Simple versus horizontal mattress suture configuration in bankart repair

Abstract

The purpose of this article was to compare the anatomy and biomechanics of different suture repair configurations for arthroscopic Bankart lesion repair. The horizontal mattress technique improves the restoration of labral height and decreases capsular strain in comparison to simple suture repairs. Further research examining the clinical outcomes of horizontal mattress suture technique is required for comparison with simple suture arthroscopic Bankart repairs.

1. Introduction

The glenohumeral joint is the most mobile joint in the human body.¹ As such, it is also the most frequently dislocated joint in the body with an incidence of 24 dislocations per 100,000 person years.² Ninety seven percent of shoulder dislocations are anterior and 85% of traumatic anterior shoulder dislocations are associated with a Bankart lesion. A Bankart lesion involves detachment of the anterior-inferior labrum and anterior band of the inferior glenohumeral ligament.^3,4

Nonsurgical management of anterior shoulder dislocations result in a recurrence rate ranging from 33 to 67% overall and 55–82% in young male athletes.⁵ The open Bankart repair has historically been the gold standard surgical technique.¹ The original Bankart procedure uses a deltopectoral approach to the shoulder.⁶ The lateral aspect of a vertical capsulotomy is attached to the glenoid bone with transosseous sutures and then the medial capsule is incorporated to reinforce the repair. The open technique has evolved with time to utilize bone anchors and suture repair of the Bankart lesion.⁵ Early arthroscopic Bankart techniques utilizing transosseous suturing, staples, and bioabsorbable tacks had inferior results compared to the open Bankart repair.¹ However, recent advances in arthroscopic Bankart repair techniques using anchors have resulted in similar outcomes to open repairs.^1,5 Most contemporary publications report a recurrence rate after arthroscopic Bankart repair to be approximately 7%.⁵ Arthroscopic Bankart repair was also associated with less postoperative pain, lower morbidity, and improved cosmesis.

In an effort to further improve arthroscopic Bankart repair one of the variables that has been examined is suture configuration with anchor repair. While most repairs are performed using a simple suture pattern there has been some recent interest in a horizontal suture pattern. This horizontal suture technique has been described with knotted suture anchors and knotless anchors.^4,7 The purpose of this article was to compare the anatomy and biomechanics of simple versus horizontal suture repair configurations for arthroscopic Bankart lesion repair.

2. Anatomy

There are several dynamic and static structures involved in the stability of the glenohumeral joint to resist anterior dislocations. Dynamic stabilizers include the rotator cuff muscles and the long head of the biceps tendon.⁵ The subscapularis contributes to anterior shoulder stability when the shoulder is in a more adducted position.⁸ Static stabilizers are the glenoid, labrum, capsule, and glenohumeral ligaments. The glenoid itself has a concavity of 2.5 mm providing minimal stability of the glenohumeral joint.⁵ The labrum adds to stability, acting as a mechanical block as the humeral head ascends its slope anteriorly, and by increasing the surface area and depth of the glenoid/labral fossa from 2.5 to 5 mm. The closed capsule allows for negative intraarticular hydrostatic pressure between the humeral head and the glenoid. The inferior glenohumeral ligament is the strongest glenohumeral ligament and provides the most resistance against anterior-inferior translation of the humeral head.² The anterior band of the inferior glenohumeral ligament provides the most restraint against anterior dislocation in the apprehension position.^9,10 A tear of the capsulolabral structure from the anterior-inferior aspect of the glenoid was originally termed by Bankart as the essential lesion after anterior shoulder dislocation that compromises anterior stability of the shoulder.^3,4

Hagstrom et al. compared recreating the height of the labrum in human cadavers for the simple versus horizontal mattress suture techniques.⁴ Bankart lesions were created from 3:00 to 6:00 in sixteen cadaveric shoulders and knotted suture anchors were placed in the 3:30, 4:30, and 5:30 positions. Then half of the models were repaired using a simple suture technique and the other half were repaired using the horizontal mattress configuration using arthroscopic instruments. They found a statistically significant decrease in labral height after simple suture repair compared to the native labral height at the 3:30, 4:30, and 5:30 positions. This was an average decrease of 1.4, 2.1, and 1.1 mm at each position, respectively. Meanwhile, there was no significant decrease in labral height in any of the positions after the horizontal suture repair. The average height of the native labrum in this study was 6.2 mm, resulting in a 15–20% loss (i.e., 1–2 mm) in labral height. Furthermore, Hagstrom et al. found that the horizontal mattress suture technique was better at recreating the height of the labrum in Bankart repair compared to simple sutures. The improved restoration of the glenoid labrum anatomy after horizontal mattress suture repair may also result in enhanced longitudinal blood flow in the labrum compared to the simple suture technique.⁷

Judson et al. examined which suture technique better covered the native footprint of the labrum in 12 human cadaveric glenoids.¹¹ Bankart lesions were created from the base of the coracoid to the 6:00 position and the native footprint was marked. Anchors were placed in the 2:30, 3:00, and 4:30 positions on the glenoid and then half of the models underwent simple suture repair and the other half were repaired using the horizontal mattress technique. On average, the simple repair covered 38.1% (57.3 mm² of 148.9 mm²) and the horizontal mattress repair covered 32.8% (74.2 mm² of 213.3 mm²) of the native footprint, with no difference between the two methods.

3. Biomechanics

The first biomechanical study comparing simple suture configuration to horizontal mattress configuration in Bankart repair was performed by Nho et al.¹² Bankart lesions were created from the 3:00 to 6:00 positions in ten human cadaveric shoulders. Knotted anchors were placed in the 4:00 and 5:00 positions, and 5 of the cadavers were repaired with a simple suture and the other 5 cadavers were repaired with a horizontal suture pattern. Under loading conditions, they found no statistically significant difference in ultimate load to failure, load at 2 mm displacement, stiffness, and cyclic elongation between simple versus horizontal mattress sutures. Method of failure differed between the two groups, such that 5/5 samples in the simple suture group failed by anchor pullout and 4/5 samples failed at the glenolabral junction and 1/5 failed by a capsular rupture in the horizontal mattress group. There were more female cadaveric specimens in the simple suture (3/5) versus horizontal mattress group (1/5), but there was no difference in age or bone mineral density between the two groups.

Judson et al. also compared the biomechanical results between the simple suture and horizontal suture repair techniques.¹¹ Their study was conducted as noted above and then biomechanical testing of the different Bankart repairs was performed using an MTS system. There was no difference in load to failure, cyclic displacement, or stiffness between simple suture and horizontal suture repairs. The modes of failure in the simple suture group included suture breakage (N = 4) and labral tears (N = 2). Meanwhile, in the horizontal mattress group the modes of failure included suture breakage (N = 2), labral tears (N = 2), and knot slips (N = 2).

The latest biomechanical study comparing simple suture and horizontal suture techniques in Bankart repair was conducted by Lacheta et al. using all-suture anchors.⁷ Thirty human cadaveric shoulders were divided into five groups: 1) native shoulders, 2) knotted simple suture repair, 3) knotless simple suture repair, 4) knotted horizontal suture repair, and 5) knotless horizontal suture repair. Bankart lesions were created from the 3:00 to 6:00 position and anchors were placed in the 3:30, 4:30, and 5:30 positions. After each respective repair was performed biomechanical testing was performed by an Instron ElectroPuls E10000 system. When anchor type was held constant there was no difference between simple and mattress suture configurations with respect to ultimate load, first failure load, and stiffness. There was a significant decrease in capsular strain at 200 N of force in the knotless horizontal mattress group (50%) compared to both the knotted mattress group (76%) and the knotless simple groups (112%). There was no statistically significant difference in ultimate load, first failure load, and stiffness when compared to the native group, except in the knotless simple suture group which had lower stiffness. In addition, only the knotless horizontal group did not result in a statistically significant increase in capsular strain at 200 N when compared to the native group. This decrease in strain could explain why they also found that there were only 36% of soft tissue failures in horizontal mattress groups and 47% in the simple suture repair groups.

4. Conclusion

From an anatomical perspective, the horizontal mattress technique does appear to provide improved restoration of labral height compared to a simple suture repair. In biomechanical testing the horizontal mattress configuration results in decreased capsular strain compared to the simple suture repair. Further research examining the clinical outcomes of horizontal mattress suture technique is required for comparison with simple suture arthroscopic Bankart repairs.

Author statement

Alexander J. Connaughton: Investigation, Methodology, and Writing. Melissa A. Kluczynski: Methodology and Writing. John M. Marzo: Conceptualization, Investigation and Writing