Comparison of Surgical Techniques for Anterior Shoulder Instability

Health condition(s) or problem(s) studied Recurrent Anterior Shoulder (glenohumeral) Instability with subcritical glenoid bone loss (10- 20%.

Interventions Intervention 1: Arthroscopic Bankart Repair Arthroscopic repair of the anterior capsulolabral complex using suture anchors to restore anterior glenohumeral stability.

Intervention 2: Dynamic Anterior Stabilization (DAS) Arthroscopic dynamic anterior stabilization using the long head of the biceps tendon to augment the anterior labrum and provide additional dynamic stabilization of the glenohumeral joint.

This was a single-center, prospective comparative clinical study. Patients presenting with complaints of recurrent anterior shoulder instability were prospectively screened for eligibility according to clinical and radiological criteria and selected for the study.

All patients underwent preoperative magnetic resonance imaging (MRI) for the assessment of soft-tissue injuries and computed tomography (CT) for the evaluation of glenoid bone loss.

30 patients underwent dynamic anterior stabilization (DAS group), whereas 30 patients underwent isolated Bankart repair (Bankart group), which is the control group. Group allocation was performed using a computer program.

Surgical Procedures and Tissue Sampling All surgical procedures were performed arthroscopically by one surgeon. Intraoperative tissue specimens were obtained from both groups for subsequent histopathological examination. In the DAS group, a bone specimen was collected from the anterior glenoid surface together with a segment of the long head of the biceps tendon. In the Bankart group, specimens were obtained from the anterior glenoid bone surface and the anterior labrum. All specimens were processed according to the same standardized histopathological protocol.

Ethics Approval and Informed Consent The study was conducted in accordance with the principles in the Declaration of Helsinki and the Oviedo Convention. Ethical approval was obtained from Riga Stradins University (No. 2-PEK-4/694/2024, 29 November 2024).

Written informed consent was obtained from all participants before enrollment in the study.

If random allocation, the trial is reported according to CONSORT and provides the registration information. The journal also requires an ICMJE-recognized registry, the original protocol, and this document is an unpublished CONSORT checklist as supplementary files.

Operative time and the requirement for additional postoperative analgesic medication were also recorded.

Preview, not for official use. All patients underwent the same standardized postoperative rehabilitation protocol regardless of treatment allocation. Histopathological Examination All collected tissue specimens were fixed in 10% neutral-buffered formalin and embedded in paraffin. Bone core biopsies obtained from the anterior glenoid measured approximately 6-8 mm in length, whereas soft-tissue specimens (both LHB and Labrum) measured approximately 8-12 mm. Sections of 3 μm thickness were prepared and stained with hematoxylin and eosin.

Histopathological assessment of the soft-tissue specimens included evaluation of inflammatory cell infiltration. The number of inflammatory cells, including lymphocytes and leukocytes, was assessed in ten high-power fields at x400 magnification and expressed as cells per mm3.

Bone tissue histomorphometry was performed according to the 2012 update of the American Society for Bone and Mineral Research (ASBMR) Histomorphometry Nomenclature Committee recommendations. The assessed parameters included core length, tissue area, bone area, and bone volume. Osteonecrosis was defined by the presence of bone trabeculae containing empty osteocyte lacunae, and the results were expressed as the percentage of necrotic bone trabeculae.

Peritrabecular fibrosis was graded using a four-point scale: grade 0, regular bone trabeculae with distinct paratrabecular borders; grade 1, focal budding, hooks, spikes, or paratrabecular apposition of new bone; grade 2, diffuse paratrabecular new bone formation with thickening of the trabeculae and occasional focal interconnections; and grade 3, extensive interconnected new bone formation with substantial effacement of the marrow spaces. Statistical Analysis: Categorical and non-parametric data were analyzed using the Chi-square test and the Mann-Whitney U test, respectively. Correlations between the clinical or histopathological variables were evaluated using the Pearson Chi-square (χ2) test. A p-value of <0.05 was considered statistically significant. The GraphPad Prism 12 software was used for data analysis.

• Arthroscopic Dynamic Anterior Stabilization (Procedure), also known as DAS, Shoulder anterior stabilization: Dynamic Anterior Stabilization (DAS) Arthroscopic stabilization of the anterior glenohumeral joint using the long head of the biceps tendon. The tendon is transferred through the subscapularis tendon and fixed to the anterior glenoid, providing dynamic anterior stabilization and augmentation of the anterior capsulolabral complex.
• Arthroscopic Bankart Repair (Procedure), also known as Bankart, Labrum glenoidale fixation: Arthroscopic stabilization of the anterior glenohumeral joint by repair and reattachment of the detached anterior capsulolabral complex to the glenoid rim using suture anchors.

Primary outcomes

• Recurrent anterior shoulder instability [Up to 24 months after surgery]: Number/proportion of patients experiencing postoperative redislocation and/or symptomatic subluxation.

Secondary outcomes

• American Shoulder and Elbow Surgeons (ASES) score. [Baseline, 1, 3, 6, 12, 24 months postoperatively.]: Shoulder function is evaluated using the ASES score, ranging from 0 to 100, with higher scores indicating better shoulder function.
• Constant - Murley Score [Baseline, 1, 3, 6, 12, 24 months postoperatively.]: Shoulder function is evaluated using the Constant - Murley Score, including pain, activities of daily living, range of motion, and strength. Ranging from 0 to 100 points, where higher scores indicate better shoulder function
• Visual Analogue Scale (VAS) [Baseline, 1, 3, 6, 12, 24 months postoperatively.]: Shoulder pain will be assessed with the Visual Analogue Scale (VAS), where higher scores indicate greater pain intensity. Ranging from 0 to 10 points.
• Return to sport and work [1, 3, 6, 12, 24 months postoperatively.]: The proportion of patients returning to their previous level of sporting activity and/or work and the time required to return will be recorded.
• Revision surgery [24 months after the index procedure.]: The number and proportion of patients requiring additional surgical treatment because of recurrent instability, persistent symptoms, or complications will be recorded.
• Postoperative complications [24 - month follow-up after procedure.]: Surgical and postoperative complications, including infection, stiffness, neurological complications, persistent pain, implant-related complications, and other adverse events, will be recorded.
• Surgery time [From the start to completion of the surgical procedure]: The duration of surgery will be measured in minutes.
• Postoperative medication use [1, 3, 6, 12, 24 months postoperatively.]: The type, duration, and amount of postoperative analgesic and anti-inflammatory medication will be recorded and compared between the DAS and Bankart groups.

Sex: All, ages: 18 Years to 50 Years

Inclusion Criteria:

* Patients aged ≤50 years;
* History of anterior shoulder dislocation and/or subluxation;
* Persistent anterior glenohumeral instability;
* MRI-confirmed anterior labral injury and Hill-Sachs lesion;
* CT-confirmed glenoid bone loss of 10-20% of the total glenoid articular surface.

Exclusion Criteria:

* Patients aged >50 years;
* Concomitant injuries or pathological conditions involving other structures of the shoulder joint;
* Multidirectional shoulder instability;
* Previous surgical procedures on the affected shoulder;
* Acute infection;
* Coagulation disorders;
* Systemic diseases, including diabetes mellitus (DM), rheumatoid arthritis (RA), gout, and autoimmune diseases (AIDs).

• Study Protocol and Informed Consent Form (PDF, 2025-11-01)