Chapter 3 Instability
a posteriorly directed force, all the while palpating the coracoid tip with the middle finger in order to estimate the anterior and posterior excursion of the humeral head in relation to a fixed point (the coracoid tip) (Fig. 3-1). This same maneuver is repeated with the patient in the lateral decubitus position, with the examiner performing this same modified load-and-shift maneuver with the arm in varying degrees of abduction (0°, 45°, 90°) while the examiner palpates the coracoid tip as a reference point to determine excursion of the humeral head (Fig. 3-2). With the arm in 0° of abduction, anterior stability is provided mainly by the superior glenohumeral ligament (SGHL), so excessive anterior excursion at 0° indicates SGHL injury or insufficiency. Similarly, a positive anterior load-and-shift maneuver at 45° abduction indicates damage or insuf- ficiency of the middle glenohumeral ligament (MGHL), and a positive test at 90° abduction suggests injury to the inferior glenohumeral ligament (IGHL). It is important to understand that the physical examination is useful in pro- viding an index of suspicion for the direction of instability, but the true direction and extent of the instability is often not evident until arthroscopic examination of the joint is performed. The next general conundrum in instability surgery is whether or not to do arthroscopy in each instability patient. For example, a patient may have documented anterior instability (e.g., from x-rays in the emergency room) along with significant glenoid bone loss (>25% loss of the infe- rior glenoid diameter confirmed by 3D CT scan images). In such a patient, the surgeon may have already decided that he or she is going to do an open Latarjet reconstruc- tion, so is there a need to do an arthroscopic evaluation as well? In our experience, the answer is a resounding “yes!” We always do an arthroscopic evaluation of every surgically treated unstable shoulder because we have
“No man ever drowned in his own sweat.” we s t e r n w i s d o m :
Introduction Instability of the shoulder is a vast topic with classification schemes that have focused on various elements such as eti- ology (traumatic versus atraumatic), direction of instability (anterior, posterior, multidirectional), bone loss (signifi- cant versus nonsignificant bone loss), and psychological factors (volitional versus nonvolitional). For purposes of the present discussion, we will subdivide our instability categories into: 1. Anterior instability (with and without bone loss) 2. Posterior instability (with and without bone loss) 3. Multidirectional instability (traumatic and atraumatic) The first general conundrum that the surgeon faces when dealing with instability is how to determine the direction of instability. Although the direction of instabil- ity may be obvious in some cases, particularly when the patient is initially seen with an unreduced dislocation in the emergency department, in other cases, the direction of instability remains obscure. This is particularly true in patients who have only had recurrent subluxations without a true dislocation. On physical examination, we utilize a modification of the load and shift test that we have found to be quite useful in determining the direction of instability. In performing this test with the patient in a sitting position, the examiner places the middle finger over the coracoid tip once he or she is sure that the shoulder is in a reduced position. Then, he or she applies an anteriorly directed force followed by
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addressing this other significant pathology, we believe that these patients likely would have remained symptomatic from their unaddressed lesions. Our general philosophy is that the surgeon should treat all pathologic elements when the patient is under anesthesia, and the only way to be sure that all the pathology has been discovered is to do a diag- nostic arthroscopy. Another general conundrum is whether to do arthroscopic instability surgery in the beach-chair position or the lateral decubitus position. The senior author (S.S.B.) spent the first 5 years of his “shoulder arthroscopy career” performing shoulder arthroscopies in the beach-chair posi- tion. After 5 years, he switched to the lateral decubitus posi- tion and immediately noticed two things: 1. Visualization for posterior instability repair was much better in the lateral decubitus position. 2. Access to the anteroinferior, inferior, and posteroinfe- rior labrum was much easier in the lateral decubitus position. Therefore, we strongly recommend the lateral decubitus position for all arthroscopic instability surgeries.
found a relatively high incidence of additional pathology that would have gone undetected and untreated without arthroscopic inspection. 1 Unexpected concomitant lesions that we have discovered and repaired include SLAP lesions, rotator cuff tears, posterior Bankart lesions, and posterior HAGL (humeral avulsion of the glenohumeral ligaments) lesions. If we had gone straight to an open Latarjet, without FIGURE 3-1 Load-and-shift test with the patient sitting. The examiner places his middle finger over the patient’s coracoid tip to serve as a reference point for translation of the humeral head as he applies first an anteriorly directed force, followed by a posteriorly directed force. If the test is positive with an anteriorly directed force in the sitting position, it suggests injury to the superior glenohumeral ligament (SGHL).
Anterior Instability Arthroscopic versus Open
Some authors have recommended open repair for contact athletes, citing unacceptable recurrence rates if arthroscopic repairs are performed; 2 however, that has not been our expe- rience. We have found that the critical factor in predicting recurrence is to determine whether or not the athlete has significant bone loss. If our criteria for significant bone loss
FIGURE 3-2 Load-and-shift test with the patient in the lateral decubitus position. A: A positive anterior load-and-shift test with the arm in 0° abduction signifies injury to the superior glenohumeral ligament (SGHL). B: A positive test at 45° abduction suggests damage to the middle glenohumeral ligament (MGHL).
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are adhered to, we have not observed an increased recur- rence rate in contact athletes treated arthroscopically. 3,4 We believe that the critical factor for recurrence is recognizing significant bone loss and treating it appropriately. Latarjet Significant Bone Loss:When Is Latarjet Necessary? On the glenoid side, we consider that a patient has signifi- cant bone loss if he or she has lost ≥ 25% of the inferior gle- noid diameter. This can be determined from 3D CT scans, comparing the diameters of the injured and normal gle- noids (Fig. 3-3). In utilizing this modality, one must be cog- nizant that this method underestimated the percentage of bone loss in 8% of patients. 5 Therefore, we continue to pre- fer direct arthroscopic measurement of glenoid bone loss based on the location of the glenoid bare spot (Fig. 3-4). In terms of glenoid bone loss, our indication for a Latarjet reconstruction with coracoid bone graft is anterior instability associated with a glenoid bone loss of ≥ 25% of the inferior glenoid diameter. We have found that whenever we do a Latarjet reconstruction, the Hill-Sachs lesion does not need to be separately addressed. That is, after Latarjet, the coracoid bone graft and the sling effect of the conjoined tendon will always prevent the Hill-Sachs lesion from engaging, no matter how large the Hill-Sachs might be.
Figure 3-2 ( Continued ) C: A positive test at 90° abduction indicates that the inferior glenohumeral ligament (IGHL) has been damaged.
FIGURE 3-3 Glenoid bone loss can be quantified with a three-dimensional CT of the (A) normal and (B) affected shoulders. The percentage of glenoid bone loss can be easily calculated on the en face view by comparing the inferior glenoid diameter of the normal side to that of the affected side.
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FIGURE 3-4 Left shoulder, anterosuperolateral viewing portal. Measuring glenoid bone loss. A: A calibrated probe introduced from a posterior portal marks the distance from the glenoid bare spot to the posterior rim. In this case, the distance is ~12 mm. B: The probe is used to measure the distance from the anterior glenoid rim to the glenoid bare spot. In this case, the distance is 6 mm. Thus, there is 6 mm of bone loss anteriorly or 25% loss of the inferior glenoid diameter. G, glenoid; H, humeral head.
Surgical Technique of Congruent-Arc Latarjet Reconstruction We call our surgical technique the congruent-arc technique because we place the coracoid graft in an orientation such that the arc of its inferior surface is a congruent extension to the glenoid articular arc. This requires that we rotate the coracoid graft 90° about its long axis prior to fixation to the anterior glenoid neck. We always perform diagnostic arthroscopy just prior to the Latarjet in order to accurately measure the amount of glenoid bone loss, to assess the Hill-Sachs lesion, and also to evaluate the joint for additional pathology, particularly SLAP lesions. We have found a 64% incidence of SLAP lesions in our patients who are undergoing Latarjet reconstruction. 1 In these cases, we perform an arthroscopic SLAP repair with the patient in the lateral decubitus position. Then, we turn the patient supine and adjust the table to a modified beach- chair position, then re-prep and redrape for the open Latarjet. Coracoid Osteotomy In performing the congruent-arc Latarjet, a standard delto- pectoral incision is used. The cephalic vein is preserved and retracted laterally with the deltoid muscle. The coracoid is exposed from its tip to the insertion of the coracoclavicular ligaments at the base of the coracoid. The coracoacromial ligament is sharply dissected from the lateral aspect of the coracoid, and the pectoralis minor tendon insertion on the medial side of the coracoid is also sharply dissected from the bone (Fig. 3-5). The medial surface of the coracoid, from which the pectoralis minor is detached, is the surface that will later be in contact with the anterior glenoid neck when the graft is secured by screws.
For the coracoid osteotomy, two options are avail- able. Option 1 involves the use of an osteotome to create the osteotomy (Fig. 3-6A). We believe that an osteotome should be used only in thin patients. In a muscular patient with a large deltoid and pectoralis major, the bulk of these
FIGURE 3-5 In preparation for coracoid osteotomy, the pectoralis minor tendon is sharply dissected off the medial edge of the coracoid.
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FIGURE 3-6 Coracoid osteotomy may be performed with (A) an osteotome or (B) an angled sawblade. C, coracoid.
The capsular incision is begun 1 cmmedial to the rimof the glenoid by subperiosteal sharp dissection to preserve enough capsular length for later reattachment (Fig. 3-8). The anterior glenoid neck is prepared as the recipient bed for the coracoid bone graft by means of a curette or a burr, being careful to preserve as much native glenoid bone as possible. “Dusting” of the anterior glenoid neck to a bleeding surface is performed with a high-speed burr without actually removing the bone. Alternatively, in our preferred technique for bone bed preparation, a 70° angled sawblade can be used to create a completely flat surface on the anterior glenoid neck that will match the flat surface of the coracoid cut, maximizing the con- tact area and thereby enhancing the chances of bone union. Coracoid Preparation While stabilizing the coracoid with a Kocher grasper, use an oscillating saw to remove a thin sliver of the bone from the medial coracoid surface where the pectoralis minor had been inserted. This is the surface that will be in contact with the anterior glenoid neck (Fig. 3-9).
muscles may prevent a proper angle of approach anterior to the glenoid, resulting in the possibility of intra-articular glenoid fracture. Option 2, for muscular patients, involves the use of an angled sawblade to create the osteotomy (Fig. 3-6B). Neurovascular structures are protected by retractors medial and inferior to the sawblade. With either technique, the osteotomy is made just anterior to the cora- coclavicular ligaments in order to obtain as much length to the coracoid graft as possible. A graft measuring 2.5 to 3.0 cm in length is ideal, though in small patients a graft of 2.0 cm is adequate for fixation with two screws. The conjoined tendon is left attached to the coracoid graft to maintain vascularity of the graft and to augment stability of the glenohumeral joint by providing a sling effect upon completion of the procedure. After mobiliza- tion of the coracoid and conjoined tendon, the muscu- locutaneous nerve is protected by retracting the coracoid medially, thereby preventing any stretch injury to the nerve. Glenohumeral Joint Exposure Once the coracoid has been osteotomized, there is a clear view of the anterior shoulder. The upper half of the subscapularis tendon is detached distally and reflected medially (Fig. 3-7). The insertion of the lower half of the subscapularis is preserved. After detachment of the upper subscapularis tendon, the plane between lower subscapu- laris tendon and anterior joint capsule is developed. Alternatively, the glenoid may be exposed by using a subscapularis split approach. A deep Gelpi retractor is used to spread the split in the muscle. The subscapularis split is made through the muscular fibers at the junction of the superior and middle thirds of the muscle. The capsule is bluntly dissected from the subscapularis, and then, the capsular incision is made. We prefer not to use the sub- scapularis-splitting approach because visualization can be quite limited, and the position of the split severely limits the surgeon’s ability to change the position of the graft on the glenoid if needed. Instead, we detach the upper half of the subscapularis and then develop the plane between the lower subscapularis and capsule.
FIGURE 3-7 Management of the subscapularis tendon. Detach the superior half of the tendon and then develop a plane between the inferior half of the subscapularis and the capsule.
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FIGURE 3-8 A: Outline of capsulotomy. B: Dissect the capsule 1 cm medial to the glenoid rim before detaching it from the glenoid neck to preserve as much capsular length as possible for later reattachment.
FIGURE 3-9 Coracoid graft preparation. A: The coracoid is grasped with an instrument. B: A straight sawblade is used to remove a thin sliver of bone from the medial surface. C: The medial surface has been cut and will be secured to the glenoid rim. C, coracoid graft.
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FIGURE 3-10 Coracoid Drill Guide. A: The Coracoid Drill Guide (Arthrex, Inc., Naples, FL) has slots for drilling the coracoid in preparation for Latarjet. B: The elongated slots are placed on the medial surface of the coracoid graft (the side that will rest against the glenoid). The guide facilitates placement of two 4-mm parallel drill holes. C, coracoid graft.
created with the Coracoid Drill Guide) to allow for easy control and positioning of the coracoid graft onto the gle- noid (Fig. 3-10). Three offset sizes are available (4, 6, and 8 mm) to adapt to various graft diameters. Some additional shaping of the graft with a rongeur or a power burr may be required to obtain the best possible fit of the guide against the graft. An optimal fit occurs when the coracoid is slightly below the overhanging offset fin once the pegs are fully engaged (Fig. 3-11). Positioning the Coracoid Graft on the Glenoid and Securing the Graft The glenoid is optimally exposed by placing a Fukuda retractor to lever the humeral head posteriorly and by plac- ing a two-pronged Hohmann retractor medially to retract the medial soft tissues. Proper position of the coracoid bone graft relative to the glenoid is critical. The graft must be placed so that it serves as an extension of the articular arc of the
Grasp the coracoid graft with the grasping Coracoid Drill Guide (Arthrex, Inc., Naples, FL) (Fig. 3-10). Position the guide on the graft so that the elongated clearance slots are on the freshened surface of the coracoid that will even- tually be in contact with the glenoid. The Coracoid Drill Guide allows the surgeon to drill two parallel 4-mm holes through the graft. Care is taken to ensure that the holes are centered on the graft and are perpendicular to the prepared bone surface. Positioning the Parallel Drill Guide on the Graft Prior to the development of the Glenoid Bone Loss Set (Arthrex, Inc., Naples, FL), the coracoid graft had to manu- ally be positioned on the glenoid in a freehand manner. This was technically very difficult and was not easily repro- ducible. The Parallel Drill Guide (Arthrex, Inc., Naples, FL) has greatly simplified this part of the procedure and has also made it very reproducible. The pegs on the Parallel Drill Guide mate with the pre- drilled holes on the coracoid graft (i.e., those that were
FIGURE 3-11 The Parallel Drill Guide (Arthrex, Inc., Naples, FL). A: Pegs on the guide mate with the predrilled holes in the coracoid graft. Different offsets are available to accommodate grafts of varying thickness. A 6-mm offset guide is pictured. B: An optimal fit occurs when the overhanging fin is flush with or slightly above the coracoid graft. C, coracoid graft.
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wires in place (Fig. 3-14B). Although the 3.75-mm, fully threaded, cannulated titanium screws are self-drilling and self-tapping, it is recommended to use the 2.75-mm can- nulated drill to penetrate only the near cortex of the native glenoid prior to screw insertion. Due to the potential prox- imity of the screws to the suprascapular nerve posteriorly, it is advisable to rely on the self-drilling and self-tapping nature of the screws to penetrate the posterior glenoid cortex. The screw length depth gauge can then be used to help determine the proper screw length. Screw length is read directly from the back end of the shorter 6-inch guide wire and from the laser line of the longer 7-inch guide wire. We have found that the most common screw lengths are 34 mm for the more inferiorly positioned screw and 36 mm for the superior screw. Each screw is inserted over its guide wire using a can- nulated hex driver. One must be careful not to overtighten the screws as this may crack or damage the graft. Once the screws are almost fully seated, the surgeon double checks the position of the coracoid graft. If the position is satisfactory, the guide pins are removed and the screws are advanced to their fully seated position (Fig. 3-14C). Intraoperative AP and axillary x-rays are taken to confirm satisfactory position of the screws and graft. At this point, the surgeon assesses the stability of the Latarjet construct. One of the most amazing things about this construct is that, with the arm in abduction and external rotation and with a manually applied anteriorly directed force, the shoulder cannot be dislocated, even though the capsule has not yet been repaired. Capsular Reattachment Place 3 BioComposite SutureTak anchors (Arthrex, Inc., Naples, FL) into the native glenoid above, between, and below the cannulated screws to repair the capsule. This makes the graft an extra-articular structure and prevents its articulation directly against the humeral head, eliminating
glenoid (Fig. 3-12). The Parallel Drill Guide is invalu- able in placing the graft flush with the articular surface of the glenoid so that it is neither too far medial nor too far lateral (Fig. 3-13). It is important to be sure that the guide is angled slightly medially, toward the face of the glenoid, to achieve the proper screw insertion angle and to avoid any potential screw penetration into the articu- lar cartilage. Use a pin driver to advance the shorter (6 inches) of the two guide wires directly through the lower hole of the guide and graft and then into the glenoid neck. The guide wires are not terminally threaded to allow for better feel when the posterior glenoid cortex is penetrated. Next, advance the longer (7-inch) guide wire through the second guide cannulation (Fig. 3-14A). Next, remove the Parallel Drill Guide. Hold the graft firmly against the glenoid with an instrument (as the pegs may be tightly wedged into the coracoid drill holes) while the Parallel Drill Guide is withdrawn, leaving both guide FIGURE 3-12 Correct placement of the coracoid bone graft occurs when the graft is flush with the glenoid surface so that the arc of the glenoid is effectively extended. The Parallel Drill Guide (Arthrex, Inc., Naples, FL) facilitates proper placement of the graft. C, coracoid graft; G, glenoid.
FIGURE 3-13 Incorrect placement of coracoid bone graft. A: The graft must not be placed so that it protrudes lateral to the joint surface and acts as a bone block. Such placement produces a high incidence of late osteoarthritis. B: Conversely, it is important also to avoid medial placement of the graft because this can predispose to recurrent dislocation or subluxation.
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FIGURE 3-14 Securing the coracoid bone graft. A: Guide wires are inserted through the Parallel Drill Guide (Arthrex, Inc., Naples, FL) to temporarily hold the graft in place. B: The drill guide is removed, and the appropriate screw length can be measured. C: Final appearance of secured graft after placement of two cannulated 3.75-mm screws. The graft is flush with the glenoid articular surface and extends the native glenoid arc. C, coracoid graft; G, glenoid.
#2 FiberWire suture (Arthrex, Inc., Naples, FL). If the tendon stump is of poor quality, then BioComposite CorkScrew FT suture anchors (Arthrex, Inc., Naples, FL) are used. It is not necessary to reattach the pectoralis minor to the residual coracoid base or adjacent soft tissues because it does not retract. We have not observed any residual symp- toms or cosmetic deformity relative to the unrepaired pec- toralis minor. After subscapularis repair, a standard skin closure is performed. Optimizing the Chances of Bone Graft Union The key to obtaining union between the coracoid graft and the anterior glenoid is to have two large flat surfaces that are in intimate contact throughout their surfaces. We believe that the common practice of using a burr to prepare the bone surface, particularly the anterior glenoid neck sur- face, leaves an uneven interface that may not have good contact with the matching surface of the graft. Therefore, we use a saw to create these surfaces to ensure that they are perfectly flat. For the coracoid graft, we have already used a straight sawblade to remove a “wafer” of the bone from the medial side of the graft (i.e., on the side where the pectoralis minor had inserted) (Fig. 3-9B).
any abrasive potential of the graft against the articular car- tilage of the humerus (Fig. 3-15). Subscapularis Repair If a subscapularis split has been used, the upper and lower subscapularis muscle segments will reapproximate themselves once the retractors have been removed, and no sutures are necessary. When the upper subscapularis has been detached and retracted medially during the exposure, it is usually repaired back to its stump with
FIGURE 3-15 Suture anchors are placed at the interface of the graft and the native glenoid arc and used to repair the anterior capsule so that the coracoid graft remains extra-articular.
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Postoperative Rehabilitation The patient uses a sling for 6 weeks, with external rota- tion restricted to 0°. After 6 weeks, the sling is discon- tinued, and overhead motion is encouraged. Gentle external rotation stretching is begun at 6 weeks post- operative, with the goal that at 3 months postoperative,
For the glenoid side, we use a 70° angled sawblade to create a flat recipient surface on the anterior glenoid neck (Fig. 3-16A). We believe that it is important to match these two flat surfaces exactly, and the 70° sawblade gives the perfect orientation for a flush fit of the two bone surfaces (Fig. 3-16B–E).
FIGURE 3-16 Schematic showing the use of the 70° angled sawblade to prepare a flat recipient surface on the anterior glenoid neck. A: A 70° angled sawblade. B: The plane of the eroded anterior glenoid is not optimal to receive the coracoid graft at an angle that will produce a smooth articular arc between the glenoid concavity and the concavity of the graft. C: The 70° angle of the sawblade allows the surgeon to approach the anterior glenoid at a comfortable working angle to make a flat cut that is approximately in line with the axis of the scapula. D: Flat saw-cut has been completed on the anterior glenoid neck. E: Fixation of the coracoid to the glenoid neck is optimized by the perfect orientation of the two flat saw-cuts.
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external rotation on the operated shoulder will be half that on the opposite shoulder. At 3 months postopera- tive, the patient begins strengthening with TheraBands. At 6 months, he or she progresses to weight lifting in the gym if the graft remains in good position and shows early signs of consolidation. Contact sports or heavy labor are generally allowed when the bone graft appears radiographically healed, which is usually 9 to 12 months postoperative.
The Cowboy’s Conundrum: Anterior Instability with 30% Glenoid Bone Loss and Moderate-sized Hill-Sachs Lesion The Surgeon’s Solution: Diagnostic Arthroscopy plus Open Latarjet Reconstruction History: ■ A 20-year-old college soccer player fell playing soc- cer 2 years ago and dislocated his right shoulder. It was reduced 2 hours later in the emergency room. Since that time, he has had four more dislocations and hundreds of subluxations. It now subluxes in his sleep. Physical Exam: ■ Full range of motion, but guards with overhead motion ■ Normal strength ■ Apprehension with combined abduction and external rotation Imaging: ■ X-rays show an anterior bony Bankart lesion (Fig. 3-17). ■ 3D CT scan shows 30% glenoid bone loss with step-off and partial resorption of anterior fragment (Fig. 3-18). Arthroscopic Findings: ■ Arthroscopic measurements with a calibrated probe confirmed 30% glenoid bone loss with an obvi- ous “inverted pear” configuration of the glenoid (Fig. 3-19). The bone fragment was atrophic and not united to the glenoid. ■ There was a moderate-sized Hill-Sachs lesion. The Hill-Sachs engaged the anterior glenoid rim in 45° of abduction plus 30° of external rotation (Fig. 3-20).
FIGURE 3-17 Axillary x-ray shows obvious bone deficiency of the anterior glenoid.
■ There were no additional lesions that needed to be addressed arthroscopically. ■ Based on bone loss criteria (>25% glenoid bone loss), we performed an open Latarjet reconstruction.
FIGURE 3-18 3D CT en face projection of the glenoid shows an atrophic and partially resorbed bone fragment of the anterior glenoid that is medially displaced. The glenoid bone defect measures 30% of the inferior glenoid diameter.
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The Cowboy’s Conundrum: Anterior Instability with Significant Bone Loss plus SLAP Lesion and Posterior HAGL Lesion The Surgeon’s Solution: Arthroscopic Posterior HAGL Repair; Arthroscopic SLAP Repair; Open Latarjet Reconstruction History: ■ An 18-year-old male soccer player who has just com- pleted his senior season in high school and plans to play college soccer. ■ In the past 2 years, he has sustained three anterior dis- locations, each requiring closed reduction. Each time, the shoulder was “out” for ~2 hours before the closed reduction. He has also had ~10 subluxation episodes. ■ Apprehension with abduction/external rotation, even at low angles of abduction Imaging: ■ X-rays show a moderate-sized Hill-Sachs lesion. ■ MRI shows an ALPSA (anterior labral periosteal sleeve avulsion) lesion with a type II SLAP lesion. ■ 3D CT scan shows 25% loss of the inferior glenoid diameter. Arthroscopic Findings: ■ Type II SLAP lesion with unstable biceps root. ■ PosteriorHAGL lesion(capsular split variant) (Fig. 3-21). ■ 25% glenoid bone loss. ■ Moderate-sized Hill-Sachs lesion. Physical Exam:
Pearls, Pitfalls, and Decision-making: ■ We always perform arthroscopy prior to doing an open Latarjet for two reasons: 1. To confirm the percentage bone loss by direct measurement 2. To arthroscopically address any additional pathol- ogy (e.g., SLAP repair, posterior Bankart repair, pos- terior HAGL repair) ■ If glenoid bone loss is >25%, we perform Latarjet. ■ If glenoid bone loss is <25%, we consider arthroscopic Bankart repair ± arthroscopic remplissage (remplis- sage is added if direct measurements and calculations reveal that the Hill-Sachs lesion is “off-track”). FIGURE 3-19 Right shoulder, anterosuperolateral viewing portal. The glenoid has an “inverted pear” configuration. The anterior glenoid bone fragment is medially displaced. G, glenoid; H, humeral head.
FIGURE 3-20 Right shoulder, anterosuperolateral viewing portal. The Hill-Sachs lesion is “perched” at the anterior margin of the inverted pear glenoid. G, glenoid; HSL, Hill-Sachs lesion.
FIGURE 3-21 Right shoulder, anterosuperolateral viewing portal. A posterior HAGL lesion (capsular split variant) is identified. G, glenoid; H, humeral head; P, posterior capsule.
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at least 2 hours for each of three dislocations (total 6 hours of total dislocation time) puts him into a cate- gory that will probably require Latarjet reconstruction. ■ Since the open Latarjet is usually performed in a beach chair position, surgeons might prefer to do their preliminary arthroscopy in the beach-chair position. This would allow them to more easily tran- sition from the arthroscopic portion of the case to the open part of the case. However, the beach-chair position for shoulder arthroscopy is well known to be a very difficult position from which to repair posterior labral or capsular pathology. Therefore, we always do the arthroscopic part of the case in the lateral decubitus position and then reposition and redrape the patient in the beach-chair position for the open procedure. The Cowboy’s Conundrum: Anterior Instability in Contact Athlete (Wide Receiver) with >20 Subluxations and Dislocations; Significant Bone Loss plus SLAP Lesion The Surgeon’s Solution: Arthroscopic SLAP Repair plus Open Latarjet Reconstruction History: ■ A 21-year-old college football player (wide receiver) with initial anterior dislocation of the left (nondomi- nant) shoulder 1½ years ago. During the past season, the shoulder dislocated or subluxed during every game, but the athlete continued to have an outstand- ing season and was voted to the All-American team. ■ He is a top professional football prospect at wide receiver. Physical Exam: ■ Positive apprehension with combined abduction and external rotation Imaging: ■ Plain radiographs demonstrate a large Hill-Sachs lesion on the AP view (Fig. 3-23A) and suggest glenoid bone loss on the axillary view (Fig. 3-23B). ■ MRI shows an ALPSA lesion (medialized Bankart lesion) (Fig. 3-24A) and a SLAP lesion (Fig. 3-24B). ■ En face view on 3D CT scan shows ~30% loss of the inferior glenoid diameter in comparison with the opposite (normal) side (Fig. 3-25). Arthroscopic Findings: ■ A type II SLAP lesion was repaired with LabralTape (Arthrex, Inc., Naples, FL) and a BioComposite PushLock anchor (Arthrex, Inc., Naples, FL) (Fig. 3-26).
■ We performed an arthroscopic repair of the posterior HAGL lesion (Fig. 3-22) and an arthroscopic SLAP repair. Then, we repositioned and reprepped the patient and did an open Latarjet reconstruction. Pearls, Pitfalls, and Decision-making: ■ This patient has 25% glenoid bone loss and plans to continue with vigorous competitive athletic activities, so he definitely requires a Latarjet reconstruction. ■ A SLAP lesion associated with anterior instability should be repaired, since SLAP repair increases the ante- rior capsular stiffness of the shoulder. And of course, the preferred means of SLAP repair is arthroscopic. ■ Because of the high incidence of additional pathology associated with anterior instability that has significant bone loss, we always do a diagnostic arthroscopy prior to the open Latarjet. If we had not done an arthros- copy in this case, we would have missed a very impor- tant component of his pathology, the posterior HAGL lesion, that likely would have remained symptomatic if it had not been discovered and repaired. In addition, we would have missed the SLAP lesion, which is a compo- nent of the anterior instability and should be repaired. ■ Total duration of dislocation can suggest whether an instability can be addressed arthroscopically or whether it will require a Latarjet reconstruction with coracoid bone graft. We have found that a total disloca- tion time of 5 hours or more generally causes enough bone compression on the glenoid and humeral sides of the joint that a Latarjet procedure will be required if one follows the usual bone loss criteria (loss of >25% of the inferior glenoid diameter requires a Latarjet). 3 In this patient, his documented dislocation time of FIGURE 3-22 Right shoulder, anterosuperolateral viewing portal. Posterior HAGL lesion (capsular split variant) has been repaired arthroscopically with side-to-side sutures. G, glenoid; H, humeral head; P, posterior capsule.
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FIGURE 3-23 A: AP x-ray shows large Hill-Sachs lesion. B: Axillary x-ray suggests glenoid bone loss.
■ There was an inverted-pear glenoid with an anteriorly subluxed humeral head (Fig. 3-27). ■ Hill-Sachs lesion was seen to engage the anterior gle- noid when the arm was brought into abduction and external rotation (Fig. 3-28). ■ Following arthroscopic SLAP repair, an open Latarjet reconstruction was performed (Fig. 3-29). Pearls, Pitfalls, and Decision-making: ■ Arthroscopy must be performed prior to the open Latarjet reconstruction in order to discover and repair concomitant pathology, in this case, a SLAP lesion. ■ An intact superior labrum contributes to mechani- cal stiffness and thereby enhances the instability repair. Therefore, a SLAP lesion that is discovered in a patient with anterior instability must be repaired. ■ Latarjet reconstruction addresses both the glenoid bone defect and the humeral bone defect (Hill-Sachs lesion) by a combination of lengthening the articu- lar arc of the glenoid plus providing a posteriorly directed force by virtue of the sling effect of the
conjoined tendon. Therefore, no additional surgical procedures (such as remplissage or humeral bone graft) need to be directed toward the Hill-Sachs lesion whenever a Latarjet reconstruction is done.
The Cowboy’s Conundrum: Locked Anterior Dislocation The Surgeon’s Solution: Open Reduction of Glenohumeral Joint and Open Latarjet Reconstruction History: ■ A 32-year-old male who is an oilfield worker. ■ He went out for a few drinks with friends. He says he was “feeling pretty good” when he tripped and fell onto his outstretched left arm. The next morning, he had pain and decreased motion in the left shoulder but he went to work and continued to work for 2 more weeks.
FIGURE 3-24 Left shoulder MRI. A: ALPSA lesion shows capsule healed in a medialized position. B: Type II SLAP lesion.
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FIGURE 3-27 Left shoulder viewed from an anterosuperolateral portal shows an inverted pear glenoid. G, glenoid; H, humeral head.
FIGURE 3-25 En face view of the glenoid on 3D CT scan shows 30% loss of inferior glenoid diameter in comparison with the opposite (normal) side. ■ At 2 weeks postinjury, he went to an orthopaedic sur- geon who x-rayed the left shoulder and found that the patient had a locked anterior dislocation. We first saw him at 3 weeks postinjury.
Physical Exam: ■ Subjectively, the patient complains of some mild tin- gling in digits 1, 2, and 3 of the left hand. However, two-point discrimination is normal. Sensory and motor examinations are otherwise normal. ■ Brachial and radial pulses are normal.
FIGURE 3-26 Type II SLAP lesion was repaired with LabralTape (Arthrex, Inc., Naples, FL) and a knotless BioComposite PushLock anchor (Arthrex, Inc., Naples, FL). BT, biceps tendon; G, glenoid.
FIGURE 3-28 Anterosuperolateral viewing portal shows the Hill-Sachs lesion engaging the anterior glenoid with combined abduction and external rotation. G, glenoid; HSL, Hill-Sachs lesion.
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FIGURE 3-29 Postoperative Grashey (A) and axillary (B) x-rays show two screws securing the coracoid bone graft.
■ Active and passive elevation is 45°. He can externally rotate to neutral. ■ He has loss of the normal contour of the left shoulder consistent with anterior shoulder dislocation. Imaging: ■ X-rays show a locked subcoracoid anterior dislocation of the left shoulder, associated with a large Hill-Sachs lesion (Fig. 3-30).
■ 3D CT scan confirms the large Hill-Sachs lesion and also suggests a loss of about 20% of the inferior gle- noid diameter (Fig. 3-31). Arthroscopic Findings: ■ In the operating room, a closed reduction was attempted under fluoroscopic C-arm control. However, the humeral head was completely locked on the ante- rior rim of the glenoid, and it was impossible to reduce.
FIGURE 3-30 Plain x-rays. A: AP view shows a locked subcoracoid anterior dislocation of the left shoulder. B: Axillary view shows a large Hill-Sachs lesion, which is locked onto the anterior rim of the glenoid.
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FIGURE 3-31 3D CT scan. A: Posterior projection of the humerus shows a large Hill-Sachs lesion. B: En face view of the glenoid shows that there is ~20% loss of the inferior glenoid diameter.
We did not think that a meaningful arthroscopic exam- ination could be carried out with a locked subcora- coid dislocation, so we proceeded to perform an open reduction with open Latarjet reconstruction. Pearls, Pitfalls, and Decision-making: ■ With attempted closed reduction under C-arm, there was absolutely no motion of the humerus relative to the glenoid. It was obvious that closed reduction or arthroscopic-assisted closed reduction would not work. So we went straight to open reduction and Latarjet reconstruction through a deltopectoral inci- sion. Latarjet was deemed necessary because of the large amount of bipolar bone loss. ■ The subscapularis and anterior capsule were extremely tight, and the only way to reduce the shoulder was to take down the entire subscapularis and the anterior capsule from their humeral attachments. After fixation of the coracoid graft and reattachment of the capsule to the native glenoid, we repaired the lower half of the subscapularis to the humerus by passing it inferior to the coracoid graft. We repaired the upper half of the subscapularis to the humerus by passing it superior to the coracoid graft. Since we had detached the entire subscapularis in order to reduce the shoulder, we thought it was important to have an extremely secure
repair of the subscapularis to the humerus. Therefore, we repaired each half of the subscapularis to the humerus with a load-sharing rip-stop construct. ■ At 4 months post-op, the patient had full active and passive range of motion and excellent strength. His x-rays at 4 months post-op showed that the coracoid graft was beginning to show radiographic evidence of uniting to the anterior glenoid (Fig. 3-32). Remplissage The Off-track (Engaging) Hill-Sachs Lesion:When Is Remplissage Indicated? Most engaging Hill-Sachs lesions are associated with sig- nificant bone loss ( ≥ 25%) on the glenoid side. When that is the case, these off-track engaging Hill-Sachs lesions are adequately treated by Latarjet reconstruction and will no longer engage after such surgery. However, the surgeon sometimes encounters Hill-Sachs lesions that will engage the anterior glenoid rim even though there is not a significant glenoid bone loss (i.e., the glenoid bone loss is <25% of the inferior glenoid diam- eter). We call such lesions “off-track” Hill-Sachs lesions, 4 and we have found that they are best treated by a combined arthroscopic Bankart repair and arthroscopic remplissage (insetting of the capsule and rotator cuff tendon into the
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FIGURE 3-32 (A) AP and (B) axillary x-rays show good position of the coracoid bone graft, which is beginning to unite to the anterior glenoid.
This is in contradistinction to an “on-track” Hill-Sachs lesion in which the medial margin of the Hill-Sachs lesion is lateral to the glenoid rim and the humeral articular sur- face is well supported by the anterior glenoid rim through- out the range of motion (Fig. 3-35). The importance of the “off-track” Hill-Sachs lesion is that it may exist in association with a glenoid that does not have significant bone loss (i.e., <25% glenoid bone loss). In such a case, if an arthroscopic Bankart repair alone is done to address the instability, the Hill-Sachs lesion will still be able to engage the anterior glenoid rim and cause recurring insta- bility, as we have demonstrated in the biomechanics lab. 8 We have also demonstrated in the biomechanics lab that remplissage will eliminate engagement of “off-track” Hill- Sachs lesions at the same time that it significantly increases the biomechanical stiffness of the repair construct. 8 Therefore, remplissage is our preferred technique for arthroscopically addressing the Hill-Sachs defect in patients with anterior instability who have an “off-track” Hill-Sachs in association with <25% glenoid bone loss. But in order to implement this arm of the treatment paradigm, the surgeon must be able to calculate whether or not the Hill-Sachs is “off-track.” So how is that done? As we have stated, in patients who have <25% glenoid bone loss in association with an off-track Hill-Sachs lesion, we prefer to treat them with a combination of arthroscopic Bankart repair and arthroscopic remplissage. We have pre- viously explained how glenoid bone loss can be measured arthroscopically or from a 3D CT scan (Fig. 3-36). 7 Similarly, one can measure the Hill-Sachs interval (HSI) and calculate the glenoid track either arthroscopically or from a 3D CT scan (Fig. 3-37). One can then deduce whether the Hill-Sachs lesion is off-track (engaging) or on-track (nonengaging). The Hill-Sachs Lesion: Is It OnTrack or Off Track?
Hill-Sachs defect to make it an extra-articular defect that can no longer engage). Determining whether a Hill-Sachs lesion is “on-track” (nonengaging) or “off-track” (engaging) requires a bit of simple math, but it is not complicated and can be eas- ily computed in the operating room from measurements taken at the time of surgery. The “glenoid track” is a concept that must be understood if one is to fully understand how to calculate whether a Hill- Sachs lesion is “off track.” 7 The glenoid track can be thought of as the imprint or “track” that the glenoid would make on the humerus as the armis abducted inmaximumexternal rotation. Think of the “footprint” that the surface of the glenoid makes on the humerus where the two bones come into contact. Then, imagine the continuous trail of consecutive “footprints” that combine as amoving contact surface between the two bones as the arm is abducted in full external rotation (Fig. 3-33A). This continuous trail of footprints is the “glenoid track.” If there is a glenoid defect, the glenoid track narrows. When there is not any glenoid bone loss, the glenoid track is typically 83% of the diameter of the inferior glenoid (because the posterior glenoid pushes the cuff attachments 17% of the glenoid width posteriorly as the arm goes into forward abduction in external rotation). If there is a glenoid defect, then the glenoid track is narrowed by the width of the defect, so that the glenoid track (GT) = 0.83D − d where D = diameter of glenoid and d = width of glenoid defect (Fig. 3-33B, C). Hill-Sachs lesions typically occupy the part of the humerus that is in contact with the glenoid track. The larger the Hill- Sachs becomes, the closer it gets to the medial margin of the glenoid track. Once the Hill-Sachs lesion reaches the point where it extends medial to the medial margin of the glenoid track, the humeral articular surface is no longer supported by the anterior glenoid margin and the humerus “falls off” the edge of the glenoid, which then engages the Hill-Sachs. At that point, we call it an “off-track” Hill-Sachs lesion (Fig. 3-34).
FIGURE 3-33 A: At any point in shoulder motion, there is a contact point between the glenoid and the humeral articular surface, as shown by the glenoid outline in this schematic. As the arm is abducted in maximum external rotation, these individual contact “footprints” merge into a continuous “track” of contact on the humeral articular surface. This zone of contact on the humerus is defined as the “glenoid track.” B: When there is no glenoid bone loss, the glenoid track is 83% of the inferior glenoid diameter (0.83D). The contact between the glenoid articular surface and the humeral articular surface is not 100% of the glenoid diameter because the posterior glenoid rim pushes the rotator cuff attachments 17% posteriorly. C: When there is a glenoid defect, the glenoid track is reduced by the width of the defect. In this schematic, the width of the defect is “a,” so that the glenoid track in this case would be 0.83D − a, which is the length of the line “b” in this figure.
FIGURE 3-35 The medial margin of the Hill-Sachs lesion is located lateral to the glenoid rim, so the Hill-Sachs lesion cannot engage the anterior glenoid rim. This is an “on-track” Hill-Sachs lesion. GT, glenoid track; d, glenoid defect.
FIGURE 3-34 The medial margin of the Hill-Sachs lesion extends medial to the glenoid rim, allowing the Hill-Sachs lesion to engage the anterior glenoid rim. This is an “off-track” Hill-Sachs lesion. GT, glenoid track; d, glenoid defect.
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FIGURE 3-36 Glenoid bone loss can be quantified with a three-dimensional computed tomography of the (A) normal and (B) affected extremities. The percentage of glenoid bone loss can be easily calculated on the en face view by comparing the inferior glenoid diameter of the normal side to that of the affected side.
FIGURE 3-37 Case with no bony defect of glenoid (A) and medium-sized Hill-Sachs lesion (B) . By use of the contralateral glenoid as a reference (100%), 83% width is determined, which is the distance from the medial margin of the footprint of the rotator cuff to the medial margin of the glenoid track. Dotted line G indicates the location of the medial margin of the glenoid track. Dotted line R represents the medial margin of the rotator cuff attachments. This Hill-Sachs lesion is on track because it lies totally within the glenoid track.
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The only thing that remains to be determined is whether or not the medial aspect of the Hill-Sachs lesion extends medial to the glenoid track, and if it does, then the Hill- Sachs lesion is off-track since the anterior glenoid rim will engage the Hill-Sachs lesion (see Fig. 3-34). In determining the medial extent of the Hill-Sachs lesion, it is useful to keep in mind the concept of the Hill-Sachs interval (HSI), which is the width of the Hill- Sachs lesion (HS) plus the width of the bone bridge (BB) between the rotator cuff attachments and the lateral aspect of the Hill-Sachs lesion: HSI HS BB = + If HSI > GT, the Hill-Sachs lesion is off-track and will engage the anterior glenoid. If HSI < GT, the Hill-Sachs lesion is on track and will not engage the anterior glenoid (see Fig. 3-35). The problem with using the 3D CT scan to measure HSI is that the bony ridge where the posterior cuff attaches is often indistinct and very difficult if not impossible to accu- rately locate on the CT scan. Therefore, we prefer to obtain all our measurements arthroscopically. In obtaining arthroscopic measurements, we first look at the glenoid through an anterosuperolateral portal. Through a posterior working portal, we insert a calibrated
The 3D CT scan can be used for obtaining these mea- surements. In terms of the glenoid, there are two important measurements: 1. The diameter (D) of the intact inferior glenoid (i.e., the diameter before any bone loss, either traumatic or attritional) and 2. The width (d) (Fig. 3-38) of the bone loss from the anterior glenoid (either attritional from compression or erosion due to repetitive dislocations, or traumatic with a bony Bankart fragment). Yamamoto et al. 7 have shown that the glenoid track width (GT) can be calculated as follows: GT D d = 0 83. − The inferior glenoid diameter (D) can easily be mea- sured from the en face 3D view of the normal glenoid (see Fig. 3-36A). The width of glenoid bone loss (d) can be calculated by subtracting the width of the inferior glenoid diameter on the involved side (D 1 ) from the inferior gle- noid diameter on the normal side (D): d D D = − 1 Now that we know both D and d, we can calculate the width of the glenoid track (GT = 0.83D − d).
FIGURE 3-38 Case with bony defect of glenoid (A) and large Hill-Sachs lesion (B) . By use of the contralateral glenoid as a reference (100%), 83% width is determined ( black double-headed arrow ). Then, the defect width (d) is subtracted from this 83% length to obtain the glenoid track width for this case ( white double-headed arrow ). Dotted line R represents the medial margin of the rotator cuff attachments. It should be noted that there is normally an intact “bone bridge” between the cuff attachments and the lateral border of the Hill-Sachs lesion. Dotted line G1 indicates the location of the medial margin of the glenoid track. If there had been no glenoid bony defect, the medial margin of the glenoid track would have been dotted line G2 . In this case, the Hill-Sachs lesion extends medially beyond the medial margin of the glenoid track ( dotted line G1 ), so this is an off- track lesion.
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