and an elastomeric component. The first shaft of the first member is positioned within a drilled hole in the first or second bone and engages and secures the second shaft of the second member thereabout such that the elastomeric component is compressed between the first and second members and expands to retain the first and second members within the hole.
Certain embodiments of the present invention include a method for surgically treating a joint condition. The method includes providing a surgical guide having a first guide member with a first pilot hole and a second guide member with a second pilot hole, connecting the surgical guide to the joint, moving the first guide member to a position where the first pilot hole is aligned with a first bone of the joint, moving the second guide member with respect to the first guide member to a position where the second pilot hole is aligned with a second bone of the joint, and using the first pilot hole to drill a first drill hole into the first bone and using the second pilot hole to drill a second drill hole into the second bone.
The method further includes providing an implant having a first implant member with a first hole and a second implant member with a second hole, wherein the second implant member receives at least a portion of the first implant member therein, and providing a plurality of fasteners having a first member, a second member, and an elastomeric component. The method further includes providing a surgical spacer for receiving the fastener and being located between the implant and the bone. For each of the first and second implant members, the method includes assembling the first member of a fastener with the elastomeric component and the second member of a fastener, inserting each of the assembled fasteners into each of the first and second holes of the first and second implant members, a spacer, and into each of the first and second drill holes and pulling the first member of each fastener in a direction out of each drill hole such that the elastomeric component of each fastener expands between the first and second members of the fastener to secure the fastener within each drill hole, and securing the first member of each fastener to the second member of each fastener such that each elastomeric component retains each fastener within each drill hole and retains each of the first and second implant members to each of the first and second bones wherein the first implant member can move telescopingly within the second implant member.
Certain embodiments of the present invention include a method for installing a surgical fastener into a drill hole in a bone. The method includes providing a fastener having a first member, a second member, and an elastomeric component. The method includes assembling the first member of the fastener with the elastomeric component and the second member of the fastener, inserting the assembled fastener into a drill hole in a bone, pulling the first member of the fastener in a direction out of the drill hole such that the elastomeric component of the fastener is compressed and expands between the first and second members of the fastener to secure the fastener within the drill hole, and securing the first member of the fastener to the second member of the fastener such that the compressed elastomeric component retains the fastener within the drill hole.
The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings.
In order to connect the members 42 and 46, the first end 50 of the insertion member 42 is slidably moved in the direction of arrow A into the mouth 66 of the reception member 46 and through the bore 62 until the first end 50 is just at the hole 58 of the reception member 46, as shown in
The insertion and reception members 42 and 46 have appropriate lengths and widths for use with the particular size of the joint that the implant 38 will stabilize. The members 42 and 46 have depths pre-determined by the strength of the materials chosen and the specific lateral bending forces the mated members 42 and 46 need to resist without interfering with the relative sliding position of the insertion member 42 to the reception member 46. The curved ends 54 and 74 of the members 42 and 46, respectively, permit axial motion at a joint without interference from surrounding soft tissues. The members 42 and 46 may be coated with materials suitable for implantation into the human body that add lubricity and anti-wear properties to the material of the reception member 46.
Referring to
Referring to
The geometry of the cap screw 166 has a rounded head 188 to provide a consistent, smooth geometry with the head 94 of the external member 78. The cap screw 166 is made from materials that are implantable into the human body. The screw cap 166 covers up the threaded hole 150 in order that bone or tissue does not grow in the threaded hole 150 in order that the engagement tool 170 can easily be used to engage the threaded hole 150 remove the fastener 82 if necessary. The screw cap 166 may have a slot in the head 188 to allow a tool to engage and disengage the screw cap 166 from the threaded hole 150.
Should the physician choose to later remove the fastener 82, the physician may simply unscrew the cap screw 166, use the engagement tool 170 (
In an alternative embodiment, the fastener 82 may be used in instances where the physician does not drill all the way through the bone 186. In such situations, the fastener 82 may be inserted such that the elastomeric component 154 bulges against walls 192 of the hole in the bone 186 and provides lateral resistance to pull-out or walk-out of the fastener 82. Additionally, the elastomeric component 154 may include coatings and materials that promote bone growth around the elastomeric component 154 and thus aid in anchoring the elastomeric component 154 further in place over time.
Returning to
The assembly of the vertical and horizontal members 214 and 210 can be adjusted and easily mounted to the base 194. The vertical member 214 is connected to the base 194 by a key 262 that extends through the slot 206 in the base 194.
In operation, the implant 38, fasteners 82, and surgical guide 190 may all be used together as part of a surgery kit or system to perform surgery on a bunion or any number of other joint or bone conditions. Referring to
Once the physician has finished using the pilot holes 250 and 286 to make properly-spaced and aligned holes in the bones 14 and 22, the physician may easily remove the horizontal and vertical members 210 and 214. The physician unlocks the horizontal member 210 from the vertical member 210 and slides the legs 282 of the horizontal member out of the vertical member 214. The physician then unlocks the vertical member 214 from the engagement piece 274 of the key 262 and slides the vertical member 214 off of the engagement piece 274. The physician then removes the key 262 from the slot 206 in the base 194. Thus, the physician has space for installing the implant 38 while maintaining the joint in a stabilized state by keeping the base 194, spacer gauge 202, and spring clamps 198 in position about the joint 200.
Referring to
Referring to
As the internal member 86 is pulled in the direction of arrow K, the elastomeric component 154 is compressed and extends outwardly to a diameter greater than that of the drilled hole between the head 138 of the internal member 86 and the bone 14 and 22 to prevent the fastener 82 from being pulled in the direction of arrow K out of the hole. The physician then turns the engagement tool 170 (
When installed, the mated members 42 and 46 of the implant 38 engage the bones 14 and 22 to prevent each of the bones 14 and 22 from moving out of their generally coplanar alignment in the direction of arrow K or arrow L and thus prevents the bones 14 and 22 from moving back into a deformed bunion or HAV state. Additionally, referring to
When the joint 200 flexes across its range of motion, the implant 38 expands by way of the insertion member 42 sliding within and away from the reception member 46. Soft connective tissue between the two bones 14 and 22 of the joint 200 provides the elastic response to contract the implant 38 back again by way of the insertion member 42 sliding within and toward the reception member 46 as the range of motion shifts to the other direction. Furthermore, during the sliding of the insertion member 42 within the reception member 46, the distal end 50 (
Patients with HAV can develop a devastating complication following surgery known as Hallux Varus. Hallux Varus is a condition in which the Hallux (big toe) moves medially away from the other toes along a transverse plane 304. Hallux Varus occurs at a rate of 2-17% following bunion correction (Trnka, H. J. et al. acquired hallux varus and clinical tolerability. Foot Ankle Int. 1997; 18:593-597). The implant 38 offers an advantage in that, when implanted to prevent HAV, the implant 38 also prevents Hallux Varus from occurring. During surgery, the MPJ 200 is stabilized in the transverse plane 304, but is allowed normal motion along the frontal and Sagittal plane 300. A result of current surgical procedures for HAV is a tightening of the joint capsule to allow for correction and maintenance of the big toe position. Post-operative motion should be minimized to be successful, however, post operative motion is necessary to prevent the sesmoid bones within the joint 200 from being pulled below the joint 200 and thus locking up the motion of the joint 200. There are several causes for Hallux Varus following HAV surgery, including over-tightening of the medial joint capsule. The implant 38 stabilizes the Hallux (big toe) such that it does not move along the transverse plane 304 but can still move along the Sagittal plane 300, and thus eliminates the need for minimizing postoperative motion of the toe. Because the joint capsule does not need to be tightened, the sesmoid bones do not need to be pulled into a locking position.
The surgical system of the different embodiments of the invention provides numerous benefits. The surgical guide allows the physician to hold the joint stable in its desired location so that holes for the fasteners can be drilled in the precise locations necessary to affix the implant.
Given the potentially large lateral forces against the mated insertion and reception members, the surgical fasteners have to resist pull out. Given the axial rotation of each member about the surgical fastener, the surgical fasteners need to resist walk out. The elastomeric component of the fastener prevents pull out and walk out from the bone while not requiring a nut to secure the distal end of the fastener. The internal and external members used with the elastomeric component allow the fastener to be inserted and secured from one side of the bone and to be easily removed from the bone. The invention thus provides for permanent fastener installation while eliminating pull-out and walk-out. However, if for whatever reason the need arises to remove the fastener, the surgeon can easily release the captured distal end from the proximal end by decompressing the elastomeric component and then remove the fastener. While the fastener is disclosed as a means of preventing pull-out or walk-out of the implant, such a fastener could be employed in many different surgical procedures that currently involve other surgical fasteners.
Another benefit of the invention is that the implant provides strength and structure to the unstable joint under load yet allows the joint to move about the Sagittal plane. It is a further advantage that the invention also allows natural mobility and function of the joint to occur without allowing bones of the joint to move transversely to the Sagittal plane. Also, because the implant prevents the bones from moving transversely to the Sagittal plane, the implant reduces the likelihood that the patient will have to seek later post-operative corrective treatment. It is an additional benefit that the invention utilizes a novel method of affixing a surgical implant to bone in such a way that normal human function will not cause the fastener to pull out of the bone or walk out of the bone. Thus the fastener creates a permanent installation of the implant or permanently holds bones together.
An additional benefit of the application of this invention is that it can permanently decompress a joint, thus alleviating joint compression pain and provide the joint with an unencumbered range of motion. Another advantage is that the compression generated by the fastener can be controlled by altering the durometer and the length of the elastomeric component in relation to the lengths of the internal and external components.
It is an additional benefit of the invention that the physician is provided with a surgical guide device that allows for fast and accurate installation of an implant device during joint surgery. For example, the surgical guide attaches to the bones of the joint and holds them in place. It employs a spacer gauge to set the exact minimum distance between the heads of the bones in the joint. It also provides pilot holes for drilling through the bones and a marking system that indicates what size implant needs to be used for the particular joint being stabilized. Lastly, it stabilizes the joint during the installation of the implant and engagement of the surgical fasteners.
While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
