The isolated inferior glenohumeral labrum injury, anterior to posterior (the ILAP): A case series

Shoulder instability in military personnel: diagnosis and outcomes of arthroscopic stabilisation

INTRODUCTION

Shoulder instability is a common problem for military personnel due to the highly physical demands of work and training. This study assessed the pattern of glenoid labrum tears suffered by serving UK military personnel, the reliability of preoperative diagnostic methods (magnetic resonance arthrogram (MRA) vs clinical examination) and, finally, the outcomes of arthroscopic stabilisation in terms of satisfaction, pain, and return to sport and full deployment.

METHODS

Retrospective demographic and clinical data were collected for all patients within our unit who underwent arthroscopic shoulder stabilisation between September 2016 and January 2019. Patients underwent clinical examination for instability and subsequent imaging with MRA. For service evaluation, patient-reported outcome measure data and occupational outcome data were gathered preoperatively and postoperatively.

RESULTS

41 military patients with shoulder instability were treated with arthroscopic stabilisation. 24.4% had an isolated anterior tear, and 41.5% had complex two-zone or pan-labral tears identified on arthroscopy. Clinical examination showed higher sensitivity, accuracy and negative predictive value for all labral tear patterns compared with MRA. Mean preoperative Oxford Shoulder Instability Score score was 18.58 (SE ±1.67) and mean postoperative score was 41.5 (SE ±1.13). 82.14% of the patients returned to full deployment during the study period and 85% had returned to sports.

CONCLUSION

Complex labral tear patterns are common in military personnel with shoulder instability, and clinical examination appears to be more effective than imaging at predicting injury pattern. Patients respond well to arthroscopic stabilisation with good rates of return to work and sport, regardless of chronicity of injury.

Histological Analysis of Regenerative Properties in Human Glenoid Labral Regions

BACKGROUND

The healing capacity of the human glenoid labrum varies by tear location. Current evidence suggests that the healing capacity of meniscal and cartilage injuries relates to cellular composition and vascularity. However, little is known about the histological characteristics of the glenoid labrum and how they may affect healing potential in specific anatomic regions.

HYPOTHESIS

Regenerative characteristics of the glenoid labrum differ based on the anatomic region.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Human glenoid labra from fresh unpreserved cadavers were transversely sectioned in different anatomic regions. Masson trichrome stain was used to determine dense and loose extracellular matrix regions and vessel densities. Hematoxylin and eosin, Ki-67+, and CD90+/CD105+ stains were performed to determine total, proliferative, and progenitor cell densities, respectively. Regression models demonstrated relationships between vascular area, progenitor cell quantity, and probability of successful operation.

RESULTS

Among all labral aspects, the superior glenoid labrum had the highest percentage (56.8% ± 6.9%) of dense extracellular matrix or avascular tissue (P < .1). The vascular region of the superior labrum had the fewest total cells (321 ± 135 cells/mm2; P < .01) and progenitor cells (20 ± 4 cells/mm2; P < .001). Vascular area was directly correlated with progenitor cell quantity (P = .006002). An increase in probability of successful operation was associated with a linear increase in vascular area (R2 = 0.765) and an exponential increase in progenitor cell quantity (R2 = 0.795). Subsequently, quadratic models of vascularity and progenitor cell quantity around the labral clock were used to assess relative healing potential. Quadratic models for percentage vascular area (P = 6.35e-07) and weighted progenitor cell density (P = 3.03e-05) around the labral clock showed that percentage vascular area and progenitor cell quantity increased as labral tissue neared the inferior aspect and diminished near the superior aspect.

CONCLUSION

Anatomic regions of the glenoid labrum differ in extracellular matrix composition, vascularity, and cell composition. The superior glenoid labrum is deficient in vascularity and progenitor cells, which may explain the high failure rates for repairs in this location.

CLINICAL RELEVANCE

Improved understanding of the composition of distinct glenoid labral positions may help to improve therapeutic strategies for labral pathology.

Arthroscopic repair of inferior glenoid labrum tears (Down Under lesions) produces similar outcomes to other glenoid tears

PURPOSE

Inferior glenoid labral tears are an uncommon but distinct shoulder injury. Only a small number of studies have reported outcomes following arthroscopic repair. The aim of the current study was to report minimum 2-year outcomes following inferior labral repair and to compare outcomes and risk factors associated with the injury to non-inferior labral tears. Whether preoperative MRI or MRA identified inferior labral tears was also assessed.

METHODS

A prospective study of 162 consecutive patients undergoing arthroscopic glenoid labral repair, excluding isolated superior labral tears, was conducted. Of the 130 patients available for follow-up, 18 (13.7%) had an inferior labral tear ("Down Under lesion"), the remainder had anterior, posterior or mixed anterior/posterior lesions that did not include the inferior pole. Mean follow-up time for the Down Under group was 44 months (SD 10, range 27-57), and 30 months (SD 14, range 4-60) for the non-Down Under group. Postoperative outcomes included the Oxford Shoulder Instability Score and recurrent instability. Associations between Down Under lesions and injury mechanism, instability at presentation, recurrent instability and family history were assessed with multivariable logistic regression. Preoperative MRI or MRA reports by radiologists were examined to determine if Down Under lesions were identified.

RESULTS

Oxford Shoulder Instability Scores indicated that most patients in both groups had little pain or shoulder problems postoperatively (average Oxford Score 41; 48 = no symptoms). Oxford Scores were not significantly different between the Down Under and non-Down Under groups. Four patients (22.2%) in the Down Under group had recurring symptoms (pain and instability) compared to 12 (10.6%) in the non-Down Under group; this difference was not statistically significant (adjusted OR 1.09, 95% CI 0.19,4.77). Family history of shoulder instability was positively associated with a Down Under lesion (adjusted OR 5.0, 95%CI 1.51,16.7). MRI or MRA identified 52.9% of Down Under lesions.

CONCLUSION

Down Under lesions were an infrequent type of glenoid labral injury, yet postoperative outcomes were similar to other labral tears. Patients with Down Under lesions had a significant risk factor due to family history of shoulder instability. MRI and MRA could not reliably identify Down Under lesions.

LEVEL OF EVIDENCE

Level III.

Differences in Failure Mode Between Simple and Mattress Suture Configuration in Arthroscopic Bankart Repairs: A Cadaveric Study

Background

Traumatic anterior shoulder dislocations disrupt the anteroinferior labrum (Bankart lesion), leading to high rates of instability and functional disability, necessitating stabilization.

Purpose

To investigate modes and locations of repair failure between simple and horizontal mattress suture configurations after arthroscopic Bankart repair using suture anchors in a cadaveric model.

Study Design

Controlled laboratory study.

Methods

A total of 48 fresh-frozen human cadaveric shoulders from 48 specimens underwent creation of Bankart lesions from either the 3:00 to 6:00 o'clock position on the right glenoid or the 6:00 to 9:00 o'clock position on the left glenoid. Shoulder laterality between specimens was alternated and randomized to either simple or mattress suture repair configurations. In each shoulder, anchors were placed on the glenoid at the 3:00, 4:30, and 6:00 o'clock positions on the right or 6:00, 7:30, and 9:00 o'clock positions on the left and were secured via standard arthroscopic knot-tying techniques. Specimens were tested in the supine anterior apprehension position using a servohydraulic testing machine that was loaded to failure, simulating a traumatic anterior dislocation. After dislocation, open inspection of specimens was performed, and failure mode and location were documented. Differences in failure mode and location were compared using nominal multivariate generalized estimating equations.

Results

Simple suture repairs most frequently failed at the labrum, while mattress suture repair failed at the capsule. Regardless of configuration, repairs failed most commonly at the 3:00 o'clock position on the right shoulder and 9:00 o'clock position on the left shoulder. Compared with mattress suture repairs, simple suture repairs failed at a significantly higher rate at the 6:00 o'clock position.

Conclusion

Traumatic anterior shoulder dislocation after arthroscopic Bankart repair in a cadaveric model resulted in simple suture configuration repairs failing most commonly via labral tearing compared with capsular tearing in mattress repairs. Both repair configurations failed predominately at the anterior anchor position, with simple suture repairs failing more commonly at the inferior anchor position.

Clinical Relevance

Horizontal mattress suture configurations create a larger area of repair, decreasing the risk of repair failure at the labrum. The extra time required for mattress suture placement at the inferior anchor position is used effectively, resulting in lower biomechanical failure rates.

Arthroscopic Repair of Inferior Labrum Anterior to Posterior Lesions of the Shoulder Using a Combined "Double-Pulley" Simple Knot Technique

Inferior labrum anterior to posterior lesions as an isolated injury or as part of an extensive traumatic labral tear are uncommon and may present as multidirectional instability of the shoulder. These lesions are hard to visualize radiographically and many times are diagnosed only during surgery. Arthroscopic repair of these lesions requires advanced arthroscopic skills and is required for restoration of glenohumeral stability. We report a combined double-pulley simple knot technique that anatomically reconstructs the inferior labrum while overcoming the typical technical challenges, providing a large footprint for healing along the inferior glenoid rim and minimizing the amount of suture material in direct contact with the articular cartilage and the risk of knot migration.