Anterior Glenohumeral Instability. Sports Med Arthrosc Rev. 2017;25:156-162. [PMID: 28777219 DOI: 10.1097/jsa.0000000000000157]

Comparison of the Glenoid Index by Computed Tomography With Magnetic Resonance Imaging

Introduction Anterior shoulder instability results in labral and osseous glenoid injuries. With a large osseous defect, there is a risk of recurrent dislocation of the joint, and therefore the patient has to undergo surgical correction. An MRI evaluation of the patient helps to assess the soft tissue injury. Currently, the volumetric three-dimensional (3D) reconstructed CT image is the standard for measuring glenoid bone loss and the glenoid index. However, it has the disadvantage of exposing the patient to radiation and additional expenses. This study aims to compare the values of the glenoid index using MRI and CT. Methodology The present study was a two-year cross-sectional study of patients with shoulder pain, trauma, and dislocation in a tertiary hospital in Karnataka. The sagittal proton density (PD) section of the glenoid and enface 3D reconstructed images of the scapula were used to calculate glenoid bone loss and the glenoid index. The baseline data were analyzed using descriptive statistics, and the Chi-square test was used to test the association of various complications with selected variables of interest. Results The glenoid index calculated in the current study using 3D volumetric CT images and MR sagittal PD images was 0.95±0.01 and 0.95±0.01, respectively. The CT and MRI glenoid bone loss was 5.41±0.65% and 5.38±0.65%, respectively. When compared, the glenoid index and bone loss calculated by MRI and CT revealed a high correlation and significance with a p-value of <0.001. Conclusions The study concluded that MRI is a reliable method for glenoid measurement. The sagittal PD sequence combined with an enface glenoid makes it possible to identify osseous defects linked to glenohumeral joint damage and dislocation. The values derived from 3D CT are identical to the glenoid index and bone loss determined using the sagittal PD sequence in MRI.

Influence of Graft Positioning during the Latarjet Procedure on Shoulder Stability and Articular Contact Pressure: Computational Analysis of the Bone Block Effect

The Latarjet procedure is the most popular surgical procedure to treat anterior glenohumeral (GH) instability in the presence of large anterior glenoid bone defects. Even though the placement of the bone graft has a considerable influence on its efficacy, no clear indications exist for the best graft position. The aim of this study was to investigate the influence of the medial-lateral positioning of the bone graft on the contact mechanics and GH stability due to the bone block effect. Four finite element (FE) models of a GH joint, with a 20% glenoid bone defect, treated by the Latarjet procedure were developed. The FE models differed in the medial-lateral positioning of the bone graft, ranging from a flush position to a 4.5 mm lateral position with respect to the flush position. All graft placement options were evaluated for two separate shoulder positions. Anterior GH instability was simulated by translating the humeral head in the anterior direction, under a permanent compressive force, until the peak translation force was reached. Joint stability was computed as the ratio between the shear and the compressive components of the force. The lateralization of the bone graft increased GH stability due to the bone block effect after a 3 mm lateralization with respect to the flush position. The increase in GH stability was associated with a concerning increase in peak contact pressure due to the incongruous contact between the articulating surfaces. The sensitivity of the contact pressures to the medial-lateral positioning of the bone graft suggests a trade-off between GH stability due to the bone block effect and the risk of osteoarthritis, especially considering that an accurate and consistent placement of the bone graft is difficult in vivo.

Clinical outcome and return to sports activity after surgical treatment for recurrent shoulder instability with a modified Latarjet procedure

INTRODUCTION

The Latarjet procedure is an attractive surgical option for the management of chronic anterior shoulder instability. The original surgical approach involves the vertical tenotomy of the subscapularis tendon. Alternatively, the subscapularis muscle is split longitudinally and the tendon left attached at the lesser tuberosity.

HYPOTHESIS

The hypothesis is that the longitudinal split is of functional advantage and may lead to better functional results and earlier return to sports activities compared to the vertical tenotomy.

MATERIAL AND METHODS

Thirty-two patients were included in this retrospective cohort study. In 14 patients, the subscapularis tendon was vertically incised (group A), whereas in 18 patients, the subscapularis muscle was split longitudinally (group B). Patients were evaluated at 1 year (FU1) and 2 years (FU2) after the Latarjet procedure. Results at follow-up were correlated with patient-specific data and compared with the preoperative status. Primary outcomes were the functional assessment based on Western Ontario Shoulder Instability (WOSI) index and Constant Score (CS) and the assessment of the return to sports activity. Patients' demographics, duration of surgery, and the rate of recurrent dislocations were recorded as secondary variables.

RESULTS

All patients started their sports activities with a mean±SD of 12.41±1.24 weeks. Interestingly, the time from surgery to full recovery of sports activities was significantly longer for group A (mean±SD of 30.17±10.36 weeks) compared to group B (mean±SD of 20.71±3.67 weeks). There is a statistically significant decrease of the WOSI score from the preoperative level compared to FU1 and FU2, indicating a decrease in instability related symptoms during the entire follow up period with no statistically significant difference between group A and B. There is an increase in shoulder function during the entire follow up period based on the CS. Most interestingly, there is a statistically significant difference between group A and B at FU1, indicating a significantly better shoulder function for group B at the early follow up timepoint (FU1). At the later follow up timepoint (FU2), no difference exists in the individual items. However, a significantly better total CS remains in group B, indicating an overall improved function compared to group A.

DISCUSSION/CONCLUSION

The longitudinal split of subscapularis muscle is a safe approach which leads to quicker functional recovery and return to sports activity compared to the vertical tenotomy, which is a benefit especially for active individuals. It is therefore recommended as the standard surgical approach.

LEVEL OF EVIDENCE

III; Retrospective cohort study.

A lower Instability Severity Index score threshold may better predict recurrent anterior shoulder instability after arthroscopic Bankart repair: a systematic review

Importance

The Instability Severity Index (ISI) score was developed to evaluate a patient’s risk of recurrent shoulder instability following arthroscopic Bankart repair. While patients with an ISI score of >6 were originally recommended to undergo an open procedure (ie, Latarjet) to minimise the risk of recurrence, recent literature has called into question the utility of the ISI score.

Objective

The purpose of this systematic review was to evaluate the efficacy of the ISI score as a tool to predict postoperative recurrence among patients undergoing arthroscopic Bankart procedures.

Evidence review

Articles were included if study participants underwent arthroscopic Bankart repair for anterior shoulder instability and reported postoperative recurrence by ISI score at a minimum of 2 years of follow-up. Methodological study quality was assessed using the Methodological Index for Non-Randomized Studies criteria. Pearson’s χ2 test was used to compare recurrence rates among patients above and below an ISI score of 4. Sensitivity, specificity, mean ISI scores and predictive value of individual factors of the ISI score were qualitatively reviewed.

Findings

Four studies concluded the ISI score was effective in predicting postoperative recurrence following arthroscopic Bankart repair; however, these studies found threshold values lower than the previously proposed score of >6 may be more predictive of recurrent instability. A pooled analysis of these studies found patients with an ISI score <4 to experience significantly lower recurrence rates when compared with patients with a score ≥4 (6.3% vs 26.0%, p<0.0001). The mean ISI score among patients who experienced recurrent instability was also significantly higher than those who did not.

Conclusions and relevance

The ISI score as constructed by Balg and Boileau may have clinical utility to help predict recurrent anterior shoulder instability following arthroscopic Bankart repair. However, this review found the threshold values published in their seminal article to be insufficient predictors of recurrent instability. Instead, a lower score threshold may provide as a better predictor of failure. The paucity of level I and II investigations limits the strength of these conclusions, suggesting a need for further large, prospective studies evaluating the predictive ability of the ISI score.

Level of evidence

IV.

Arthroscopic Bankart Repair With Inferior to Superior Capsular Shift in Lateral Decubitus Position

Traditional Bankart repairs for anterior labral tears of the shoulder use suture anchors to repair the anterior shoulder labrum and capsule to the glenoid. The technique described here involves releasing the anterior capsule of the glenoid and shifting it superiorly along with the labrum before anchoring. The intention of this extra step is to replicate the open technique, where the entire capsule is shifted superiorly on the glenoid.

Anterior glenohumeral instability: Current review with technical pearls and pitfalls of arthroscopic soft-tissue stabilization

The glenohumeral joint (GHJ) allows for a wide range of motion, but is also particularly vulnerable to episodes of instability. Anterior GHJ instability is especially frequent among young, athletic populations during contact sporting events. Many first time dislocators can be managed non-operatively with a period of immobilization and rehabilitation, however certain patient populations are at higher risk for recurrent instability and may require surgical intervention for adequate stabilization. Determination of the optimal treatment strategy should be made on a case-by-case basis while weighing both patient specific factors and injury patterns (i.e., bone loss). The purpose of this review is to describe the relevant anatomical stabilizers of the GHJ, risk factors for recurrent instability including bony lesions, indications for arthroscopic vs open surgical management, clinical history and physical examination techniques, imaging modalities, and pearls/pitfalls of arthroscopic soft-tissue stabilization for anterior glenohumeral instability.

Management of bone loss in recurrent traumatic anterior shoulder instability: a survey of North American surgeons

Background

Management of bone loss in recurrent traumatic anterior shoulder instability remains a topic of debate and controversy in the orthopedic community. The purpose of this study was to survey members of 4 North American orthopedic surgeon associations to assess management trends for bone loss in recurrent anterior shoulder instability.

Methods

An online survey was distributed to all members of the American Shoulder and Elbow Surgeons, American Orthopaedic Society for Sports Medicine, and Canadian Orthopaedic Association and to fellow members of the Arthroscopy Association of North America. The survey comprised 3 sections assessing the demographic characteristics of survey respondents, the influence of prognostic factors on surgical decision making, and the operative management of 12 clinical case scenarios of varying bone loss that may be encountered in clinical practice.

Results

A total of 150 survey responses were returned. The age of the patient and quantity of bone loss were consistently considered important prognostic criteria. However, little consensus was reached for critical thresholds of bone loss and how this affected the timing (ie, primary or revision surgery) and type of bony augmentation procedure to be performed once a critical threshold was reached, especially in the context of critical humeral and bipolar bone loss.

Conclusions

Consistent trends were found for the management of recurrent anterior shoulder instability in cases in which no bone loss existed and when isolated critical glenoid bone loss was present. However, inconsistencies were observed when isolated critical humeral bone loss and bipolar bone loss were present.