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Treatment of the Unstable Shoulder With Humeral Head Bone Loss
PROCEDURE 23
Treatment of the Unstable Shoulder With Humeral Head Bone Loss Anthony Miniaci and Mia Smucny INDICATIONS PITFALLS
• Failure to recognize the contribution of a significant humeral head defect (in addition to the capsulolabral deficiency) in a patient with symptomatic anterior glenohumeral instability can result in continued shoulder instability if only the Bankart lesion is addressed at the primary operation. • Contraindications include advanced glenohumeral arthrosis, an existing infection, and unaddressed or irreparable rotator cuff deficiency.
INDICATIONS CONTROVERSIES
• Large Hill-Sachs lesions that “fall into” the glenoid rim with the shoulder in a functional position of abduction and external rotation (i.e., “engaging” Hill-Sachs lesions), if they are identified prior to undergoing initial surgical treatment, can be addressed as part of the primary anterior stabilization procedure. • Patients who are at a high risk of redislocation (e.g., epilepsy with recurrent anterior instability and large Hill-Sachs defects) may have their humeral head defect addressed at the primary operation. • Challenges related to allograft reconstruction include graft availability and potential hardware failure or graft resorption. Use of partial resurfacing arthroplasty eliminates the potential hardships of allograft reconstruction; however, there are no published long-term studies on resurfacing implants at this time.
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INDICATIONS • The indications for anatomic allograft reconstruction of humeral head defects are ongoing symptomatic anterior glenohumeral instability or painful clicking, catching, or popping in a patient with a large engaging Hill-Sachs lesion. • Partial humeral head resurfacing with a prosthesis is an emerging alternative technique to allograft reconstruction for the management of significant humeral head bone loss. • These procedures are often used as a secondary operation in patients who have failed previous soft tissue stabilization procedures.
EXAMINATION/IMAGING • Systematic physical examination of the shoulder with a humeral head defect should first focus on inspection for previous incisions or asymmetry to the unaffected shoulder. • Additional examination includes: • Thorough assessment of active and passive shoulder range of motion. • Evaluation of the integrity and strength of the rotator cuff, compared to the unaffected arm. • Detailed examination for glenohumeral laxity in the anterior, posterior, and inferior directions. • An apprehension examination should be performed in multiple arm positions in patients with Hill-Sachs lesions. Patients with large Hill-Sachs lesions will typically exhibit apprehension with the arm in significantly less than 90 degrees of abduction and 90 degrees of external rotation. • Plain radiographs • Anteroposterior (AP) in internal and external rotation, true AP of the glenohumeral joint, axillary lateral, and Stryker notch view of the involved shoulder. • Plain radiographs often significantly underestimate the size of the Hill-Sachs defect. Fig. 23.1 shows AP (Fig. 23.1A) and axillary lateral (Fig. 23.1B) views of a large Hill-Sachs defect in a patient with a history of recurrent anterior shoulder dislocations. • Computed tomography (CT) • All patients should have a preoperative axial CT imaging study to more fully define the bony architecture, morphology, and articular arc defect of the Hill-Sachs lesion. • Care must be taken when interpreting these axial studies, since the plane of the Hill-Sachs defect is oblique to the plane of the axial image and, therefore, the size of these defects may be underestimated on axial cuts. • Fig. 23.2 shows axial (see Fig. 23.2A) and coronal (see Fig. 23.2B) CT images of a patient with recurrent anterior shoulder dislocations. There is a large engaging Hill-Sachs lesion seen in the posterosuperolateral humeral head. Note that the patient had a previous open reduction and internal fixation of a greater tuberosity fracture fixed with two screws, which are seen within the images. • Three-dimensional CT reconstructions can aid in more clearly defining the size and location of the defect and to provide an estimation of the amount of articular surface involved.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
A
B FIG. 23.1 A–B
A
B FIG. 23.2 A–B
• Magnetic resonance imaging (MRI) • MRI will aid in the assessment of associated soft tissue injury as well as provide details of the bony defect. Axial MRI can also be helpful in identifying not only the bony anatomy of a large Hill-Sachs defect but also the soft tissue pathology associated with anterior shoulder dislocations (Figs. 23.3 and 23.4). • Dynamic MRI with the arm in abduction and external rotation may be of value when attempting to determine the contribution of the bony defect when the shoulder is in a position of instability. • CT scan (standard or three-dimensional reconstruction) and/or MRI data are used preoperatively to determine the appropriate size of a humeral head allograft prior to allograft reconstruction. Plain radiographs with magnification markers can also be used. Appropriate sizing of a proximal humeral allograft requires a specific protocol to be arranged between the surgeon and the supplying tissue bank. • For partial resurfacing, templating can be based preoperatively off radiographs and then fine-tuned for final sizing at the time of surgery.
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PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
FIG. 23.3
TREATMENT OPTIONS
• Conventional guidelines suggest that nonoperative treatment can be undertaken for humeral head defects that involve less than 25% of the articular surface without clinical signs of glenohumeral instability. • Surgical options for symptomatic engaging defects that involve 25%–40% of the humeral head articular surface are quite varied in the literature. These include open anterior procedures, such as open capsular shift, designed to limit external rotation such that the humeral head defect is kept from engaging; rotational proximal humeral osteotomy; transfer of the infraspinatus into the defect to render the lesion essentially extraarticular or an arthroscopic remplissage; or filling in of the Hill-Sachs defect so that it can no longer engage, using either a corticocancellous iliac graft, femoral head osteoarticular allograft, or partial resurfacing implant. If the defect is severe (i.e., >45% or severe articular involvement), prosthetic replacement using either hemiarthroplasty or a total shoulder arthroplasty is recommended, especially in the setting of chronic dislocations and arthritis.
FIG. 23.4
SURGICAL ANATOMY • A standard deltopectoral approach is used. • Anatomic landmarks include: • Anterior, lateral, and posterior borders of the acromion • Coracoid process • Acromioclavicular joint • Deltopectoral groove • Superficial dissection • The internervous plane is between the deltoid muscle (axillary nerve) and the pectoralis major muscle (medial and lateral pectoral nerves). • The cephalic vein is identified. • Retraction of the pectoralis major medially and the deltoid laterally exposes the conjoined tendon. • Deep dissection • The conjoined tendon is retracted medially, taking care to avoid injury to the musculocutaneous nerve. The nerve enters the body of the coracobrachialis medially about 5–8 cm distal to the muscle’s origin at the coracoid process. • A triad of the anterior humeral circumflex vessels traverses and indicates the inferior border of the subscapularis muscle. • The axillary nerve lies deep to the anterior humeral circumflex vessels and superficial to the subscapularis muscle at the level of the glenoid. It then courses directly inferior to the glenoid and can be damaged by aggressive dissection of the inferior labrum. • The subscapularis muscle tendon is transected vertically in its entirety 0.5 cm medial to its insertion on the lesser tuberosity and tagged with sutures for later repair. • The interval between the subscapularis and the anterior/inferior capsule is carefully developed using sharp dissection, continuing medial to the glenoid neck. • Further details regarding the approach to the humeral head chondral defect are described in the Portals/Exposures section.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
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FIG. 23.5
POSITIONING • After the administration of general endotracheal anesthesia, the patient is positioned in the modified beach chair position with the head of the bed raised 30–45 degrees. Regional anesthesia is a matter of surgeon preference; we prefer use of postoperative interscalene block so that a reliable neurologic exam can be taken after surgery. • A bump is placed under the medial border of the scapula, and the involved upper extremity should be free to allow for maximal external rotation and extension as needed. • Examination under anesthesia (EUA) can be undertaken at this point. • Diagnostic arthroscopy may be undertaken prior to open intervention, although it is not always necessary. • In Fig 23.5, diagnostic arthroscopy reveals chondral damage on the glenoid and an absence of the anteroinferior labrum in a patient with a history of recurrent anterior shoulder dislocations.
PORTALS/EXPOSURES • After appropriate positioning of the patient in the beach chair position, a standard deltopectoral approach is used. • An incision of approximately 6–10 cm in line with the deltopectoral groove is made, extending from the tip of the coracoid and directed distally toward the axilla to improve cosmesis (Video 23.1) • The deltopectoral interval is developed, and the cephalic vein is taken laterally. The interval and cephalic vein are most easily identified at the superior portion of the exposure. Lateral retraction of the cephalic vein is preferred because it helps preserve venous outflow from the deltoid. • The deltoid and pectoralis major muscles are retracted bluntly. • The lateral border of the conjoined tendon is identified and gently retracted medially to expose the underlying subscapularis muscle. A blunt retractor placed under the conjoined tendon will facilitate exposure while minimizing risk to the musculocutaneous nerve. • The bursa atop the subscapularis muscle insertion is identified and removed. The anterior humeral circumflex vessels, which define the inferior aspect of the subscapularis tendon, are located and ligated.
POSITIONING PEARLS
• EUA will allow the surgeon to assess the degree and position of instability and to determine if a given humeral head defect “engages” the glenoid rim in a functional arm position. In turn, EUA will enable the surgeon to confirm that maximal range of motion of the shoulder can be achieved with operative positioning of the patient. • When undertaking reconstruction of humeral head defects either with matched allograft or with prosthetic resurfacing, some surgeons may elect to obtain intraoperative fluoroscopic images to judge the reconstruction. If so, the surgical team should ensure that adequate views will be acquired with the given patient position. To do so, it is recommended that the desired views be obtained with the fluoroscopic machine after patient positioning and prior to prepping and draping of the patient.
POSITIONING PITFALLS
• Care must be taken to ensure that the entire involved extremity has been draped free, allowing for maximal range of motion of the shoulder as needed to address the defect. POSITIONING CONTROVERSIES
• Diagnostic arthroscopy prior to open intervention is useful to assess the soft tissue and chondral injury as well as the size, location, and “behavior” of the humeral head defect in various arm positions.
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PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
PORTALS/EXPOSURES PEARLS
• It is important to separate the subscapularis and the capsule medial to the joint line to address a Bankart lesion if necessary. • Unroofing the synovial expansion of the supraspinatus, which overlies the tendon of the long head of the biceps, will allow the humerus to be more fully externally rotated, allowing better visualization and access to the Hill-Sachs lesion. • We recommend against use of anesthetic paralysis during the case to avoid inadvertent damage to the musculocutaneous and axillary nerves during dissection. PORTALS/EXPOSURES PITFALLS
• Anterior-inferior capsular release from the anatomic neck of the humerus is an important step to obtain adequate exposure. Take care to release the capsule directly off of bone to minimize risk to the axillary nerve.
PORTALS/EXPOSURES CONTROVERSIES
• The anterior capsule and the subscapularis can be left together and elevated as one complex; however, we prefer to repair the capsulolabral structures separately, particularly in cases where capsular tightening is needed. • It has been described by some authors that patients with recurrent anterior instability and large humeral head defects can be addressed first arthroscopically (Bankart lesion), and then via a limited posterior approach to the humeral head to address the Hill-Sachs defect (Kropf and Sekiya, 2007). For allograft reconstruction and prosthetic resurfacing of humeral head defects, we feel that the deltopectoral approach is still the “gold standard” and most familiar approach.
STEP 1 PEARLS
• To best restore the native anatomy and improve chances of appropriate healing, care should be given to creating precise, flat surfaces along the base and sides of the defect that will allow for the best fit for the donor allograft. This can be accomplished by further smoothing the defect edges with a hand rasp. • It is best to err on the side of creating a larger allograft plug that can be fine-tuned to fit the defect, as little can be done if the allograft piece is too small. If the donor piece has some irregular contours at the edges, bone graft can be used to fill in these small edges of incongruity to exact a better fit of the allograft (see Fig. 23.12).
STEP 1 PITFALLS
• Failure to recognize that adjustments in one plane will affect the final size of the allograft in the other two dimensions will result in a graft that is mismatched to the recipient defect.
FIG. 23.6
• Tag sutures are placed in the lateral aspect of the subscapularis tendon to help retract the tendon and for definitive repair at the conclusion of the procedure. The entire tendon is transected vertically 0.5–1 cm medial to its insertion onto the lesser tuberosity. As the subscapularis tendon is released, external rotation and adduction of the humerus will help minimize the risk of injury to the axillary nerve at this point. • Using sharp dissection, the interval between the subscapularis and the anterior capsule is then carefully developed, continuing medial to the neck of the glenoid. The inferior capsule is then further isolated using careful blunt dissection with a medium Cobb elevator. Separate tag sutures are placed in the capsule for later repair. • A laterally based capsulotomy is made with the vertical limb in line with the subscapularis incision and continuing superiorly. If a Bankart lesion will be addressed, the capsule is taken directly off the glenoid for exposure and future capsular tightening and the rotator interval capsule is released between the subscapularis and the anterior edge of the supraspinatus. • The anterior-inferior capsule is released off of the surgical neck of the humerus with intraarticular dissection using a periosteal elevator. • A humeral head retractor (i.e., Fukuda) is placed into the glenohumeral joint to allow inspection of the glenoid and anterior/inferior capsulolabral structures for any pathology. • If a Bankart lesion or glenoid bone loss is present, we prefer to address this after fully addressing the humeral defect. • The humeral head retractor is removed and the humerus is extended and brought into maximal external rotation to expose the Hill-Sachs lesion. • A flat, narrow retractor is then placed in a position over the reflected undersurface of the subscapularis tendon and behind the neck of the humerus on the posterior cuff to lever out the humeral head and present the Hill-Sachs lesion for reconstruction (Fig. 23.6).
PROCEDURE: ALLOGRAFT RECONSTRUCTION Step 1 • After adequate exposure of the Hill Sachs defect, a microsagittal saw is used to smooth and reshape the defect into a chevron-type configuration and to provide a bed of bleeding subchondral bone onto which the allograft will be fixed. The chevrontype defect should be constructed so as to correspond to a wedge-shaped piece of matching allograft humeral head that will press-fit into the defect (Fig. 23.7). • Required measurements of the defect are then obtained. Fig. 23.8 shows a schematic of the base (x), height (y), length (z), and outside partial circumference (c) of the defect; the graft is sculpted to match the defect to the nearest millimeter.
Step 2 • The anatomic quadrant of the matched humeral head allograft that corresponds to the location of the defect on the humeral head is identified and marked (Fig. 23.9).
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
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c y
x z
FIG. 23.7
FIG. 23.8
FIG. 23.9
FIG. 23.10
• A chevron-type defect is cut from the allograft humeral head. This wedge is approximately 2–3 mm larger in all dimensions than the measured defect (Fig. 23.10). • The allograft segment is then provisionally placed into the Hill-Sachs defect and resized in all three planes. Excess length is then carefully trimmed with the microsagittal saw. It is also very important to reshape the graft in the other two planes to ensure appropriate size and match. • Fine-tuning of graft size is then continued in one plane at a time until a perfect size match is achieved in all planes, including base, height, length, and outside partial circumference.
STEP 2 CONTROVERSIES
• Headless, variable-pitch compression screws may also be used for allograft fixation. Nonetheless, it is absolutely imperative that the screw heads be countersunk below the articular cartilage. Moving the shoulder through a range of motion intraoperatively will help ensure this.
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PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
FIG. 23.11
FIG. 23.12
Step 3 • Once the appropriate size and configuration are obtained, the allograft is placed into the defect and aligned so as to achieve a congruent articular surface. • The allograft is then provisionally secured in place with two or three smooth 0.045inch Kirschner wires (Fig. 23.11). • The wires are then sequentially replaced with 3.5-mm fully threaded cortical screws placed in a lag fashion. The screw heads are countersunk so that they are below the level of the articular surface. Fig. 23.12 presents an intraoperative view of the final fixation of the allograft secured with two screws.
Step 4 • The joint is then copiously irrigated, and the shoulder is taken through a range of motion to ensure that the reconstructed humeral head provides a smooth, congruent articulating surface. • Absorbable suture is used to close the capsulotomy, and any previously placed sutures that were used to repair the capsulolabral pathology (if present) are tied. Capsular tightening can be performed if necessary. • The subscapularis tendon is then reapproximated to its stump anatomically with nonabsorbable suture, taking care not to shorten the tendon. • The conjoined tendon, deltoid, and pectoralis major muscles are allowed to fall back into their normal anatomic positions, and the deltopectoral interval is not closed. • The subcutaneous layer is closed with a 2-0 absorbable stitch, and a running 4-0 absorbable subcuticular suture is used to approximate the skin.
PROCEDURE: HUMERAL HEAD PARTIAL RESURFACING ARTHROPLASTY • Surgical approach and exposure of the Hill Sachs defect for partial resurfacing arthroplasty (HemiCAP prosthesis; Arthrosurface, Franklin, Massachusetts) is the same as described previously in the chapter. • Once exposed, a drill guide that fully circumscribes the lesion is centered over the defect and a guide pin advanced into the humeral head (Fig. 23.13 and Video 23.2). The drill guide determines the appropriate diameter to cover the defect and establishes perpendicularity. There should be at least four points of contact between the guide and the articular surface.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
A FIG. 23.13
B
C FIG. 23.14 A–C
A FIG. 23.15
B FIG. 23.16 A–B
• A cannulated drill (Fig. 23.14, A) and tap (Fig 23.14, B) are sequentially placed over the guide pin followed by insertion of a permanent taper post (Fig. 23.14, C). The height of the taper post is assessed to ensure that it is flush or slightly below the articular cartilage surface to avoid proud placement of the final implant. In case of osteopenic bone, cement may be injected to secure the post. • A sizing probe is inserted into the taper post to obtain the appropriate size of the articular component (Fig. 23.15). Sizing should be obtained and recorded for four index points: superior/inferior and medial/lateral. • The appropriately sized surface reamer (Fig. 23.16, A) is placed over the guide pin and advanced into the cancellous bone until the reamer makes contact with the top of the taper post (Fig. 23.16, B). Care should be taken to avoid bending the guide pin, as this will result in malaligned reaming. • Trial implant is placed in position to confirm correct sizing. • The final articular component is then placed in proper orientation and firmly seated into the morse taper post with an impactor (Fig. 23.17). The surface of the implant should be flush with the articular cartilage (Fig. 23.18). • After thorough irrigation and addressing any glenoid deficiency, the capsulolabral repair and wound closure proceeds as in the previous section.
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FIG. 23.18
FIG. 23.17
A
B FIG. 23.19 A–B
POSTOPERATIVE CARE AND EXPECTED OUTCOMES • After surgery, the patient is placed in a sling for comfort. • We restrict passive external rotation for 6 weeks due to the subscapularis detachment and repair. Otherwise, full passive range of motion as tolerated is allowed immediately in all other planes. • Due to the subscapularis detachment, the patient is protected against active and resisted internal rotation for a period of 6 weeks. After the initial 6-week period, patients are allowed terminal stretching and strengthening exercises. • Shoulders are imaged with repeat radiographs at 6 weeks and 6 months. Postoperative radiographs showing anatomic allograft reconstruction of an engaging HillSachs defect are shown in Fig. 23.19. For the humeral head allograft procedure, a CT scan is obtained at 6 months to assess for consolidation and incorporation of the graft. Postoperative radiographs from the partial resurfacing arthroplasty at 6 weeks are shown in Fig. 23.20 (this patient also received a glenoid allograft reconstruction). • The patient is generally not cleared for return to sport or strenuous overhead activity until at least 6 months after the date of surgery. For the allograft procedure, we look for radiographic evidence of graft consolidation prior to final clearance.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
A
B FIG. 23.20 A–B
Expected Outcomes for Allograft Reconstruction • Published reports of allograft reconstruction of humeral head defects are mostly limited to case reports or small case series, with follow-up data ranging from 2 to 5 years. • In the largest study of anatomic allograft reconstruction of humeral head defects in patients who failed previous attempts at surgical stabilization, this technique of allograft reconstruction has been shown to be effective (Miniaci and Gish, 2004). Patients demonstrated improvement in stability, loss of apprehension, and high subjective approval, allowing return to near-normal function with no further episodes of instability at average of 50 months’ follow-up. • More recent case series looking at the treatment of reverse Hill-Sachs lesions with matched allograft reconstruction following posterior locked shoulder dislocations have also shown good results, with improvements in patient satisfaction rates and functional assessment scores.
Expected Outcomes for Partial Resurfacing Arthroplasty • Published reports for partial resurfacing arthroplasty are limited to case reports and small series. The largest published series (Raiss et al., 2009) demonstrated a 41-point increase in Constant score with mean follow-up of 2 years among patients with fixed anterior glenohumeral dislocation. There were no clinical or radiographic signs of component loosening. One patient had recurrent instability.
Complications • Complications that have been reported after humeral osteoarticular allograft reconstruction of Hill-Sachs lesions include radiographic follow-up evidence of partial graft collapse, failure at the graft-host junction, early evidence of osteoarthritis, continued sensation of catching and/or subluxation, and hardware complications in extreme external rotation (which was relieved after removal of the screws 2 years postoperatively). • To date there is no evidence of implant-interface loosening or osteolysis after partial humeral resurfacing arthroplasty for Hill-Sachs defects. Long-term studies are needed. • Although infrequently a cause for clinical concern, Hill-Sachs defects can be the source of significant disability and recurrent instability in a subset of patients. Anatomic allograft reconstruction or partial humeral head resurfacing arthroplasty of these defects are viable treatment options resulting in favorable clinical outcomes, although long-term studies are still needed.
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EVIDENCE Currently in the literature, there are no prospective, randomized Level I trials that clinically or biomechanically compare the various treatment options for large defects of the humeral head. Most published reports examining osteoarticular allograft reconstruction and partial resurfacing arthroplasty for the treatment for Hill-Sachs defects are limited to case series with few patients and short-term follow-up. Burkhart SS, De Beer JF. Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs: significance of the inverted-pear glenoid and the humeral engaging HillSachs lesion. Arthroscopy. 2000;16:677–94. This case series analyzed the results of 194 consecutive arthroscopic Bankart repairs by suture anchor technique (performed by two surgeons with an identical suture anchor technique) to identify specific factors related to recurrence of instability. The average follow-up was 27 months. There were 101 contact athletes, and the authors identified significant bone defects on either the humerus or the glenoid. The authors found 14 recurrent dislocations and 7 recurrent subluxations. Of those 21 shoulders with recurrent instability, 14 had significant bone defects. For contact athletes without significant bone defects, there was a 6.5% recurrence rate, whereas for contact athletes with significant bone defects, there was an 89% recurrence rate. The authors concluded that arthroscopic Bankart repairs give results equal to open Bankart repairs if there are no significant structural bone deficits. However, contact athletes with bone deficiency require open surgery aimed at their specific anatomic deficiencies. Delaney RA, Freehill MT, Higgins LD, Warner JJP. Durability of partial humeral head resurfacing. J Shoulder Elbow Surg. 2014;23:e14–22. Retrospective review of 39 shoulders who underwent partial resurfacing arthroplasty for a variety of indications, including traumatic arthritis, avascular necrosis, and Hill-Sachs lesions, with an average follow-up of 26.6 months. While six patients of the total cohort underwent revision procedure due to progression of arthritis, none of the instability cases (four patients) required revision surgery. Gerber C, Lambert SM. Allograft reconstruction of segmental defects of the humeral head for the treatment of chronic locked posterior dislocation of the shoulder. J Bone Joint Surg [Am]. 1996;78:376–82. The authors presented a case series of four consecutive patients who had a chronic locked posterior dislocation of the glenohumeral joint, associated with a defect of the humeral head that was at least 40% of the articular surface, who were managed with reconstruction of the shape of the humeral head with use of an allogenic segment of the femoral head. Stability was restored and maintained in each patient at an average of 68 months after the procedure. Three patients reported little or no pain and no or slight functional restrictions in the activities of daily living, and they considered the result to be satisfactory. The fourth patient had mild pain and moderate to severe dysfunction secondary to avascular necrosis of the remaining portion of the humeral head after a symptom-free period of 6 years. Giles JW, Elkinson I, Ferreira LM, et al. Moderate to large engaging Hill-Sachs defects: an in vitro biomechanical comparison of the remplissage procedure, allograft humeral head reconstruction, and partial resurfacing arthroplasty. J Shoulder and Elbow Surg. 2012;21:1142–51. A biomechanical study comparing remplissage to allograft reconstruction and partial resurfacing arthroplasty for moderate to large engaging Hill-Sachs defects. Investigators found that while all three procedures effectively improve stability, remplissage significantly restricted range of motion compared to the intact state by 12–17 degrees in internal/external rotation. In their model, the partial resurfacing arthroplasty did experience residual defect engagement, but this was because the investigators accepted coverage mismatch of the implant over the defect. Kropf EJ, Sekiya JK. Osteoarticular allograft transplantation for large humeral head defects in glenohumeral instability. Arthroscopy. 2007;23:322e1–5. The authors use a limited posterior approach to address a Hill-Sachs lesion with allograft transplantation, combined with arthroscopy for anterior labral repair. Their goals were to preserve range of motion in a highly athletic population by avoiding an open anterior approach. They report a case report with one year outcomes. Martinez AA, Calvo A, Domingo J, Cuenca J, Herrera A, Malillos M. Allograft reconstruction of segmental defects of the humeral head associated with posterior dislocations of the shoulder. Injury. 2008;39:319–22. This case series looked at six patients who underwent operative management of large humeral head defects involving at least 40% of the articular surface following posterior humeral head dislocation. Time between dislocation and surgery ranged from 7 to 8 weeks. All defects were treated with humeral head allograft reconstruction and followed for mean of 63 months. Four patients had improved subjective scores. Two patients had a poor clinical result and were found to have flattening and collapse of the graft at their last radiographic follow-up. Miniaci A, Gish MW. Management of anterior glenohumeral instability associated with large Hill-Sachs defects. Tech Shoulder Elbow Surg. 2004;5:170–5. In this largest case series reviewing osteoarticular allograft reconstruction for large humeral head defects, the authors performed the above-described procedure on 18 patients with failed previous attempts at surgical stabilization and defects comprising greater than 25% of the humeral head.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss Patients were assessed pre- and postoperatively with history, physical examination, imaging, as well as validated clinical evaluation measures (Constant-Murley shoulder scale, Western Ontario Shoulder Instability Index, and Short Form-36). All patients demonstrated improvement in stability, loss of apprehension, and high subjective approval, allowing return to near-normal function with no further episodes of instability at average of 50 months’ follow-up. Raiss P, Aldinger PR, Kasten P, Rickert M, Loew M. Humeral head resurfacing for fixed anterior glenohumeral dislocation. Int Othop. 2009;33:451–6. Case series of 10 shoulders that underwent cementless humeral surface replacement arthroplasty after fixed anterior dislocation. Average age was 67 years and follow-up was 2 years. Constant scores improved from 20 points to 61 points postoperatively. There were no clinical or radiographic signs of component failure by final follow-up. One patient had recurrent instability. Sweet SJ, Takara T, Ho L, Tibone JE. Primary partial humeral head resurfacing: outcomes with the HemiCAP implant. AJSM. 2015;43:579–87. Retrospective case series of 20 shoulders that underwent partial resurfacing for osteoarthritis. With mean follow-up period of 32.7 months (range 17–66 months), there was no radiographic evidence of periprosthetic fracture, component loosening, osteolysis, or device failure. Prosthesis survival could be extrapolated to the instability population.
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Treatment of the Unstable Shoulder With Humeral Head Bone Loss Anthony Miniaci and Mia Smucny INDICATIONS PITFALLS
• Failure to recognize the contribution of a significant humeral head defect (in addition to the capsulolabral deficiency) in a patient with symptomatic anterior glenohumeral instability can result in continued shoulder instability if only the Bankart lesion is addressed at the primary operation. • Contraindications include advanced glenohumeral arthrosis, an existing infection, and unaddressed or irreparable rotator cuff deficiency.
INDICATIONS CONTROVERSIES
• Large Hill-Sachs lesions that “fall into” the glenoid rim with the shoulder in a functional position of abduction and external rotation (i.e., “engaging” Hill-Sachs lesions), if they are identified prior to undergoing initial surgical treatment, can be addressed as part of the primary anterior stabilization procedure. • Patients who are at a high risk of redislocation (e.g., epilepsy with recurrent anterior instability and large Hill-Sachs defects) may have their humeral head defect addressed at the primary operation. • Challenges related to allograft reconstruction include graft availability and potential hardware failure or graft resorption. Use of partial resurfacing arthroplasty eliminates the potential hardships of allograft reconstruction; however, there are no published long-term studies on resurfacing implants at this time.
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INDICATIONS • The indications for anatomic allograft reconstruction of humeral head defects are ongoing symptomatic anterior glenohumeral instability or painful clicking, catching, or popping in a patient with a large engaging Hill-Sachs lesion. • Partial humeral head resurfacing with a prosthesis is an emerging alternative technique to allograft reconstruction for the management of significant humeral head bone loss. • These procedures are often used as a secondary operation in patients who have failed previous soft tissue stabilization procedures.
EXAMINATION/IMAGING • Systematic physical examination of the shoulder with a humeral head defect should first focus on inspection for previous incisions or asymmetry to the unaffected shoulder. • Additional examination includes: • Thorough assessment of active and passive shoulder range of motion. • Evaluation of the integrity and strength of the rotator cuff, compared to the unaffected arm. • Detailed examination for glenohumeral laxity in the anterior, posterior, and inferior directions. • An apprehension examination should be performed in multiple arm positions in patients with Hill-Sachs lesions. Patients with large Hill-Sachs lesions will typically exhibit apprehension with the arm in significantly less than 90 degrees of abduction and 90 degrees of external rotation. • Plain radiographs • Anteroposterior (AP) in internal and external rotation, true AP of the glenohumeral joint, axillary lateral, and Stryker notch view of the involved shoulder. • Plain radiographs often significantly underestimate the size of the Hill-Sachs defect. Fig. 23.1 shows AP (Fig. 23.1A) and axillary lateral (Fig. 23.1B) views of a large Hill-Sachs defect in a patient with a history of recurrent anterior shoulder dislocations. • Computed tomography (CT) • All patients should have a preoperative axial CT imaging study to more fully define the bony architecture, morphology, and articular arc defect of the Hill-Sachs lesion. • Care must be taken when interpreting these axial studies, since the plane of the Hill-Sachs defect is oblique to the plane of the axial image and, therefore, the size of these defects may be underestimated on axial cuts. • Fig. 23.2 shows axial (see Fig. 23.2A) and coronal (see Fig. 23.2B) CT images of a patient with recurrent anterior shoulder dislocations. There is a large engaging Hill-Sachs lesion seen in the posterosuperolateral humeral head. Note that the patient had a previous open reduction and internal fixation of a greater tuberosity fracture fixed with two screws, which are seen within the images. • Three-dimensional CT reconstructions can aid in more clearly defining the size and location of the defect and to provide an estimation of the amount of articular surface involved.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
A
B FIG. 23.1 A–B
A
B FIG. 23.2 A–B
• Magnetic resonance imaging (MRI) • MRI will aid in the assessment of associated soft tissue injury as well as provide details of the bony defect. Axial MRI can also be helpful in identifying not only the bony anatomy of a large Hill-Sachs defect but also the soft tissue pathology associated with anterior shoulder dislocations (Figs. 23.3 and 23.4). • Dynamic MRI with the arm in abduction and external rotation may be of value when attempting to determine the contribution of the bony defect when the shoulder is in a position of instability. • CT scan (standard or three-dimensional reconstruction) and/or MRI data are used preoperatively to determine the appropriate size of a humeral head allograft prior to allograft reconstruction. Plain radiographs with magnification markers can also be used. Appropriate sizing of a proximal humeral allograft requires a specific protocol to be arranged between the surgeon and the supplying tissue bank. • For partial resurfacing, templating can be based preoperatively off radiographs and then fine-tuned for final sizing at the time of surgery.
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FIG. 23.3
TREATMENT OPTIONS
• Conventional guidelines suggest that nonoperative treatment can be undertaken for humeral head defects that involve less than 25% of the articular surface without clinical signs of glenohumeral instability. • Surgical options for symptomatic engaging defects that involve 25%–40% of the humeral head articular surface are quite varied in the literature. These include open anterior procedures, such as open capsular shift, designed to limit external rotation such that the humeral head defect is kept from engaging; rotational proximal humeral osteotomy; transfer of the infraspinatus into the defect to render the lesion essentially extraarticular or an arthroscopic remplissage; or filling in of the Hill-Sachs defect so that it can no longer engage, using either a corticocancellous iliac graft, femoral head osteoarticular allograft, or partial resurfacing implant. If the defect is severe (i.e., >45% or severe articular involvement), prosthetic replacement using either hemiarthroplasty or a total shoulder arthroplasty is recommended, especially in the setting of chronic dislocations and arthritis.
FIG. 23.4
SURGICAL ANATOMY • A standard deltopectoral approach is used. • Anatomic landmarks include: • Anterior, lateral, and posterior borders of the acromion • Coracoid process • Acromioclavicular joint • Deltopectoral groove • Superficial dissection • The internervous plane is between the deltoid muscle (axillary nerve) and the pectoralis major muscle (medial and lateral pectoral nerves). • The cephalic vein is identified. • Retraction of the pectoralis major medially and the deltoid laterally exposes the conjoined tendon. • Deep dissection • The conjoined tendon is retracted medially, taking care to avoid injury to the musculocutaneous nerve. The nerve enters the body of the coracobrachialis medially about 5–8 cm distal to the muscle’s origin at the coracoid process. • A triad of the anterior humeral circumflex vessels traverses and indicates the inferior border of the subscapularis muscle. • The axillary nerve lies deep to the anterior humeral circumflex vessels and superficial to the subscapularis muscle at the level of the glenoid. It then courses directly inferior to the glenoid and can be damaged by aggressive dissection of the inferior labrum. • The subscapularis muscle tendon is transected vertically in its entirety 0.5 cm medial to its insertion on the lesser tuberosity and tagged with sutures for later repair. • The interval between the subscapularis and the anterior/inferior capsule is carefully developed using sharp dissection, continuing medial to the glenoid neck. • Further details regarding the approach to the humeral head chondral defect are described in the Portals/Exposures section.
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FIG. 23.5
POSITIONING • After the administration of general endotracheal anesthesia, the patient is positioned in the modified beach chair position with the head of the bed raised 30–45 degrees. Regional anesthesia is a matter of surgeon preference; we prefer use of postoperative interscalene block so that a reliable neurologic exam can be taken after surgery. • A bump is placed under the medial border of the scapula, and the involved upper extremity should be free to allow for maximal external rotation and extension as needed. • Examination under anesthesia (EUA) can be undertaken at this point. • Diagnostic arthroscopy may be undertaken prior to open intervention, although it is not always necessary. • In Fig 23.5, diagnostic arthroscopy reveals chondral damage on the glenoid and an absence of the anteroinferior labrum in a patient with a history of recurrent anterior shoulder dislocations.
PORTALS/EXPOSURES • After appropriate positioning of the patient in the beach chair position, a standard deltopectoral approach is used. • An incision of approximately 6–10 cm in line with the deltopectoral groove is made, extending from the tip of the coracoid and directed distally toward the axilla to improve cosmesis (Video 23.1) • The deltopectoral interval is developed, and the cephalic vein is taken laterally. The interval and cephalic vein are most easily identified at the superior portion of the exposure. Lateral retraction of the cephalic vein is preferred because it helps preserve venous outflow from the deltoid. • The deltoid and pectoralis major muscles are retracted bluntly. • The lateral border of the conjoined tendon is identified and gently retracted medially to expose the underlying subscapularis muscle. A blunt retractor placed under the conjoined tendon will facilitate exposure while minimizing risk to the musculocutaneous nerve. • The bursa atop the subscapularis muscle insertion is identified and removed. The anterior humeral circumflex vessels, which define the inferior aspect of the subscapularis tendon, are located and ligated.
POSITIONING PEARLS
• EUA will allow the surgeon to assess the degree and position of instability and to determine if a given humeral head defect “engages” the glenoid rim in a functional arm position. In turn, EUA will enable the surgeon to confirm that maximal range of motion of the shoulder can be achieved with operative positioning of the patient. • When undertaking reconstruction of humeral head defects either with matched allograft or with prosthetic resurfacing, some surgeons may elect to obtain intraoperative fluoroscopic images to judge the reconstruction. If so, the surgical team should ensure that adequate views will be acquired with the given patient position. To do so, it is recommended that the desired views be obtained with the fluoroscopic machine after patient positioning and prior to prepping and draping of the patient.
POSITIONING PITFALLS
• Care must be taken to ensure that the entire involved extremity has been draped free, allowing for maximal range of motion of the shoulder as needed to address the defect. POSITIONING CONTROVERSIES
• Diagnostic arthroscopy prior to open intervention is useful to assess the soft tissue and chondral injury as well as the size, location, and “behavior” of the humeral head defect in various arm positions.
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PORTALS/EXPOSURES PEARLS
• It is important to separate the subscapularis and the capsule medial to the joint line to address a Bankart lesion if necessary. • Unroofing the synovial expansion of the supraspinatus, which overlies the tendon of the long head of the biceps, will allow the humerus to be more fully externally rotated, allowing better visualization and access to the Hill-Sachs lesion. • We recommend against use of anesthetic paralysis during the case to avoid inadvertent damage to the musculocutaneous and axillary nerves during dissection. PORTALS/EXPOSURES PITFALLS
• Anterior-inferior capsular release from the anatomic neck of the humerus is an important step to obtain adequate exposure. Take care to release the capsule directly off of bone to minimize risk to the axillary nerve.
PORTALS/EXPOSURES CONTROVERSIES
• The anterior capsule and the subscapularis can be left together and elevated as one complex; however, we prefer to repair the capsulolabral structures separately, particularly in cases where capsular tightening is needed. • It has been described by some authors that patients with recurrent anterior instability and large humeral head defects can be addressed first arthroscopically (Bankart lesion), and then via a limited posterior approach to the humeral head to address the Hill-Sachs defect (Kropf and Sekiya, 2007). For allograft reconstruction and prosthetic resurfacing of humeral head defects, we feel that the deltopectoral approach is still the “gold standard” and most familiar approach.
STEP 1 PEARLS
• To best restore the native anatomy and improve chances of appropriate healing, care should be given to creating precise, flat surfaces along the base and sides of the defect that will allow for the best fit for the donor allograft. This can be accomplished by further smoothing the defect edges with a hand rasp. • It is best to err on the side of creating a larger allograft plug that can be fine-tuned to fit the defect, as little can be done if the allograft piece is too small. If the donor piece has some irregular contours at the edges, bone graft can be used to fill in these small edges of incongruity to exact a better fit of the allograft (see Fig. 23.12).
STEP 1 PITFALLS
• Failure to recognize that adjustments in one plane will affect the final size of the allograft in the other two dimensions will result in a graft that is mismatched to the recipient defect.
FIG. 23.6
• Tag sutures are placed in the lateral aspect of the subscapularis tendon to help retract the tendon and for definitive repair at the conclusion of the procedure. The entire tendon is transected vertically 0.5–1 cm medial to its insertion onto the lesser tuberosity. As the subscapularis tendon is released, external rotation and adduction of the humerus will help minimize the risk of injury to the axillary nerve at this point. • Using sharp dissection, the interval between the subscapularis and the anterior capsule is then carefully developed, continuing medial to the neck of the glenoid. The inferior capsule is then further isolated using careful blunt dissection with a medium Cobb elevator. Separate tag sutures are placed in the capsule for later repair. • A laterally based capsulotomy is made with the vertical limb in line with the subscapularis incision and continuing superiorly. If a Bankart lesion will be addressed, the capsule is taken directly off the glenoid for exposure and future capsular tightening and the rotator interval capsule is released between the subscapularis and the anterior edge of the supraspinatus. • The anterior-inferior capsule is released off of the surgical neck of the humerus with intraarticular dissection using a periosteal elevator. • A humeral head retractor (i.e., Fukuda) is placed into the glenohumeral joint to allow inspection of the glenoid and anterior/inferior capsulolabral structures for any pathology. • If a Bankart lesion or glenoid bone loss is present, we prefer to address this after fully addressing the humeral defect. • The humeral head retractor is removed and the humerus is extended and brought into maximal external rotation to expose the Hill-Sachs lesion. • A flat, narrow retractor is then placed in a position over the reflected undersurface of the subscapularis tendon and behind the neck of the humerus on the posterior cuff to lever out the humeral head and present the Hill-Sachs lesion for reconstruction (Fig. 23.6).
PROCEDURE: ALLOGRAFT RECONSTRUCTION Step 1 • After adequate exposure of the Hill Sachs defect, a microsagittal saw is used to smooth and reshape the defect into a chevron-type configuration and to provide a bed of bleeding subchondral bone onto which the allograft will be fixed. The chevrontype defect should be constructed so as to correspond to a wedge-shaped piece of matching allograft humeral head that will press-fit into the defect (Fig. 23.7). • Required measurements of the defect are then obtained. Fig. 23.8 shows a schematic of the base (x), height (y), length (z), and outside partial circumference (c) of the defect; the graft is sculpted to match the defect to the nearest millimeter.
Step 2 • The anatomic quadrant of the matched humeral head allograft that corresponds to the location of the defect on the humeral head is identified and marked (Fig. 23.9).
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c y
x z
FIG. 23.7
FIG. 23.8
FIG. 23.9
FIG. 23.10
• A chevron-type defect is cut from the allograft humeral head. This wedge is approximately 2–3 mm larger in all dimensions than the measured defect (Fig. 23.10). • The allograft segment is then provisionally placed into the Hill-Sachs defect and resized in all three planes. Excess length is then carefully trimmed with the microsagittal saw. It is also very important to reshape the graft in the other two planes to ensure appropriate size and match. • Fine-tuning of graft size is then continued in one plane at a time until a perfect size match is achieved in all planes, including base, height, length, and outside partial circumference.
STEP 2 CONTROVERSIES
• Headless, variable-pitch compression screws may also be used for allograft fixation. Nonetheless, it is absolutely imperative that the screw heads be countersunk below the articular cartilage. Moving the shoulder through a range of motion intraoperatively will help ensure this.
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FIG. 23.11
FIG. 23.12
Step 3 • Once the appropriate size and configuration are obtained, the allograft is placed into the defect and aligned so as to achieve a congruent articular surface. • The allograft is then provisionally secured in place with two or three smooth 0.045inch Kirschner wires (Fig. 23.11). • The wires are then sequentially replaced with 3.5-mm fully threaded cortical screws placed in a lag fashion. The screw heads are countersunk so that they are below the level of the articular surface. Fig. 23.12 presents an intraoperative view of the final fixation of the allograft secured with two screws.
Step 4 • The joint is then copiously irrigated, and the shoulder is taken through a range of motion to ensure that the reconstructed humeral head provides a smooth, congruent articulating surface. • Absorbable suture is used to close the capsulotomy, and any previously placed sutures that were used to repair the capsulolabral pathology (if present) are tied. Capsular tightening can be performed if necessary. • The subscapularis tendon is then reapproximated to its stump anatomically with nonabsorbable suture, taking care not to shorten the tendon. • The conjoined tendon, deltoid, and pectoralis major muscles are allowed to fall back into their normal anatomic positions, and the deltopectoral interval is not closed. • The subcutaneous layer is closed with a 2-0 absorbable stitch, and a running 4-0 absorbable subcuticular suture is used to approximate the skin.
PROCEDURE: HUMERAL HEAD PARTIAL RESURFACING ARTHROPLASTY • Surgical approach and exposure of the Hill Sachs defect for partial resurfacing arthroplasty (HemiCAP prosthesis; Arthrosurface, Franklin, Massachusetts) is the same as described previously in the chapter. • Once exposed, a drill guide that fully circumscribes the lesion is centered over the defect and a guide pin advanced into the humeral head (Fig. 23.13 and Video 23.2). The drill guide determines the appropriate diameter to cover the defect and establishes perpendicularity. There should be at least four points of contact between the guide and the articular surface.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss
A FIG. 23.13
B
C FIG. 23.14 A–C
A FIG. 23.15
B FIG. 23.16 A–B
• A cannulated drill (Fig. 23.14, A) and tap (Fig 23.14, B) are sequentially placed over the guide pin followed by insertion of a permanent taper post (Fig. 23.14, C). The height of the taper post is assessed to ensure that it is flush or slightly below the articular cartilage surface to avoid proud placement of the final implant. In case of osteopenic bone, cement may be injected to secure the post. • A sizing probe is inserted into the taper post to obtain the appropriate size of the articular component (Fig. 23.15). Sizing should be obtained and recorded for four index points: superior/inferior and medial/lateral. • The appropriately sized surface reamer (Fig. 23.16, A) is placed over the guide pin and advanced into the cancellous bone until the reamer makes contact with the top of the taper post (Fig. 23.16, B). Care should be taken to avoid bending the guide pin, as this will result in malaligned reaming. • Trial implant is placed in position to confirm correct sizing. • The final articular component is then placed in proper orientation and firmly seated into the morse taper post with an impactor (Fig. 23.17). The surface of the implant should be flush with the articular cartilage (Fig. 23.18). • After thorough irrigation and addressing any glenoid deficiency, the capsulolabral repair and wound closure proceeds as in the previous section.
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FIG. 23.18
FIG. 23.17
A
B FIG. 23.19 A–B
POSTOPERATIVE CARE AND EXPECTED OUTCOMES • After surgery, the patient is placed in a sling for comfort. • We restrict passive external rotation for 6 weeks due to the subscapularis detachment and repair. Otherwise, full passive range of motion as tolerated is allowed immediately in all other planes. • Due to the subscapularis detachment, the patient is protected against active and resisted internal rotation for a period of 6 weeks. After the initial 6-week period, patients are allowed terminal stretching and strengthening exercises. • Shoulders are imaged with repeat radiographs at 6 weeks and 6 months. Postoperative radiographs showing anatomic allograft reconstruction of an engaging HillSachs defect are shown in Fig. 23.19. For the humeral head allograft procedure, a CT scan is obtained at 6 months to assess for consolidation and incorporation of the graft. Postoperative radiographs from the partial resurfacing arthroplasty at 6 weeks are shown in Fig. 23.20 (this patient also received a glenoid allograft reconstruction). • The patient is generally not cleared for return to sport or strenuous overhead activity until at least 6 months after the date of surgery. For the allograft procedure, we look for radiographic evidence of graft consolidation prior to final clearance.
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B FIG. 23.20 A–B
Expected Outcomes for Allograft Reconstruction • Published reports of allograft reconstruction of humeral head defects are mostly limited to case reports or small case series, with follow-up data ranging from 2 to 5 years. • In the largest study of anatomic allograft reconstruction of humeral head defects in patients who failed previous attempts at surgical stabilization, this technique of allograft reconstruction has been shown to be effective (Miniaci and Gish, 2004). Patients demonstrated improvement in stability, loss of apprehension, and high subjective approval, allowing return to near-normal function with no further episodes of instability at average of 50 months’ follow-up. • More recent case series looking at the treatment of reverse Hill-Sachs lesions with matched allograft reconstruction following posterior locked shoulder dislocations have also shown good results, with improvements in patient satisfaction rates and functional assessment scores.
Expected Outcomes for Partial Resurfacing Arthroplasty • Published reports for partial resurfacing arthroplasty are limited to case reports and small series. The largest published series (Raiss et al., 2009) demonstrated a 41-point increase in Constant score with mean follow-up of 2 years among patients with fixed anterior glenohumeral dislocation. There were no clinical or radiographic signs of component loosening. One patient had recurrent instability.
Complications • Complications that have been reported after humeral osteoarticular allograft reconstruction of Hill-Sachs lesions include radiographic follow-up evidence of partial graft collapse, failure at the graft-host junction, early evidence of osteoarthritis, continued sensation of catching and/or subluxation, and hardware complications in extreme external rotation (which was relieved after removal of the screws 2 years postoperatively). • To date there is no evidence of implant-interface loosening or osteolysis after partial humeral resurfacing arthroplasty for Hill-Sachs defects. Long-term studies are needed. • Although infrequently a cause for clinical concern, Hill-Sachs defects can be the source of significant disability and recurrent instability in a subset of patients. Anatomic allograft reconstruction or partial humeral head resurfacing arthroplasty of these defects are viable treatment options resulting in favorable clinical outcomes, although long-term studies are still needed.
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EVIDENCE Currently in the literature, there are no prospective, randomized Level I trials that clinically or biomechanically compare the various treatment options for large defects of the humeral head. Most published reports examining osteoarticular allograft reconstruction and partial resurfacing arthroplasty for the treatment for Hill-Sachs defects are limited to case series with few patients and short-term follow-up. Burkhart SS, De Beer JF. Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs: significance of the inverted-pear glenoid and the humeral engaging HillSachs lesion. Arthroscopy. 2000;16:677–94. This case series analyzed the results of 194 consecutive arthroscopic Bankart repairs by suture anchor technique (performed by two surgeons with an identical suture anchor technique) to identify specific factors related to recurrence of instability. The average follow-up was 27 months. There were 101 contact athletes, and the authors identified significant bone defects on either the humerus or the glenoid. The authors found 14 recurrent dislocations and 7 recurrent subluxations. Of those 21 shoulders with recurrent instability, 14 had significant bone defects. For contact athletes without significant bone defects, there was a 6.5% recurrence rate, whereas for contact athletes with significant bone defects, there was an 89% recurrence rate. The authors concluded that arthroscopic Bankart repairs give results equal to open Bankart repairs if there are no significant structural bone deficits. However, contact athletes with bone deficiency require open surgery aimed at their specific anatomic deficiencies. Delaney RA, Freehill MT, Higgins LD, Warner JJP. Durability of partial humeral head resurfacing. J Shoulder Elbow Surg. 2014;23:e14–22. Retrospective review of 39 shoulders who underwent partial resurfacing arthroplasty for a variety of indications, including traumatic arthritis, avascular necrosis, and Hill-Sachs lesions, with an average follow-up of 26.6 months. While six patients of the total cohort underwent revision procedure due to progression of arthritis, none of the instability cases (four patients) required revision surgery. Gerber C, Lambert SM. Allograft reconstruction of segmental defects of the humeral head for the treatment of chronic locked posterior dislocation of the shoulder. J Bone Joint Surg [Am]. 1996;78:376–82. The authors presented a case series of four consecutive patients who had a chronic locked posterior dislocation of the glenohumeral joint, associated with a defect of the humeral head that was at least 40% of the articular surface, who were managed with reconstruction of the shape of the humeral head with use of an allogenic segment of the femoral head. Stability was restored and maintained in each patient at an average of 68 months after the procedure. Three patients reported little or no pain and no or slight functional restrictions in the activities of daily living, and they considered the result to be satisfactory. The fourth patient had mild pain and moderate to severe dysfunction secondary to avascular necrosis of the remaining portion of the humeral head after a symptom-free period of 6 years. Giles JW, Elkinson I, Ferreira LM, et al. Moderate to large engaging Hill-Sachs defects: an in vitro biomechanical comparison of the remplissage procedure, allograft humeral head reconstruction, and partial resurfacing arthroplasty. J Shoulder and Elbow Surg. 2012;21:1142–51. A biomechanical study comparing remplissage to allograft reconstruction and partial resurfacing arthroplasty for moderate to large engaging Hill-Sachs defects. Investigators found that while all three procedures effectively improve stability, remplissage significantly restricted range of motion compared to the intact state by 12–17 degrees in internal/external rotation. In their model, the partial resurfacing arthroplasty did experience residual defect engagement, but this was because the investigators accepted coverage mismatch of the implant over the defect. Kropf EJ, Sekiya JK. Osteoarticular allograft transplantation for large humeral head defects in glenohumeral instability. Arthroscopy. 2007;23:322e1–5. The authors use a limited posterior approach to address a Hill-Sachs lesion with allograft transplantation, combined with arthroscopy for anterior labral repair. Their goals were to preserve range of motion in a highly athletic population by avoiding an open anterior approach. They report a case report with one year outcomes. Martinez AA, Calvo A, Domingo J, Cuenca J, Herrera A, Malillos M. Allograft reconstruction of segmental defects of the humeral head associated with posterior dislocations of the shoulder. Injury. 2008;39:319–22. This case series looked at six patients who underwent operative management of large humeral head defects involving at least 40% of the articular surface following posterior humeral head dislocation. Time between dislocation and surgery ranged from 7 to 8 weeks. All defects were treated with humeral head allograft reconstruction and followed for mean of 63 months. Four patients had improved subjective scores. Two patients had a poor clinical result and were found to have flattening and collapse of the graft at their last radiographic follow-up. Miniaci A, Gish MW. Management of anterior glenohumeral instability associated with large Hill-Sachs defects. Tech Shoulder Elbow Surg. 2004;5:170–5. In this largest case series reviewing osteoarticular allograft reconstruction for large humeral head defects, the authors performed the above-described procedure on 18 patients with failed previous attempts at surgical stabilization and defects comprising greater than 25% of the humeral head.
PROCEDURE 23 Treatment of the Unstable Shoulder With Humeral Head Bone Loss Patients were assessed pre- and postoperatively with history, physical examination, imaging, as well as validated clinical evaluation measures (Constant-Murley shoulder scale, Western Ontario Shoulder Instability Index, and Short Form-36). All patients demonstrated improvement in stability, loss of apprehension, and high subjective approval, allowing return to near-normal function with no further episodes of instability at average of 50 months’ follow-up. Raiss P, Aldinger PR, Kasten P, Rickert M, Loew M. Humeral head resurfacing for fixed anterior glenohumeral dislocation. Int Othop. 2009;33:451–6. Case series of 10 shoulders that underwent cementless humeral surface replacement arthroplasty after fixed anterior dislocation. Average age was 67 years and follow-up was 2 years. Constant scores improved from 20 points to 61 points postoperatively. There were no clinical or radiographic signs of component failure by final follow-up. One patient had recurrent instability. Sweet SJ, Takara T, Ho L, Tibone JE. Primary partial humeral head resurfacing: outcomes with the HemiCAP implant. AJSM. 2015;43:579–87. Retrospective case series of 20 shoulders that underwent partial resurfacing for osteoarthritis. With mean follow-up period of 32.7 months (range 17–66 months), there was no radiographic evidence of periprosthetic fracture, component loosening, osteolysis, or device failure. Prosthesis survival could be extrapolated to the instability population.
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