Arthroscopic Repair of Inferior Labrum From Anterior to Posterior Lesions Associated With Multidirectional Instability of the Shoulder

Abstract

Multidirectional instability (MDI) of the shoulder may arise spontaneously; however, recent evidence suggests that traumatic events may play a role in this syndrome. Variable degrees of injury around the circumference of the glenoid have been reported, ranging from Bankart and Kim lesions to 270° of injury and even 360° of injury. Hyperabduction injury may cause inferior subluxation of the shoulder and result in traumatic isolated injury to the inferior labrum from anterior to posterior. This particular lesion spans approximately 180° of the inferior hemisphere and may lead to symptomatic MDI. In contrast to open or arthroscopic plication procedures for atraumatic MDI without labral injury, the goal in these cases is anatomic arthroscopic repair of the inferior labrum tear without the need for capsular plication, volume reduction, or rotator interval closure.

Multidirectional instability (MDI) of the shoulder was classically described by Neer and Foster¹ in 1980 as atraumatic capsular redundancy in a patient with ligamentous laxity and treated with open inferior capsular shift after failed conservative management. Recent work has shown that the disease may lie on a spectrum ranging from an atraumatic cause to traumatic labral tears occupying variable degrees around the circumference of the glenoid.² Successful treatment has been reported with arthroscopic repair of these various lesions.^2-6

Traumatic inferior glenohumeral subluxation may result in inferior hemispheric labral tearing from anterior to posterior (inferior labrum from anterior to posterior [ILAP] lesions) encompassing the inferior approximately 180° of the glenoid labrum. This tear pattern can destabilize the inferior labrum along with the corresponding anterior and posterior bands of the inferior glenohumeral ligament, contributing to symptomatic MDI. This lesion is similar to Kim lesions, Bankart lesions, 270° lesions, and 360° lesions. However, this lesion specifically encompasses all, or nearly all, of the inferior hemisphere, in contrast to Kim and Bankart lesions, but does not pass beyond this 180° zone, in contrast to 270° or 360° lesions. It thus appears as a mirror image of a type II SLAP tear on arthroscopic visualization of the lesion.

In these traumatic cases anatomic arthroscopic labral repair may provide satisfactory stability without the need for capsular plication or other volume-reduction procedures. We have identified and treated 2 athletes with the described tear pattern after traumatic injury. In these athletes extensive conservative care failed before surgery, and they were then able to return to their respective sports (water polo and skydiving) at the same level or a higher level after arthroscopic repair. They returned to sport at a mean time of 4.8 months postoperatively, with a mean Kerlan-Jobe Orthopaedic Clinic score⁷ of 86 of 100 measured at a mean of 9 months postoperatively.

In this report we outline a surgical technique for arthroscopic repair of traumatic inferior labral tearing from anterior to posterior (ILAP lesion), which has manifested as symptomatic MDI. Video 1 is a cadaveric demonstration of our repair technique in a left shoulder.

Surgical Procedure

Patient Setup and Positioning

Our preference is to use an interscalene block followed by general anesthesia with endotracheal intubation. Appropriate preoperative antibiotics are given with a preference for agents that provide coverage for Propionibacterium acnes in all shoulder arthroscopy cases. The patient is placed in the lateral decubitus position on a beanbag with an axillary roll in place, in hip and knee flexion, and with appropriate lower extremity padding to prevent common peroneal nerve compression on the downside leg. Bilateral lower extremity sequential compression devices are used in all cases. An examination under anesthesia is performed to determine the pattern and severity of instability in these MDI cases. The patient is then placed into balanced suspension using 10 lb of traction and with the shoulder at 60° of abduction and 10° to 15° of forward flexion. If desired, lateral traction with a device such as the Star Sleeve (Arthrex, Naples, FL) may be used to improve visualization of the inferior glenohumeral joint; however, this is not mandatory. The shoulder is then prepared and draped in the standard sterile fashion. Anatomic landmarks including the acromion, clavicle, and coracoid process are outlined with a pen.

Portal Placement and Diagnostic Arthroscopy

A standard posterior viewing portal is marked 2 cm inferior and 1 cm medial to the posterolateral acromion. The portal is made, and a 30° arthroscope is placed into the glenohumeral joint. At this time, an anterior portal is localized in an outside-in manner with an 18-gauge spinal needle through the rotator interval anterior to the biceps tendon. This portal is dilated over a switching stick, and a 7-mm cannula is inserted. A second anteroinferior portal is localized in an outside-in manner with a spinal needle 3 cm inferior to the anterosuperior portal and just lateral to the coracoid process. The spinal needle enters the joint just above the upper border of the subscapularis tendon to facilitate the appropriate trajectory for anterior and anteroinferior anchor placement. This portal is also dilated, and a 7-mm cannula is placed. A diagnostic arthroscopy is performed to identify the ILAP lesion, which in a left shoulder runs from approximately the 9-o’clock position anteriorly, proceeding inferiorly around to the 3-o’clock position posteriorly (Fig 1). The joint is inspected to identify any concomitant injury to the rotator cuff, articular surfaces, and biceps tendon and anchor and to evaluate for any bone loss or Hill-Sachs deformity. The presence or absence of an arthroscopic drive-through sign is also noted at this time. The 2 cases that we have treated showed moderate arthroscopic drive-through signs.

Fig 1.

Posterior view of a left shoulder showing the inferior labrum from anterior to posterior tear. The most inferior portion is displaced inferior to the glenoid, and the tear extends to approximately the 8-o’clock position anteriorly.

Inferior Labral Preparation

After confirmation of an isolated inferior labral tear from anterior to posterior (ILAP lesion), the arthroscope is placed into the anterosuperior cannula for viewing. A posterolateral portal is localized in an outside-in fashion with a spinal needle beginning 2 cm inferior and 1 cm lateral to the posterolateral acromion (Fig 2). This position typically provides the appropriate trajectory for posterior and posteroinferior anchor placement. This portal is made, dilated over a switching stick, and filled with a 7-mm cannula. The standard posterior viewing portal can now be either dilated for cannula placement or alternatively used for percutaneous suture management. The remainder of the procedure is performed viewing from the anterosuperior portal.

Fig 2.

Posterior view of a patient's left shoulder showing the posterior viewing portal (PV) and the posterolateral portal (PL), which is used for posterior anchor placement.

The ILAP tear is mobilized with a 15° or 30° arthroscopic elevator (Arthrex), working through both the anteroinferior and posterolateral portals. Visualization of the subscapularis muscle belly anteriorly and spontaneous reduction of the labrum to the glenoid both anteriorly and posteriorly will indicate sufficient mobilization. An arthroscopic motorized shaver is then used to debride the glenoid margin along the tear down to a bleeding bone surface, avoiding excessive resection of the marginal articular cartilage and bone.

Anchor Placement and Repair

Posterior anchor placement and repair are performed first, working from inferior to superior, followed by anterior anchor placement and repair in a similar fashion. If the anterior compartment is somewhat tight, it may be advisable to repair anterior first and then posterior to avoid further obscuring of the anterior working space after posterior repair.

While viewing from anterosuperior, the surgeon places a drill sleeve for the suture anchor (3.0-mm Bio-SutureTak; Arthrex) through the posterolateral portal to the 5-o’clock position (in a left shoulder) 1 to 2 mm onto the face of the glenoid. The surgeon holds the camera and drill sleeve while the assistant drills the tunnel and places the anchor. The sutures are then loosened from the anchor inserter handle, and the inserter is gently removed with combined rotation and backward traction. Firm pressure on the drill sleeve or tapping the drill sleeve gently down to bone with a mallet before drilling is important to avoid skiving of either the sleeve or drill bit. The planned post limb of the suture is retrieved through the anteroinferior portal with a suture grasper. A 25° angled-right and curved tissue penetrator and shuttling device (SutureLasso; Arthrex) is used to pass around the anteroinferior labrum at or near the level of each anchor. The angle direction of the suture-passing device is important to achieve the proper trajectory for safe tissue penetration and suture passage. For a left shoulder posterior, the device used is angled to the right, and for a left shoulder anterior, it is angled to the left, with the opposite angles being applied for a right shoulder. With each anchor, the labrum is captured in a single pass without additional capsular plication passes through the capsule. The flexible shuttle wire is retrieved from the anteroinferior portal, and the suture is then shuttled in a retrograde fashion to create a simple suture configuration such that the post limb of the suture is through the tissue. A simple sliding knot is used with past-pointing to lock it and secure the loop, and then 3 alternating half-hitches are used to achieve good knot security. The suture knots are kept away from the articular surface to prevent postoperative suture abrasion. Alternatively, any commercially available knotless suture anchor of appropriate size may be used in lieu of knot tying as long as the appropriate trajectory can be achieved with such anchors for anchor deployment. The aforementioned sequence is then repeated at the 4-o’clock position for the second posterior anchor in a left shoulder.

Anterior anchors are also placed while the surgeon is viewing from the anterosuperior portal. The drill sleeve is passed through the anteroinferior portal to the 7-o’clock position first. The anchor is deployed as described earlier, and the post limb of the suture is retrieved with a suture grasper through the posterolateral portal. A 25° curved, angled-left SutureLasso is used for a single pass around the labrum at or near the level of the anchor without plication passes. The passing wire is retrieved through the posterolateral portal, and the post limb is then shuttled back out the anteroinferior portal for tying. Tying is performed in the same fashion as previously described. The final anchor is placed at the 8-o’clock position with identical suture passage, management, and tying to follow. The drive-through sign should be eliminated, and the joint should appear well balanced from the anterosuperior view (Fig 3).

Fig 3.

Anterosuperior view of a left shoulder after inferior labrum from anterior to posterior repair. The sutures at the 8- and 4-o’clock positions are visualized, whereas the sutures at the 5- and 7-o’clock positions are obscured by the humeral head in this view.

Discussion

We present a technique for arthroscopic repair of traumatic tears of the ILAP that have manifested as MDI. This technique is in contrast to arthroscopic plication for atraumatic MDI in which there is no labral involvement, and this repair therefore does not include intentional shifting of the capsule or volume reduction. In this technique suture passage occurs at or very near the level of each anchor, around the labral tissue only, without additional capsular plication passes. We believe that the avoidance of capsular plication maneuvers or shifting maneuvers in these traumatic cases may increase the margin of safety by keeping the suture-passing devices further away from the axillary nerve; in addition, this may help to prevent over-tightening of the glenohumeral joint, especially in an overhead athlete. This may also render the suture-passage portion of the procedure somewhat less technically demanding. In our experience this technique restores the anatomic position and bumper effect of the labrum and thereby re-tensions the corresponding anterior and posterior bands of the inferior glenohumeral ligament, restoring stability to the joint (Table 1).

Table 1.

Benefits and Limitations of Arthroscopic ILAP Repair

Benefits

Anatomic repair of the labrum with restoration of the labral bumper

Re-tensioning of the anterior and posterior bands of the inferior glenohumeral ligament

Decreased risk of axillary nerve injury and over-constraint of the shoulder by avoiding capsular plication

Indicated for traumatic inferior labral injury with MDI

Limitations

Requirement for advanced arthroscopic skills and knowledge of anatomy

Tight working space of the inferior glenohumeral joint can be technically challenging

Not indicated for patients with atraumatic MDI without labral injury or for patients with severely patulous capsules in which plication would be more appropriate

ILAP, inferior labrum from anterior to posterior; MDI, multidirectional instability.

Previous work has shown successful outcomes with arthroscopic repair of similar lesions that may present as MDI,⁶ and the ILAP lesion appears to fall anatomically within a continuum of these other reported tear patterns. This ILAP pattern may appear arthroscopically as a posterior extension of a Bankart-type lesion or as an anterior extension of a Kim-type lesion. It does not extend beyond but does encompass the inferior hemispheric zone of the glenoid. In the 2 patients that we have treated, no antecedent symptoms were present before traumatic injury and symptoms resolved after anatomic arthroscopic repair, allowing a return to sport.

Potential limitations of this technique are that it requires knowledge and practice of advanced arthroscopic techniques including safe and effective placement of portals, lesion preparation, suture passage and management, and knot tying (or the use of knotless devices if chosen) and that visualization of the inferior portion of the glenoid can be challenging to achieve. An alternative to our technique might include the use of a device that also provides lateral traction to the proximal humerus to improve inferior visualization and a safe working space if good visualization is not achieved with balanced suspension alone. A bolster in the axilla or brief manual lateral distraction can also be used as needed.

Arthroscopic repair of injury to the ILAP is an effective technique to restore stability to the glenohumeral joint in the setting of a patient with a traumatic MDI etiology and this tear pattern. With specific attention to the appropriate placement of the anteroinferior and posterolateral portals for anchor placement and tissue management, this repair can be achieved without capsular plication maneuvers. Repairing the labrum to its anatomic position should re-tension the anterior and posterior bands of the inferior glenohumeral ligament and restore the normal bumper effect of the inferior labrum, stabilizing the joint.

Supplementary Data

Video 1

Inferior labrum from anterior to posterior repair in a cadaveric left shoulder.