Patent ID: 12193682

DETAILED DESCRIPTION OF THE INVENTION

Abbreviations and Definitions

Detailed descriptions of one or more preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in any appropriate manner.

The singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

Wherever any of the phrases “for example,” “such as,” “including” and the like are used herein, the phrase “and without limitation” is understood to follow unless explicitly stated otherwise. Similarly “an example,” “exemplary” and the like are understood to be nonlimiting.

The term “substantially” allows for deviations from the descriptor that do not negatively impact the intended purpose. Descriptive terms are understood to be modified by the term “substantially” even if the word “substantially” is not explicitly recited.

The terms “comprising” and “including” and “having” and “involving” (and similarly “comprises,” “includes,” “has,” and “involves”) and the like are used interchangeably and have the same meaning. Specifically, each of the terms is defined consistent with the common United States patent law definition of “comprising” and is therefore interpreted to be an open term meaning “at least the following,” and is also interpreted not to exclude additional features, limitations, aspects, etc. Thus, for example, “a process involving steps a, b, and c” means that the process includes at least steps a, b and c. Wherever the terms “a” or “an” are used, “one or more” is understood, unless such interpretation is nonsensical in context.

As used herein, the term “about” can refer to approximately, roughly, around, or in the region of. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” can be used herein to modify a numerical value above and below the stated value by a variance of 20 percent up or down (higher or lower).

For purposes of the present disclosure, it is noted that spatially relative terms, such as “up,” “down,” “right,” “left,” “beneath,” “below,” “lower,” “above,” “upper” and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over or rotated, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terms “subject” and “patient” as used herein include all members of the animal kingdom including, but not limited to, mammals, animals (e.g., cats, dogs, horses, swine, etc.) and humans.

The terms “cutting guide,” “cut guide,” “cutting block,” and “block” are used interchangeably to refer to the various exemplary embodiments of the humeral head cut guide.

The term “rotator interval” describes an anatomical space within the shoulder of a subject, the uppermost boundary of which is defined by the supraspinatus muscle tendon, and the lower boundary of which is defined by the subscapularis muscle tendons.

Description of Selected Embodiments

FIG.1provides various views of a humeral head cut guide100in one embodiment. The top surface101and the back surface103of the humeral head cut guide100are clearly seen inFIG.1A. The guide100can include at least two setting spikes131,132along the front surface104that are configured to assist with placement of the guide100during the rotator interval approach to shoulder arthroplasty (discussed in more detail below). In embodiments, the setting spikes131,132extend about 0.5 to 5 mm from the front surface104of the cut guide104. The setting spikes131,132, can extend about 1 to 4 mm from the front surface104of the cut guide100. In one embodiment, the setting spikes131,132extend about 2 to 3 mm from the front surface104of the cut guide104.

As clearly shown in the cross-sectional view ofFIG.1B, two non-converging pin holes or channels121,122extend across the transverse axis of the guide100. In operation, the pin holes121,122receive surgical pins to secure the guide in place while the humeral head is cut. Each of the pin holes121,122can comprise diameters that are substantially similar to the other. In embodiments, the pin holes121,122have diameters that are distinct from one another. The diameter of at least one pin hole can be up to about 7 mm. In embodiments, the diameter of at least one pin hole can be between about 0.5 mm to about 7 mm, inclusive. The diameter of at least one pin hole can be between about 1 mm to about 5 mm. In certain embodiments, the diameter of at least one pin hole is about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, or about 8 mm. In one embodiment, the diameter of at least one pin hole is about 2.5 mm.

The guide100includes a receiving portion110that is configured to permit reversible attachment of the guide100to an attachment arm assembly seen at200inFIGS.3A-B. The receiving portion100terminates in a threaded opening115that extends partially into the guide100and is configured to further secure the guide100to the attachment arm assembly200. In embodiments, the threaded portion of the threaded opening115is at least 0.2 mm long. The threaded portion can be between about 0.2 mm to about 0.7 mm long, inclusive. In embodiments, the threaded portion is about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, or about 0.7 mm long. In one embodiment, the threaded portion is about 0.5 mm long.

FIG.1Cprovides a clear view of the bottom surface102and the back surface103of the cut guide100. The entry point of the right pin channel122can be seen on the side of the guide100, and the threaded opening115of the cut guide is visible within the U-shaped receiving portion110of the guide. InFIG.1D, the setting spikes131,132and the exit points of both pin channels121,122are visible on the front surface104of the guide100. Although the entry points of the pin channels121,122are disposed upon the sides of the cut guide100inFIGS.1and2, the entry point of the pin channels can be disposed on the back surface103of the cutting block100in alternative embodiments (seeFIG.8).

FIG.1Eprovides a clear view of the entire right pin channel122extending transversely across the guide100. The cross-sectional view ofFIG.1Fprovides an unobstructed view of the threaded opening115extending partially into the cutting guide100.

FIG.2provides additional views of the cutting guide under the embodiment ofFIG.1.

The humeral head cut guide100can comprise various shapes and sizes that are configured to fit within an opened rotator interval (described in more detail below). In embodiments, the front surface104of the cut guide100is longer than the back surface103. The length of the front surface104can be between about 110% and 200% the length of the back surface103. In certain embodiments, the length of the front surface104is from about 115% to about 150% the length of the back surface103. The length of the front surface104can be between about 120% to 130% the length of the back surface103. In one embodiment, the length of the front surface104is about 125% the length of the back surface103. In an alternative embodiment, length of the the front surface104is about 120% the length of the back surface. The front surface can be up to about 75 mm in length. The front surface104can be between about 10 mm to about 50 mm long. In embodiments, the front surface104is between about 15 mm to 40 mm long. The front surface104can comprise a length of up to 35 mm. In embodiments, the front surface104is between about 20 mm to 30 mm. In embodiments, the length of the front surface104is about 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, or 30 mm. In one embodiment, the front surface is about 25 mm long. In an alternative embodiment, the front surface104is about 30 mm long.

The back surface130of the guide100can be up to about 50 mm in length. The back surface103can be between about 5 mm to about 40 mm long. In embodiments, the back surface103is between about 10 mm to 30 mm long. The back surface103can comprise a length of between about 15 mm to 25 mm. In embodiments, the length of the back surface103is about 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, or 25 mm. In one embodiment, the back surface103is about 20 mm long. In an alternative embodiment, the back surface103is about 25 mm long.

The length of at least one side of the guide100can be up to about 50 mm. At least one side can be between about 5 mm to about 40 mm long. In embodiments, at least one side is between about 10 mm to 30 mm long. At least one side can comprise a length of between about 15 mm to 25 mm. In embodiments, at least one side is about 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, or 25 mm. In one embodiment, at least one side is about 20 mm long. In an alternative embodiment, at least one side is about 17 mm long.

The height of the cut guide100can be continuous across the guide100. The height of the guide can be up to about 25 mm. The height of the guide100can be between about 3 mm to about 2 mm to 15 mm. In embodiments, the height of the guide100is between about 5 mm to 10 mm. The guide100can be 5 mm, 6, mm, 7 mm, 8 mm, 9 mm, or 10 mm in height. In one embodiment, the guide100comprises a height of about 8 mm. In an alternative embodiment, the height of the guide100is about 7 mm.

In embodiments, the front surface104is configured to fit securely around at least a portion of the humeral head of the subject. In embodiments, the front surface104of the guide100is curved around an arc that is generally complementary to the shape of the subject's humeral head. In one embodiment, the shape of the front surface104is generally complementary to that of the average adult humeral head of a human subject.

In theFIGS.1,2, and11embodiments, the shape of humeral head cut guide100substantially comprises an isosceles trapezoid polyhedron. In embodiments, the humeral head cut guide comprises any trapezoidal polyhedron. The humeral head cut guide can comprise at least two substantially parallel sides. In embodiments, the front surface104and the back surface103are substantially parallel to one another. Alternative embodiments comprise any polygonal shape. The size, shape, or configuration of the cut guide100can vary depending on needs or preferences of the subject or surgeon.

In alternative embodiments, the humeral head cut guide100includes a slot that extends transversely through the guide100(see the guide shown inFIGS.7and8). In slotted embodiments, the slot is configured to receive the blade of the safety saw for precision cuts of the humeral head.

Additional embodiments can comprise a magnetic guide to further secure the saw in place. In magnetic embodiments, the top or bottom surface of the guide can comprise a plurality of depressions and a steel plate with a plurality of legs that are configured to be magnetically connected to the plurality of depressions. When magnetically connected to the cut guide, the steel plate provides a mechanism for holding the saw in place during humeral head osteotomy.

FIG.3shows the attachment arm assembly200with the humeral head cut guide100reversibly connected thereto. The attachment arm assembly200comprises a vertical arm220and a horizontal arm230. The vertical arm220is configured to be anchored to the subject during placement of the humeral head cut guide100. The vertical arm220and the horizontal arm230are secured to one another via a set screw210that extends through a set screw slot of the vertical arm225and a set screw slot of the horizontal arm235. In theFIG.3embodiment, the vertical arm further220comprises a horizontal arm receiving slot226that is configured to receive and hold the horizontal arm230therein. When so arranged, the attachment arm assembly200can be adjusted to the appropriate height and depth by moving the horizontal arm230vertically and horizontally within the horizontal arm slot226of the vertical arm220. After the suitable position is achieved, the set screw210can be tightened within the set nut215to secure the attachment arm assembly200in place. In alternative embodiments, the horizontal arm can contain a receiving slot configured to receive and hold the vertical arm.

The attachment arm assembly200of theFIG.3embodiment further comprises a cut guide retaining rod250. The retaining rod250includes a portion that is configured to reversibly secure the cut guide100to the attachment arm assembly200during placement of the cut guide100in preparation for humeral head osteotomy. In embodiments, the retaining rod250includes a threaded portion that is complementary to the threaded opening of the cut guide (shown at115ofFIGS.1B and1F) and is configured to be threadably inserted therein. In other embodiments, the cut guide100is reversibly secured to the retaining arm250via alternative means.

Another aspect of the present invention includes a method of shoulder arthroplasty using the humeral head cut guide100, the attachment arm assembly200, or both in accordance with any embodiment disclosed within this specification or otherwise apparent from the descriptions herein.

In one embodiment, a subject is placed under general anesthesia and placed in a traditional “beach chair” position with all bony prominences well padded.

A longitudinal incision is made in the skin beginning from about the anteriorlateral acromion. The incision can be an anterosuperior, straight Sabre incision made along Langer's lines. The incision can begin at about 1 cm medial to the anterolateral acromion margin in the anterior-inferior direction. In embodiments, the incision begins at more than 1 cm medial to the anterolateral acromion margin. The skin incision can begin up to about 5 cm medial to the anterolateral acromion margin. The skin incision can begin at about 1 cm, about 2 cm, about 3 cm, about 4 cm, or about 5 cm medial to the anterolateral acromion margin. The length of the incision depends upon the size of the subject. In embodiments, the incision can be between one to ten inches long. The incision can be between two and five inches long. In embodiments, the incision extends for about three to four inches. The incision can be carried medially to the level of the acromioclavicular joint (the “AC joint”) and anteroinferiorly to expose the raphe between the middle and anterior deltoid. Gelpi retractors can be employed for subdermal exposure down to deltoid fascia. The length and location of a planned incision under one embodiment can be seen inFIG.4A.

The deltoid is then split at the raphe between the middle and anterior deltoid. In embodiments, the deltoid split occurs between the anterior and middle heads from the AC joint, along the anterior acromion to 3-4 cm lateral to the acromial edge. In embodiments, the spilt extends for 3-4 cm anterior and inferior to the acromial edge. In embodiments, the deltoid split occurs in the periosteal plane and comprises the shape of a wide V. The Gelpi retractors can then be removed and two self-retaining retractors with blunt tips are placed at right angles to each other to achieve subdeltoid exposure. As shown in theFIG.4Bembodiment, one of the self-retaining retractors can be between the deltoid heads, and the other can retract the skin. In certain embodiments, the self-retaining retractors comprise modified Kolbel self-retaining retractors.

Mobilization of the deltoid is then performed via subdeltoid adhesion release. Subdeltoid adhesions release can be achieved via blunt dissection. In embodiments, the subdeltoid adhesion release is achieved through the use of a Langenbeck elevator, blunt-tipped retractors, the surgeon's finger, or a combination thereof. Mobilization of the deltoid adhesions serves to increase exposure of the underlying tissue. This step is particularly important when the subject has limited pre-operative motion. Bursa can be excised as needed.

The dissection can then proceed through the rotator interval. To achieve the procession, the shoulder can be externally rotated to bring the rotator interval into the field of view. In embodiments, this rotation further places the subscapularis under tension. The rotator interval can be identified by palpating the biceps long head.

The rotator interval is then opened. In embodiments, a flap of interval tissue is incised posterior to the long head of the biceps tendon. Electrocautery can be used to create the flap of rotator interval tissue (seeFIG.5). In embodiments, tissue is cauterized along the lateral greater tuberosity margin from about 5 mm posterior to the biceps tendon to the palpable upper subscapularis margin. The capsule can then be opened in a direct line back to the glenoid. As shown in theFIG.6embodiment, when so opened, the tissue creates a “trap door” which is preserved for closing upon completion of the shoulder arthroplasty. Tenodesis of the biceps long head can be performed at the transverse ligament, and the biceps is tenolysed.

In one exemplary embodiment, the “trap door” is created as described within this paragraph. Tissue is electrocauterized from about 5 mm posterior to the long head of the biceps tendon, and the incision exits the shoulder joint and pierces the coracohumeral ligament. The incision is carried down to the articular insertion of the subscapularis. Once the longhead of the biceps is clearly identified, it is released from the supraglenoid tubercle and then tenodesed at the transverse ligament after cauterization of the arcuate artery within the groove. Tenolysation of the biceps distally ensures proper tension of the long head of the biceps. After removal of the biceps tendon from the interval, the interval can be incised back to the glenoid from the upper edge of the subscapularis to create the triangular “trap door” attached to the supraspinatus.

The trap door can then be tucked under the supraspinatus for preservation. In embodiments, the trap door is tucked under the supraspinatus and retracted using blunt-tipped retractors, such as modified Kolbel self-retaining retractors. In embodiments, the the rotator interval can be spread up to 35 mm medially and 35 mm laterally.

As shown inFIG.7, the junction of cuff attachment with the articular cartilage can then be identified and marked at the articular margin for reference when placing the cut guide100. In embodiments, a darrach retractor can be used to define the interface between the rotator cuff tendon and the articular cartilage. At this point, the insertion of the subscapularis onto the humerus is readily visible. The hinge point where the supraspinatus attaches at the junction of the humeral articular surface and the greater tuberosity footprint can then be exposed. In certain embodiments, this exposure is accomplished via a second darrach retractor. Electrocautery can then be used to mark the line from the articular side of subscapularis to the articular side of the supraspinatus. As discussed briefly above and shown in theFIG.7embodiment, this line will serve as a reference point for cut guide placement and the saw blade entrance during humeral head osteotomy.

The insertion point used to place the attachment arm assembly200(also referred to herein as “the intramedullary insertion guide”) can then be identified. In one embodiment, this insertion point is posterior to the biceps, nearest the highest point of the humerus. This point can be about 5 mm away from the supraspinatus insertion. In embodiments, the insertion point is about five to ten mm posterior and medial to the bicipital groove. Once located, the intramedullary canal can be opened with a rongeur to prepare for insertion of the attachment arm assembly200therein. In embodiments, an anchoring rod of the attachment arm assembly is inserted into the intramedullary insertion point. Before insertion of the guide, the supraspinatus can be retracted out of the cutting plane if present therein.

The anchoring rod or the intramedullary insertion guide of the attachment arm assembly200can then be inserted within the intramedullary cannal. In embodiments, insertion of the anchoring rod or guide can be facilitated by extension of the shoulder in adduction with a small darrach under the supraspinatus and infraspinatus.FIG.4Cshows the attachment arm assembly as inserted within the intramedullary canal during placement of the cutting guide, under one embodiment.

The cutting block100can then be centered in the opened interval and aligned to begin the cut on the marked articular margin. In embodiments, the bottom surface102of the cutting block100can be used as a guide for the saw blade (seeFIG.7B). Alternatively, as shown inFIG.8, the top surface101of the cutting block100can be used a guide for the saw blade. As shown inFIG.7A, certain embodiments of the cutting block100comprise a slot that can be configured to receive the blade of a surgical saw for guidance during humeral head osteotomy. Retroversion can be between 25-35 degrees, inclusive.

Once properly aligned, the cut guide100can be pinned into the appropriate position using the pin channels121,122disposed upon the side or back of the cut guide100. After pinning the block100in place, the attachment arm assembly200can be removed from the subject. If necessary, additional adjustment of the cutting block100can be made following removal of the attachment arm assembly to optimize the saw cut through the articular margin.

Following placement of the guide, the humeral head can be cut in preparation for humeral head osteotomy. In one embodiment, the humeral head is cut at 132.5 degrees. A safety saw can be utilized for the cutting of the humeral head to avoid injury to the anterior and posterior cuff. In certain embodiments, the middle 80% of the head can be cut followed by removal of the block before completing the cut. After completing the cut, the humeral head can be removed. In embodiments, removal of the cut humeral head can be simplified by making a coronal cut through the head and removing a ¼ to ½ slice of the head. Coronal cuts are particularly useful when the subject has a large shoulder or there are significant abnormalities or deformities of the humeral head.

Following removal of the humeral head, self-retaining retractors can be set deeper and adjusted to maximize exposure of the glenoid (seeFIG.10A). Circumferential resection of the labrum can then be performed. The bicep stump can also be resected. The inferior capsule can then be released from the glenoid. In one embodiment, the inferior capsule is released from approximately the inferior ⅔ of glenoid. In certain embodiments, the inferior capsule is released from 10 O'clock to 2 O'clock in the periosteal plane. In embodiments, the capsule is released to a depth of about 1-2 cm. The capsule can be removed via electrocautery.

The final glenoid component can be placed after sizing, preparation, drilling, and trialing per surgical technique.

As shown inFIG.10B, the location of a center hole can be marked upon the glenoid using an appropriate glenoid guide. The center pin can then be placed, and the articular cartilage can be removed with a reamer while preserving the subchondral bone. Next, the center hole can be drilled into the glenoid.

The peripheral pinholes can then be drilled using the guide while adjusting the rotation as needed. In one embodiment, the superior hole is drilled first and secured with a pin. The first inferior hole can then be drilled and subsequently pinned. In certain embodiments, it can be useful to depress the cut humeral surface to improve the accuracy of the fit. The second pin hole can then be drilled and pinned. If required, the guide and pins can be subsequently removed to permit deepening of the peripheral hole.

A glenoid trial can then be inserted and impacted to achieve a good circumferential fit. Cement can then be inserted into the peripheral peg holes followed by insertion of the glenoid component. In embodiments, the surgeon can check to ensure that no soft tissue is trapped between the component and the glenoid.

After determination of the appropriate replacement humeral head size, the humerus can be sound and broach trialed using the version angle guide.

The humeral head stem component can be inserted into the humerus using the rotator interval humeral broach/stem insertor/extractor shown inFIG.13.

Briefly, the broach/stem insertor/extractor can comprise a strike plate connected to a rod. In one embodiment, the strike plate is configured to be reversibly attached to the rod. The strike plate may comprise a threaded portion for reversible attachment of the striker plate to the rod. In theFIG.13embodiment, the rod terminates at an angle that is complementary to that of the cut humeral head. In one embodiment, the angle of rod termination is about 135 degrees. The rod can further comprise a widened area or a small apron configured to facilitate engagement of the insertor/extractor with the broach or stem component. In one embodiment, the rod comprises a channel through which a heavy gauge wire extends. In this embodiment, the wire serves as a pin for insertion of the broach or humeral stem. This wire is particularly useful when the broach or humeral stem comprises a complementary channel configured to receive the pin. The rod may further comprise a means for permitting customization of the wire as needed. In one embodiment, the means for permitting customization of the wire comprises a set screw. In an embodiment, the wire is comprised of nickel titanium or Nitinol. The broach/stem insertor/extractor can further comprise a locking pin trigger that is configured to release the wire upon depression of the trigger. Thus, in operation, the humeral broach or stem can be inserted by applying pressure to the striker plate of the insertor/extractor to set the humeral broach or stem within the humerus. Once an appropriate humeral broach or stem is inserted, the locking trigger of the insertor/extractor can be depressed to release the broach or stem from the insertor/extractor.

An alternative insertor/extractor configured to reversibly engage and hold a broach or stem is provided inFIGS.17A-17D. As shown in theFIG.17embodiment, the alternative insertor/extractor can comprise a trigger that is designed to release the broach or stem from the insertor/extractor, wherein depression of the trigger releases the broach or stem from the insertor/extractor after the humeral broach or stem is inserted into the humerus.FIGS.17A,17C, and17D, show the insertor/extractor with the trigger mechanism in a locked position. In this exemplary embodiment, an engagement mechanism can be seen extending from the termination point of the insertor/extractor.FIG.17Dshows an exemplary insertor/extractor with a stem reversibly attached thereto. As shown in theFIG.17Bembodiment, depression of the trigger mechanism retracts the engagement mechanism and causes a trigger arm to extend from the insertor/extractor. Thus, in this particular embodiment, depression of the trigger releases the broach or stem from the insertor/extractor through retraction of the engagement mechanism. The interior/extractor can be reattached to the broach or stem or attached to a new broach or stem. In embodiments, the insertor/extractor is attached to the broach or stem by inserting the termination point of the insertor/extractor into a receiving portion of the broach or stem followed by depression of the trigger arm to extend the engagement mechanism and return the trigger mechanism to its locked position (seeFIGS.17A,17C, and17D). In alternative embodiments, depression of the trigger engages the broach or stem and depression of the trigger arm releases the broach or stem from the insertor/extractor.

Following insertion of the humeral stem component, trialing and insertion of the humeral head prosthesis is completed.

The humeral head prosthesis can be impacted using the curved impactor shown inFIG.14. The curved impactor represents an improvement over straight impactors when employing the rotator interval approach of shoulder arthroplasty as described herein because a straight impactor introduces shear at the Morse taper interface, which reduces the compressive force. As shown inFIG.14, a low profile, curved impactor, as disclosed herein, permits maximal compressive force when impacting the humeral head prosthetic into the humeral stem using the rotator interval approach.

Closure of the surgical site can be performed after insertion of the humeral head prosthesis.

In embodiments, closure comprises retrieval and closing of the trap door tissue. Closure of the trap door can be achieved using absorbable interrupted suture. The deltoid can then be closed medially and laterally. In one embodiment, #2 nonabsorbable inverted transosseous suture is used for medial closure of the deltoid, and #0 absorbable suture is used for lateral closure. Finally, the skin can be closed via the surgeon's preferred method.

EXAMPLES

Examples are provided below to facilitate a more complete understanding of the invention. The following examples illustrate the exemplary modes of making and practicing the invention. However, the scope of the invention is not limited to specific embodiments disclosed in these Examples, which are for purposes of illustration only, since alternative methods can be utilized to obtain similar results.

Example 1

The Rotator Interval Approach for Total Shoulder Arthroplasty

The procedure comprises the following steps:1. POSITIONING Beachchair, with the patient at the edge of the table so that the arm can be easily brought over the side of the table. Use a hip bolster for security and a low armboard for support of the arm.2. SKIN INCISION Sabre incision from the anteriorlateral acromion 3-4″, in Langer's lines; Gelpi retractors for subdermal exposure down to deltoid fascia.3. DELTOID SPLIT Between the anterior and middle heads from the acromioclavicular joint, along the anterior acromion to 3 cm lateral to the acromial edge. Remove Gelpi retractors and use modified Kolbel self-retaining retractors placed at right angles to each other; one is between the deltoid heads, the other retracts skin.4. MOBILIZE DELTOID Release subdeltoid adhesions bluntly, adjusting Kolbel retractors as needed. Excise bursa as needed, rotate the shoulder and identify the rotator interval by palpating the biceps long head.5. OPEN THE ROTATOR INTERVAL Use cautery along the lateral greater tuberosity margin from 5 mm posterior to the biceps tendon to the palpable upper subscapularis margin; then open the capsule in a direct line back to the glenoid, creating a ‘trap door’ of capsular tissue which is preserved by placing it under the Kolbel retractor. Tenodesis of the biceps long head is done at the transverse ligament and the biceps is tenolysed.6. IDENTIFY THE ARTICULAR CARTILAGE MARGIN Use a small darrach retractor to feel the junction of cuff attachment with articular cartilage; mark this margin with cautery7. IDENTIFY THE ENTRY POINT FOR THE INTRAMEDULLARY GUIDE This point is usually 5-10 mm posterior and medial to the bicipital groove. Insert the guide; this can sometimes be facilitated by extension of the shoulder in adduction with a small darrach under the supraspinatus and infraspinatus.8. PIN THE GUIDE The cutting block is centered in the opened interval with the slot aligned to begin the cut on the marked articular margin. Retroversion is typically 25-35 degrees. Pin the block, remove the rod and adjust the block as needed to optimize the saw cut through the articular margin.9. CUT THE HUMERAL HEAD Using a safety saw and protecting the cuff as needed with a darrach. It is often best to cut the middle 80% of the head, remove the block and finish the cut. Removing the cut head is often eased by making a coronal cut through the head and removing a ¼ to ½ slice of the head. Finish any cortical margin cuts as needed, protecting the soft tissues with a darrach.10. EXPOSE THE GLENOID Readjust the Kolbel retractors to maximize glenoid exposure. Fully excise the labrum and release the inferior capsule from the glenoid from 10 O'clock to 2 O'clock in the periosteal plane 1-2 cm deep. Check the release with a Langenbock elevator and release more as needed.11. ASSESS ANY REMAINING GOATBEARD OSTEOPHYTE Carefully remove with osteotome and curettes as required.12. CENTER THE GLENOID PREPARATION Mark the center hole using the appropriate glenoid guide, being sure to visualize all glenoid margins. Place the center pin and remove articular cartilage with the reamer, preserving subchondral bone. Drill the center hole.13. DRILL PERIPHERAL HOLES Using the guide, adjust rotation as needed. Drill the superior hole first and secure with a pin. Drill the first inferior hole and pin; it may be useful to depress the cut humeral surface with the drill shaft in order to have an accurate fit. Pin the second inferior hole, remove the guide and pins; deepen the peripheral holes as needed.14. TRIAL THE GLENOID When the glenoid trial is inserted and impacted with good circumferential fit, mix a small amount of cement. Remove the trial, irrigate and dry the glenoid. Use a 10 cc syringe to insert cement into the peripheral peg holes, pressuring with a fingertip. After excess cement is removed, insert the glenoid component and check to insure no soft tissue is trapped between the component and the glenoid.15. HUMERAL PREPARATION Using upward pressure on the elbow, deliver the cut humeral surface into the operative field, being careful of the glenoid component. Measure the cut humeral surface in several diameters in order to estimate the desired humeral head size. Sound and broach trial the humerus using the version angle guide. I recommend NOT removing the inserter handle. Remove the broach.16. INSERT THE HUMERAL STEM COMPONENT I leave the component about 1 mm proud. Check for any humeral bone that might prevent seating of the humeral head Morse taper.17. TRIAL THE SELECTED HEAD Insure there is no impingment of the cuff tendons. Note the head rotation number in the rotator interval and check balancing of the shoulder joint. Remove the head trial.18. HUMERAL HEAD INSERTION Irrigate and dry the humeral Morse taper socket. Insert and orient the humeral head component using the fork, making sure no soft tissue is trapped. Seat the Morse taper and check. In some embodiments, one may have to adjust or even remove the Kolbel retractor to insert the head easily.19. FINAL CHECK Check stability and sweep the soft tissues with an elevator to insure there is no entrapment.20. CLOSURE Retrieve and close the trap door tissue anatomically using absorbable interrupted suture. Close the deltoid medially with #2 nonabsorbable inverted transosseous suture and laterally with #0 absorbable suture. Close the skin by your preferred method (I close subq and subcuticular with absorbable suture). Apply waterproof adhesive; final dressing is a nonadherent strip, single gauze and Tegaderm™.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific substances and procedures described herein. Such equivalents are considered to be within the scope of this invention, and are covered by the following claims.