Preoperative MRI Shoulder Findings Associated with Clinical Outcome 1 Year after Rotator Cuff Repair

Ultrasonic shear wave elastography predicts the quality of the residual tendon before the rotator cuff repair

BACKGROUND AND PURPOSE

Effective evaluation of rotator cuff tear residual tendon quality is the key to surgical repair. However, until now, the evaluation of rotator cuff tissue by ultrasonic shear wave elasticity (SWE) has been controversial. This prospective study analyzed the association between preoperative SWE and arthroscopic residual tendon quality scores.

METHODS

The shear wave velocity (SWV) of the deltoid muscle, the supraspinatus tendon, and the supraspinatus muscle were measured in full-thickness rotator cuff tear patients. Tendon quality was scored according to tear size, tendon margin, tendon thickness, and footprint coverage during arthroscopy. The arthroscopic scores were used as the gold standard, and the SWV ratio of tendon and muscle (supraspinatus tendon/deltoid and supraspinatus muscle/deltoid) were calculated and correlated with the arthroscopic scores.

RESULT

Eighty-nine patients (129 shoulders) were enrolled, including 89 operation shoulders and 40 control shoulders. In the group of operation shoulders, both the SWV ratios of tendon (SWV-RT) and the SWV ratio of muscle (SWV-RM) were negatively correlated with arthroscopic scores (The correlation coefficient (R) ranged from -0.722 to -0.884 and -0.569 to -0.689). The SWV-RT and SWV-RM of the operation shoulders were significantly lower than that of the control shoulders (p < 0.05).

CONCLUSION

SWE could be used to predict the quality of the residual tendon before the rotator cuff repair. SWV of the supraspinatus tendon and muscle was a useful parameter to predict the quality of the residual tendon.

CRITICAL RELEVANCE STATEMENT

Measuring the shear wave velocity of the supraspinatus tendon and muscle with SWE is useful for predicting the quality of the residual tendon which is one of the key factors for a successful rotator cuff repair.

KEY POINTS

• Evaluating the quality of the residual tendon is important before surgery. • Elasticity measurements were negatively correlated with the arthroscopic score. • SWE is useful for predicting the quality of the residual tendon.

Reliability of Magnetic Resonance Imaging Criteria for the Preoperative Assessment of Rotator Cuff Tears: A Systematic Review

BACKGROUND

Magnetic resonance (MR) imaging is the most common modality for assessment of the rotator cuff before and after surgery. Several classifications have been described aiming to define main tear characteristics. However, there is still confusion when it comes to the reliability of those classifications.

PURPOSE

(1) To identify all MR classifications available in the literature for preoperative assessment of rotator cuff tears, (2) to summarize available data on the reliability of identified classifications, and (3) to assess the methodological quality of reliability studies.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

This systematic review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All studies reporting MR assessment in patients with a superior or posterosuperior rotator cuff tear were included. After identification of the available MR criteria, reliability studies were analyzed. Descriptive statistics were used to summarize findings. Methodological quality was assessed using the Quality Appraisal of Reliability Studies checklist.

RESULTS

A total of 75 studies were included in this review. Eight categories of outcomes could be identified. Of the total, 62 studies reported interobserver reliability whereas 32 reported intraobserver reliability of some of the identified criteria. Each category reflected a variety of reliability, ranging from poor to excellent agreement. MR proved to be a reliable imaging modality to detect the structural integrity of the posterosuperior cuff, especially in cases of full-thickness tear; it was also reliable in terms of tear width and length and muscle atrophy based on a tangent sign or Thomazeau classification. All other classifications did not prove acceptable reliability. Methodological quality was high for 23 articles and moderate for 14.

CONCLUSION

Preoperative MR is a reliable imaging modality to identify full-thickness tears, measure tear size and morphology, and identify muscle atrophy with tangent sign or Thomazeau classification. All other outcomes and classifications did not show acceptable reliability; therefore, caution is needed when using them for preoperative evaluation of a rotator cuff tear.

Preoperative Shoulder MRI Findings to Predict Subscapularis Tendon Tear Requiring Surgical Repair

Purpose

This study aimed to investigate which indirect parameters on preoperative MRI were the principal predictors of subscapularis tendon tears (STTs) requiring surgical repair.

Materials and Methods

Preoperative MRI scans of 86 patients were retrospectively reviewed for visual assessment of the STT, pathology of the long head of the biceps tendon (LHBT), posterior decentering (PD) of the humeral head, humeral rotation, fatty degeneration, and subscapularis muscle atrophy. To evaluate atrophy, visual grading using the anatomical line connecting the coracoid tip to the glenoid base, designated as the base-to-tip line (BTL), and thickness measurements were performed in the en-face view.

Results

Arthroscopically, 31 patients (36%) exhibited Lafosse type III or IV STT and underwent surgical repair. LHBT pathology (p = 0.002), PD of the humeral head (p = 0.012), fatty degeneration (p < 0.001), and BTL grade (p = 0.003) significantly correlated with STT. In the multivariate analysis, PD of the humeral head (p = 0.011, odds ratio [OR] = 5.14) and fatty degeneration (p = 0.046, OR = 2.81) were independent predictors of STT.

Conclusion

PD of the humeral head and fatty degeneration of the subscapularis can help to diagnose clinically significant STT. Interpretation of these findings may contribute to the planning of an optimal surgical strategy.

Development and clinical validation of deep learning for auto-diagnosis of supraspinatus tears

BACKGROUND

Accurately diagnosing supraspinatus tears based on magnetic resonance imaging (MRI) is challenging and time-combusting due to the experience level variability of the musculoskeletal radiologists and orthopedic surgeons. We developed a deep learning-based model for automatically diagnosing supraspinatus tears (STs) using shoulder MRI and validated its feasibility in clinical practice.

MATERIALS AND METHODS

A total of 701 shoulder MRI data (2804 images) were retrospectively collected for model training and internal test. An additional 69 shoulder MRIs (276 images) were collected from patients who underwent shoulder arthroplasty and constituted the surgery test set for clinical validation. Two advanced convolutional neural networks (CNN) based on Xception were trained and optimized to detect STs. The diagnostic performance of the CNN was evaluated according to its sensitivity, specificity, precision, accuracy, and F1 score. Subgroup analyses were performed to verify its robustness, and we also compared the CNN's performance with that of 4 radiologists and 4 orthopedic surgeons on the surgery and internal test sets.

RESULTS

Optimal diagnostic performance was achieved on the 2D model, from which F1-scores of 0.824 and 0.75, and areas under the ROC curves of 0.921 (95% confidence interval, 0.841-1.000) and 0.882 (0.817-0.947) were observed on the surgery and internal test sets. For the subgroup analysis, the 2D CNN model demonstrated a sensitivity of 0.33-1.000 and 0.625-1.000 for different degrees of tears on the surgery and internal test sets, and there was no significant performance difference between 1.5 and 3.0 T data. Compared with eight clinicians, the 2D CNN model exhibited better diagnostic performance than the junior clinicians and was equivalent to senior clinicians.

CONCLUSIONS

The proposed 2D CNN model realized the adequate and efficient automatic diagnoses of STs, which achieved a comparable performance of junior musculoskeletal radiologists and orthopedic surgeons. It might be conducive to assisting poor-experienced radiologists, especially in community scenarios lacking consulting experts.

Prognostic Factors for Clinical Outcomes After Arthroscopic Rotator Cuff Repair

Background

Limited knowledge exists regarding prognostic factors after rotator cuff repair.

Purpose

To identify pre- and perioperative predictors for functional outcomes after arthroscopic rotator cuff repair.

Study Design

Case-control study; Level of evidence, 3.

Methods

This study included patients who underwent arthroscopic rotator cuff repair between January 2013 and April 2019 and who had preoperative magnetic resonance imaging scans. The procedures were performed by 4 shoulder surgeons at a single institution. Excluded were patients who had previous surgeries, those who underwent open surgery, and those without 12- and 24-month follow-up clinical data. Patient-reported outcomes (American Shoulder and Elbow Surgeons [ASES] Standardized Shoulder Assessment Form and University of California, Los Angeles [UCLA] Shoulder Rating Scale scores) were assessed preoperatively and at 6, 12, and 24 months postoperatively. Using multiple linear regression analysis, the authors evaluated the influence of 29 variables relating to patient, lesion, and procedure characteristics on postoperative outcomes, with the 24-month ASES score as the dependent variable.

Results

The study sample consisted of 474 patients (500 shoulders). The median ASES score increased from 41.6 preoperatively to 88.3 at 24 months (P < .001), and the median UCLA score increased from 14 preoperatively to 32 in the same period (P < .001). The following variables were found to be independent predictors for higher 24-month postoperative ASES score: male sex, absence of rheumatologic disease, older age, lower degree of supraspinatus muscle fatty degeneration, acromioplasty, and a higher preoperative ASES score.

Conclusion

The prognostic factors for better clinical results at 24 months after arthroscopic rotator cuff repair were male sex, absence of rheumatologic disease, older age, lower degree of fatty degeneration of the supraspinatus muscle, concomitant acromioplasty, and higher preoperative ASES score.

Clinical value of three-dimensional ultrasonography in the morphologic evaluation of rotator cuff tear: a prospective study

OBJECTIVE

To study the clinical value of three-dimensional ultrasonography (3D-US) in the morphological evaluation of rotator cuff tears (RCTs).

METHODS

Based on previously published literature, RCT patterns in our study were divided into crescent, L-shaped with the remnant tendon retracted to the anterior rotator cuff (aL-shaped), L-shaped with the remnant tendon retracted to the posterior rotator cuff (pL-shaped), T-shaped (a tear pattern that is a combination of aL-shaped and pL-shaped), U-shaped, and massive type. Two radiologists prospectively assessed the tear patterns using 3D-US as well as magnetic resonance imaging (MRI) and compared these results using arthroscopy to calculate diagnostic accuracy.

RESULT

Fifty-two patients (52 shoulders) were enrolled. The overall diagnostic accuracy of 3D-US in evaluating RCT patterns (82.7%, 43/52; 95% CI: 72.1-93.3%) was significantly higher (p = 0.008) than that of the MRI (57.7%, 31/52; 95% CI: 45.8-73.4%). The accuracy of 3D-US was higher than that of MRI for most types of tears (crescent: 95.0% vs. 55.0%, aL-shaped: 83.3% vs. 77.8%, pL-shaped: 50.0% vs. 25.0%, T-shaped: 75.0% vs. 0.0%, and massive type: 80.0% vs. 100.0%). The accuracies of 3D-US with respect to evaluation by the two radiologists were 84.6% (44/52) and 76.9% (40/52), and there was substantial agreement evident (κ = 0.709). The time taken by the two radiologists to reconstruct the 3D-US images and evaluate the tear pattern was < 5 min.

CONCLUSION

The 3D-US can be used for the preoperative evaluation of RCT patterns, and thus be useful for the correct selection of the surgical repair technique for RCTs.

KEY POINTS

• Few studies have been found exploring the value of 3D-US for the morphological evaluation of RCTs and correlated with the arthroscopic findings. • Based on previous studies on the morphological classification, anterior L shape (aL-shaped), and posterior L shape (pL-shaped) were used for the first time to describe the torn patterns of RCT.

Correlation of defect size with fatty infiltration on MRIs of rotator cuff tendinopathy

Introduction

Sizable rotator cuff defects with limited muscle atrophy and fat replacement may represent acute traumatic ruptures that are less likely to recur after surgery to close the defect, while closure of defects with poor quality muscle are associated with defect recurrence. These distinct lesions are both referred to as tears. We analyzed the relationship between rotator cuff defect size and muscle quality to determine the relative proportion of sizable defects associated with good muscle and factors associated with muscle deterioration.

Material and methods

A cohort of 230 consecutive shoulder MRIs in patients with full-thickness rotator cuff tendon defects, limited acromioclavicular arthrosis (to avoid hindrance of defect measurement), and a duration of symptoms in the radiology report from a large urban center in the United States was evaluated for the measured distance between the supraspinatus tendon edge and the greater tuberosity medial to lateral (coronal plane defect size), anterior to posterior (sagittal plane defect width), and fatty infiltration (Goutallier classification), and atrophy (Warner classification) of the supraspinatus. We sought factors independently associated with fatty infiltration and muscle atrophy in multivariable logistic regression analyses.

Results

Forty-nine of 109 shoulders (45%) with a coronal plane defect >20 mm had reasonable muscle quality as defined by Goutallier grade less than 2 and Warner grade less than 2. Both greater fatty infiltration of the supraspinatus muscle and greater supraspinatus muscle atrophy were associated with older age and greater coronal plane defect size.

Conclusion

The observation that supraspinatus muscle health deteriorates with age and defect size, but nearly half of the largest defects had good muscle, suggests an important distinction between relatively recent traumatic ruptures and old untreated rupture or gradual attrition that may be obfuscated by referring to all lesions as tears.

Level of evidence

Level III; Retrospective diagnostic cohort.

Rotator Cuff Injury and Repair

Rotator cuff pathology is a commonly encountered clinical and radiologic entity that can manifest as tendinopathy or tearing. Magnetic resonance imaging (MRI) and ultrasonography offer similar sensitivity and specificity for the evaluation of the native rotator cuff, and the chosen modality may vary, depending on local practice and accessibility. MR arthrography is frequently used in the postoperative setting as a problem-solving tool. Key findings to include in the preoperative MRI report include the size and location of the tear, thickness of the tendon involved (partial versus full thickness), and overall tendon quality. The report should also address features associated with poor surgical outcomes, such as fatty atrophy, a decreased acromiohumeral interval, and evidence of rotator cuff arthropathy. Musculoskeletal radiologists should be familiar with the various surgical techniques and expected postoperative imaging appearance of rotator cuff repairs. Imaging also plays a role in identifying recurrent tearing, graft failure, hardware loosening, infection, and other complications.

Prognostic factors for improvement of shoulder function after arthroscopic rotator cuff repair: a systematic review

Background

The identification of factors that specify prognostic models for postoperative results should be based on the best scientific evidence and expert assessment. We aimed to identify, map, and evaluate potential prognostic factors for the improvement of shoulder function in patients undergoing arthroscopic rotator cuff repair.

Methods

Longitudinal primary studies of arthroscopic rotator cuff repair reporting any multivariable factor analyses for shoulder function improvement with an endpoint assessment of at least 6 months were included. We systematically searched EMBASE, Medline, and Scopus for articles published between January 2014 and June 2021. The risk of bias of included studies and the quality of evidence were assessed using the Quality in Prognosis Studies tool and an adapted Grading of Recommendations, Assessment, Development, and Evaluations framework.

Results

Overall, 24 studies including 73 outcome analyses were included. We classified younger age and smaller tear size as probably prognostic for a greater improvement in objective outcomes. Shorter symptom duration, absence of a worker compensation claim, low preoperative level of functional status, and high preoperative pain level were classified as probably prognostic for greater improvement in patient-reported outcome measures. The quality of the synthesized evidence was low. Twenty-one studies had an overall high risk of bias.

Conclusion

Six potential prognostic factors for shoulder function after arthroscopic rotator cuff repair were identified. Along with ongoing expert opinion assessments, they will feed into a prognostic model-building process.

Utility of Preoperative Shear-Wave Elastography of the Supraspinatus Muscle for Predicting Successful Rotator Cuff Repair: A Prospective Observational Study With MRI Correlation

BACKGROUND. After rotator cuff tear, properties of the torn muscle predict failed surgical repair. OBJECTIVE. The purpose of our study was to explore the utility of preoperative shear-wave elastography (SWE) measurements of the supraspinatus muscle to predict successful rotator cuff repair, including comparison with MRI-based measures. METHODS. This prospective study included 74 patients (37 men, 37 women; mean age, 63.9 ± 10.0 [SD] years) who underwent rotator cuff repair between May 2019 and January 2021. Patients underwent preoperative clinical shoulder MRI and investigational shoulder ultrasound including SWE using shear modulus. The mean elasticity values of the supraspinatus and trapezius muscles were measured, and the elasticity ratio (i.e., ratio of mean elasticity of supraspinatus muscle to mean elasticity of trapezius muscle) was calculated. The muscular fatty infiltration score (1-3 scale) was recorded on gray-scale ultrasound. On MRI, muscular fatty infiltration was assessed by Goutallier grade (0-4 scale), and muscular atrophy was assessed by the occupation ratio (ratio of cross-sectional areas of supraspinatus muscle and supraspinatus fossa) and by the muscle atrophy grade (0-3 scale). After rotator cuff repair, the surgeon classified procedures as achieving sufficient (n = 60) or insufficient (n = 14) repair. RESULTS. Patients with insufficient repair, versus those with sufficient repair, more commonly exhibited a large (3-5 cm) tear (100.0% vs 50.0%). Patients with insufficient, versus sufficient, repair exhibited higher mean Goutallier grade (3.8 ± 0.4 vs 1.9 ± 1.1), mean muscle atrophy grade (2.0 ± 0.8 vs 0.5 ± 0.7), mean supraspinatus elasticity (44.15 ± 8.06 vs 30.84 ± 7.89 kPa), mean elasticity ratio (3.66 ± 0.66 vs 1.83 ± 0.58), and mean gray-scale fatty infiltration grade (2.86 ± 0.36 vs 1.63 ± 0.66) and showed lower mean occupation ratio (0.3 ± 0.1 vs 0.6 ± 0.1) (all, p < .001). AUC for predicting insufficient repair was 0.945 for Goutallier grade, 0.961 for occupation ratio, 0.900 for muscle atrophy grade, 0.874 for mean elasticity, 0.971 for elasticity ratio, and 0.912 for gray-scale fatty infiltration grade. Elasticity ratio (cutoff ≥ 2.51) achieved sensitivity of 100.0% and specificity of 90.0% for insufficient repair. At multivariable analysis including tear size, the three MRI measures, elasticity ratio, and gray-scale fatty infiltration grade, the only independent predictors of insufficient repair were muscle atrophy grade of 2-3 (odds ratio [OR] = 9.3) and elasticity ratio (OR = 15.7). CONCLUSION. SWE-derived elasticity is higher in patients with insufficient rotator cuff repair; the elasticity ratio predicts insufficient repair independent of tear size and muscle characteristics. CLINICAL IMPACT. Preoperative SWE may serve as a prognostic marker in patients with rotator cuff tear.

3D MRI of the Shoulder

Magnetic resonance imaging provides a comprehensive evaluation of the shoulder including the rotator cuff muscles and tendons, glenoid labrum, long head biceps tendon, and glenohumeral and acromioclavicular joint articulations. Most institutions use two-dimensional sequences acquired in all three imaging planes to accurately evaluate the many important structures of the shoulder. Recently, the addition of three-dimensional (3D) acquisitions with 3D reconstructions has become clinically feasible and helped improve our understanding of several important pathologic conditions, allowing us to provide added value for referring clinicians. This article briefly describes techniques used in 3D imaging of the shoulder and discusses applications of these techniques including measuring glenoid bone loss in anterior glenohumeral instability. We also review the literature on routine 3D imaging for the evaluation of common shoulder abnormalities as 3D imaging will likely become more common as imaging software continues to improve.

Quantitative analysis of repaired rabbit supraspinatus tendons (± channeling) using magnetic resonance imaging at 7 Tesla

Background

The quantitative assessment of supraspinatus tendons by conventional magnetic resonance is limited by low contrast-to-noise ratio (CNR). Magnetic resonance imaging (MRI) scanners operating at 7 Tesla offer high signal-to noise ratio (SNR), low CNR and high spatial resolution that are well-suited for rapidly relaxing tissues like tendons. Few studies have applied T2 and T2* mapping to musculoskeletal imaging and to the rotator cuff tendons. Our objective was to analyze the T2 and T2* relaxation times from surgically repaired supraspinatus tendons and the effect of bone channeling.

Methods

One supraspinatus tendon of 112 adult female New Zealand white rabbits was surgically detached and repaired one week later. Rabbits were randomly assigned to channeling (n=64) or control (n=48) groups and harvested at 0, 1, 2, and 4 weeks. A 7T magnet was used for signal acquisition. For T2 mapping, a sagittal multi slice 2D multi-echo spin-echo (MESE) CPMG sequence with fat saturation was applied and T2* mapping was performed using a 3D UTE sequence. Magnetic resonance images from supraspinatus tendons were analyzed by two raters. Three regions of interest were manually drawn on the first T2-weighted dataset. For T2 and T2*, different ROI masks were generated to obtain relaxation times.

Results

T2-weighted maps but not T2*-weighted maps generated reliable signals for relaxation time measurement. Torn supraspinatus tendons had lower T2 than controls at the time of repair (20.0±3.4 vs. 25.6±3.9 ms; P<0.05). T2 increased at 1, 2 and 4 postoperative weeks: 22.7±3.1, 23.3±3.9 and 24.0±5.1 ms, respectively, and values were significantly different from contralateral supraspinatus tendons (24.8±3.1; 26.8±4.3 and 26.5±3.6 ms; all P<0.05). Bone channeling did not affect T2 (P>0.05).

Conclusions

Supraspinatus tendons detached for 1 week had shorter T2 relaxation time compared to contralateral as measured with 7T MRI.

Deep learning method for segmentation of rotator cuff muscles on MR images

OBJECTIVE

To develop and validate a deep convolutional neural network (CNN) method capable of (1) selecting a specific shoulder sagittal MR image (Y-view) and (2) automatically segmenting rotator cuff (RC) muscles on a Y-view. We hypothesized a CNN approach can accurately perform both tasks compared with manual reference standards.

MATERIAL AND METHODS

We created 2 models: model A for Y-view selection and model B for muscle segmentation. For model A, we manually selected shoulder sagittal T1 Y-views from 258 cases as ground truth to train a classification CNN (Keras/Tensorflow, Inception v3, 16 batch, 100 epochs, dropout 0.2, learning rate 0.001, RMSprop). A top-3 success rate evaluated model A on 100 internal and 50 external test cases. For model B, we manually segmented subscapularis, supraspinatus, and infraspinatus/teres minor on 1048 sagittal T1 Y-views. After histogram equalization and data augmentation, the model was trained from scratch (U-Net, 8 batch, 50 epochs, dropout 0.25, learning rate 0.0001, softmax). Dice (F1) score determined segmentation accuracy on 105 internal and 50 external test images.

RESULTS

Model A showed top-3 accuracy > 98% to select an appropriate Y-view. Model B produced accurate RC muscle segmentations with mean Dice scores > 0.93. Individual muscle Dice scores on internal/external datasets were as follows: subscapularis 0.96/0.93, supraspinatus 0.97/0.96, and infraspinatus/teres minor 0.97/0.95.

CONCLUSIONS

Our results show overall accurate Y-view selection and automated RC muscle segmentation using a combination of deep CNN algorithms.