The present invention relates generally to the field of orthopedics, and, more particularly, to glenoid component apparatuses for shoulder arthroplasty and methods for using them.
In the shoulder, a person's glenoid fossa may become worn, causing severe shoulder pain and limiting the range of motion of the patient's shoulder joint. Shoulder arthroplasty may be performed to alleviate such pain and increase the patient's range of motion. Arthroplasty is the surgical replacement of one or more bone structures of a joint with one or more prostheses.
Shoulder arthroplasty often involves replacement of the glenoid fossa of the scapula with a prosthetic glenoid component. The conventional glenoid component typically provides a generally laterally or outwardly facing generally concave bearing surface against which a prosthetic humeral head (or, alternatively, the spared natural humeral head in the case of a glenoid hemi-arthroplasty) may bear during operation of the joint. The conventional glenoid component typically also includes a generally medially or inwardly projecting stem for fixing the glenoid component in a cavity constructed by suitably resecting the glenoid fossa and suitably resecting cancellous bone from the glenoid vault.
However, in patients suffering from Cuff Tear Arthropathy (CTA), a standard shoulder replacement is not an option. In such cases, a reverse shoulder is often used. A reverse shoulder, as shown in
In some forms of CTA, the glenoid vault may be severely eroded. In such instances, the metaglene 10 cannot properly fit on the glenoid fossa 12. When dealing with those types of situations, surgeons may use bone graft to fill in the space in the glenoid vault. In some instances, the bone graft may be formed from the resected humeral head. Currently, surgeons may use allograft or bone resected from other parts of the body such as the resected humeral head or portions of the femur. In these types of resections, the surgeon must resect the bone graft (or allograft) from the humeral head using tools created for other uses. This results in poorly shaped bone grafts and requires a lot of extra time in the operating room.
Therefore, there is a need for an instrument that can efficiently and accurately resect and shape a properly shaped bone graft or allograft.
According to one embodiment, the present invention is an instrument including at least one cutting portion configured to resect a graft section from the graft. The instrument also includes a drive portion operably coupled to the cutting portion and configured to receive a rotational force. At least one reaming portion is positioned proximally to the cutting portion, the reaming portion is configured to ream a surface of the graft. The reaming portion and the cutting portion are positioned with respect to each other such that when the instrument is positioned against the graft and the rotational force is applied to the drive portion, the cutting section rotationally forms the graft section from the graft and the reaming portion rotationally reams a proximal section of the graft.
According to another embodiment of the present invention, a kit is provided and the kit includes a power extension adapted to couple to a power tool and having a power transfer portion at one end. The kit also includes an instrument having at least one cutting portion configured to resect a graft section from the graft. The instrument further includes a drive portion operably coupled to the cutting portion and configured to receive a rotational force. At least one reaming portion is positioned proximally to the cutting portion, the reaming portion configured to ream a surface of the graft. A drilling portion is also part of the instrument and is configured to rotationally create a bore in the graft. The drilling portion is positioned distally from the reaming portion and is operably coupled to the drive portion. The reaming portion and cutting portion are positioned with respect to each other such that when the instrument is positioned against the graft and the rotational force is applied, the cutting portion rotationally forms the graft section and the reaming portion rotationally reams a proximal section of the graft section. Also, the drive portion is adapted to be coupled to the power transfer portion of the power extension.
According to yet another embodiment of the present invention, a method for preparing a graft section from a sample is provided. An instrument is used, the instrument having at least one cutting portion configured to resect the graft section from the bone sample, at least one reaming portion positioned proximally to the cutting portion, the reaming portion configured to ream a surface of the graft section, and a drilling portion configured to rotationally create a bore in the graft, the drilling portion being positioned distally from the reaming portion. The sample is obtained and instrument is positioned adjacent the sample. The cutting portion cuts a section of the sample, while the proximal section of the sample is reamed and a bore is drilled in the sample.
Like reference numerals refer to like parts throughout the following description and the accompanying drawings.
With reference to
A number of reaming fins 50 extend from the reaming portion 44 toward the drill portion 48. The reaming fins 50 curve proximally and outwardly from the lower central portion of the reaming portion 44 to the outer periphery of the cutting portion 46. The reaming fins 50 include an arcuate leading edge 52.
The cutting portion 46 includes a smooth cylindrical wall 54 surrounding the reaming portion 44. In the embodiment illustrated in
The drilling portion 48, which may include a drill bit, extends away from the reaming portion 44 to a distal tip 62. Two flutes 64 and 66 extend helically about the drilling portion 48 between the reaming portion 44 and the distal tip 62. A guide bore 68 extends from the distal tip 62 to the drive portion 42. In the illustrated embodiment, the distal tip 62 does not extend past the edge 56 of the cutting portion 46. In other embodiments, the distal tip 62 may extend past the edge 56 of the cutting portion 46.
As discussed in further detail below, a kit may include one or more instruments 40 along with various instrumentation to facilitate use of the instrument 40. By way of example,
The power transfer portion 74 is shaped to be complimentary to the drive portion 42. In the embodiment of
To couple the instrument 40 with the power extension 70, the power transfer portion 74 is aligned with the drive portion 42 as shown in
A kit including the instrument 40 and the power extension 70 may be used in preparing a bone graft from a resected humeral shoulder 100 (
At step s204, the assembled power extension 70 and instrument 40 are slid over the guide wire. The guide wire 102 extends through the guide bore 68 of the instrument 40 and the guide bore 82 of the power extension 70 as shown in
A rotary tool (not shown) is then coupled to the instrument 40 at step s206. In some embodiments, a rotary tool may be directly coupled to the instrument 40. In this example, the power extension 70 is coupled to the instrument 40 as described above. Thus, the rotary tool is coupled to the power receiving portion 72 of the power extension 70 so as to be indirectly coupled to the instrument 40.
Power is then applied to the rotary tool causing the rotary tool to rotate the power extension 70. Rotary force is transferred to the drive portion 42 of the instrument 40 through the power transfer portion 74. As the instrument 40 initially rotates about the guide wire 102, the reaming portion 44, the cutting portion 46, and the drilling portion 48 all contact the resected humeral head 100 and begins to cut a bone graft 104 from the head at step s208. The cutting, drilling and reaming all occur as a single step, reducing time in the operating room. As the cutting portion 46 cuts the bone graft 104, the drilling portion 48 then engages the bone graft 104 and begins boring a hole over the guide wire 102. As the bone graft 104 is created and a hole is formed in the bone graft 104 by the drilling portion 48, the instrument 40 is guided by the guide wire 102 such that the reaming fins 50 come into contact with a proximal portion of the bone graft 104 as depicted in
The power tool is de-energized and disconnected at step s210. At step s208, a cutting guide or other tool may be used to disengage the bone graft 104 from the humeral head 100, leaving the humeral head 100 as shown in
The size of the drilling portion 48, both in length and diameter, is selected to be complimentary to the size of a center peg 152 of a metaglene component 154 (FIG. 17). Thus, upon completion of the reaming, the bore formed by the drilling section is sized to receive the center peg 152.
The bone graft 104, as shown in
The above method describes using the instrument 40 to prepare a portion of bone graft (or allograft) such that the reaming portion 44 is configured to prepare a surface that will mate with the back side of the metaglene component 154. In other embodiments, the reaming portion 44 may be used to prepare a surface that will mate with the glenoid. In other words, the bone graft 104 will have two opposing sides 156, 158 as shown in
Turning now to
As shown in
Once the bone graft 104 is securely in place, a reamer (not shown) may be used to ream the other side 156 of the bone graft 104. The reamer is used to prepare the other side 156 of the bone graft 104 to abut the metaglene component 154 (
The foregoing description of the invention is illustrative only, and is not intended to limit the scope of the invention to the precise terms set forth. Further, although the invention has been described in detail with reference to certain illustrative embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.