The natural course of and risk factors for tear progression in conservatively treated full-thickness rotator cuff tears

Parathyroid hormone promotes induction of beige adipocytes and reversibly ameliorates muscle quality and atrophy following chronic rotator cuff tear in a rat model

BACKGROUND

Fatty infiltration (FI) and muscle atrophy (MA) in the rotator cuff muscles following rotator cuff tears (RCT) persist postrepair, increasing the risk of re-tears. Brown adipocyte-like "beige adipocytes" are expected to have a therapeutic effect on intramuscular FI and MA due to their lipolytic activity and the muscle regenerative effects of their secreted factors. However, whether parathyroid hormone (PTH) ameliorates the already advanced FI and MA remains unknown. Therefore, this study aimed to clarify whether PTH promotes the expression of beige adipocytes and ameliorates advanced FI and MA following chronic RCT in rats.

METHODS

Supraspinatus muscles were harvested from rats with chronic RCT after 4 or 8 weeks of PTH treatment and compared to those in the control group or to those at the start of treatment. FI was assessed by Oil Red O staining, and the staining area was evaluated as a percentage of the muscle cross-sectional area. MA was evaluated by measuring muscle wet weight and cross-sectional area of muscle fiber. Beige adipocyte expression was evaluated by immunostaining for uncoupling protein 1 (UCP1). Fibro-adipogenic progenitors (FAPs) were separated from muscle-injured mice. We assessed whether PTH could diminish fat droplet accumulation by promoting the differentiation of FAPs into beige adipocytes.

RESULTS

After 4 weeks, PTH reduced the area fraction of FI in the rat supraspinatus muscle following chronic RCT compared with that at the beginning of treatment (P = .028). In addition, PTH increased wet muscle mass (P < .001), and muscle fiber cross-sectional area (P = .018) compared with measurements at the start of treatment. PTH administration promoted the expression of UCP1, a beige adipocyte marker, in the supraspinatus muscle (P = .019). PTH increased gene expression of beige adipocyte-related markers and suppressed fat droplet accumulation even after adipogenic differentiation of FAPs (P = .004) but did not reduce fat droplets that had already accumulated in in vitro experiments.

CONCLUSIONS

PTH facilitated beige adipocyte expression and reversibly ameliorated muscle quality and atrophy following chronic RCT by hindering fat droplet accumulation and facilitating muscle regeneration. Therefore, PTH may be a medical treatment for FI and MA following RCT, leading to expanded rotator cuff repair indications.

Natural History of Quantitative Fatty Infiltration and 3D Muscle Volume After Nonoperative Treatment of Symptomatic Rotator Cuff Tears: A Prospective MRI Study of 79 Patients

BACKGROUND

The severity of fatty infiltration (FI) predicts the treatment outcome of rotator cuff tears. The purpose of this investigation was to quantitatively analyze supraspinatus (SSP) muscle FI and volume at the initial presentation and after a 3-month minimum of conservative management. We hypothesized that progression of FI could be predicted with initial tear size, FI, and muscle volume.

METHODS

Seventy-nine shoulders with rotator cuff tears were prospectively enrolled, and 2 magnetic resonance imaging (MRI) scans with 6-point Dixon sequences were acquired. The fat fraction within the SSP muscle was measured on 3 sagittal slices, and the arithmetic mean was calculated (FI SSP ). Advanced FI SSP was defined as ≥8%, pathological FI SSP was defined as ≥13.5%, and relevant progression was defined as a ≥4.5% increase in FI SSP . Furthermore, muscle volume, tear location, size, and Goutallier grade were evaluated.

RESULTS

Fifty-seven shoulders (72.2%) had normal FI SSP , 13 (16.5%) had advanced FI SSP , and 9 (11.4%) had pathological FI SSP at the initial MRI scan. Eleven shoulders (13.9%) showed a ≥4.5% increase in FI SSP at 19.5 ± 14.7 months, and 17 shoulders (21.5%) showed a ≥5-mm 3 loss of volume at 17.8 ± 15.3 months. Five tears (7.1%) with initially normal or advanced FI SSP turned pathological. These tears, compared with tears that were not pathological, had significantly higher initial mediolateral tear size (24.8 compared with 14.3 mm; p = 0.05), less volume (23.5 compared with 34.2 mm 3 ; p = 0.024), more FI SSP (9.6% compared with 5.6%; p = 0.026), and increased progression of FI SSP (8.6% compared with 0.5%; p < 0.001). An initial mediolateral tear size of ≥20 mm yielded a relevant FI SSP progression rate of 81.8% (odds ratio [OR], 19.0; p < 0.001). Progression rates of 72.7% were found for both initial FI SSP of ≥9.9% (OR, 17.5; p < 0.001) and an initial anteroposterior tear size of ≥17 mm (OR, 8.0; p = 0.003). Combining these parameters in a logistic regression analysis led to an area under the receiver operating characteristic curve (AUC) of 0.913. The correlation between FI SSP progression and the time between MRI scans was weak positive (ρ = 0.31).

CONCLUSIONS

Three risk factors for relevant FI progression, quantifiable on the initial MRI, were identified: ≥20-mm mediolateral tear size, ≥9.9% FI SSP , and ≥17-mm anteroposterior tear size. These thresholds were associated with a higher risk of tear progression: 19 times higher for ≥20-mm mediolateral tear size, 17.5 times higher for ≥9.9% FI SSP , and 8 times higher for ≥17-mm anteroposterior tear size. The presence of all 3 yielded a 91% chance of ≥4.5% progression of FI SSP within a mean of 19.5 months.

LEVEL OF EVIDENCE

Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Intra-articular site-specific distribution of advanced glycation end products in the shoulder of patients with diabetes mellitus having rotator cuff tears

BACKGROUND

Advanced glycation end products (AGEs) are compounds formed due to aging and diabetes mellitus (DM). They activate NADPH oxidase (NOX) by binding to their receptors, thereby increasing the production of reactive oxygen species (ROS), which cause oxidative stress. In this study, we investigated the effects of AGEs on the tissues of the shoulder joint (such as rotator cuff synovium, and capsule) in patients with DM having rotator cuff tears.

METHODS

This study included eight patients with DM who underwent surgical treatment for rotator cuff tears with contracture. The rotator cuff, synovium, and joint capsule were harvested at the time of surgery and evaluated by hematoxylin-eosin staining. Furthermore, immunostaining was used for evaluating AGEs and receptor for AGEs (RAGE), cell activity, ROS, and apoptosis. Quantitative real-time polymerase chain reaction (qPCR) was employed for the cellular evaluation of NOX, interleukins, RAGE, and collagen.

RESULTS

The AGEs and RAGE staining as well as the ratio of ROS and apoptosis were in the following order: rotator cuff > joint capsule > synovium. In contrast, the cellular activity was significantly higher in the synovium than in the other regions. The type I collagen expression (as shown by qPCR) as well as the RAGE and NOX expressions were as follows: rotator cuff > joint capsule > synovium. Conversely, the expression of inflammatory cytokines (i.e., IL-6 and IL-1β) was higher in the synovium than in the other regions.

CONCLUSIONS

Our study is among the first to evaluate the effects of AGEs on each tissue of the shoulder joint in patients with DM having rotator cuff tears and contractures. The accumulation of AGEs in each tissue of the shoulder joint could reveal the locations affected by DM, which can lead to a better understanding of the pathophysiology of DM-related shoulder diseases.

The pathology of oxidative stress-induced autophagy in a chronic rotator cuff enthesis tear

Partial-thickness rotator cuff tears (PTRCTs) are often found in daily orthopedic practice, with most of the tears occurring in middle-aged patients. An anaerobic process and imbalanced oxygenation have been observed in PTRCTs, resulting in oxidative stress. Studies have shown the roles of oxidative stress in autophagy and the potential of unregulated mechanisms causing disturbance in soft tissue healing. This article aims to review literature works and summarize the potential pathology of oxidative stress and unregulated autophagy in the rotator cuff enthesis correlated with chronicity. We collected and reviewed the literature using appropriate keywords, in addition to the manually retrieved literature. Autophagy is a normal mechanism of tissue repair or conversion to energy needed for the repair of rotator cuff tears. However, excessive mechanisms will degenerate the tendon, resulting in an abnormal state. Chronic overloading of the enthesis in PTRCTs and the hypovascular nature of the proximal tendon insertion will lead to hypoxia. The hypoxia state results in oxidative stress. An autophagy mechanism is induced in hypoxia via hypoxia-inducible factors (HIFs) 1/Bcl-2 adenovirus E1B 19-kDa interacting protein (BNIP) 3, releasing beclin-1, which results in autophagy induction. Reactive oxygen species (ROS) accumulation would induce autophagy as the regulator of cell oxidation. Oxidative stress will also remove the mammalian target of rapamycin (mTOR) from the induction complex, causing phosphorylation and initiating autophagy. Hypoxia and endoplasmic reticulum (ER) stress would initiate unfolded protein response (UPR) through protein kinase RNA-like ER kinase (PERK) and activate transcription factor 4, which induces autophagy. Oxidative stress occurring in the hypovascularized chronic rotator cuff tear due to hypoxia and ROS accumulation would result in unregulated autophagy directly or autophagy mediated by HIF-1, mTOR, and UPR. These mechanisms would disrupt enthesis healing.

Osteopathic Manipulative Treatment for a Chronic Rotator Cuff Tear: A Case Report

Rotator cuff tears, particularly involving the supraspinatus muscle and/or tendon, are highly prevalent among individuals engaged in repetitive shoulder motions. Occupations demanding constant and repetitive shoulder movements are especially susceptible to rotator cuff injuries, potentially leading to prolonged joint wear and tear and an increased likelihood of joint replacement. Considering the impact of social determinants of health, including access to healthcare and socioeconomic status, it is imperative to explore conservative treatment modalities that alleviate financial burdens and reduce lengthy recovery periods. In this report, we present a case of a 64-year-old female hairdresser diagnosed with a chronic partial thickness rotator cuff tear who remained unresponsive to physical therapy and chiropractic manipulation but exhibited improvement following osteopathic manipulative treatment. Additionally, osteopathic considerations and pertinent literature are reviewed to provide insight into the broader context of shoulder pain management.

Adduction Manipulation of the Glenohumeral Joint versus Physiotherapy for Atraumatic Rotator Cuff Tears: A Randomized Controlled Trial

BACKGROUND

Atraumatic rotator cuff tears (ARCTs) are frequently concomitant with adduction restriction of the glenohumeral joint (GHJ). Adduction manipulation (AM) removes the restriction and relieves pain. The present study aimed to investigate the clinical efficacy of AM versus physiotherapy (PT) in ARCTs.

METHODS

Eighty-eight patients with adduction restriction were allocated to the AM and PT groups (n = 44 per group). The glenohumeral adduction angle (GAA) was calculated using X-rays at the first and last follow-up appointments. We recorded pain severity (visual analog scale, VAS), flexion, abduction, external rotation (ER), internal rotation (IR), and American Shoulder and Elbow Society (ASES) and Constant scores at baseline and at 1-, 3-, 6-, and 12- month follow-ups.

RESULTS

Forty-three patients (23 males, average age 71.3 years) in the AM group and 41 (16 males, average age 70.7 years) in the PT group were consequently analyzed. At the 1-month follow-up, VAS, shoulder motion except ER, ASES and Constant scores were much better in the AM group than in the PT group, whereas those in the PT group improved gradually up to 12 months. At the final follow-up, flexion, abduction, and Constant score were significantly better in the AM group than in the PT group. The GAA at the initial and final examinations was -21.6° and -3.2°, respectively, in the AM group, and -21.1° and -14.4°, respectively, in the PT group.

CONCLUSIONS

The AM procedure, which had better clinical efficacy than PT, is recommended as the first conservative treatment option for ARCTs.

Functional Considerations in Bilateral, Simultaneous Tendon Injuries of the Upper Extremity: A Narrative Review of Current Literature

» Bilateral, simultaneous same-tendon injuries of the upper extremity are rarely encountered, yet their unique complexity poses a substantial challenge for treating orthopaedic surgeons.» In general, extremities with more tendon retraction should be repaired acutely while contralateral injuries can be treated in a staged or simultaneous manner depending on injury morphology, location, and anticipated functional impairment.» Combinations of accelerated and conventional rehabilitation protocols can be used for individual extremities to minimize the length of functional impairment.

Nonoperative Treatment of Rotator Cuff Tears

Rotator cuff tears are common with prevalence increasing with age. Diagnosis by physical examination may require a cluster of tests. Although radiographs can be helpful, MRI, MRI arthrography, and ultrasound represent the most used imaging technique to identify rotator cuff tears. Although surgery is sometimes necessary, a large portion of patients may respond to conservative treatment including physical therapy and injections. Physical therapy should include restoring the range of motion, addressing any pectoralis minor or posterior capsule stiffness, and restoring motor control/strength to the scapula and rotator cuff. Other conservative treatments may include nonsteroidal anti-inflammatory drugs, corticosteroid injects, and platelet-rich plasma.

Risk factors of tear progression in symptomatic small to medium-sized full-thickness rotator cuff tear: relationship between occupation ratio of supraspinatus and work level

BACKGROUND

Previous studies reported that full-thickness rotator cuff tear (FTRCT) is a risk factor for tear progression. However, there is no clear consensus on the risk factors of tear progression in FTRCT.

PURPOSE

To identify the demographic and radiologic risk factors of tear progression in small to medium FTRCTs.

METHODS

We retrospectively reviewed 81 shoulders of patients diagnosed with small or medium FTRCTs using magnetic resonance imaging (MRI) who underwent conservative treatment from January 2017 to November 2021. Various demographic factors, including patient work level and radiological factors such as atrophy of rotator cuff muscles were analyzed to evaluate their association with tear progression. Work level was divided into high (heavy manual labor), medium (manual labor with less activity), and low (sedentary work activity). The atrophy of rotator cuff muscles was calculated by occupation ratio.

RESULTS

Tear progression was observed in 48% (39/81) of patients (criterion for tear progression was medial-lateral or anterior-posterior tear length > 5 mm). In patients with tear progression, the lengths of medial-lateral and anterior-posterior tears progressed by 6 mm and 3 mm, respectively. Among the rotator cuff muscles, fatty degeneration and occupation ratio of the supraspinatus were only worsened (P = .014, P = 0.013, respectively). The mean MRI follow-up duration was 14.8 ± 9.0 months. The significant risk factors of tear progression were high work level (odds ratio [OR], 7.728; 95% CI, 1.204-49.610; P = .031), and occupation ratio of the supraspinatus muscle (OR, 0.308; 95% CI, 0.158-0.604; P = .001). The optimal cutoff value for the occupation ratio of the supraspinatus was 0.55 (sensitivity 74%, specificity 62%).

CONCLUSIONS

Tear progression was observed in approximately 50% of patients with symptomatic small to medium FTRCTs. High physical work level and atrophy of the supraspinatus muscle were independent risk factors of tear progression. The risk of tear progression increases with occupation ratio of the supraspinatus muscle < 0.55 and heavy manual labor.

Signal intensity on MRI after conservative treatment of patients with full-thickness rotator cuff tears: Correlation with shoulder pain

BACKGROUND

High signal intensity (HSI) on T2-weighted or fat-suppressed magnetic resonance imaging (MRI) around the shoulder is often observed in patients who have a rotator cuff tear, and is generally recognized as an indicator of shoulder pain, especially pain at night. We hypothesized these HSI volumes are reduced after improvement of symptoms. We sought to compare HSI before and after conservative treatment, and to determine if HSI is associated with the patient's pain status over time.

METHODS

We enrolled 55 patients (average age 65 years) into the study. All the patients complained of pain at night (University of California, Los Angeles (UCLA) pain score ≤2, Japanese Orthopedic Association (JOA) pain score ≤10) at their initial visits and underwent conservative treatment. MRI was obtained at their initial visit and after improvement of pain when their initial UCLA pain score was ≥6 points or JOA pain score was ≥20 points. The mean time between the MRI examinations was 11.8 months (SD 7.7) (range 2.5-39). HSI was assessed at the location of the subacromial-subdeltoid bursa, glenohumeral joint, subcoracoid bursa, and sheath of the long head of the biceps tendon, and graded. Factors correlating with the improvement of MRI findings were evaluated retrospectively.

RESULTS

HSI had improved in 30 shoulders in all or some of the locations (I-group). There was no change in 25 shoulders for any location or aggravation in one or more locations (N-group). Multivariate logistic regression analysis found that the time from pain improvement until the second MRI was the only independent factor related to the improvement in HSI (p = .045).

CONCLUSION

Improvement of shoulder symptoms is not directly associated with MRI findings. Improvement in HSI followed symptom improvement after a delay; the changes varied for each shoulder location.

Two-year outcomes with a bioinductive collagen implant used in augmentation of arthroscopic repair of full-thickness rotator cuff tears: final results of a prospective multicenter study

BACKGROUND

Full-thickness rotator cuff tears (FTRCTs) represent a common shoulder injury that, if untreated, can progress in size, become increasingly painful, and inhibit function. These lesions are often surgically repaired, with double-row arthroscopic repair often preferred for larger tears. Biological augmentation technologies have been developed to improve rates of postoperative radiographic retear and enhance patient-reported outcomes after surgical FTRCT repair. This study sought to confirm that augmented repair with a bioinductive bovine collagen implant results in favorable retear rates and patient outcomes with follow-up to 2 years.

METHODS

A prospective multicenter cohort study was undertaken to determine the efficacy and safety of augmenting single- or double-row arthroscopic repair of FTRCTs with a bioinductive bovine collagen implant. Of 115 adult patients participating, 66 (57.4%) had medium (1-3-cm) tears and 49 (42.6%) had large (3-5-cm) tears. Magnetic resonance imaging and patient-reported outcomes (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES] and Constant-Murley Score [CMS]) were performed and recorded at baseline, 3 months, 1 year, and 2 years.

RESULTS

Mean duration of follow-up was 2.1 years (range, 1.5-2.9 years). Between baseline and 2-year follow-up, mean total thickness of the supraspinatus tendon increased by 12.5% for medium tears and by 17.1% for large tears. Radiographic retear was noted in 7 of 61 available patients (11.5%) with medium tears, and in 14 of 40 patients (35.0%) with large tears. In both groups, these tears primarily occurred before the 3-month follow-up visit (13 of 21 [61.9%]). Radiographic retear with the supplemented double-row (DR) repair technique was 13.2% overall (12 of 91 DR patients; 11.3% for medium tears and 15.8% for large tears). The minimal clinically important difference was achieved by >90% of patients with both medium and large tears for both ASES and CMS. There were 2 serious adverse events classified by the treating surgeon as being possibly related to the device and/or procedure (1 case of swelling/drainage and 1 case of intermittent pain). Nine patients (7.8%; 4 medium tears and 5 large tears) required reoperation of the index rotator cuff surgery.

CONCLUSION

Final 2-year data from this study confirm that using this implant in augmentation of arthroscopic double-row repair of FTRCTs provides favorable rates of radiographic retear and substantial functional recovery. The relative safety of the device is also further supported.

Anterolateral Acromioplasty Does Not Change the Critical Shoulder Angle and Acromion Index in a Clinically Relevant Amount

PURPOSE

Assessment on whether radiographic parameters of the acromion measured in radiographs change significantly after anterolateral acromioplasty.

METHODS

This retrospective study included patients that underwent an arthroscopic anterolateral acromioplasty between January 2014 and September 2020. n = 435 subjects with high-quality preoperative and postoperative radiographs according to Suter-Henninger criteria were included in the final assessment. All measurements were independently performed by the first and second author in a blinded fashion using dicomPACS software: acromion index (AI), critical shoulder angle (CSA), lateral acromial angle (LAA), beta angle, acromio-humeral distance (AHD), Aoki angle, frontal supraspinatus outlet angle (FSOW), and acromion type, according to Bigliani. SPSS software was used for statistical analysis.

RESULTS

The beta angle and the CSA did not significantly change after operation (alpha power 0.32 and 0.11, respectively). In a subgroup analysis of patients with a pathological CSA >35° (n = 194), the CSA changed from 38.62 (range: 35.08-47.52, SD 2.83) to 38.04 (range: 29.18-48.12, SD 3.77) postoperatively (P = .028) (Fig 8). All other parameters changed significantly after operation (AI, AHD, FSOW, and Aoki; P = .001, LAA; P = .039) (Fig. 9). The interobserver and intraobserver reliability was good to excellent in the majority of measured values. Mean patient age was 59.2 years (range: 18.1-87.1; SD 11.3), mean height was 1.73 meters (range: 1,50-1.98, SD 0.09), mean weight was 80.2 kg (range: 37.0-133.0, SD 16.68), and mean body mass index was 26.6 (range: 0.0-46.1, SD 4.73).

CONCLUSION

Anterolateral acromioplasty producing a flat acromion undersurface did not result in a significant change of the CSA in the study population. Pathological preoperative CSA values of >35° were significantly reduced but not to normal values, but only by a small amount that puts the clinical relevance into question.

LEVEL OF EVIDENCE

IV, diagnostic study, case series.

Progression of Symptomatic Partial-Thickness Rotator Cuff Tears: Association With Initial Tear Involvement and Work Level

Background

Partial-thickness rotator cuff tears (PTRCTs) often progress to full-thickness rotator cuff tears (FTRCTs). Thus, it is important to analyze the risk factors for tear progression to determine the proper timing of repair.

Purpose

To identify the risk factors associated with progression of PTRCT.

Study Design

Case-control study; Level of evidence, 3.

Methods

Included were 89 patients diagnosed with PTRCT on magnetic resonance imaging (MRI) scans who underwent nonoperative treatment at the authors' institution between August 2012 and August 2019. Patient characteristics, shoulder stiffness (compared with the contralateral shoulder); work level (classified as high [heavy manual labor], medium [manual labor with less activity], and low [sedentary activity]); and radiological factors including initial tear size, acromion type (flat, curved, hooked, or heel-shaped), and initial tear involvement (as a percentage of the rotator cuff tendon footprint length) were analyzed to assess their association with tear progression, defined as >20% increase in tear involvement.

Results

The mean MRI follow-up period was 22.3 ± 17.2 months (median, 16.1 months; range, 6.4-89.5 months), and tear progression was observed in 12 patients (13.5%). In these 12 patients, tear involvement increased by 60% of the rotator cuff footprint, while mediolateral (ML) and anteroposterior (AP) tear sizes progressed by 1.1 and 1.8 mm, respectively. Univariate regression analysis showed that shoulder stiffness (P = .031), work level (P = .001), initial tear involvement (P < .001), ML and AP tear sizes (P < .001 and P = .005, respectively), and acromion type (P = .003) were significantly associated with tear progression. Multivariate regression analysis showed that initial tear involvement (odds ratio [OR], 1.053; 95% CI, 1.006-1.102; P = .026) and high work level (OR, 15.831; 95% CI, 1.150-217.856; P = .039) were independent risk factors for tear progression. The cutoff value for initial tear involvement was 47.5% (sensitivity, 81.8%; specificity, 85.7%).

Conclusion

Tear progression was observed in 14% of patients with PTRCT in this study. To predict tear progression, evaluating the tear involvement during initial MRI is essential. The risk of tear progression increased with initial tear involvement >47.5% and a heavy work level.

Operative versus conservative treatment of small, nontraumatic supraspinatus tears in patients older than 55 years: over 5-year follow-up of a randomized controlled trial

BACKGROUND

Nontraumatic rotator cuff tear is a common shoulder problem that can be treated either conservatively or operatively. In the previous publications of the 1- and 2-year results of this trial, we found no significant between-group clinical differences. The aim of this study was to investigate the differences in mid-term clinical and radiologic outcomes in patients older than 55 years.

MATERIALS AND METHODS

One hundred eighty shoulders with symptomatic, nontraumatic supraspinatus tears were randomly assigned to 1 of the 3 cumulatively designed treatment groups: physiotherapy (group 1); acromioplasty and physiotherapy (group 2); and rotator cuff repair, acromioplasty, and physiotherapy (group 3). The change in the Constant score was the primary outcome measure. The secondary outcome measures were the change in the visual analog scale score for pain and patient satisfaction. Radiologic analysis included evaluation of glenohumeral osteoarthritis (OA) and rotator cuff tear arthropathy (CTA).

RESULTS

A total of 150 shoulders (mean age, 71 years) were available for analysis after a mean follow-up period of 6.2 years. The mean sagittal tear size of the supraspinatus tendon tear at baseline was 10 mm in all groups (P = .33). During follow-up, 8 shoulders in group 1 and 2 shoulders in group 2 crossed over to rotator cuff repair. The mean baseline Constant score was 57.1, 58.2, and 58.7 in groups 1, 2, and 3, respectively (P = .85). There were no significant differences (P = .84) in the mean change in the Constant score: 18.5 in group 1, 17.9 in group 2, and 20.0 in group 3. There were no statistically significant differences in the change in the visual analog scale pain score (P = .74) and patient satisfaction (P = .83). At follow-up, there were no statistically significant differences in the mean progression of glenohumeral OA (P = .538) or CTA (P = .485) among the groups. However, the mean progression of glenohumeral OA from baseline to follow-up was statistically significant in the trial population (P = .0045).

CONCLUSIONS

On the basis of this study, operative treatment is no better than conservative treatment regarding small, nontraumatic, single-tendon supraspinatus tears in patients older than 55 years. Operative treatment does not protect against degeneration of the glenohumeral joint or CTA. Conservative treatment is a reasonable option for the primary initial treatment of these tears.

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.