Arthroscopic Findings in Anterior Shoulder Instability

A Comparative Study on the Diagnostic Value of CTA and MRA in Anterior Dislocation of Shoulder

Objective

To investigate the diagnostic value of CTA and MRA in anterior dislocation of shoulder.

Methods

The detection of inferior glenohumeral ligament injuries, anterior inferior labrum injuries, and bone and cartilage injuries by the two examination procedures was observed and compared with the results of arthroscopy or surgery on patients referred to our hospital owing to anterior dislocation of shoulder. Results. A total of 36 patients with shoulder injuries were gathered for this study. 32 cases with anterior inferior labrum tearings (27 cases detected by CTA and 30 cases by MRA), 24 cases with inferior glenohumeral ligament tearings (14 cases detected by CTA and 22 cases by MRA), 24 cases with inferior glenohumeral ligament tearings (14 cases detected by CTA and 22 cases by MRA), and 24 cases with inferior glenohumeral ligament tearings (14 cases detected by CTA and 22 cases by MRA) were detected. There were 30 bone and cartilage injuries, including 18 fractures (CTA identified 18), 10 bone contusions (CTA detected 0), and 5 cartilage damage (CTA detected 0) (CTA detected 0, MRA detected 5).

Conclusion

The detection rate of MRA is better than that of CTA for inferior glenohumeral ligament injuries. For anterior inferior labrum injury, the detection rate of CTA and MRA was similar. CTA is more conducive to the detection of fracture blocks, while MRA is more advantageous for the observation of bone contusion and cartilage damage.

Risk Factors for Recurrent Anterior Glenohumeral Instability and Clinical Failure Following Primary Latarjet Procedures: An Analysis of 344 Patients

BACKGROUND

Patients with a greater risk of recurrent instability and inferior clinical outcomes following a primary Latarjet procedure can be preoperatively identified on the basis of clinical, radiographic, and demographic criteria. The purpose of this study was to identify risk factors influencing the rates of recurrent anterior glenohumeral instability and clinical failure following a primary Latarjet procedure.

METHODS

All patients who underwent a primary Latarjet procedure were prospectively enrolled and evaluated. The Western Ontario Shoulder Instability Index (WOSI) and Single Assessment Numeric Evaluation (SANE) outcome scores were collected at a minimum 5-year follow-up along with evidence of recurrent instability. Recurrent instability (recurrent subluxation or dislocation) was considered as a failure. Clinical failure was defined as a postoperative WOSI score of ≥630 points (≤70% normal) or a SANE score of ≤70 points.

RESULTS

From 2004 to 2014, 344 patients (358 shoulders) with a mean age of 30.6 years (range, 16 to 68 years) were enrolled and had a mean follow-up time of 75 months (range, 61 to 89 months). The median postoperative WOSI score was 265 points (range, 0 to 1,100 points), and the median SANE score was 88 points (range, 50 to 100 points). Recurrence occurred in 17 shoulders (4.7%), 5 with dislocation and 12 with subluxation; and 28 (8.2%) of 341 shoulders without recurrent instability were clinical failures following a Latarjet procedure. The risk factors for recurrence included atraumatic dislocation (odds ratio [OR], 4.6; p < 0.01) and bilateral instability (OR, 4.0; p = 0.01), whereas the risk factors for clinical failure (WOSI score of ≥630 points or SANE score of ≤70 points) were female sex (OR, 2.8; p < 0.01) and bilateral instability (OR, 4.6; p = 0.01).

CONCLUSIONS

Outcomes at a mean of >6 years following a primary Latarjet procedure for anterior shoulder instability were very good, with an overall recurrence rate of 4.7%. An additional 8.2% of cases were defined as clinical failures. Patients with an atraumatic mechanism of primary dislocation, bilateral instability, and female sex were identified to be at a greater risk of recurrence or clinical failure. Although additional work is necessary, patients with capsuloligamentous laxity, relatively atraumatic instability history, bilateral instability, and female sex may be preoperatively identified as having a higher risk of treatment failure after a primary Latarjet procedure.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Anterior Instability: What to Look for

Most first-time anterior glenohumeral dislocations occur as the result of trauma. Many patients suffer recurrent episodes of anterior shoulder instability (ASI). The anatomy and biomechanics of ASI is addressed, as is the pathophysiology of capsulolabral injury. The roles of imaging modalities are described, including computed tomography (CT) and MR imaging with the additional value of arthrography and specialized imaging positions. Advances in 3D CT and MR imaging particularly with respect to the quantification of humeral and glenoid bone loss is discussed. The concepts of engaging and nonengaging lesions as well as on-track and off-track lesions are examined.

Imaging modality for measuring the presence and extent of the labral lesions of the shoulder: a systematic review and meta-analysis

BACKGROUND

Multiple published studies quantitatively analysing the diagnostic value of MRI, MR arthrography (MRA) and CT arthrography (CTA) for labral lesions of the shoulder have had inconsistent results. The aim of this meta-analysis was to systematically compare the diagnostic performance of MRI, MRA, CTA and CT.

METHODS

Two databases, PubMed and EMBASE, were used to retrieve studies targeting the accuracy of MRI, MRA, CTA and CT in detecting labral lesions of the shoulder. After carefully screening and excluding studies, the studies that met the inclusion criteria were used for a pooled analysis, including calculation of sensitivity and specificity with 95% confidence intervals (CIs) and the area under the hierarchical summary receiver operating characteristic (HSROC) curves.

RESULTS

The retrieval process identified 2633 studies, out of which two reviewers screened out all but 14 studies, involving a total of 1216 patients who were deemed eligible for inclusion in the meta-analysis. The results assessing the diagnostic performance of MRI vs. MRA for detecting labral lesions showed a pooled sensitivity of 0.77 (95% CI 0.70-0.84) vs. 0.92 (95% CI 0.84-0.96), a specificity of 0.95 (95% CI 0.85-0.98) vs. 0.98 (95% CI 0.91-0.99), and an area under the HSROC curve of 3.78 (95% CI 2.73-4.83) vs. 6.01 (95% CI 4.30-7.73), respectively.

CONCLUSION

MRA was suggested for use in patients with chronic shoulder symptoms or a pathologic abnormality. MRI is by far the first choice recommendation for the detection of acute labral lesions. CT should be a necessary supplemental imaging technique when there is highly suspected glenoid bone damage.

Variability of shoulder girdle proprioception in 44 healthy volunteers

BACKGROUND

Improved knowledge of normal shoulder girdle proprioception should benefit the treatment and rehabilitation of shoulder disorders. Whereas many of the available methods for assessing joint position sense (JPS) are costly and complex, Balke et al. have described a simple test. The primary objective of this study was to use this test to identify factors that influence shoulder-girdle JPS evaluation in healthy individuals. The secondary objective was to determine reference values based on the values obtained and on the factors associated with their variability.

HYPOTHESIS

Age and dominant limb influence the results of shoulder girdle JPS evaluation, creating a need for reference values that take these factors in account.

PATIENTS AND METHODS

A single-centre prospective study of healthy volunteers was performed between September 2012 and January 2013. In each volunteer, shoulder repositioning accuracy was assessed bilaterally as described by Balke et al. A line was drawn on the floor parallel to and 1 metre away from a wall. A target on the wall showed marks corresponding to three angles of arm elevation: 55°, 90°, and 125°. The volunteer was asked to raise the arm to the three positions, in abduction and in flexion, while memorising the joint positions, then to replicate the same positions with the eyes closed. The absolute differences between the replicated positions and the reference positions, designated angle deviations, were measured in degrees. Age, sex, and dominant upper limb were recorded.

RESULTS

The 88 shoulders of 44 healthy volunteers were studied. No significant difference was found between males and females (p>0.05). The only significant difference between sides was better replication by the dominant arm of flexion at 55° (p=0.03). By univariate analysis, age was the only factor significantly associated with repositioning errors (p=0.003); neither dominant limb nor sex were significant (p=0.29 and p=0.59, respectively). In flexion, the angle deviation increased significantly with movement amplitude. The measurements were used to create a chart of expected angle deviations in healthy individuals according to age and to plane and amplitude of movement.

DISCUSSION

The test described by Balke et al. is simple and feasible in everyday practice. Age, dominance, and plane of movement should be considered when evaluating abnormal shoulders. Further studies in larger numbers of individuals are needed to better define normal angle deviations related to these factors.

LEVEL OF EVIDENCE

IV.

A Prospective Analysis of Patients With Anterior Versus Posterior Shoulder Instability: A Matched Cohort Examination and Surgical Outcome Analysis of 200 Patients

BACKGROUND

Anterior and posterior shoulder instabilities are entirely different entities. The presenting complaints and symptoms vastly differ between patients with these 2 conditions, and a clear understanding of these differences can help guide effective treatment.

PURPOSE

To compare a matched cohort of patients with anterior and posterior instability to clearly outline the differences in the initial presenting history and overall outcomes after arthroscopic stabilization.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Consecutive patients with either anterior or posterior glenohumeral instability were prospectively enrolled; patients were excluded if they had more than 10% anterior or posterior glenoid bone loss, multidirectional instability, neurologic injury, or prior surgery. Patients were assigned to anterior or posterior shoulder instability groups based on the history and clinical examination documenting the primary direction of instability, with imaging findings to confirm a labral tear associated with the specific direction of instability. Preoperative demographic data, injury history, and overall clinical outcome scores (American Shoulder and Elbow Surgeons [ASES], Single Assessment Numeric Evaluation [SANE], and Western Ontario Shoulder Index [WOSI]) were assessed and compared statistically between the 2 cohorts. Patients were indicated for surgery if they elected to proceed with surgical management or did not respond to a course of nonoperative management.

RESULTS

The study included 103 patients who underwent anterior stabilization (mean age, 23.5 years; range, 18-36 years) and 97 patients who underwent posterior stabilization (mean age, 24.5 years; range, 18-36 years). The mean follow-up was 39.7 months (range, 24-65 months), and there were no age or sex differences between the groups. No patients were lost to follow-up. The primary mechanism of injury in the anterior cohort was a formal dislocation event (82.5% [85/103], of which 46% [39/85] required reduction by a medical provider), followed by shoulder subluxation (12%, 12/103), and "other" (6%, 6/103; no forceful injury). No primary identifiable mechanism of injury was found in the posterior cohort for 78% (75/97) of patients; lifting and pressing (11%, 11/97) and contact injuries (10% [all football blocking], 10/97) were the common mechanisms that initiated symptoms. Only 10 patients (10.3%) in the posterior cohort sustained a dislocation. The most common complaints for patients with anterior instability were joint instability (80%) and pain with activities (32%). In the posterior cohort, the most common complaint was pain (90.7%); only 13.4% in this cohort reported instability as the primary complaint. Clinical outcomes after arthroscopic stabilization were significantly improved in both groups, but the anterior cohort had significantly better outcomes in all scores measured: ASES (preoperative: anterior 58.0, posterior 60.0; postoperative: anterior 94.2 vs posterior 87.7, P < .005), SANE (preoperative: anterior 50.0, posterior 60.0; postoperative: anterior 92.9 vs posterior 84.9, P < .005), and WOSI (preoperative: anterior 55.95, posterior 60.95; postoperative: anterior 92% of normal vs posterior 84%, P < .005).

CONCLUSION

This study outlines clear distinctions between anterior and posterior shoulder instability in terms of presentation and clinical findings. Patients with anterior instability present primarily with an identifiable mechanism of injury and complaints of instability, whereas most patients with classic posterior instability have no identifiable mechanism of injury and their primary symptom is pain. Anterior instability outcomes in this matched cohort were superior in all domains versus posterior instability after arthroscopic stabilization, which further highlights the differences between anterior and posterior instability.