Role of Critical Shoulder Angle in Degenerative Type Rotator Cuff Tears: A Turkish Cohort Study.

BACKGROUND This retrospective study investigated the association between the critical shoulder angle (CSA) and the development of full-thickness rotator cuff tears (FTRCTs) in the Turkish population. The CSA is an imaging parameter that quantifies the relationship between the inclination of the glenoid and the lateral extension of the acromion in the coronal plane. The CSA is an anatomical measurement, and higher CSA values have been associated with an increased incidence of FTRCTs. However, there is a lack of data on CSA regarding the Turkish population. MATERIAL AND METHODS In this study, CSA measurements were recorded in 2 groups: 50 patients with FTRCT who had arthroscopic repair (group 1) and 50 age- and sex-matched individuals with no FTRCT detected by magnetic resonance imaging (group 2). Sex, age, affected side, dominant side, and smoking status were recorded for each patient. The CSA measurements of the affected sides were performed on true anterior-posterior view radiographs. RESULTS The results showed a statistically significant difference between the mean CSA values of group 1 (37.48°) and group 2 (33.53°), P<0.001. CSA values of 36 and above had a sensitivity of 73.58%, specificity of 74.47%, positive predictive value of 75%, and negative predictive value of 74.47% for detecting FTRCT. CONCLUSIONS CSA measurement on radiographs is a useful diagnostic tool in the Turkish population, and an above-average CSA value is associated with a significantly increased incidence of degenerative-type FTRCT.

Posterior deltoid-sparing approach for displaced inferior or posterior glenoid fossa fractures: technical note and case series.

Scapular surgery has usually been performed through the posterior Judet approach. This approach allows access to the entire posterior scapular body, but causes significant soft tissue damage and detaches the deltoid muscle. To date, there has been no clinical study of a deltoid-preserving approach to access the joint for displaced postero-inferior glenoid fractures (Ideberg type II or Ib). We describe an easy and less invasive approach to the postero-inferior glenoid fossa.

Imaging in an academic orthopedic shoulder service: a report on incidental lung pathology findings.

INTRODUCTION: Computed tomography (CT) is often utilized for both diagnostic and pre-operative planning purposes in shoulder arthroplasty. Our study reports on the incidence of pulmonary findings in our pre-operative shoulder arthroplasty population over 14 years at our institution. METHODS: We conducted a retrospective review of all "shoulder CT" exams ordered by two orthopedic upper extremity surgeons between the years of 2008 and 2021. These exams were then further analyzed to include only those ordered for the purpose of pre-operative "shoulder arthroplasty" planning. All incidental findings were documented and those with pulmonary findings were then further analyzed. A detailed chart review was then performed on these patients to determine the impact on their planned shoulder arthroplasty. RESULTS: A total of 363 shoulder pre-operative CTs were ordered by our two upper extremity orthopedic surgeons at our institution between the years of 2008 and 2021. Primary lung cancer in the form of adenocarcinoma (n = 3) had an incidence of 0.8% of all CT scans and 1.4% of all pulmonary incidental findings. Fifteen patients (4% of all CT scans and 7% of all pulmonary incidental findings) had no concern for malignancy and were appropriately evaluated with further imaging based on their initial shoulder CT. CONCLUSION: While shoulder arthroplasty and pre-operative planning with CT imaging continue to become more common, so too is the incidence of reported pulmonary findings. From a patient care standpoint, it is important that these findings are accurately identified, appropriately triaged, and communicated clearly to our patients.

Preliminary exploration of deep learning-assisted recognition of superior labrum anterior and posterior lesions in shoulder MR arthrography.

PURPOSE: MR arthrography (MRA) is the most accurate method for preoperatively diagnosing superior labrum anterior-posterior (SLAP) lesions, but diagnostic results can vary considerably due to factors such as experience. In this study, deep learning was used to facilitate the preliminary identification of SLAP lesions and compared with radiologists of different seniority. METHODS: MRA data from 636 patients were retrospectively collected, and all patients were classified as having/not having SLAP lesions according to shoulder arthroscopy. The SLAP-Net model was built and tested on 514 patients (dataset 1) and independently tested on data from two other MRI devices (122 patients, dataset 2). Manual diagnosis was performed by three radiologists with different seniority levels and compared with SLAP-Net outputs. Model performance was evaluated by the receiver operating characteristic (ROC) curve, area under the ROC curve (AUC), etc. McNemar's test was used to compare performance among models and between radiologists' models. The intraclass correlation coefficient (ICC) was used to assess the radiologists' reliability. p < 0.05 was considered statistically significant. RESULTS: SLAP-Net had AUC = 0.98 and accuracy = 0.96 for classification in dataset 1 and AUC = 0.92 and accuracy = 0.85 in dataset 2. In dataset 1, SLAP-Net had diagnostic performance similar to that of senior radiologists (p = 0.055) but higher than that of early- and mid-career radiologists (p = 0.025 and 0.011). In dataset 2, SLAP-Net had similar diagnostic performance to radiologists of all three seniority levels (p = 0.468, 0.289, and 0.495, respectively). CONCLUSIONS: Deep learning can be used to identify SLAP lesions upon initial MR arthrography examination. SLAP-Net performs comparably to senior radiologists.

Can We Control Lateral Shoulder Balance Through Proximal Thoracic Curve Correction in Lenke Type 2 Adolescent Idiopathic Scoliosis?

BACKGROUND: Proximal thoracic curve (PTC) correction has been considered to prevent lateral shoulder imbalance in Lenke Type 2 adolescent idiopathic scoliosis (AIS) patients; however, postoperative shoulder imbalance (PSI) commonly occurs despite these strategies with PTC correction. We investigated the hypothesis that PTC correction would not directly affect PSI in the majority of Lenke type 2 AIS cases. Furthermore, we investigated the risk factors for lateral PSI after corrective surgery. METHODS: This study examined the records for AIS patients with Lenke type 2 who underwent corrective surgery and followed up for >2 years. Patients were categorized into PSI (-); radiologic shoulder height (RSH)<15 mm, and PSI (+); RSH≥15 mm. Repeated measures analysis of variance was performed at preoperatively, postoperatively, 1 month, and final follow-up. Postoperative lateral shoulder imbalance was predicted by the identification of univariate analysis and multivariate analysis. RESULTS: Among the 151 patients reviewed, 29 (19.2%) showed PSI at final follow-up. Lateral shoulder balance parameters showed different directionalities between PSI (-) and (+) groups at postoperatively, 1 month, and final follow-up ( P <0.01 each). Preoperative PTC, middle thoracic curve (MTC) curve and MTC correction showed strong correlations with the RSH ( P =0.01, 0.03, and 0.04, respectively). However, PTC correction did not show a significant correlation with the RSH. Moreover, only a smaller MTC curve and larger MTC correction rate were related to lateral PSI in multivariate analysis. CONCLUSIONS: In Lenke type 2 AIS curves, the MTC curve and its correction predominantly influence lateral shoulder imbalance after corrective surgery, irrespective of the PTC correction extent. Consequently, overemphasizing the correction of the PTC curve may not necessarily lead to an improved lateral shoulder balance. When MTC curve is smaller, surgeons should be more careful for MCT overcorrection leading to a lateral shoulder imbalance. LEVEL OF EVIDENCE: Level III.

Quantifying changes in shoulder orientation between the prone and supine positions from magnetic resonance imaging.

BACKGROUND: Predicting breast tissue motion using biomechanical models can provide navigational guidance during breast cancer treatment procedures. These models typically do not account for changes in posture between procedures. Difference in shoulder position can alter the shape of the pectoral muscles and breast. A greater understanding of the differences in the shoulder orientation between prone and supine could improve the accuracy of breast biomechanical models. METHODS: 19 landmarks were placed on the sternum, clavicle, scapula, and humerus of the shoulder girdle in prone and supine breast MRIs (N = 10). These landmarks were used in an optimization framework to fit subject-specific skeletal models and compare joint angles of the shoulder girdle between these positions. FINDINGS: The mean Euclidean distance between joint locations from the fitted skeletal model and the manually identified joint locations was 15.7 mm ± 2.7 mm. Significant differences were observed between prone and supine. Compared to supine position, the shoulder girdle in the prone position had the lateral end of the clavicle in more anterior translation (i.e., scapula more protracted) (P < 0.05), the scapula in more protraction (P < 0.01), the scapula in more upward rotation (associated with humerus elevation) (P < 0.05); and the humerus more elevated (P < 0.05) for both the left and right sides. INTERPRETATION: Shoulder girdle orientation was found to be different between prone and supine. These differences would affect the shape of multiple pectoral muscles, which would affect breast shape and the accuracy of biomechanical models.

Automated Shoulder Implant Manufacturer Detection using Encoder Decoder based Classifier from X-ray Images.

Total shoulder arthroplasty is the process of replacing the damaged ball and socket joint in the shoulder with a prosthesis made with polyethylene and metal components. The prosthesis helps to restore the normal range of motion and reduce pain, enabling the patient to return to their daily activities. These implants may need to be replaced over the years due to damage or wear and tear. It is a tedious and time-consuming process to identify the type of implant if medical records are not properly maintained. Artificial intelligence systems can speed up the treatment process by classifying the manufacturer and model of the prosthesis. We have proposed an encoder-decoder based classifier along with the supervised contrastive loss function that can identify the implant manufacturer effectively with increased accuracy of 92% from X-ray images overcoming the class imbalance problem.

The in vivo passive stretch response of the pectoralis major is region-specific.

The pectoralis major (PM) is a broad muscle commonly divided into three regions, which contribute uniquely to shoulder stability and movement. The PM muscle regions likely respond differently to stretch, but this has never been shown in vivo. We used shear wave elastography to assess the stretch response of different PM muscle regions during shoulder abduction and external rotation in 20 healthy male participants. Participants' shoulder was passively rotated through their range of motion in 5.7° increments and shear wave velocities (SWV) were obtained for each muscle region. A piece-wise model was fitted to the SWV-joint angle data, from which slack angle, slack stiffness and elasticity coefficient were determined. For shoulder abduction, we found that the sternocostal region had a significantly smaller slack angle (p = 0.049) and greater slack stiffness (p = 0.005) than the abdominal region, but there was no difference for elasticity coefficient (p = 0.074). For external rotation, only slack stiffness was greater for the sternocostal than the abdominal region (p < 0.001) with no differences found for slack angle (p = 0.18) and elasticity coefficient (p = 0.74). However, our data indicates that neither region was slack in this condition. These findings indicate that the sternocostal and abdominal regions respond differently to passive stretch, highlighting the PM's functional differentiation. This differentiation should be considered during treatment interventions such as PM muscle harvesting or treatments for breast cancer.

The impact of shoulder pathologies on job discontinuation and return to work: a pilot ultrasonographic investigation.

BACKGROUND: Ultrasound imaging has emerged as one of the most useful tools for evaluating shoulder disorders. To date, the association between shoulder ultrasonography and a patient's work status has rarely been explored by antecedent studies. AIM: This study aimed to investigate the association between sonographically diagnosed shoulder pathologies and job discontinuation and return to work. DESIGN: A cross-sectional study. SETTING: Outpatient clinic in the university hospital. POPULATION: Fifty-nine patients who were older than 20 years of age and had worked in a full-time job within the past three years. METHODS: All participants underwent clinical evaluation using the visual analog scale (for pain), Shoulder Pain and Disability Index, Pittsburgh Sleep Quality Index, and shoulder ultrasound examination. The work-related ergonomic risks, including dealing with heavy objects, repeated use and requiring forceful motion of the affected upper extremity, were assessed. The ultrasound-identified shoulder pathologies associated with job discontinuation, that is, sick leave due to painful shoulder for more than two consecutive months, were considered as the primary outcome. In the job discontinuation subgroup, we further investigated the association between return to work and the clinical/sonographic findings. RESULTS: Univariate analysis revealed a positive association between job discontinuation and shoulder surgery or work types requiring forceful upper-limb movements. Multivariate analysis demonstrated that job discontinuation was positively associated with supraspinatus tendon full-thickness tears (risk ratio, 8.80; 95% CI, 1.77-10.56; P=0.018). Of the patients who received shoulder surgery, 46.6% had recurrent rotator cuff tears. Return to work was likely to be related to pain scores during overhead activities and shoulder function impairment but not to sonographic findings. CONCLUSIONS: Job discontinuation is associated with shoulder surgery, work that necessitates forceful upper-extremity movements and supraspinatus tendon full-thickness tears detected by ultrasound. CLINICAL REHABILITATION IMPACT: Sonographic findings should not be used as the only standard for evaluating the patient's work capability.

Spontaneous pneumothorax after shoulder arthroscopy under general anesthesia: a case report.

A woman in her early 70s presented with a right fifth rib fracture along with left scapular body and glenoid fractures resulting from a traffic accident. She had no history of lung disease. The patient underwent multi-incisional video-guided arthroscopic fracture reduction and screw fixation in the right lateral decubitus position under general anesthesia, and surgery was followed by chest tube insertion. Left-sided pneumothorax was found during routine postoperative radiography despite the absence of relevant symptoms or signs such as hypoxia, chest pain, or respiratory difficulty. We herein report this unusual case with a brief literature review.

Comparison of the Analgesic Efficacy between Arthroscopically Placed Continuous Suprascapular Nerve Block and Ultrasound-guided Continuous Superior Trunk Block: A Double-blinded Randomized Controlled Trial.

BACKGROUND: Single-shot suprascapular nerve block and superior trunk block have been reported to provide a noninferior analgesic effect after shoulder surgery with a lesser incidence of hemidiaphragmatic paresis compared with interscalene brachial plexus block. This study hypothesized that continuous suprascapular nerve block provides noninferior analgesia with minimal effects on diaphragmatic movement compared with continuous superior trunk block in patients undergoing arthroscopic shoulder surgery. METHODS: 100 patients were randomized undergoing arthroscopic shoulder surgery between December 2020 and October 2021 into continuous suprascapular nerve block and continuous superior trunk block groups. Before the surgery, patients received either a single-shot superior trunk block or subomohyoid suprascapular nerve block. Thereafter, a superior trunk catheter was inserted by anesthesiologists in patients in the continuous superior trunk block group, and a posterior suprascapular nerve catheter was inserted with arthroscopic assistance during the surgery by surgeon in the continuous suprascapular nerve block group. The primary outcome was the postoperative pain score at postoperative 24 h, and the incidence of hemidiaphragmatic paresis was also compared. RESULTS: Overall, 98 patients were included in the final analysis. The worst and resting pain scores at postoperative 24 h in the continuous suprascapular nerve block group were inferior compared with those in the continuous superior trunk block group in the test with a noninferiority margin of 1 (worst pain score: mean difference, 0.9; 95% CI, 0.1 to 1.7; resting pain score: mean difference, 0.5; 95% CI, 0.0 to 1.0). However, the continuous suprascapular nerve block group had a significantly lower incidence of hemidiaphragmatic paresis at postoperative 24 h than the continuous superior trunk block group. CONCLUSIONS: Continuous suprascapular nerve block provides statistically inferior analgesia compared to the continuous superior trunk block; however, the continuous suprascapular nerve block had a minimal effect on the phrenic nerve function.

Suprascapular nerve entrapment caused by a large hematoma of the scapula: a case report.

BACKGROUND: Suprascapular nerve entrapment is a rare disorder that is frequently misdiagnosed as another disease. The suprascapular nerve is commonly entrapped at the following two sites: the suprascapular and spinoglenoid notches. Nerve entrapment at the spinoglenoid notch causes infraspinatus muscle weakness and atrophy. Patients present with posterior shoulder pain and weakness. Magnetic resonance imaging is used to confirm the diagnosis of a spinoglenoid cyst and nerve compression. Open or arthroscopic aspiration or decompression is indicated for patients with cysts in whom conservative treatment has failed and those with cysts associated with suprascapular nerve compression. CASE PRESENTATION: Herein, we describe the case of a 49-year-old man with suprascapular nerve entrapment caused by a large cyst, namely, a hematoma, in the superior scapular and spinoglenoid notches. Open surgical decompression of the suprascapular nerve was performed owing to an intact rotator cuff and glenoid labrum. CONCLUSION: Posterior shoulder pain promptly resolved without complications.

Application of quantitative T1, T2 and T2* mapping magnetic resonance imaging in cartilage degeneration of the shoulder joint.

To investigate and compare the values of 3.0 T MRI T1, T2 and T2* mapping quantification techniques in evaluating cartilage degeneration of the shoulder joint. This study included 123 shoulder joints of 119 patients, which were scanned in 3.0 T MRI with axial Fat Suppression Proton Density Weighted Image (FS-PDWI), sagittal fat suppression T2 Weighted Image (FS-T2WI), coronal T1Weighted Image (T1WI), FS-PDWI, cartilage-specific T1, T2 and T2* mapping sequences. Basing on MRI images, the shoulder cartilage was classified into grades 0 1, 2, 3 and 4 according to the International Cartilage Regeneration & Joint Preservation Society (ICRS). The grading of shoulder cartilage was based on MRI images with ICRS as reference, and did not involve arthroscopy or histology.The T1, T2 and T2* relaxation values in the superior, middle and inferior bands of shoulder articular cartilage were measured at all grades, and the differences in various indicators between groups were analyzed and compared using a single-factor ANOVA test. The correlation between T1, T2 and T2* relaxation values and MRI-based grading was analyzed by SPSS software. There were 46 shoulder joints with MRI-based grade 0 in healthy control group (n = 46), while 49 and 28 shoulder joints with grade 1-2 (mild degeneration subgroup) and grade 3-4 (severe degeneration subgroup) in patient group (n = 73), accounting for 63.6% and 36.4%, respectively. The T1, T2 and T2* relaxation values of the superior, middle and inferior bands of shoulder articular cartilage were significantly and positively correlated with the MRI-based grading (P < 0.01). MRI-basedgrading of shoulder cartilage was markedly associated with age (r = 0.766, P < 0.01). With the aggravation of cartilage degeneration, T1, T2 and T2* relaxation values showed an upward trend (all P < 0.01), and T1, T2 and T2* mapping could distinguish cartilage degeneration at all levels (all P < 0.01). The T1, T2 and T2* relaxation values were significantly different between normal group and mild degeneration subgroup, normal group and severe degeneration subgroup, mild degeneration subgroup and severe degeneration subgroup (all P < 0.05). Quantitative T1, T2 and T2* mapping can quantify the degree of shoulder cartilage degeneration. All these MRI mapping quantification techniques can be used as critical supplementary sequences to assess shoulder cartilage degeneration, among which T2 mapping has the highest value.

Ultrasound guided interscalene brachial plexus block.

Peripheral nerve blocks have long been established as a crucial part of the enhanced recovery pathways after surgery. Interscalene brachial plexus block (ISB) is mainly indicated for anaesthesia and analgesia during shoulder and proximal arm surgery. Ultrasound technology has remarkably improved the efficacy and success rates of the ISB while limiting its potential complications.

Assessment of three-dimensional rotation of the shoulder complex and scapulohumeral rhythm during sagittal movement.

BACKGROUND: Due to the influence of spinal and respiratory movements, it is difficult to accurately measure the range of motion of each joint. OBJECTIVE: To conduct a three-dimensional (3D) measurement of each joint in the shoulder complex in different postures in the sagittal plane of the upper extremity. METHODS: Thirteen healthy adults with no history of shoulder surgery for trauma or chronic pain were enrolled in the present study. The computed tomography (CT) imaging data of the shoulder complex were acquired in four postures via the reconstruction and alignment of 3D images. The angles of the postural changes were measured, and rotation vectors were used for descriptions and statistical analyses. RESULTS: There was a statistical difference in the rotation angles between the dominant and non-dominant sides of the sternoclavicular joint when the posture changed from a resting position to a posterior inferior position. During the postural change from a resting position to a horizontal position, the regression coefficient (ß) of the humerothoracic joint to the sternoclavicular joint was 0.191, and the ß of the humerothoracic joint to the glenohumeral joint was 0.621. During the postural change from the horizontal position to the rear upper position, the ß of the humerothoracic joint to the sternoclavicular joint was 0.316, and the ß of the humerothoracic joint to the glenohumeral joint was 0.845. During the postural change from the resting position to the rear lower position, the ß of the humerothoracic joint to the glenohumeral joint was 0.991. CONCLUSION: The application of the image alignment technique enabled the direct and accurate measurement of the bony structures of the shoulder joint. The helical approach accurately described the scapulohumeral rhythm during 3D motion. There was a scapulohumeral rhythm of the shoulder complex during 3D composite sagittal movement, with different ratios for different joints and postures.

Posterior shoulder stiffness was associated with shoulder pain during throwing in college baseball players: assessment of shear wave elastography.

PURPOSE: To investigate shoulder stiffness on the throwing and non-throwing sides in college baseball players using ultrasound shear wave elastography (SWE), and investigate the relationship between stiffness and shoulder pain during throwing. METHODS: Forty-nine college baseball players (98 shoulders) were recruited. Shoulder range of motion was evaluated. SWE was used to measure stiffness of the bilateral supraspinatus tendons, infraspinatus tendons, subscapularis tendons, supraspinatus muscles, infraspinatus muscles (ISPM), and posterior capsules. Participants were divided into pain and no pain groups based on the presence or absence of shoulder pain during throwing within 1 month before measurements on the throwing side. Items were compared between the throwing and non-throwing sides, and between the pain and no pain groups. Factors affecting shoulder pain during throwing were also investigated via multiple logistic regression analysis. RESULTS: Compared with the non-throwing side, the throwing side had significantly greater external rotation at 90° abduction, significantly lesser internal rotation at 0° abduction and internal rotation at 90° abduction (AbdIR), significantly higher SWE values of the infraspinatus tendon, ISPM, and posterior capsule, and significantly lower SWE values of the subscapularis tendon. Compared with the no pain group, the pain group had a significantly higher SWE value of the ISPM, and significantly lesser AbdIR. Increased ISPM SWE values and decreased AbdIR were significantly correlated with shoulder pain during throwing. CONCLUSIONS: The posterior tissue was stiffer than the anterior tissue on the throwing side. Decreased AbdIR and increased ISPM stiffness may be correlated with shoulder pain during throwing.

Computational dosimetry in MRI in presence of hip, knee or shoulder implants: do we need accurate surgery models?

Objective.To quantify the effects of different levels of realism in the description of the anatomy around hip, knee or shoulder implants when simulating, numerically, radiofrequency and gradient-induced heating in magnetic resonance imaging. This quantification is needed to define how precise the digital human model modified with the implant should be to get realistic dosimetric assessments.Approach. The analysis is based on a large number of numerical simulations where four 'levels of realism' have been adopted in modelling human bodies carrying orthopaedic implants.Main results. Results show that the quantification of the heating due to switched gradient fields does not strictly require a detailed local anatomical description when preparing the digital human model carrying an implant. In this case, a simple overlapping of the implant CAD with the body anatomy is sufficient to provide a quite good and conservative estimation of the heating. On the contrary, the evaluation of the electromagnetic field distribution and heating caused by the radiofrequency field requires an accurate description of the tissues around the prosthesis.Significance. The results of this paper provide hints for selecting the 'level of realism' in the definition of the anatomical models with embedded passive implants when performing simulations that should reproduce, as closely as possible, thein vivoscenarios of patients carrying orthopaedic implants.

Incidence and risk factors of postoperative medial shoulder imbalance in Lenke Type 2 adolescent idiopathic scoliosis with lateral shoulder balance.

BACKGROUND: In clinical practice, there are a significant percentage of Lenke 2 AIS patients suffered from medial shoulder imbalance (MSI) despite achieving good lateral shoulder balance (LSB) following surgery. However, there are few studies evaluating the features of the medial shoulder. The objective of this study was to determine the incidence and independent risk factors of MSI with LSB after Lenke 2 AIS corrective surgery. METHODS: One hundred and twenty Lenke 2 AIS patients with LSB at the last follow-up were reviewed from 2009 to 2018. Preoperative, and 3-month and the last postoperative follow-up radiographs were measured using a number of specific measurements. At the last follow-up, patients were divided into medial shoulder balance (MSB) group and the MSI group according to whether the T1 tilt was greater than 3°. A stepwise multiple linear regression analysis was used to examine the independent risk factors for MSI. Scoliosis Research Society (SRS)-30 questionnaire was used to assess clinical outcomes. RESULTS: Up to 69.2% of patients suffered from MSI with LSB after Lenke Type 2 AIS corrective surgery. Multiple regression showed that postoperative upper instrumented vertebra tilt (UIVt), proximal thoracic curve (PTC), the ratio of PTC and main thoracic curves (PTC/MTC) and T2 vertebra rotation ratio (T2-VR) were significant predictors for MSI (UIVt: b = 0.398, p < 0.001; PTC/MTC: b = 2.085, p < 0.001; PTC: b = 0.155, p < 0.001; T2-VR: b = 3.536, p = 0.008; adjusted R2 = 0.711). 72 patients completed the SRS-30 questionnaire survey, and the MSB group were scored the higher (p ≤ 0.001) in self-image domain (4.18 ± 0.43 vs. 3.70 ± 0.35), satisfaction domain (4.39 ± 0.54 vs. 3.95 ± 0.46) and total average (4.31 ± 0.23 vs. 4.11 ± 0.19). CONCLUSION: Although the patients with Lenke 2 AIS achieve LSB after corrective surgery, up to 69.2% of them suffered from MSI. Postoperative UIVt, PTC, PTC/MTC and T2-VR were significant predictors for MSI. Sufficient correction of these variables may facilitate the achievement of MSB.

The clinical performance of ultra-low-dose shoulder CT scans: The assessment on image and physical 3D printing models.

OBJECTIVES: Evaluation of the clinical performance of ultra-low-dose computed tomography (CT) images of the shoulder joint on image-based diagnosis and three-dimensional (3D) printing surgical planning. MATERIALS AND METHODS: A total of 93 patients with displaced shoulder fractures were randomly divided into standard-dose, low-dose, and ultra-low-dose groups. Three-dimensional printing models of all patients' shoulder joints were fabricated. The subjective image quality and 3D-printing model were evaluated by two senior orthopedic surgeons who were blinded to any scanning setting. A 3-point scale system was used to quantitatively assess the image quality and 3D printing model, where more than 2 points meant adequate level for clinical application. RESULTS: Compared with the standard dose protocol, ultra-low-dose technique reduced the radiation dose by 99.29% without loss of key image quality of fracture pattern. Regarding the subjective image quality, the assessment scores for groups of standard, low, and ultra-low doses were 3.00, 2.76, 2.00 points on scapula and humerus, and 3.00, 2.73, 2.44 points on clavicle. Scores of the three groups for the assessment of 3D printing models were 3.00, 2.80, 1.34 on scapula and humerus, and 3.00, 2.90, 2.06 on clavicle. In the ultra-low-dose group, 24 out of 33 (72.7%) 3D printing models of scapula and humerus received lower than 2 points of the evaluation score, while nearly 94% of the clavicle models reached the adequate level. CONCLUSION: An ultra-low-dose protocol is adequate for the diagnosis of either displaced or non-displaced fractures of the shoulder joint even though minor flaws of images are present. Three-dimensional printing models of shoulder joints created from ultra-low-dose CT scans can be used for surgical planning at specific bone like the clavicle but perform insufficiently in the overall surgical planning for shoulder injuries due to the significant geometric flaws.