Arthroscopic Knotless Subscapularis Bridge Technique for Reverse Hill-Sachs Lesion With Posterior Shoulder Instability

Abstract

Posterior shoulder dislocations are an uncommon cause of glenohumeral instability; they are frequently missed and are associated with humeral head defects and capsulolabral lesions. Despite surgical treatment often being mandatory, there is still no standardized treatment for anterior impaction fractures of the humeral head (reverse Hill-Sachs lesions). Arthroscopic surgery is typically indicated, with a tendency toward resorting to knotless techniques in recent years. We present a method for the treatment of posterior shoulder dislocations with engaging reverse Hill-Sachs lesions that achieves full defect coverage using an arthroscopic all-in-the-box knotless subscapularis bridge technique with 2 anchors-with one crossing the subscapularis tendon and the other embracing it-along with posterior capsulolabral complex restoration. This promising technique is a potentially superior alternative for the treatment of these lesions that can also be used in the presence of concomitant partial subscapularis tears.

Fig 1

Right shoulder. Computed tomography (CT) scan and/or magnetic resonance imaging (MRI) is mandatory for decision making in patients with posterior shoulder instability. (A) CT scan, axial view at the coracoid level, showing the gamma angle. This angle is defined using the best-fit circle technique while measuring the angle between the posterior edge of the reverse Hill-Sachs lesion (RHSL) and the bicipital groove. When this angle is greater than 90°, the lesion is considered an engaging RHSL. (B) MRI scan, axial view under the coracoid level, revealing that the gamma angle—measured with the same references as the CT scan—is greater than 90°. The posterior glenoid rim presents a 3.63-mm defect at this level of the axial segment. This is a bipolar lesion (RHSL plus glenoid defect) that results in an engaging RHSL. The measured gamma angle at a different level of the axial view, on CT or MRI scans, shows an engaging RHSL using the “gamma concept angle” described by Moroder et al. The white circle indicates the best-fit circle to the humeral head passing through the cartilage, and the double arrow indicates the posterior cartilage line to calculate the posterior glenoid defect. (C) CT scan with 3-dimensional reconstruction, coronal oblique view, showing the superior-to-inferior dimension of the anteromedial lesion at the humeral head (arrow), known as an RHSL. (D) Two-dimensional CT scan, sagittal view, showing the width of the RHSL (arrow) close to the coracoid process.

Fig 2

Right shoulder, in lateral oblique position, showing anterior portal with cannula (AP) and posterior portal (P). The needle (N) shows the anteroinferior portal, through which the inferior screw loaded with FiberTape is introduced percutaneously, for the subscapularis knotless bridge technique to treat a reverse Hill-Sachs lesion with posterior shoulder instability. (S, superior portal with camera.)

Fig 3

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position. (A) View from posterior portal. The arrow indicates the partial subscapularis tendon tear. (B) View from superior portal. The reverse Hill-Sachs lesion (RHS) is identified and palpated using a hook (H) introduced from the standard anterior portal. (HH, humeral head; LHB, long head of biceps; ML, medial glenohumeral ligament; SS, subscapularis tendon.)

Fig 4

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal, showing posterior capsular lesion. (A) Posterior capsular lesion, medial portion of retracted capsule, and infraspinatus muscle (IM). (B) Infraspinatus muscle (IM) with underlying border of lateral capsular lesion. (HH, humeral head; LC, lateral border of posterior capsular defect; MC, medial border of posterior capsular defect.)

Fig 5

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal, showing posterior capsular lesion after releasing its borders. The posterior capsular lesion and its lateral border (LC) and medial border (MC) are being released with a shaver (S) from the infraspinatus muscle (IM) to allow proper identification and facilitate its reduction. (HH, humeral head.)

Fig 6

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal, showing reparation of capsular lesion. (A) A suture passer (SP) loaded with a nitinol wire has been passed through an accessory percutaneous posterolateral portal to the medial border of the posterior capsular lesion. (B) The nitinol wire previously passed through the posterior capsular lesion has been replaced with a FiberWire suture (F). (HH, humeral head; IM, infraspinatus muscle; LC, lateral border of posterior capsule; MC, medial border of posterior capsule.)

Fig 7

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal, showing reparation of capsular lesion. (A) The FiberWire suture (F) has been passed through the lateral and medial borders of the posterior capsular lesion. (B) Two parallel FiberWire sutures (F) have been passed through the medial and lateral borders of the posterior capsular lesion. (HH, humeral head; IM, infraspinatus muscle; LC, lateral border of posterior capsule; MC, medial border of posterior capsule.)

Fig 8

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. (A) Posterior labral lesion (PL) being tested with a hook (H). (B) Final view of repaired posterior capsular lesion and posterior capsulolabral complex with two 2.9-mm Bio-PushLock knotless anchors after being debrided with curette and shaver. (F, FiberWire suture; G, glenoid; HH, humeral head; P, repaired labral lesion; PC, posterior capsule.)

Fig 9

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. The reverse Hill-Sachs lesion (RHSL) is debrided using a curette (C) introduced from the standard anterior portal. (HH, humeral head; IL, inferior glenohumeral ligament; ML, medial glenohumeral ligament.)

Fig 10

(A, B) Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. With removal of the cannula from the standard anterior portal using an electrocoagulation device (E), the pre-subscapularis working space is developed between the anterior side of the upper third of the subscapularis muscle and the lateral side of the conjoint tendon. This is the space where the first and inferior trans-subscapularis screw will be passed. (CT, conjoint tendon and clavipectoral fascia; ST, subscapularis tendon.)

Fig 11

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. (A) Previously prepared pre-subscapularis working space. The puncher (P) is introduced through the percutaneous accessory portal, lateral to the conjoint tendon and anterior to the subscapularis tendon. (B) The puncher (P) is introduced through the subscapularis tendon in the reverse Hill-Sachs lesion (RHSL) to prepare the inferior anchor hole bed. (C) Tapper (T) through anterior working space, after removal of puncher. (D) The tapper (T) is introduced through the subscapularis tendon in the RHSL to prepare the inferior anchor hole. (CT, conjoint tendon; D, deltoid; HH, humeral head; IL, inferior glenohumeral ligament; ML, medial glenohumeral ligament; ST, subscapularis tendon.)

Fig 12

(A) A Bio-SwiveLock anchor loaded with FiberTape suture is introduced into the inferior percutaneous portal, crossing the pre-subscapularis working space, to continue through the subscapularis tendon. (B) Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. The anchor is introduced into the inferior anchor hole previously made in the reverse Hill-Sachs lesion (RHS), going across the subscapularis. (A, Bio-SwiveLock anchor; AP, anterior portal with cannula; F, FiberTape suture; G, glenoid; HH, humeral head; IL, inferior glenohumeral ligament; ML, medial glenohumeral ligament; S, superior portal with camera; ST, subscapularis tendon.)

Fig 13

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. By use of the tapper, a second anchor hole (AH) is made through the cannula in the anterior portal and superiorly to the first hole in the upper side of the reverse Hill-Sachs lesion (RHS). The inferior anchor with the FiberTape suture (F) is noted. (G, glenoid; IL, inferior glenohumeral ligament.)

Fig 14

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. (A) From the pre-subscapularis working space, the FiberTape suture (F)—from the anchor placed in the inferior edge of the reverse Hill-Sachs lesion (RHS) through the anteroinferior portal—is retrieved from the anterior portal through the cannula. (B) The FiberTape suture (F) is introduced into the joint by pushing the retriever. (C) The FiberTape suture (F) is recovered with the retriever from the posterior portal and pulled to assess the proper coverage of the anterior bone defect (RHS) with the subscapularis tendon before anchoring. (D) The FiberTape suture (F) is loaded in the eyelet core screw. (CT, conjoint tendon; ML, medial glenohumeral ligament; ST, subscapularis tendon; TR, tape retriever.)

Fig 15

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. (A) The Bio-SwiveLock screw is inserted in the second hole of the superior aspect of the reverse Hill-Sachs lesion (RHSL), superiorly and without piercing the subscapularis tendon (ST). (B) With the screw almost fully inserted, the subscapularis tendon (ST) filling the defect can be noted. (A, Bio-SwiveLock anchor; HH, humeral head.)

Fig 16

Arthroscopic view of right shoulder with posterior shoulder instability, in lateral oblique position, from superior portal. (A) Final FiberTape suture bridge construct. The FiberTape suture, before the tape is cut, wraps the subscapularis tendon and covers the reverse Hill-Sachs lesion. (B) Final suture bridge construct covering reverse Hill-Sachs lesion. (F, FiberTape sutures; G, glenoid; HH, humeral head; ST, subscapularis tendon.)

Fig 17

Graphical representation of final subscapularis bridge construct for reverse Hill-Sachs lesion (RHSL) treatment with posterior shoulder instability: sagittal plane (A) and coronal plane (B). The FiberTape sutures preloaded in the inferior anchor cross the subscapularis tendon to reach the inferior part of the RHSL. The superior knotless anchor is loaded with the FiberTapes coming from the inferior anchor, bypassing the subscapularis tendon. This leaves the whole RHSL covered by the subscapularis tendon bridge.

Fig 18

Graphical representation of final subscapularis bridge construct for reverse Hill-Sachs lesion treatment with posterior shoulder instability: axial plane. The superior knotless anchor is loaded with the FiberTape coming from the inferior anchor, wrapping the subscapularis tendon and covering the reverse Hill-Sachs lesion.

Fig 19

Postoperative magnetic resonance imaging control of subscapularis bridge construct for reverse Hill-Sachs lesion (RHSL) treatment with posterior shoulder instability. (A) On the coronal view, 2 Bio-Composite knotless screws (Arthrex), used to fix the subscapularis in the anterior humeral defect (RHSL), can be noted (black and white arrows). (B) On the sagittal view, the superior knotless screw can be seen wrapping the subscapularis tendon (left) and the inferior knotless screw can be seen crossing the subscapularis tendon (right) (white arrows). (C) The axial view at the coracoid process level (left) and under the coracoid process (right) shows the RHSL filled with the subscapularis tendon (white arrows).

Fig 20

Graphical representation of gamma angle (γ) in axial view of shoulder for reverse Hill-Sachs lesion (RHSL) with posterior shoulder instability. The gamma angle is measured between the posterior aspect of the bicipital groove and the most posterior edge of the RHSL. This angle defines the location and size of the RHSL. Best-fit circle indicates circle performed across the articular cartilage and dashed line indicates a gamma angle.

Fig 21

Graphical representation of delta angle (δ) in axial view of shoulder for reverse Hill-Sachs lesion with posterior shoulder instability. The delta angle is measured between a line drawn from the center of the best-fit circle to the posterior reverse Hill-Sachs defect edge and another line drawn from the center of the circle to the posterior glenoid rim. This angle determines the number of degrees by which the humeral head can internally rotate until engagement. Best-fit circle indicates circle performed across the articular cartilage and black and red line indicates delta angle. (γ, gamma angle.)

Fig 22

Graphical representation of gamma angle concept for reverse Hill-Sachs lesion with posterior shoulder instability.