Rotator cuff injury is one of the most common causes of shoulder pain and functional impairment, and its incidence increases substantially with age. Arthroscopic rotator cuff repair has become the gold-standard treatment for rotator cuff tears; however, surgical success does not necessarily result in optimal functional recovery. A considerable proportion of patients continue to experience persistent pain, muscle weakness, and restricted range of motion after surgery, leading to unsatisfactory outcomes. Postoperative rehabilitation is a critical component of rotator cuff repair and requires an appropriate balance between the biological requirements of tendon healing and the rehabilitative goal of functional recovery. To protect the repaired tendon during early healing, conventional rehabilitation protocols typically involve strict immobilization during the early postoperative period, followed by cautious, progressive, low-load exercise. However, this strategy inevitably results in rapid disuse atrophy and loss of strength in the periarticular shoulder muscles. Blood flow restriction training (BFRT) , developed in Japan in 1966, combines low-load resistance exercise with tourniquet-mediated restriction of arterial inflow and venous outflow. By partially restricting blood flow to the limb, BFRT can induce substantial gains in muscle strength and hypertrophy at low exercise intensities. BFRT has been increasingly used in postoperative orthopaedic rehabilitation and can improve muscle strength, particularly when low-load BFRT produces effects comparable to those of high-load resistance training. Low-intensity BFRT induces acute hemodynamic responses in the affected limb, with systolic blood pressure decreasing significantly after exercise and then returning to baseline. It may therefore be a suitable option for patients unable to tolerate high-intensity rehabilitation. BFRT has also demonstrated beneficial effects on joint pain and limb stability, suggesting that it may provide an alternative approach to enhancing muscle strength and accelerating recovery after rotator cuff repair. Numerous studies of lower-extremity BFRT have confirmed its effectiveness in improving muscle strength, muscle size, and endurance. Nevertheless, its clinical value in rehabilitation after shoulder arthroscopy remains insufficiently investigated.

To investigate the effects of low-intensity BFRT on muscle strength, shoulder function, and time to return to activity after arthroscopic repair of small- to medium-sized rotator cuff tears.

Patients who underwent arthroscopic rotator cuff repair at our institution between January 2022 and December 2024 were assigned to a BFRT group (n = 37) or a control group (n = 35) . Both groups received a standardized postoperative rehabilitation program. Beginning in the second postoperative week, the BFRT group underwent low-intensity resistance training at 20% of the one-repetition maximum, combined with individualized blood flow restriction at 50% of the limb occlusion pressure. Peak torque during shoulder external rotation and forward flexion was measured using an isokinetic strength-testing system preoperatively and at 8 and 24 weeks postoperatively. Shoulder function was evaluated using the American shoulder and elbow surgeons (ASES) score. The time required to return to activities of daily living and light physical activity was also recorded.

At 8 weeks postoperatively, the BFRT group demonstrated significantly greater peak torque during external rotation than the control group [ (10.48±0.75) N . m, (8.93±0.88) N . m, P < 0.001] and significantly greater peak torque during forward flexion [ (16.58±0.87) N . m, (14.08±1.06) N . m, P < 0.001] . The ASES score at 8 weeks was also significantly higher in the BFRT group than in the control group [ (74.38±2.99) points, (67.80±3.48) points, P < 0.001] . At 6 months postoperatively, the BFRT group continued to demonstrate significantly greater external-rotation peak torque [ (14.30±0.82) N . m, (11.82±1.04) N . m, P < 0.001] and forward-flexion peak torque [ (22.51±1.06) N . m, (19.21±1.34) N . m, P < 0.001] . The 6-month ASES score was significantly higher in the BFRT group [ (88.08±2.43) points, (81.23±3.15) points, P < 0.001] . Patients in the BFRT group returned to activities of daily living significantly earlier than those in the control group [ (3.60±0.38) weeks, (4.95±0.50) weeks, P < 0.001] . They returned to light physical activity earlier as well [ (7.93±0.47) weeks, (9.81±0.66) weeks, P < 0.001] .

BFRT improves peak torque of the periarticular shoulder muscles and patient-reported shoulder function after arthroscopic rotator cuff repair while shortening the time required to return to activity. The beneficial effects of BFRT on muscle performance may underlie these improvements.

Although the scapular girth is a common site for musculoskeletal tumors, labrum tumors of the shoulder joint remain very rare. At present, various reconstruction methods include humeral suspension, inactivation, and replantation of allogeneic or autologous bone, prosthesis replacement, and so on. Because prostheses can achieve a good appearance and certain shoulder joint function, they are currently widely used. Currently, common scapular prostheses include simple scapular prostheses, restrictive orthoshoulder prostheses, restrictive reverse shoulder prostheses, and non-restrictive reverse shoulder prostheses. When a restrictive prosthesis replacement is adopted, recovery of shoulder joint function in patients after surgery is often unsatisfactory. In a few foreign studies, patients who underwent non-restrictive reverse shoulder replacement all achieved relatively satisfactory function after the operation, and reports have noted shoulder abduction reaching 120° after the operation.

To introduce a surgical method for treating scapular glenoid tumors by combining 3D printing with trans-unrestricted scapular prosthesis, and evaluate its clinical efficacy and function.

A 23-year-old young female was diagnosed with invasive osteoblastoma in the left scapular glenoid. We treated her with 3D printing and a transunrestricted scapular prosthesis, and used biological patches to enhance the prosthesis's static stability. The clinical and functional outcomes and complications were retrospectively analyzed using MSTS and DASH scores.

During the operation, extensive resection and prosthesis reconstruction were performed on the scapular glenoid tumor. Four days after the operation, joint dislocation occurred. Reincision reduction and component replacement were performed. No complications occurred in the later stage. During the follow-up period, no local recurrence or distant metastasis occurred. The MSTS and DASH scores were 25.5/30 and 12.5, respectively.

Three-dimensional printing combined with unrestricted scapular prosthesis for the treatment of scapular glenoid tumors is a relatively reliable method. It has high expectations for surgeons' reconstruction of soft-tissue balance. After satisfactory reconstruction, it can bring better clinical and functional results.

Reverse total shoulder arthroplasty (RTSA) , originally designed by Grammont and Baulot, improved shoulder pain and range of motion in patients with rotator cuff tear joint disease . In clinical applications, numerous studies have also demonstrated RTSA's effectiveness . With the rapid development of RTSA, its indications have gradually expanded to include various serious shoulder joint diseases such as acute complex proximal humeral fractures and old shoulder dislocations that cannot be reduced. Nowadays, RTSA has become the preferred treatment option for large, irreparable rotator cuff tears, as it can effectively alleviate shoulder joint pain and improve function. However, its relatively high incidence of postoperative complications remains a key focus for all clinicians. At present, the mainstream prostheses used in clinical practice are often designed and optimized based on the anatomical features of the scapula in European and American populations. However, these features differ across racial groups. A few studies have provided reference parameters for designing bases suitable for the Asian population and have indicated that the glenoid is smaller in Asians than in Europeans and Americans. Therefore, the use of traditional prostheses may lead to a mismatch between the prosthesis and the glenoid, which, in turn, causes scapular impingement and eventually results in loosening of the glenoid prosthesis. In addition, the contact area between the base and the bone surface is an important factor affecting the prosthesis's survival rate. Currently, many types of prostheses are available for clinical selection, and the contact area between the base and the glenoid varies among them. Accurate understanding of the fine anatomical characteristics of the glenoid in the Asian population is crucial for ensuring the correct selection and precise fixation of prostheses and for reducing the risk of surgical complications. 2D-CT scanning image measurement has been widely used in morphological research on shoulder joints, with good methodological consistency and population comparability. Compared with other measurement methods, it is more convenient to operate and is suitable for large-scale population studies in the future. Secondly, the two-dimensional cross-section can clearly display bony markers, facilitating standardized measurement and ensuring high stability and reliability. In addition, this study focuses on analyzing the bony geometric characteristics, and two-dimensional measurements are sufficient to meet the research requirements. Therefore, in this study, we retrospectively used 2D-CT images of the glenoid from 142 Asian populations for anatomical measurements and combined 3D-CT images to measure several anatomical indicators.

To provide references and design ideas for the optimization of reverse total shoulder (RTS) prosthesis design suitable for the Asian population by measuring the anatomical structural-related data of the glenoid in the Asian population and comparing the differences between them and the European and American populations.

A retrospective analysis was conducted on the unilateral shoulder joint imaging data of 142 healthy adults who underwent 2D-CT scans of the shoulder joint in the Department of Imaging of the Affiliated Hospital of Nanjing University of Chinese Medicine from January 2021 to July 2023. Among them, 60 were male, and 82 were female. The height, width, posterior inclination Angle, upward inclination Angle, axial and coronal curvature radii of the glenoid were measured through three-dimensional reconstruction and image archiving and communication system (PACS) . Statistical analysis was conducted using SPSS (version 26.0) , and the results were compared with those of previous research on the anatomical measurements of the scapula and scapular glenoid in European and American populations over the past 5 years.

The width (29.13±2.23) mm and height (36.66±2.81) mm of the glenoid in males were both greater than those in females (25.02±2.14 ) mm, (32.73±2.57) mm, with significant differences (P <0.001) ; The glenoid retroversion Angle in males was 3.10 (1.90, 5.23) °, and that in females was 1.85 (0.62, 4.10) °, with a significant difference (P <0.001) . The superior inclination Angle was 11.50 (7.58, 13.00) ° for males and 9.65 (6.15, 14.20) ° for females. There was no significant difference between the genders (P >0.05) . The axial curvature radii of males and females were 32.35 (26.53, 38.30) mm and 35.70 (27.80, 43.15) mm, respectively, and there was significant difference between the genders (P <0.05) . The average coronal curvature radii of males and females were 28.95 (26.90, 31.68) mm and 27.45 (25.05, 29.45) mm, respectively, and there was significant difference between the genders (P <0.05) . Correlation analysis showed that the size of the glenoid was positively correlated with gender, height, and weight (P <0.001) .

Compared with the previously reported anatomical data of the glenoid in European and American populations, the glenoid size and curvature radius of the Asian population are smaller. The curved base may be more conducive to fitting the articular surface morphology of the Asian population, with relatively small glenoid and a smaller curvature radius, thereby theoretically improving the matching between the base and the bone surface and optimizing the initial mechanical environment. For elderly patients with small glenoids or limited bone mass, this design may have potential application value. However, its specific impact on contact area, bone resection volume, and long-term fixation effect still needs further research to verify.

Proximal humeral fractures account for approximately 5% of all fractures. The greater tuberosity of the humerus is an important anatomical structure involved in shoulder abduction and external rotation, and isolated greater tuberosity fractures account for 14%-21% of all proximal humeral fractures. Greater tuberosity fractures are also present in 5%-30% of anterior shoulder dislocations. Previous studies have recommended surgical treatment when displacement of a greater tuberosity fracture exceeds 5 mm. If inadequately treated, these injuries may result in poor functional outcomes. Compared with nonoperative treatment, surgical treatment aims to restore the anatomical position of the displaced greater tuberosity and preserve rotator cuff tendon integrity, thereby providing adequate mechanical stability, facilitating early postoperative rehabilitation, and reducing the risk of adhesion formation. However, no universally accepted gold-standard treatment has been established for displaced greater tuberosity fractures. Although most surgical techniques for displaced isolated greater tuberosity fractures have produced predictable outcomes, recurrent complete or partial displacement of fracture fragments remains frequently reported after surgery for comminuted greater tuberosity fractures involving three or more fragments. Such displacement may compromise postoperative rehabilitation, and the optimal treatment remains controversial.

To retrospectively compare the clinical outcomes of low-profile anatomic locking plate fixation combined with either suture fixation or suture anchor fixation for comminuted greater tuberosity fractures of the humerus.

A total of 54 patients with comminuted greater tuberosity fractures of the humerus who underwent low-profile anatomic locking plate fixation combined with either sutures or suture anchors at Jiangshan People's Hospital between January 2022 and August 2025 were included. The two groups were compared in terms of operative time, intraoperative blood loss, time to fracture union, Constant-Murley scores at 3 and 6 months postoperatively, postoperative pain, and complications.

Surgery was completed successfully in all patients. In the suture anchor group, the mean operative time was (54.13± 9.24) min, mean intraoperative blood loss was (56.68± 14.42) ml, and mean time to fracture union was (11.39± 2.25) weeks. The corresponding values in the suture group were (53.59± 10.12) min, (57.59± 12.27) ml, and (10.74± 3.12) weeks, respectively. No statistically significant differences were observed between the groups for these variables (all P > 0.05) . The Constant-Murley scores at 3 and 6 months postoperatively were significantly higher in the suture anchor group than in the suture group (both P < 0.05) . Visual analogue scale pain scores at both postoperative time points were significantly lower in the suture anchor group (both P < 0.05) . Regarding complications, partial loss of fracture reduction occurred in 2 patients in the suture anchor group. In the suture group, subacromial impingement occurred in 4 patients, and partial loss of fracture reduction occurred in 5 patients. The difference in the overall incidence of complications between the groups was statistically significant (P < 0.05) .

Low-profile anatomic locking plate fixation combined with suture anchors provides better short-term clinical outcomes than locking plate fixation combined with sutures for comminuted greater tuberosity fractures of the humerus. However, this conclusion is based on a relatively small sample and requires confirmation in larger studies.

Reverse shoulder arthroplasty (RSA) shifts the glenohumeral rotation center medially and distally to lengthen the deltoid moment arm, which has become mainstream surgical treatment for patients with irreparable rotator cuff tear arthropathy. Nevertheless, long-term clinical follow-up records demonstrate a considerable revision rate caused by screw micromotion-induced wear, osteolysis and glenoid baseplate loosening, which originate from high interfacial shear stress generated by lever mechanics. Modified RSA implants with lateralized or distalized geometry can partially improve mechanical environments yet fail to eliminate screw shear damage throughout the full abduction range. A novel concentric variable-diameter prosthesis (CVDP) recovers the native anatomical rotation center and adopts humeral-side large-area press-fit fixation to avoid screw-related loosening complications. However, its biomechanical advantages have not been quantitatively verified under an integrated mechanical framework.

To establish a unified two-dimensional quasi-static rigid-body mechanical model encompassing the normal shoulder, RSA and CVDP, to quantitatively compare their moment arms, joint reaction forces, and implant-bone interface stresses, to elucidate the mechanical mechanism of screw micromotion wear in RSA, and to verify the biomechanical advantages of CVDP.

A coronal-plane coordinate system was built with the geometric sphere center as origin, and abduction angle θ ranged from 0-90°. All model parameters were derived from anatomical measurements: upper limb weight W=45 N, gravity arm Lg=280 mm, axial distance of deltoid insertion dd=100 mm, humeral shaft radius Rshaft=15 mm, and deltoid origin coordinate A= (55, 45) mm. Moment equilibrium equations were solved to calculate deltoid tension, joint reaction force and distributed shear load on RSA screws. A cantilever deflection model was adopted to quantify screw-bone micromotion, and service life was predicted via calibrated wear coefficient. Parametric sensitivity analysis was performed to assess how rotation center displacement alters screw shear load.

The COR position parameters (x_A, y_A) significantly affected screw shear force: medialization (increasing x_A) showed angle-dependent sensitivity—positive (unfavorable) at small and large abduction angles and negative (favorable) only at mid-ranges, whereas distalization (increasing y_A) showed negative sensitivity across all angles, indicating a universally favorable direction but with limited physiological adjustability. For the optimized RSA (x_A=70 mm, y_A=55 mm) , the single-screw shear force at 60° abduction decreased to 28.1 N, with screw-bone interface shear stress τ_RSA≈2.81 MPa, micromotion displacement δ≈11.6 μm, wear rate per cycle of 2.75×10^-5 μm/cycle (approximately 10.0 μm/year) , and the wear life calculation at the peak abduction angle (60°) is self-consistent with the calibration baseline (approximately 10 years) , indicating that the screw shear micromotion wear mechanism is quantitatively compatible with the 8-12 year radiolucent line progression window reported by Melis et al. CVDP, utilizing screwless press-fit fixation with an interface area Afix≈400 mm² (approximately 13 times the total screw area of RSA) , achieved a peak interface shear stress of only 0.244 MPa—approximately 1/11 of RSA.

The RSA screw anchorage design has inherent biomechanical deficiencies: COR medialization alters the direction of the joint reaction force, increasing the shear component acting on the fixation screws at small and large abduction angles, but its sensitivity to screw shear force is angle-dependent, being unfavorable at small and large abduction angles; distalization is universally favorable but constrained by anatomy. Consequently, parameter optimization alone cannot fundamentally resolve the mechanical conflict between "increasing deltoid moment arm" and "reducing screw shear force" in RSA. CVDP, by restoring the anatomical center of rotation and employing large-area press-fit fixation, is expected to reduce the risk of screw shear wear and demonstrates biomechanical advantages in reducing implant-bone interface stress.