Three-dimensional MRI of the glenoid labrum

Shoulder Instability: Interobserver and Intraobserver Agreement in the Assessment of Labral Tears

Background:

The glenohumeral joint combines large range of motion and insufficient bony stabilization, making it susceptible to instability and dislocations. Arthroscopic surgery is routinely used as a diagnostic tool and has been considered the gold standard for the diagnosis of shoulder lesions. However, several studies have demonstrated variability in intraobserver and interobserver agreement.

Purpose:

To evaluate interobserver and intraobserver agreement in the assessment of intra-articular lesions associated with shoulder instability among fellowship-trained shoulder surgeons.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

A total of 24 arthroscopic videos from patients treated for recurrent shoulder instability were shown to a group of 10 fellowship-trained shoulder surgeons who are members of the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group. They were presented to the surgeons on 2 different occasions at least 2 months apart. They were asked to classify labral tears by their position, type, extension, other intra-articular abnormality, and preferred treatment. No patient history or physical examination data were provided. The primary outcome was the median overall percentage of agreement for the surgeons performing a video review, measured for each variable evaluated. Intraclass correlation coefficients were used to evaluate continuous variables, and kappa values were used for categorical items.

Results:

Interobserver agreement was good for anterior labral lesions; good for Hill-Sachs lesions; and moderate for lesions of the superior labrum, posterior labrum, anterior sublabral foramen, and position and extension of the tear. Intraobserver agreement was either good or very good for all variables evaluated, except for being poor for inferior labral lesions and moderate for lesions of the meniscoid superior labrum.

Conclusion:

Interobserver and intraobserver reliability for the arthroscopic assessment of labral tears in patients with recurrent shoulder instability were good to moderate for the majority of anatomic structures assessed. There was relatively good agreement between shoulder instability surgeons on assessing and documenting shoulder instability–associated abnormalities. These findings are important when interpreting collaborative clinical cohort studies with numerous surgeons involved in the research.

Three-dimensional ultrasonography of shoulders with rotator cuff tears

BACKGROUND

It is possible to evaluate the size of rotator cuff tears by ultrasonography (US) or magnetic resonance imaging. However, there are only a few reports on the imaging assessment of the configuration of cuff tears, which could provide important preoperative information that assists performing an optimal anatomical repair. The purpose of this study was to determine quantitatively the reproducibility of three-dimensional US in the assessment of rotator cuff tear configuration.

METHODS

Ten embalmed cadaveric shoulders with rotator cuff tears were examined. After resecting the proximal humerus with the rotator cuff, we put it in water and scanned it using high-resolution US with a three-dimensional linear probe. Actual tear lengths and widths were compared with sonographic measurements (Pearson correlation coefficient). By superimposing the real photographic image on the reconstructed three-dimensional image, we calculated the concordance rate (ratio of the concordance area to the tear area).

RESULTS

The actual tear length (16.6 +/- 7.1 mm; mean +/- SD) and width (8.4 +/- 4.4 mm) were correlated with the tear length (16.4 +/- 7.5 mm) and width (8.2 +/- 4.4 mm) measured from reconstructed three-dimensional ultrasonograms (r = 0.998 and 0.994, respectively). The mean concordance rate was 91.4%, indicating that almost exactly the same configuration was reconstructed by US.

CONCLUSIONS

Three-dimensional US is useful for evaluating the configuration of rotator cuff tears. This is the first report to quantify the similarity between the configuration evaluated by US and the actual configuration. Using this method, we can visualize the configuration of rotator cuff tears preoperatively, facilitating optimal repair design.

The inter-rater reliability of shoulder arthroscopy

PURPOSE

The purpose of this study was to determine the inter-rater reliability of orthopaedic shoulder surgeons in evaluating the intra-articular structures involved in real-time diagnostic shoulder arthroscopy by use of a videotape model.

METHODS

Twenty patients (nineteen male patients and one female patient) diagnosed with recurrent anterior shoulder instability with a mean age of 27.9 years (range, 15 to 44 years) consented to participate in the study. Standardized diagnostic shoulder arthroscopies (modified Snyder protocol) were done by a single experienced surgeon, and the procedures were videotaped. The patients' clinical information, radiographs, and videotape of the arthroscopy were sent to 6 experienced shoulder surgeons. The surgeons reviewed the clinical information, assessed the intra-articular structures shown on the videotape, and recorded their diagnoses on a standardized data collection form. The primary outcome was the median overall percent agreement for the video review surgeons by structure evaluated.

RESULTS

The median values for overall agreement for the video review surgeons were as follows: anterior labrum, 90%; inferior labrum, 75%; superior labrum, 60%; posterior labrum, 65%; superior glenohumeral ligament, 50%; middle glenohumeral ligament, 50%; anterior inferior glenohumeral ligament, 25%; glenoid surface, 35%; detection of Hill-Sachs lesion, 85%; biceps tendon, 70%; supraspinatus tendon, 85%; infraspinatus tendon, 70%; and subscapularis tendon, 80%.

CONCLUSIONS

The inter-rater reliability for orthopaedic shoulder surgeons' arthroscopic assessment of intra-articular anatomy in patients with anterior shoulder instability varied by structure examined. It was very good (>80%) for the anterior labrum and supraspinatus tendon and in detecting a Hill-Sachs lesion, poor (<40%) for the glenoid and anterior inferior glenohumeral ligament, and intermediate for all other structures examined.

LEVEL OF EVIDENCE

Level V, diagnostic study, expert opinion.

Normal anatomy and common labral lesions at MR arthrography of the shoulder

MR arthrography of the shoulder is the most accurate imaging modality in demonstrating abnormalities of the glenoid labrum and associated structures. Tears of the labrum, the capsule or the gleno-humeral ligaments can lead to pain, catching, popping or instability. The anatomy of this region is complex. We present the normal anatomy of the glenoid labrum, biceps anchor and gleno-humeral ligaments together with their normal variants and then describe common labral-ligamentous pathologies.

Direct MR arthrography of the shoulder: 2D vs. 3D gradient-echo imaging

The aim of this study was to determine the value of a fat suppressed 3D gradient-echo sequence (GRE) data set in comparison to a 2D GRE sequence in direct MR arthrography of the shoulder. For this purpose we examined 50 consecutive patients with subacute or chronic disorders of the shoulder using a 1.5 T scanner: Transverse T1-weighted 2D (slice thickness 4 mm) and 3D GRE (slice thickness 1.5 mm reconstructed from 3 mm), oblique coronal T2- and T1-weighted turbo spin-echo (TSE) and sagittal T1-weighted TSE with fat saturation were applied. Visual image analysis of anatomical and pathological structures was performed by two independent observers. A correlation to surgical results was available in 21 patients. Transverse GRE sequences were well suited for analysis of the anterior/posterior labrum, the middle glenohumeral ligament, and cartilage. 3D GRE with fat suppression was slightly superior to 2D GRE without fat suppression in the evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament, whereas for cartilage no significant differences were found between both sequences. Concerning pathological findings, in most of the cases 2D delivered the same results as 3D. In conclusion, a T1-weighted 3D GRE data set with fat saturation in transverse orientation may be useful for evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament. However, similar measured slice thickness of 3 mm-even if interpolated to 1.5 mm-compared to a 2D sequence with 4 mm does not provide significant diagnostic advantages.