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

Occupation ratio and fatty infiltration are important parameters for evaluating patients with rotator cuff tears. We analyzed the occupation ratio using a deep-learning framework and studied the fatty infiltration of the supraspinatus muscle using an automated region-based Otsu thresholding technique. To calculate the amount of fatty infiltration of the supraspinatus muscle using an automated region-based Otsu thresholding technique. The mean Dice similarity coefficient, accuracy, sensitivity, specificity, and relative area difference for the segmented lesion, measuring the similarity of clinician assessment and that of a deep neural network, were 0.97, 99.84, 96.89, 99.92, and 0.07, respectively, for the supraspinatus fossa and 0.94, 99.89, 93.34, 99.95, and 2.03, respectively, for the supraspinatus muscle. The fatty infiltration measure using the Otsu thresholding method significantly differed among the Goutallier grades (Grade 0; 0.06, Grade 1; 4.68, Grade 2; 20.10, Grade 3; 42.86, Grade 4; 55.79, p < 0.0001). The occupation ratio and fatty infiltration using Otsu thresholding demonstrated a moderate negative correlation (ρ = − 0.75, p < 0.0001). This study included 240 randomly selected patients who underwent shoulder magnetic resonance imaging (MRI) from January 2015 to December 2016. We used a fully convolutional deep-learning algorithm to quantitatively detect the fossa and muscle regions by measuring the occupation ratio of the supraspinatus muscle. Fatty infiltration was objectively evaluated using the Otsu thresholding method. The proposed convolutional neural network exhibited fast and accurate segmentation of the supraspinatus muscle and fossa from shoulder MRI, allowing automatic calculation of the occupation ratio. Quantitative evaluation using a modified Otsu thresholding method can be used to calculate the proportion of fatty infiltration in the supraspinatus muscle. We expect that this will improve the efficiency and objectivity of diagnoses by quantifying the index used for shoulder MRI.

Background: A concomitant rotator cuff tear (RCT) with frozen shoulder is a common but challenging clinical scenario. The effect of frozen shoulder on clinical outcomes is open to discussion. Purpose/Hypothesis: This study aimed to evaluate the effect of preoperative frozen shoulder on postoperative clinical outcomes of an RCT. We hypothesized that the treatment results of an RCT concomitant with preoperative frozen shoulder would be comparable with those of an isolated RCT. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 212 patients were divided into 2 groups: 154 in the non–frozen shoulder (NFS) group and 58 in the preoperative frozen shoulder (FS) group. All patients underwent a thorough preoperative evaluation that included range of motion (ROM) and the pain visual analog scale, functional visual analog scale, Constant score, and American Shoulder and Elbow Surgeons (ASES) score. The same evaluation was performed at 6 months and 1 and 2 years postoperatively. The healing status of the repaired RCT of all patients was evaluated by postoperative magnetic resonance imaging. Results: The FS group showed statistically significantly worse functional outcomes than the NFS group at 6 months and 1 year postoperatively ( P < .05). At 2 years postoperatively, active assisted ROM was equivalent between the groups, although the ASES and Constant scores were significantly lower for the FS group ( P < .033 and P < .001, respectively). The retear rates were 5.3% and 12.3% for the FS and NFS groups, respectively ( P = .013). Conclusion: Preoperative frozen shoulder positively affected rotator cuff healing but negatively affected most functional outcomes, including ROM, at 6 months and 1 year postoperatively. At 2 years after surgery, there was no significant difference in active motion, but outcome scores remained lower in the FS group. For patients with preoperative frozen shoulder, a delay in surgery for additional physical therapy might not be necessary. The retear rate for the NFS group was more than double that for the FS group in the current study, which indicates that surgery for an RCT combined with frozen shoulder might provide better results in the long term because of an intact, healed rotator cuff.