Authors Felix H. Savoie III, MD, and Michael O’Brien, MD Introduction The Hill-Sachs defect is a compression fracture of the humeral head associated with instability. At the time of shoulder dislocation, the soft cancellous bone of the humeral head is impressed against the hard cortical bone of the anterior glenoid rim, creating a compression fracture in the humeral head. This can be visualized on an internal rotation radiograph of the shoulder, as first described by Hill and Sachs in 1940 [1]. The incidence of the
defect approaches 100% in patients with recurrent anterior shoulder instability. Larger lesions with advanced bone loss are more likely to engage, resulting in shoulder instability at lower arm abduction angles. In patients with moderate bone loss, the defect may be managed by arthroscopically filling in the defect with the infraspinatus tendon or with allograft corticocancellous plugs. Arthroscopic management of these defects includes:
The true incidence of Hill-Sachs lesions is unknown. While reported to occur in 40% to 90% of patients with an initial dislocation event [2-5], the incidence may be as high as 100% with recurrent instability [5]. The size of the defect is often related to the amount of time the shoulder remains dislocated, thus quite small with the first dislocation. With each subsequent dislocation, the compression fracture enlarges, becoming more evident on follow-up radiographs. A growing body of evidence in the orthopaedic literature supports the notion that recurrent instability of the shoulder leads to progressive bone loss, both on the glenoid and the humeral head. Bone loss on either side of the joint may lead to recurrent instability at lower arm abduction angles, as well as feelings of instability with activities of daily living. Shoulder dislocations can occur with less force, such as while sleeping at night or with the arm adducted at the side. A substantial amount of literature describes the well-established relationship between anterior glenoid bone loss and recurrent instability [6-9]. However, there is little published data on management of bone defects on the humeral side [10]. Reverse Hill-Sachs lesions are located on the anterior-superior humeral head, and they are associated with posterior shoulder dislocations. The incidence of this type of lesion is difficult to quantify, as posterior dislocations are much less common, although the reverse lesion may occur in up to 86% of posterior instability cases [4]. Pathoanatomy Hill-Sachs lesions most commonly occur during anterior glenohumeral instability episodes. The shoulder typically is in an abducted, externally rotated position. As the humeral head is forced anteriorly, the capsule, glenohumeral ligaments, and glenoid labrum are stretched and likely torn. As the humeral head translates farther anteriorly, a compression fracture occurs along the posterior-superior-lateral aspect of the humeral head as it comes into contact with the anterior glenoid rim. In cases of recurrent anterior shoulder instability, the static restraints to glenohumeral translation (capsuloligamentous structures and labrum) become increasingly attenuated. This makes it easier for the relatively softer cancellous bone of the humeral head to sustain continued damage as it makes repeated contact with the harder cortical bone of the anterior glenoid rim [10]. Hill-Sachs lesions are typically described as engaging or non-engaging:
Hill-Sachs lesions rarely occur in isolation. They most commonly occur in conjunction with an anterior capsulolabral avulsion, the Bankart lesion [3]. Other common coexisting injuries include:
Anteroinferior glenoid bone loss may ultimately become large enough to create a glenoid with the appearance of an inverted pear [6]; this presentation is associated with recurrent anterior shoulder instability. Optimal management requires close evaluation because significant bone loss in the shoulder (ie, greater than 5-6 mm on the glenoid side in the presence of a Hill-Sachs defect) is frequently a bipolar phenomenon that results in failure of surgery aimed at correction of the soft tissue defects alone. History The patient with a Hill-Sachs defect will uniformly have a history of shoulder instability, whether a single dislocation or recurrent instability events. It is important for the examiner to inquire about:
The ease of shoulder dislocation, number of dislocation events, and arm position all provide information on the stability of the shoulder. Shoulders that dislocate easily with activities of daily living, and those that dislocate in lower arm abduction angles, are more likely to have bone loss, both on the anterior glenoid and humeral head. The patient with glenoid bone loss or an engaging Hill-Sachs defect may describe a sensation of catching as the humeral head falls outside the glenoid track during arm movement. He or she may actually describe that “the shoulder falls out” when leaning forward during activities. These scenarios suggest bone loss, and when corroborated with physical examination, may lead the examiner to order advanced imaging of the shoulder. Clinical Examination Examination of the shoulder begins with inspection. The overall posture of the patient should be noted (ie, sitting up straight or slouching forward), as well as the attitude of the shoulder and whether the shoulder and upper arm are held in a position of protraction or retraction. Fullness in the anterior shoulder may represent an anterior dislocation, while an arm fixed in internal rotation may represent a locked posterior dislocation. The musculature should be inspected for atrophy, specifically the deltoid and supraspinatus fossa. Assessment can be made for generalized ligamentous laxity. The shoulder should be palpated and any tender spots noted. Tenderness over the acromioclavicular joint may indicate acromioclavicular separation, and coracoid process tenderness may indicate tightness of the pectoralis minor and shoulder protraction. Both active and passive range of motion should be determined. During passive range of motion, care should be taken to observe any apprehension by the patient, especially as the arm approaches the position of abduction and external rotation. The examiner places one hand on the patient’s shoulder to stabilize the scapula, while grasping the patient’s forearm with the other hand. Beginning with the patient’s arm adducted to the side, the arm is externally rotated while bringing the patient’s arm into increasing abduction angles. With an unstable shoulder, apprehension will be evident in the position of abduction and external rotation. Crepitus may be palpable in this position if the patient has a labral tear and anterior shoulder instability. Apprehension and instability at lower arm abduction angles is indicative of severe glenohumeral instability, and raises the suspicion of bone loss. The strength of the rotator cuff must be assessed, especially in patients over age 40. In this patient population, shoulder instability may result in subscapularis rupture or avulsion of the supraspinatus and infraspinatus. Proximal biceps lesions may also occur, producing positive biceps provocative maneuvers. Provocative maneuvers may reproduce a patient’s pain and confirm the diagnosis of instability:
Imaging Several imaging studies can be useful in diagnosing glenohumeral instability with bone loss. Imaging always begins with a full series of shoulder radiographs, including an anteroposterior (AP) radiograph of the glenohumeral joint, a scapular Y or outlet view, and an axillary view. We also try to get a Bernageau view in all our instability patients, as recommended by Edwards, to evaluate for glenoid bone loss. Irregularities on initial radiographs may raise the suspicion of bone loss:
Several other radiographs are useful in the evaluation of bone loss specifically. The West Point axillary view is very useful in evaluating glenoid bone loss, while the Stryker Notch view is specific in evaluating for Hill-Sachs defects [13]. The Stryker Notch view is particularly useful because the internal rotation of the humeral head brings the posterolateral bone defect into view. Computed tomography (CT) scan is a superior imaging modality for evaluating bone loss. Three-dimensional CT, in particular, helps to quantify the size and location of bone defects on the humeral head and glenoid (Figure 1) [14]. Digital subtraction of the humeral head allows for precise determination of bone loss on the glenoid [15]. Figure 1. 3D CT scan of a Hill-Sachs defect, with computer generated ruler measuring the exact size of the lesion. Magnetic resonance imaging (MRI) and MRI arthrography can provide useful information on the presence of tears of the capsulolabral tissue. These images are invaluable in preoperative planning for surgical stabilization, as the decision can be made whether bone grafting of the defects will be necessary. Hill-Sachs defects that occupy less than 30% of the humeral head can be managed effectively with an arthroscopic remplissage; defects greater than 30% of the humeral head may require open bone grafting with humeral head allograft [17, 18]. Indications/Contraindications Indications for surgery include shoulder instability with bone loss that causes pain and lack of function in patients who have failed appropriate conservative management (Figure 2). Contraindications to surgery include active infection and patients that are habitual dislocaters. Severe bone loss may be a relative contraindication to arthroscopic repair, as it may require an open bone grafting procedure. Figure
2. Decision-making algorithm for shoulder instability. This algorithm was developed by Dr. Michael O’Brien to assist in determining the best method to manage the Hill-Sachs defect. Remplissage is performed in patients with moderate to large Hill-Sachs defects associated with glenoid defects of less than 25%. Patients with larger glenoid defects may require conversion to an open bone grafting procedure, such as the Latarjet procedure. Arthroscopic Treatment, Surgical Technique Patient Positioning Surgery can be performed either in the beach-chair or lateral decubitus position. The authors prefer to perform the procedure with the patient under general anesthesia and in the lateral decubitus position on a beanbag, reclining 30° posterior. If the beach-chair position is utilized, the surgeon must be facile with the anterior inferior and posterior inferior portals to ensure adequate shift and repair of the inferior shoulder capsule. Examination under anesthesia is essential at the beginning of the case to allow the surgeon to evaluate for anterior, posterior, and inferior subluxation and compare the findings with the opposite side. This is paramount in identifying the direction of instability and the degree of instability at different arm positions. The pathology can be identified and a surgical plan can be made prior to skin incisions. The use of an arm suspensory device and 10 pounds of traction is standard. This provides distraction across the glenohumeral joint to assist with visualization, as well as equal access to the anterior and posterior compartments and rotator cuff. Traction can be removed so the arm can be taken through a full range of motion to determine if a Hill-Sachs lesion is engaging or non-engaging. Diagnostic Arthroscopy Diagnostic arthroscopy begins with the arthroscope in the posterior portal, which allows all anterior structures to be assessed:
This dynamic assessment will confirm the presence of an engaging lesion, which must be addressed at the time of surgery for a successful outcome. The diagnostic arthroscopy is continued with the arthroscope in the anterior-superior portal, which provides a 360-degree view of the glenohumeral joint:
Figure 3. Superior view of a shaver inside the Bankart lesion in preparation for repair (left). View of a moderate-sized Hill-Sachs defect (right). Arthroscopic BankartRepair with Remplissage After completion of the diagnostic arthroscopy and identification of all pathology, the repair can be performed. The case begins with preparation of the glenoid labrum.
Figure 4. View of sutures from the most inferior (6 o’clock) anchor being passed through the posterior labrum. Next the Hill-Sachs defect is prepared.
Figure 5. Superior view of the Hill-Sachs defect after anchor placement and suture passage (Figure 5a, left). Superior view of the Hill-Sachs defect after tying of the first mattress suture (Figure 5b, right). Finally, the Bankart labral repair is completed.
Open Bone Grafting of Hill–Sachs Defect For large Hill-Sachs defects occupying greater than 30% of the humeral head articular surface, an open bone grafting procedure may be necessary [17,18]. This procedure may be performed in the beach-chair position through an anterior approach utilizing the deltopectoral interval. It may also be performed in the lateral decubitus position via a split between the middle and posterior deltoid muscles.
Figure 6. Radiographic view of the bone graft in place and stabilized by two screws. Postoperative Treatment In the postoperative period, an abduction sling is utilized for 4 weeks. Patients are allowed to remove the sling to shower, dress, and perform elbow range of motion exercises. Patients are encouraged to begin posture training and scapular retraction exercises. At 4 weeks, the abduction sling is discontinued. Formal physical therapy is initiated for passive and active-assisted range of motion. Rotator cuff and periscapular strengthening is initiated at 12 weeks. Full return to sport is allowed at 5 months postoperative. Literature Review Remplissage, French for filling, is an arthroscopic technique used to fill a Hill-Sachs defect with local capsulotendinous soft tissue. It is a modification of the Connolly procedure [19], originally described as an open procedure transferring the infraspinatus tendon and a small portion of the greater tuberosity into the humeral head defect. In 2008, Eugene Wolf [20] described an arthroscopic modification, performing a posterior capsulodesis and infraspinatus tenodesis with fixation of the tissue to the surface of the Hill-Sachs defect. This successfully fills the humeral defect by converting it from an engaging, intra-articular defect into extra-articular lesions. The goal is to prevent engagement of the lesion with the anterior glenoid. In 2009, the technique was modified by Koo et al [21], who described a double-pulley suture technique in which two anchors were used to insert the infraspinatus tendon into the entire Hill-Sachs defect. This modification created a broader footprint of fixation, and tying the sutures over rather than through the infraspinatus tendon allowed for a more anatomic and tissue-preserving approach. Advantages of the remplissage technique include:
Additionally, this approach has none of the risks and morbidity associated with open bone grafting procedures. Potential disadvantages include:
In 2008, Deutsch and Kroll [22] described a case of significant postoperative loss of external rotation following remplissage. Motion was improved following arthroscopic release of the infraspinatus tenodesis. The authors proposed that the infraspinatus tendon and posterior capsular tissue created a mechanical block to motion, limiting external rotation. Limitations to motion have been corroborated by other studies, yet the clinical significance is unknown. Elkinson et al [23] evaluated shoulder stability and range of motion following remplissage in a cadaveric model. The addition of remplissage to Bankart repair resulted in a statistically significant reduction in shoulder internal-external range of motion in adduction (15.1°), but not in abduction (7.7°). Remplissage provided little additional benefit in specimens with a 15% Hill-Sachs defect, but was effective in preventing engagement and recurrent instability in specimens with a 30% Hill-Sachs defect. Giles et al [24] compared remplissage to humeral head allograft and partial resurfacing arthroplasty in cadaveric specimens with 30% and 45% Hill-Sachs defects. Remplissage effectively prevented engagement in all specimens, but caused a greater reduction in range of motion compared with allograft reconstruction and resurfacing arthroplasty. Elkinson et al [25] compared three remplissage techniques in a cadaveric model to assess the effect on shoulder stability. The three remplissage techniques included:
All remplissage techniques enhanced shoulder stability, but restricted range of motion and increased joint stiffness. Medial suture placement resulted in the greatest joint stiffness. Stiffness observed in a cadaveric model may be more severe than that observed clinically. Boileau et al [26] noted a loss of external rotation of 8° in adduction and 9° in abduction compared with the contralateral side in 47 patients after Bankart repair with remplissage. Ninety-eight percent of patients had a stable shoulder, 90% were able to return to playing sports post-operatively, and 68% returned to the previously level of sport, including overhead athletes. Park et al [27] found no subjective complaints of decreased range of motion in 20 patients after Bankart repair with remplissage. Three patients (15%) reported a subsequent instability episode, but none required additional surgery. Nourissat et al [28] also found no significant statistical difference in range of motion between arthroscopic Bankart repair alone versus Bankart repair plus remplissage at 2-year follow-up, with a difference in external rotation at the side of 4° and in abduction of 3°. Summary Several options are available to treat large Hill-Sachs defects in patients with recurrent shoulder instability. Arthroscopic remplissage is a safe, effective technique for the management of bone loss on the humeral head. Postoperative reductions in external rotation may occur, but these differences may not be clinically significant. It is paramount for the orthopaedic surgeon to recognize engaging Hill-Sachs defects and treat them accordingly. Failure to recognize bone loss at the time of operative stabilization may result in failure of soft-tissue reconstruction surgery. Author Information Felix H. Savoie III, MD, and Michael O’Brien, MD, are from Tulane University, New Orleans, Louisiana. References
What is a HillA Hill-Sachs lesion is a fracture in the long bone in the upper arm (humerus) that connects to the body at the shoulder. You doctor might have discovered this condition if you've experienced a dislocated shoulder. In this case, the arm bone slips out of the socket and is compressed against the socket's rim.
What causes HillHill-Sachs lesions are caused when your shoulder is dislocated. If your humerus (your upper arm bone) is pressed against the edge of the socket it's usually in, that pressure can cause a dent or divot in your humerus.
Where is HillA Hill–Sachs lesion, or Hill–Sachs fracture, is a cortical depression in the posterolateral head of the humerus. It results from forceful impaction of the humeral head against the anteroinferior glenoid rim when the shoulder is dislocated anteriorly.
Where on the humeral head is a HillA Hill-Sachs lesion, or Hill-Sachs impaction fracture, is an injury to the back portion of the rounded top of your upper arm bone (humerus). This injury occurs when you dislocate your shoulder.
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