[Effect of critical shoulder angle on deltoid muscle strength reduction in patients with rotator cuff tears].

Objective: To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength. Methods: A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores. Results: Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05). Conclusion: Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.

The Longitude-Latitude-Loop Used for Complex Bankart Lesion Repair: An All-Arthroscopic Technique.

The most frequent operation for anterior shoulder instability is the arthroscopic Bankart repair, which has a positive outcome and a low rate of complications. A variety of restoration procedures have been reported to reconstruct labral height and reproduce a dynamic concavity-compression reaction. The longitude-latitude loop is a knotless high-strength suture method that simultaneously tightens the joint capsule in the warp and weft direction and resists tearing. The suture method is safe and reproducible. This study aimed to present a longitude-latitude loop suture for joint capsule labral complex repair during Bankart arthroscopy surgery.

Biomechanical Analysis of Lark-Loop, Lasso-Loop and Krackow Suture Technique in Tenodesis.

OBJECTIVE: Strong tendon grasping is vital to the success of a tenodesis operation. The purpose of this study was to evaluate the initial tendon-fixation strength of the Lark-Loop technique in arthroscopic suprapectoral biceps tenodesis and compare it with others commonly used techniques. METHODS: Thirty-three porcine superficial flexor digitorum tendons were harvested from a local slaughterhouse and randomly divided into three groups to perform three tendon fixation techniques (Lasso-Loop stich group, Lark-Loop stich group or Krackow stich group; 11 tendons each group) with a No. 2 suture, respectively. Each tendon was pre-tensioned in 5°N for 2 min and then cyclically loaded 5 to 30°N for 500 cycles to assess displacement. After cyclic loading, the tendon was loaded to ultimate tendon-suture configuration failure at the rate of 1 mm/s. Finally, the mode of failure and the construct stiffness of the tendon were recorded and calculated. RESULTS: After cyclical loading, the displacement of the Lark-Loop group was equivalent to the Krakow group (P > 0.9999) but significantly smaller than the Lasso-Loop group (P = 0.0009). The ultimate load to failure for the Lark-Loop was equivalent to the Krakow technique group (P = 0.1463) but significantly greater than the Lasso-Loop group (P < 0.0001). The stiffness for the Lark-Loop was equivalent to the Krakow group (P = 0.4718) but significantly greater than the Lasso-Loop technique group (P < 0.0001). In the Lark-Loop and Krackow group, all the tendons failed by suture breakage, while all the tendons failed by suture cutting through the tendon in the Lasso-Loop technique group. CONCLUSION: Lark-Loop suture technique has biomechanical properties comparable to Krackow and superior to the Lasso-Loop in terms of suture displacement, ultimate load to failure, and stiffness. Therefore, the Lark-Loop suture fixation technique may be beneficial for arthroscopic biceps tenodesis.

Machine learning model successfully identifies important clinical features for predicting outpatients with rotator cuff tears.

PURPOSE: The aim of this study is to develop a machine learning model to identify important clinical features related to rotator cuff tears (RCTs) using explainable artificial intelligence (XAI) for efficiently predicting outpatients with RCTs. METHODS: A retrospective review of a local clinical registry dataset was performed to include patients with shoulder pain and dysfunction who underwent questionnaires and physical examinations between 2019 and 2022. RCTs were diagnosed by shoulder arthroscopy. Six machine-learning algorithms (Stacking, Gradient Boosting Machine, Bagging, Random Forest, Extreme Gradient Boost (XGBoost), and Adaptive Boosting) were developed for the prediction. The performance of the models was assessed by the area under the receiver operating characteristic curve (AUC), Brier scores, and Decision curve. The interpretability of the predicted outcomes was evaluated using Shapley additive explanation (SHAP) values. RESULTS: A total of 1684 patients who completed questionnaires and clinical tests were included, and 417 patients with RCTs underwent shoulder arthroscopy. In six machining learning algorithms for predicting RCTs, the accuracy, AUC values, and Brier scores were in the range of 0.81-0.86, 0.75-0.92, and 0.15-0.19, respectively. The XGBoost model showed superior performance with accuracy, AUC, and Brier scores of 0.85(95% confidence interval, 0.82-0.87), 0.92 (95% confidence interval,0.90-0.94), and 0.15 (95% confidence interval,0.14-0.16), respectively. The Shapley plot showed the impact of the clinical features on predicting RCTs. The most important variables were Jobe test, Bear hug test, and age for prediction, with mean SHAP values of 1.458, 0.950, and 0.790, respectively. CONCLUSION: The machine learning model successfully identified important clinical variables for predicting patients with RCTs. In addition, the best algorithm was also integrated into a digital application to provide predictions in outpatient settings. This tool may assist patients in reducing their pain experience and providing prompt treatments. LEVEL OF EVIDENCE: Level III.

Allogeneic Tendon Transplantation for the Treatment of Pathological Patellar Ligament Defect in Children: Technical Note and 4-Year Follow-Up.

OBJECTIVE: The absence of patellar ligament will bring about a severe negative impact on daily life. Many reconstruction techniques have been described in adults. However, there is a lack of technical introduction regarding the reconstruction of the patellar ligament in children. The purpose of this study was to report a surgical technique for reconstructing the patellar ligament in children. METHOD: A retrospective analysis of the clinical data on a patellar ligament (tendon sheath fibroma) patient with allogeneic tendon reconstruction. An 8-year-old child with postoperative recurrence of left patellar ligament tumor was enrolled in our study. Anterior tibialis tendon allograft was used to reconstruct the patellar ligament after complete resection of the patellar ligament for the tumor. The tunnels were constructed on the deep surface of the tibial tubercle and the root of the quadriceps tendon (to decrease the harmful impact on patella development), respectively. The allogeneic tendon was passed through the tunnels above in the shape of "8," and the two ends of the tendon were attached to the bleeding bone bed at the inferior edge of the patella with suture anchors to achieve better bone-tendon healing. During the follow-up, the knee's range of motion and imaging manifestations were recorded. RESULT: Postoperative pathology suggests chondromesenchymal hamartoma, a rare benign soft tissue tumor different from the previous operation (tendon sheath fibroma). During the 4-year follow-up, the patient's active range of motion of the knee achieved 0° to 120°; and the patient could walk normally without any external help. Physical examinations (the apprehension sign and J sign) showed no ligamentous instability or patellar ligament tenderness. Imaging analysis showed that the ratio length of the patellar ligament to the patella was almost normal. The integrity, continuity, and shape of the allogeneic ligament showed excellent results in MRI. Combined with clinical and imaging findings, allogeneic tendon patellar ligament reconstruction was deemed successful. CONCLUSION: Allogeneic ligament reconstruction technique can provide a treatment option by reconstructing the extensor mechanism, minimizing the impact on patellar development, and augmenting biological healing for children with the absence of the patellar ligament.

The high resistance loop (H-loop) technique used for all-inside arthroscopic knotless suprapectoral biceps tenodesis: A case series.

Introduction: Suprapectoral tenodesis is a common technique for the treatment of long head biceps tendon lesions. However, so far, there is no gold standard treatment in all-inside arthroscopy. The purpose of the present study was to introduce and evaluate the functional outcomes of an innovative, all-inside arthroscopic high resistance loop (H-loop, high resistance to tissue cutout and 360° grasping of the tendon) technique for long head of biceps (LHB) tenodesis. Method: From September 2020 to March 2022, a series of cases of 32 consecutive patients (28 rotator cuff tear with LHBT pathology and 4 superior labrum anterior-posterior (SLAP) tears which including 2 type II and 2 type IV) who received LHB tenodesis using all-inside arthroscopic high resistance loop technique were included in this study. The American Shoulder and Elbow Surgeon Score (ASES), Visual Analog Scale (VAS), Simple Shoulder Test Score (SST), Constant-Murley scores, and University of California at Los Angeles Scoring System (UCLA) were used to evaluate the clinical outcomes of patients in preoperative and final follow-up. Meanwhile, postoperative complications were also observed. Result: 32 patients (14 women and 18 men, average age was 55.7 years) underwent all-inside arthroscopic knotless suprapectoral biceps tenodesis using the H-Loop stitch technique. The mean time of follow-up was 16.2 ± 2.6 months. The ASES, VAS, Constant-Murley, SST, and UCLA scores improved from 51.5 ± 15.8, 5.5 ± 1.6, 57.8 ± 14.7, 5.0 ± 2.8, and 16.1 ± 3.8 preoperatively, to 89.1 ± 7.5, 1.0 ± 0.8, 87.3 ± 5.5, 10.4 ± 1.5, and 31.3 ± 2.6 in the last follow-up, respectively (p < 0.001). During the follow-up, no patients in this study experienced postoperative complications such as infection of the wound, injury of nerves, and hardware failure; no patients required revision after their operation. In addition, none of the patients had cramping or a "Popeye" deformity during follow-up. Conclusion: This article presents an innovative, all-arthroscopic H-loop technique for LHB tenodesis. This technique for LHB tenodesis showed favorable functional and cosmetic outcomes, as well as high satisfaction rates. Due to its simplicity of operation and satisfactory preliminary clinical outcomes, H-loop technique is perhaps another option to choose in all-inside arthroscopic LHB tenodesis.

The Application of H-Loop in Arthroscopic Knotless Double-Row Rotator Cuff Repairs.

OBJECTIVE: To determine the functional outcomes after a novel method of H-loop knotless double-row technique in patients with rotator cuff tears. METHOD: From June 2020 to September 2020, a total of six patients (five women, one man) with arthroscopic rotator cuff repair using the H-loop knotless double-row technique were enrolled in our study. The average age is 54 years (range: 50-61 years). The preoperative and final follow-up clinical outcome were evaluated using the American Shoulder and Elbow Surgeons (ASES) score, visual analog scale (VAS), University of California Los Angeles (UCLA) score, and Constant-Murley score. The active shoulder range of motion (ROM) was also collected preoperatively and postoperatively at the final follow-up (forward flexion and abduction). Accordingly, intraoperative and postoperative complications were observed as well. RESULT: There were six patients that underwent arthroscopic rotator cuff repair using the H-loop knotless double-row technique. The average follow-up period was 7.52 ± 0.70 months. The VAS, UCLA, ASES, and Constant-Murley scores improved from 5 ± 2.45, 15.67 ± 3.44, 47.67 ± 17.41 and 49.17 ± 8.98 preoperatively, to 0.83 ± 0.75, 36.27 ± 3.83, 91.67 ± 10.76 and 85.83 ± 4.31 at the final follow-up, with statistical significances of P = 0.009, P < 0.001, P = 0.006, and P = 0.001, respectively. Meanwhile, the active shoulder ROM (forward flexion and abduction) improved from 135.00 ± 46.80 and 125 ± 56.48 preoperatively, to 173.67 ± 4.13 and 172 ± 3.27 at final follow-up, respectively (P = 0.082, P = 0.088). During the follow-up, there were no postoperative complications such as wound-site infection, nerve or vessel damage, subcutaneous hematoma, and suture anchor problems. CONCLUSION: With the benefit of reducing the possibility of strangulation and blood supply affection for the rotator cuff, The H-loop knotless double row technique may be an alternative method to significantly improve subjective functional outcomes and increase the healing rate of medium-sized rotator cuff tears with degeneration issues and poor tissue quality.