Increased Load to Failure in Biceps Tenodesis With All-Suture Suture Anchor Compared With Interference Screw: A Cadaveric Biomechanical Study

All-suture anchor size and drill angle influence load to failure in a porcine model of subpectoral biceps tenodesis, a biomechanical study

BACKGROUND

Tenodesis of the long head of the biceps tendon is frequently performed in shoulder surgery, and all-suture anchors have become more popular as fixation methods. However, uncertainty still exists regarding the ultimate load to failure of all-suture anchors and the best insertion angle at a cortical humeral insertion point.

PURPOSE

The purpose of this study was to compare the biomechanical characteristics of three types of all-suture anchors frequently used for biceps tenodesis. In addition, the influence of two different insertion angles was observed in a porcine humeri model.

METHODS

The ultimate load to failure and failure mode of three types of all-suture anchors (1.6 FiberTak®, 1.9 FiberTak®, 2.6 FiberTak®, Arthrex®) applicable for subpectoral biceps tenodesis were evaluated at 90° and 45° insertion angles in 12 fresh-frozen porcine humeri. The anchors were inserted equally alternated in a randomized manner at three different insertion sites along the bicipital groove, and the suture tapes were knotted around a rod for pullout testing. In total, 36 anchors were evaluated in a universal testing machine (Zwick & Roell).

RESULTS

The 2.6 FiberTak® shows higher ultimate loads to failure with a 90° insertion angle (944.0 N ± 169.7 N; 537.0 N ± 308.8 N) compared to the 1.9 FiberTak® (677.8 N ± 57.7 N; 426.3 N ± 167.0 N, p-value: 0.0080) and 1.6 FiberTak® (733.0 N ± 67.6 N; 450.0 N ± 155.8 N, p-value: 0.0018). All anchor types show significantly higher ultimate loads to failure and smaller standard deviations at the 90° insertion angle than at the 45° insertion angle. The major failure mode was anchor pullout. Only the 2.6 FiberTak® anchors showed suture breakage as the major failure mode when placed with a 90° insertion angle.

CONCLUSIONS

All three all-suture anchors are suitable fixation methods for subpectoral biceps tenodesis. Regarding our data, we recommend 90° as the optimum insertion angle.

CLINICAL RELEVANCE

The influence of anchor size and insertion angle of an all-suture anchor should be known by the surgeon for optimizing ultimate loads to failure and for achieving a secure fixation.

Biomechanical properties of suprapectoral biceps tenodesis with double-anchor knotless luggage tag sutures vs. subpectoral biceps tenodesis with single-anchor whipstitch suture using all-suture anchors

Background

As the use of all-suture anchors continues to increase, limited biomechanical data on the use of these anchors in various configurations for tenodesis of the long head biceps tendon (LHBT) exists. The aim of this study was to compare the biomechanical properties of a 2-anchor luggage tag suprapectoral biceps tenodesis (Sup-BT) vs. a single-anchor whipstitch subpectoral biceps tenodesis (Sub-BT) using all-suture anchors. The hypothesis was that the Sub-BT will have a higher ultimate load to failure and less creep relative to the Sup-BT construct.

Methods

Eighteen fresh frozen cadaveric humeri were used. The specimens were randomly divided into 2 groups of 9; i) The Sup-BT were performed with 2 1.8 mm knotless all-suture anchors using a luggage-tag fixation configuration, ii) The Sub-BT were performed using a single 1.9 mm all-suture anchor and a whipstitch suture configuration with a tied knot. The humeri were tested on a hydraulic MTS machine where the specimens were preloaded at 5 N for 2 minutes and then cyclically loaded from 5 to 50 N for 1000 cycles at 1 Hz while maximum displacement was recorded with a motion system and markers attached to the bone and bicep tendon. The tendon was then tensioned at a rate of 1 mm/s to obtain the ultimate load to failure. CT scans of the specimens were used to calculate the bone mineral density at the site of the anchor/bone interface and video recordings were captured during load to failure to document all modes of failure.

Results

There was no significant difference in the average load to failure of the Sup-BT and Sub-BT groups (197 N ± 45 N (SD), 164 N ± 68 N (SD) respectively; P = .122) or creep under fatigue between the Sup-BT vs. Sub-BT specimens (3.1 mm, SD = 1.5 vs. 2.2 mm, SD = 0.9; P = .162). The bone mineral density was statistically different between the 2 groups (P < .001); however, there were no observed failures at the anchor/bone interface and no correlation between failure load and bone mineral density.

Conclusion

The ultimate load to failure and creep between a Sup-BT with 2 knotless all-suture anchors using a luggage tag suture configuration was equivalent to a Sub-BT with 1 all-suture anchor using a whipstitched suture configuration and a tied knot. Surgeons can perform either technique confidently knowing that they are biomechanically equivalent in a cadaver model at time zero, and they offer similar strength to other fixation methods cited in the literature.

Arthroscopic Shoulder Biceps Suspensionplasty for Hemiplegic Shoulder Painful Inferior Subluxation

Inferior glenohumeral subluxation represents one of the causes of disabling pain in patients with hemiplegia after a stroke. In the case of failure of medical treatment by orthosis or electrical stimulation, surgical treatment of suspensionplasty has been described with good results. We describe here an arthroscopic technique of glenohumeral suspensionplasty by tenodesis of the biceps, proposed in the context of a painful glenohumeral subluxation in patients with hemiplegia.

Single- and Double-Loaded All-Suture Anchor Repairs of Anteroinferior Labral Tears Are Biomechanically Similar in a Cadaveric Shoulder Model

Purpose

To compare the biomechanical strength of single- versus double-loaded all-suture constructs in an anteroinferior glenoid labral repair.

Methods

Anteroinferior labral lesions were created on 6 matched pairs of cadaveric shoulder specimens. Each shoulder in a matched pair was randomized to either receive capsulolabral repair with 3 single-loaded all-suture anchors or 3 double-loaded all-suture anchors. Immediately following capsulolabral repair, the specimens underwent mechanical testing, which included cyclic testing (5 N to 50 N for 500 cycles) and load-to-failure testing (rate of 15 mm/min). The gap formation between the repaired labrum and glenoid (measured at 1, 25, 100, and 500 cycles), the load at 2-mm gap formation, the maximum load at failure and the method of failure were recorded. Data were analyzed with paired Student t tests and Bonferroni correction factor.

Results

The single and double all-suture constructs did not differ significantly in gap formation at any number of cycles, load to 2-mm gap formation (P = .75), or maximum load to failure (P = .46) between the 2 groups.

Conclusions

In this study, single-loaded and double-loaded all-suture anchor constructs demonstrated comparable biomechanical performance and did not significantly differ in gap formation, load to 2-mm gap formation, or maximum load to failure when used in the capsulolabral repair of anteroinferior glenoid labral tears in human cadaveric specimens.

Clinical Relevance

Although studies have evaluated the biomechanical properties of various arthroscopic labral stabilization techniques, the biomechanical properties of all-suture anchors with regard to labral stabilization are not well understood.

Arthroscopic Biceps Tenotomy Using a Single Portal for Working and Viewing: A Rabbit Model and Technique

Biceps tenotomy (BT) is a common surgery used to address anterior shoulder pain and joint dysfunction in humans. Using animal models to simulate human conditions is an effective and essential research strategy to further understand histologic and biomechanical processes that occur after BT, including the pathology of the detached biceps, secondary tendinopathic conditions of the rotator cuffs, and glenohumeral functional changes. This Technical Note presents a comprehensive step-by-step description of an arthroscopic BT procedure in rabbits. This technique is particularly beneficial, as the mini-invasive arthroscopic technique in a rabbit model is similar to that performed in humans. which resulted in less scarring and injuries to other adjacent structures in comparison with open surgery.

Single-Portal Proximal Biceps Tenodesis Using an All-Suture Anchor

The long head of the biceps is an important pain generator of the shoulder joint. Pathologies of the long head of the biceps involve superior labrum anterior to posterior lesions, pulley lesions, partial tears of the biceps tendon, biceps tendonitis, and medial biceps subluxation caused by full-thickness subscapularis tendon tears. Treatment of an inflamed or injured long head of the biceps by either tenotomy or tenodesis is often mandatory during shoulder arthroscopy to avoid persisting pain and possible revision procedures. In comparison with a tenotomy of the biceps tendon, a biceps tenodesis preserves the tension, anatomy, and cosmesis of the biceps muscle. The presented technique demonstrates a single portal technique for a proximal biceps tenodesis in the bicipital groove using an all-suture anchor.

Editorial Commentary: All-Suture Anchor for Shoulder Biceps Tenodesis Results in Excellent Outcomes

Patients have a strong preference for biceps tenodesis rather than a tenotomy in both Eastern and Western countries, regardless of age, and the annual number of biceps tenodeses has significantly increased in recent years. Previous studies have supported the use of suture anchors in biceps tenodesis. All-suture anchors are also a viable option because of their comparable biomechanical properties and the lower risk of humerus fractures. Recent research has evaluated the clinical outcomes after subpectoral biceps tenodesis using all-suture anchors. Encouragingly, satisfactory clinical outcomes have been reported, making this technique more attractive in clinical practice.

Editorial Commentary: What Is More Important: Strength or Displacement? Findings of All-Suture Anchor Versus Interference Screw for Biceps Tenodesis

Tendinopathy of the long head of the biceps tendon (LHB) encompasses a range of pathology, including inflammatory tendinitis to degenerative tendinosis that can lead to pain, as well as instability of the LHB and its surrounding stabilizers. Accordingly, tenodesis of the LHB during shoulder surgery has been increasingly cited in the literature as a viable surgical option for the treatment of LHB pathology. While current treatment options include the use of multiple devices for tenodesis of the LHB, there remains a paucity of literature that investigates the biomechanical advantages of all-suture anchor devices compared to interference screws.