Anterior Instability: Arthroscopic Bankart Repair With Remplissage

Peter B. MacDonald

Stefania Spano

Matthew Dawdy

Treny Sasyniuk

INTRODUCTION

Significant osseous defects of the glenohumeral joint can lead to failure of arthroscopic shoulder stabilization procedures.¹ Historically, the significance of an engaging Hill-Sachs (HS) lesion as a contributor to shoulder instability was identified and reported as early as 1890.¹^,² In 2000, Burkhart and De Beer reported a 67% failure rate of arthroscopic Bankart repair (BR) in the setting of significant glenoid bone loss and/or large HS lesions in a retrospective series.²

Several different approaches to address humeral and/or glenoid bone loss have been reported, but the optimal treatment remains controversial.³^, ⁴^, ⁵^, ⁶^, ⁷^, ⁸^, ⁹ ^and ¹⁰ Rotational osteotomies, disimpaction bone grafting and structural allograft have been reported to reduce the incidence of recurrent instability, but can be technically demanding and are associated with several complications including hardware failure, neurovascular damage, and nonunion.³^,¹¹^, ¹²^, ¹³^, ¹⁴ ^and ¹⁵ Shoulder arthroplasty has been recommended for failed instability repairs or severe bone loss.¹⁶^, ¹⁷ ^and ¹⁸

An open procedure designed to limit the engagement of the HS deformity by imbricating the infraspinatus into the HS defect was described by Connolly.¹⁹ Named after the French word “to fill in,” the remplissage, is thought to prevent engagement of the humeral defect on the glenoid rim. Wolf and Pollack were the first to describe an arthroscopic method of placing the infraspinatus tendon into a HS deformity.²⁰ An all-arthroscopic approach avoids the morbidities associated with open surgery, but the possibility of loss of external or internal rotation due to tethering of the infraspinatus exists with both the open and arthroscopic remplissage techniques.²¹ Boileau and colleagues reported a mean loss of less than 10° of external rotation (ER) in their series with no significant loss of forward elevation or internal rotation.²²

Although the arthroscopic remplissage brings a theorized reduction in the risk of redislocation and surgical morbidity, the procedure slightly increases both operative time and costs due to additional anchors. For these reasons, the authors believe it is scientifically and fiscally necessary to determine the difference in the outcome between arthroscopic BR with and without remplissage.

INDICATIONS

Traumatic anterior shoulder dislocations account for over 90% of primary shoulder dislocations in the general population,²³^,²⁴ with reported redislocation rates ranging from 19% to 88%. Males and patients under 21 years are at particularly high risk for recurrence. Surgical stabilization is the treatment of choice for recurrent traumatic anterior shoulder instability, as well as for anterior shoulder instability that remains symptomatic despite an appropriate course of physical therapy.

Arthroscopic Anterior Stabilization

The primary indication for arthroscopic anterior shoulder stabilization is recurrent anterior instability with:

TABLE 37-1 Anatomical Algorithm for Surgical Management of Anterior Shoulder Instability With Bipolar Bone Loss

		Hill-Sachs Lesion
		On-Track	OffTrack
Glenoid Defect	<15%	Arthroscopic Bankart repair + remplissage	Arthroscopic Bankart repair + humeral-sided procedure^b
	≥15	Bony glenoid reconstruction^a	Bony glenoid reconstruction ± humeral-sided procedure^b
^aBony glenoid reconstruction: Latarjet, free bone graft (eg, distal clavicle, ICBG, distal tibia). ^bHumeral-sided procedure: Remplissage or humeral bone reconstruction (grafting, resurfacing, arthroplasty).

No/minimal glenoid bone loss less than 15%;
Evidence of a Bankart lesion on MRI;
Normal joint laxity on physical examination; and
A well-developed inferior glenohumeral ligament (IGHL) complex (Table 37-1).

Relative indications include first-time traumatic dislocations in competitive and/or contact sports as well as equal to or less than 30-year-old noncontact athletes, with increased rate of return to sport (RTS) and similar recurrence rates to open stabilization.²⁵^,²⁶ Consideration is also made for patients who have previously undergone arthroscopic anterior stabilization but continue to experience instability without evidence of glenoid defects on advanced imaging. Three-dimensional computed tomography (CT) scan remains the gold standard for assessing glenoid bone loss.

Bipolar Bone Loss and Glenoid Tract

Adjuncts and alternatives to BR vary according to the presence and severity of bone loss on the glenoid and/or humerus and their relationship to one another (Figure 37-1). Bipolar bone loss (bone loss involving both the glenoid and humerus) is a risk factor for recurrent shoulder instability, occurring in up to 84% of cases. It can be managed by addressing one or both of the deficient articular surfaces. Previous dogma defined “critical” glenoid bone loss as >25% based on cadaveric studies,²⁷^,²⁸ though thresholds as low as 13.5% have been reported.²⁹^, ³⁰ ^and ³¹ More recent literature supports an updated benchmark of >15%.³²^, ³³ ^and ³⁴

FIGURE 37-1 Engaging Hill-Sachs lesion from anterior superior portal.

Similarly, HS lesions are defined according to the “glenoid track” concept. The glenoid track is equivalent to the width of the area of the humeral head articular surface that is in contact with the glenoid, and is equal to 83% of the width of the intact inferior glenoid. A HS lesion is said to be “ontrack” if its perimeter is within this glenoid track, and thus it does not engage with the anterior rim of the glenoid. Lesions, the medial border of which extends beyond the glenoid track are considered “offtrack,” override and engage the anterior glenoid rim. There is an inverse relationship between the size of the anterior glenoid defect and the size of the glenoid track; thus, a narrower glenoid is more likely to engage any concomitant HS lesions. Offtrack, engaging lesions are at a higher risk for dislocation.⁴^,³³^,³⁵^,³⁶ Offtrack lesions may be converted to ontrack lesions by enlarging the glenoid articular surface (eg, Latarjet procedure, free iliac crest bone graft augment), and/or filling the HS lesion (eg, remplissage, bone grafting, resurfacing).

Remplissage

Remplissage technique utilizes capsulotenodesis of the infraspinatus tendon and posterior shoulder capsule to fill (and thus eliminate) a HS lesion.¹ Evidence supports the combination of arthroscopic anterior stabilization with remplissage for offtrack HS lesions between 20% and 40% of the total volume.³⁷ Recently, indications for remplissage have expanded. Randomized control trials in patients with anterior shoulder instability and subcritical glenoid bone loss (<15%) demonstrate significantly lower rates of redislocation at 24 months following combined BR and remplissage, compared to BR alone (4% vs 18%, respectively).³⁸ In particular, redislocation rates are significantly lower when remplissage is performed in patients with HS lesions ≥20 mm and/or ≥15% of humeral head diameter,³⁸^,³⁹ a size known to be at a high risk for dislocation.⁴⁰

Open Stabilization and Bony Augmentation

Patients with subcritical glenoid bone loss and offtrack HS lesions who would be candidates for remplissage instead may also be considered for glenoid bone augmentation procedures, eg, Latarjet. In comparing remplissage versus modified Latarjet for subcritical glenoid bone loss in the general population, both yield satisfactory results.⁴¹^, ⁴² ^and ⁴³ The Latarjet is associated with higher complication rates; however, it yields better results among contact/collision athletes and patients with revision instability surgery. It also has lower recurrence and revision rates for patients with ≥10% glenoid bone loss. However, patients who undergo a Latarjet procedure have lower rates of return to overhead and contact sports.⁴²

For patients with critical glenoid bone loss (≥15%), glenoid deficits should be addressed with bony glenoid reconstruction. Options include coracoid transfer (eg, Latarjet), iliac crest bone graft, or distal tibia autograft.³² For advance bone loss and/or revision surgery, distal tibial allograft is commonly used.⁴⁴ For patients with HS lesions >40%, humeral bone reconstruction, resurfacing, or arthroplasty is recommended. Humeral head resurfacing is reserved for low-demand patients over 65, as young, active patients experience high failure rates with this technique.⁴⁵ In patients with a combination of critical glenoid bone loss and engaging HS lesion, bony augmentation of the glenoid is recommended; subsequent management of the humeral defect can be determined based on whether it continues to engage after the glenoid articular surface has been reconstituted.

Bony augmentation is recommended for patients with an Instability Severity Index Score (ISIS) ≥ 6 points (Table 37-2), as they demonstrate a 70% risk of recurrent dislocation if managed with soft-tissue stabilization alone.⁴⁶ Patients with multidirectional instability or laxity should also be considered for bony augmentation. Either open or arthroscopic surgery may be performed to address lesions of the humeral avulsion of the glenohumeral ligament (HAGL) and in the revision of failed previous arthroscopic management.⁴⁸^, ⁴⁹ ^and ⁵⁰

TABLE 37-2 Instability Severity Index Score (After Balg and Boileau, 2007)⁴⁶

Prognostic Factors		Points
Clinical History	Age at the Time of Surgery (Years)
	<20	0
	≥20	2
	Degree of Preoperative Sport Participation
	Recreational or none	0
	Competitive	2
	Type of Preoperative Sport
	Other	0
	Contact or forced overhead	1
Clinical Examination	Shoulder Hyperlaxity
	Normal laxity	0
	Anterior or inferior hyperlaxity	1
AP^a Radiographs	Hill-Sachs Lesion
	Not visible in ER	0
	Visible in ER	2
	Glenoid Loss of Contour
	No lesion	0
	Loss of contour	2
	Total	10^b
^aAP, anteroposterior; ER, external rotation. ^bISIS score ≥6 points = up to 70% risk of recurrent dislocation after isolated arthroscopic Bankart repair.
From Phadnis J, Arnold C, Elmorsy A, Flannery M. Utility of the instability severity index score in predicting failure after arthroscopic anterior stabilization of the shoulder. Am J Sports Med. 2015;43(8):1983-1988; Balg F, Boileau P. The instability severity index score. A simple pre-operative score to select patients for arthroscopic or open shoulder stabilisation. J Bone Joint Surg Br. 2007;89(11):1470-1477; and Rouleau DM, Hébert-Davies J, Djahangiri A, Godbout V, Pelet S, Balg F. Validation of the instability shoulder index score in a multicenter reliability study in 114 consecutive cases. Am J Sports Med. 2013;41(2):278-282.

COMPLICATIONS

Complications after arthroscopic anterior stabilization are relatively rare.⁴⁷ The addition of remplissage to anterior stabilization does not significantly increase complication rates.³⁸^,⁵¹ When compared to open or arthroscopic bone block stabilization procedures, there is a significant lower complication rate.⁵¹^, ⁵² ^and ⁵³ General complications related to anesthesia are possible but rare and surgical infections are reported at a rate of <1%.⁴⁷^,⁵¹ Proper preoperative assessment helps avoid complications. Misdiagnosis is a common cause of recurrent symptoms. This can be avoided by thorough physical examination, patient history, and adequate imaging as previously discussed. Failure to identify concomitant pathology such as rotator cuff tears, HAGL lesions, ALPSA lesions, and SLAP tears, or critical glenoid bone loss >25% can lead to persistent shoulder symptoms and recurrent instability.⁵¹^,⁵²^,⁵⁴ At the time of surgery, full shoulder examination under anesthesia and diagnostic arthroscopy should confirm preoperative diagnosis.

At the time of surgery, ulnar nerve and down leg common peroneal nerve neuropraxia have been reported. Intraoperatively, the axillary nerve is at risk 1 to 1.5 cm below the inferior glenohumeral capsule, while the musculocutaneous nerve is at risk 5 to 8 cm inferior to the coracoid. Both should be considered during portal placement and capsulorrhaphy.⁵¹^,⁵⁴ Overtightening or inadequate capsulorrhaphy tension can lead to impaired shoulder ROM or ongoing instability, respectively.⁵⁴ Overtightening the anterior-inferior capsule could be detrimental, particularly in overhead throwing athletes.⁵⁴^,⁵⁵ Bony Bankart lesions should be incorporated into repairs when possible, to help restore glenoid concavity. Anchors should be buried below the articular cartilage with firm purchase into the subchondral bone to avoid damage to articular cartilage.⁵⁴ Biomechanical and cadaveric studies evaluating remplissage anchor placement suggest that anchors should be placed into the “safe zone,” which is 3 cm distal and 1 cm lateral to the posterior lateral corner of the acromion. This avoids muscle fiber damage to the infraspinatus, ensures accurate placement into the infraspinatus tendon, and limits loss of ER.⁵⁶ Remplissage anchors placed too medial can improve stability but undesirably limit ER.⁵⁶^, ⁵⁷ ^and ⁵⁸ Biomechanical studies have shown that two
knotless anchors have the highest load to failure when used for the remplissage portion of the procedure.⁵³^,⁵⁷^,⁵⁸

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