Biomechanical Comparison of the Long Head of the Biceps Tendon Versus Conjoint Tendon Transfer in a Bone Loss Shoulder Instability Model

Background: Augmentation of Bankart repair with long head of the biceps tendon transfer has been previously described, although there is a paucity of literature describing its biomechanical effects. Purpose/Hypothesis: The purpose of this study was to assess the effect of augmenting Bankart repair with either the conjoint tendon or the long head of the biceps tendon, both with and without subcritical (13%) glenoid bone loss. We hypothesized that, in a cadaveric model, augmenting Bankart repair with the long head of the biceps tendon would restore a greater degree of stability compared with augmenting Bankart repair with the conjoint tendon. Study Design: Controlled laboratory study. Methods: A total of 12 cadaveric shoulders were tested on a 6-degrees-of-freedom robotic musculoskeletal simulator to measure the peak resistance force due to an anterior displacement of 1 cm. The rotator cuff muscles were loaded during testing to simulate physiological conditions. The following test conditions were used for each specimen: (1) intact shoulder, (2) Bankart lesion with 13% anterior bone loss, (3) 13% bone loss with Bankart repair (anchors placed at the 3-, 4-, and 5-o’clock positions), (4) 13% bone loss with both Bankart repair and transfer of the long head of the biceps tendon, and (5) 13% bone loss with Bankart repair and transfer of the conjoint tendon. Results: Labral repair with the addition of long head of the biceps tendon transfer had the greatest peak resistance force to anterior displacement among all groups (54.1 ± 5.5 N) and was significantly stronger than both standard Bankart repair by 16.3% (46.5 ± 7.6 N; P = .039) and the conjoint transfer procedure by 16.6% (46.4 ± 7.7 N; P = .008). Conclusion: Given the susceptibility of recurrent instability in shoulders with subcritical bone loss after isolated labral repair, it is important to consider augmenting Bankart repair in high-risk patients to avoid potential recurrence and the need for reoperations. Transferring the long head of the biceps tendon to the anterior glenoid represents one possible augmentation. Clinical Relevance: We present biomechanical data for a relatively novel technique for augmenting capsulolabral repair strength in an anterior instability model with subcritical bone loss. These data represent biomechanical justification for the utilization of this relatively novel technique.

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The 6 O’Clock Anchor Increases Labral Repair Strength in a Biomechanical Shoulder Instability Model

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00271 ◽

2019 ◽

Vol 7 (7_suppl5) ◽

pp. 2325967119S0027

Author(s):

Steven L. Bokshan ◽

Steven F. DeFroda ◽

Joseph Gil ◽

J.J. Trey Crisco ◽

Brett D. Owens

Keyword(s):

Bone Loss ◽

Bone Defect ◽

Suture Anchor ◽

Peak Force ◽

Bankart Lesion ◽

Bankart Repair ◽

Resistance Force ◽

Loss Model ◽

Anterior Glenoid ◽

Peak Resistance

Objectives: Despite a growing body of literature regarding optimal repair configurations, little is known about inferior suture anchor placement (6 o’clock position). Here, we determine the biomechanical strength of adding a 6’oclock anchor to a “standard” Bankart repair in a normal glenoid and a 13% anterior bone loss model. Methods: 12 cadaveric shoulders were tested on a six axis industrial robot to measure the peak resistance to translation force with anterior displacement (1 centimeter). The rotator cuff muscles were loaded during testing to simulate physiological conditions. Test conditions included intact shoulder, Bankart lesion, Bankart repair (3, 4, and 5 o’clock anchors), and Bankart repair with a 6 o’clock anchor. A 13% anterior bone defect was then created (based on pretest CT scan) and all conditions were repeated. Repeated measures ANOVA was used to test for significant differences among groups. Results: In the no bone loss group, the addition of a 6 o’clock anchor yielded the highest peak resistance force (52.8 N, SD: 4.5 N) and was significantly stronger than the standard Bankart repair by 15.8% (7.2 N, p = 0.003). With 13% bone loss from the anterior glenoid, both the standard Bankart repair (peak force 49.3 N, SD: 6.1 N, p = 0.02) and repair with the addition of the 6 o’clock anchor (peak force 52.6 N, SD: 6.1 N, p = 0.006) had a significantly higher peak resistance force compared to the bone loss with Bankart lesion group (35.2 N, SD: 5.8 N). While the 6 o’clock anchor did increase the strength of the standard repair by 6.7%, this was not statistically significant (p = 0.9) in the bone loss model. Conclusion: The addition of a 6 o’clock suture anchor to a ”standard” Bankart repair increases to the peak resistance to translation force (no bone loss), although this additional strength is lost with creation of a 13% anterior glenoid bone defect.

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Dynamic anterior shoulder stabilization using the long head of the biceps tendon: a biomechanical study: DAS: a biomechanical study

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00209 ◽

2019 ◽

Vol 7 (5_suppl3) ◽

pp. 2325967119S0020

Author(s):

J. Mehl ◽

F. Imhoff ◽

E. Obopilwe ◽

F. Dyrna ◽

A. Lädermann ◽

...

Keyword(s):

External Rotation ◽

Biceps Tendon ◽

Surgical Techniques ◽

Biomechanical Study ◽

Bankart Repair ◽

Shoulder Stabilization ◽

Glenoid Defect ◽

Defect Groups ◽

Anterior Glenoid ◽

Long Head

Objectives A new concept of dynamic anterior shoulder stabilization (DAS) combining Bankart repair with the additional sling effect of the long head of the biceps (LHB) tendon to treat anterior glenohumeral instability has recently been introduced. The purpose of this study was to biomechanically investigate the stabilizing effect of the DAS technique in comparison to standard Bankart repair in different defect models. Methods Twenty-four fresh frozen cadaver shoulders (average ± SD: age 60.1 ± 8.6 years) were mounted in a shoulder-testing system allowing 6 degrees of freedom. According to cross sectional area ratios the rotator cuff muscles and the LHB tendon were loaded with 40 N and 10 N, respectively. Glenohumeral translation was tested in 60° abduction and 60° external rotation (ABER position) while forces of 20 N, 30 N and 40 N were applied. The translation was measured using a 3D-digitizer and the total translation and the relative translation in relation to the native starting position were determined. Maximal external and internal rotation after application of 1.5 Nm torque to the humerus were measured. All specimens went through for 4 different conditions (Intact, defect, isolated Bankart repair, DAS) and were randomized to 3 different defect groups (Isolated Bankart lesion; 10% anterior glenoid defect; 20% anterior glenoid defect). Results Both surgical techniques resulted in decreased anterior glenohumeral translation in comparison to the defect conditions in all defect groups. In comparison with isolated Bankart repair DAS showed significant less relative anterior translation in 10% glenoid defects (30 N: 2.6 ± 3.4 mm vs. 5.3 ± 4.2 mm; p=0.044) and in 20% glenoid defects (40 N: 2.1 ± 6.6 mm vs. 6.0 ± 5.7 mm; p=0.035). However, in 20% defects DAS led to a relevant posterior and inferior shift of the humeral head in ABER position and to a relevant increase of inferior glenohumeral translation. Both surgical techniques did not limit the rotational range of motion. Conclusion In the context of minor glenoid bone defects the DAS technique demonstrates superior results in comparison to isolated Bankart repair.

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Long Head of Biceps Tendon Transfer for Anterior Shoulder Instability

Techniques in Shoulder & Elbow Surgery ◽

10.1097/bte.0000000000000153 ◽

2018 ◽

Vol 19 (4) ◽

pp. 175-178

Author(s):

Mario H. Lobão Gonçalves ◽

Anand M. Murthi

Keyword(s):

Shoulder Instability ◽

Tendon Transfer ◽

Biceps Tendon ◽

Anterior Shoulder Instability ◽

Long Head Of Biceps ◽

Long Head

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Critical Glenoid Bone Loss in Posterior Shoulder Instability

The American Journal of Sports Medicine ◽

10.1177/0363546518758015 ◽

2018 ◽

Vol 46 (5) ◽

pp. 1058-1063 ◽

Cited By ~ 12

Author(s):

Christopher Nacca ◽

Joseph A. Gil ◽

Rohit Badida ◽

Joseph J. Crisco ◽

Brett D. Owens

Keyword(s):

Bone Loss ◽

Lateral Displacement ◽

Peak Force ◽

Glenoid Bone Loss ◽

Bankart Lesion ◽

Bankart Repair ◽

Labral Repair ◽

Glenoid Defect ◽

The Mean ◽

Osseous Defect

Background: There is currently no consensus regarding the amount of posterior glenoid bone loss that is considered critical. Critical bone loss is defined as the amount of bone loss that occurs in which an isolated labral repair will not sufficiently restore stability. Purpose: The purpose is to identify the critical size of the posterior defect. Study Design: Controlled laboratory study. Methods: Eleven cadaveric shoulders were tested. With the use of a custom robot device, a 50-N compressive force was applied to the glenohumeral joint, and the peak force that was required to translate the humeral head posteriorly and the lateral displacement that occurred with translation were measured. The defect size was measured as a percentage of the glenoid width. Testing was performed in 11 conditions: (1) intact glenoid and labrum, (2) simulated reverse Bankart lesion, (3) the reverse Bankart lesion repaired, (4) a 10% defect, (5) the reverse Bankart lesion repaired, (6) a 20% defect, (7) the reverse Bankart lesion repaired, (8) a 30% defect, (9) the reverse Bankart lesion repaired, (10) a 40% defect, and (11) the reverse Bankart repaired. Results: Force and displacement decreased as the size of the osseous defect increased. The mean peak force that occurred with posterior displacement in specimens with a glenoid defect ≥20% and a reverse Bankart repair (13 ± 9 N) was significantly lower than the peak force that occurred in specimens with an isolated reverse Bankart repair (22 ± 10 N) ( P = .0451). In addition, the mean lateral displacement was significantly less in the specimens with a 20% glenoid defect and a reverse Bankart repair (0.61 ± 0.57 mm) compared with the lateral displacement that occurred in specimens with an isolated reverse Bankart repair (1.6 ± 0.78 mm) ( P = .0058). Conclusion: An osseous defect that is ≥20% of the posterior glenoid width remains unstable after isolated reverse Bankart repair. Clinical Relevance: A bony restoration procedure of the glenoid may be necessary in shoulders with a posterior glenoid defect that is ≥20% of the glenoid width.

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Dynamic Anterior Shoulder Stabilization With the Long Head of the Biceps Tendon: A Biomechanical Study

The American Journal of Sports Medicine ◽

10.1177/0363546519833990 ◽

2019 ◽

Vol 47 (6) ◽

pp. 1441-1450 ◽

Cited By ~ 4

Author(s):

Julian Mehl ◽

Alexander Otto ◽

Florian B. Imhoff ◽

Matthew Murphy ◽

Felix Dyrna ◽

...

Keyword(s):

External Rotation ◽

Biceps Tendon ◽

Surgical Techniques ◽

Bankart Repair ◽

Shoulder Stabilization ◽

Glenoid Defect ◽

Anterior Translation ◽

Defect Groups ◽

Anterior Glenoid ◽

Long Head

Background: The concept of dynamic anterior shoulder stabilization (DAS) combines a Bankart repair with the additional sling effect of the long head of the biceps (LHB) tendon to treat anterior glenohumeral instability. This surgical technique was created to close the gap between the indications for isolated Bankart repair and those requiring bone transfer techniques. Purpose: To biomechanically investigate the stabilizing effects of the DAS technique in comparison with the standard Bankart repair in different defect models. Study Design: Controlled laboratory study. Methods: Twenty-four fresh-frozen cadaveric shoulders (mean ± SD age, 60.1 ± 8.6 years) were mounted in a 6 degrees of freedom shoulder testing system. With cross-sectional area ratios, the rotator cuff muscles and LHB tendon were loaded with 40 N and 10 N, respectively. Anterior and inferior glenohumeral translation was tested in 60° of abduction and 60° of external rotation (ABER position) while forces of 20 N, 30 N, and 40 N were applied to the scapula in the posterior direction. Total translation and relative translation in relation to the native starting position were measured with a 3-dimensional digitizer. Maximal external rotation and internal rotation after application of 1.5-N·m torque to the humerus were measured. All specimens went through 4 conditions (intact, defect, isolated Bankart repair, DAS) and were randomized to 1 of 3 defect groups (isolated Bankart lesion, 10% anterior glenoid defect, 20% anterior glenoid defect). The DAS was performed by transferring the LHB tendon through a subscapularis split to the anterior glenoid margin, where it was fixed with an interference screw. Results: Both surgical techniques resulted in decreased anterior glenohumeral translation in comparison with the defect conditions in all defect groups. As compared with isolated Bankart repair, DAS showed significantly less relative anterior translation in 10% glenoid defects at translation forces of 20 N (0.3 ± 1.7 mm vs 2.2 ± 1.8 mm, P = .005) and 30 N (2.6 ± 3.4 mm vs 5.3 ± 4.2 mm, P = .044) and in 20% glenoid defects at all translation forces (20 N: –3.2 ± 4.7 mm vs 0.8 ± 4.1 mm, P = .024; 30 N: –0.9 ± 5.3 mm vs 4.0 ± 5.2 mm, P = .005; 40 N: 2.1 ± 6.6 mm vs 6.0 ± 5.7 mm, P = .035). However, in 20% defects, DAS led to a relevant posterior and inferior shift of the humeral head in the ABER position and to a relevant increase in inferior glenohumeral translation. Both surgical techniques did not limit the rotational range of motion. Conclusion: In the context of minor glenoid bone defects, the DAS technique demonstrates less relative anterior translation as compared with an isolated Bankart repair at time zero. Clinical Relevance: The new DAS technique seems capable of closing the gap between the indications for isolated Bankart repair and bone transfer techniques.

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