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BACKGROUND: Due to the variability in evidence supporting either trans-syndesmosis fixation or deltoid ligament repair in unstable ankle fractures with medical clear space (MCS) widening makes it unclear which surgical technique leads to the best patient outcomes. The goal of our systematic review and meta-analysis was to compare clinical outcomes of trans-syndesmotic fixation versus anatomic deltoid ligament repair in the management of unstable ankle fractures with MCS widening. METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized in this study. A comprehensive and systematic search was conducted using the PubMed, Embase, Web of Science and Cochrane Library databases. Outcomes investigated in this review included the rates of syndesmotic malreduction, removal of hardware, postoperative complications including wound issues, and functional/pain scores. RESULTS: A total of five level-3 studies were selected in this review, with 280 unstable ankle fractures with MCS widening: 165 for the trans-syndesmotic fixation group and 115 for the anatomic deltoid ligament repair group. Three out of five studies evaluated syndesmotic malreduction using CT. Compared to the trans-syndesmosis fixation group, the deltoid repair group showed significant lower rates of syndesmotic malreduction rates and removal of hardware: 6.5 % (4/61) Vs. 27 % (16/59) (RR=0.26, 95 % CI=[0.10, 0.68]), and 2.6 % (3/115) Vs.54.5 % (90/165) (RR=0.06, CI=[0.02, 0.14]), respectively. No significant differences were found between the two groups in postoperative wound complications, reoperations, and functional scores including AOFAS and VAS pain score. CONCLUSIONS: Based on our findings, anatomic deltoid ligament repair was associated with a lower rate of syndesmotic malreduction and the need for hardware removal while there was no significant difference in terms of postoperative wound complications, reoperation, AOFAS score, or VAS pain score. These results should be interpreted with caution due to limitations related to heterogeneity among the studies. Further high-level RCTs with larger sample sizes are necessary to establish a robust consensus.

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Background and aim The deltoid is a common site for intramuscular injections, but guidelines for administration lack standardization. Global researchers propose various techniques, and recent study reports indicate a 1.5-15% incidence of nerve palsies due to injections. This pilot cadaveric study aimed to standardize the deltoid intramuscular injection sites in the Southeast Asian population. Methods This cadaveric study of a two-year duration was conducted in the Department of Anatomy as an intramural research project in collaboration with the Departments of Anatomy and Orthopedics. In the first year of study, which was the pilot phase of the project, the available six cadavers, i.e., 12 upper extremity specimens were dissected. Anthropometric measurements of deltoid muscle along with the distance of underlying neurovascular structures like the axillary nerve and posterior circumflex humeral artery were measured from neighboring bony landmarks. This article presents the observations of the six cadavers studied in the pilot phase and shall be followed up by another article after the project. Results In adults, in anatomical position, the mean distances of the axillary nerve and posterior circumflex humeral artery from the mid-acromial point are 8.19±0.616 and 8.66±0.968 cm, respectively. The deltoid thickness at 3, 5, and 7 cm from mid-acromial point was observed to be 1.079±0.13 cm (0.5-1.78 cm), 1.599±0.12 cm (1-2.96 cm), and 1.815±1.0 cm (1.2-2.5 cm), respectively. The acquired qualitative and quantitative data were tabulated, graphically represented, and statistically analyzed. Conclusions The deltoid intramuscular injection (IMI) must be given at or below the level of the midpoint of the deltoid muscle, but never in the upper half. We recommend a site, 4 fingerbreadths/9 cm below the mid-acromion point as the safest site to avoid injury to any underlying neurovascular structures.

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OBJECTIVE: The bench press is a resistance training exercise that targets several upper body muscles, including the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB). The purpose of this study was to influence the PM activity pattern during the bench press after a 10-week targeted resistance training intervention. METHODS: Sixteen men with significant experience in strength training participated in this study. They were divided into two groups: experimental and control. The experimental group underwent targeted training of PM and bench press, while the control group only did bench press. Electromyography (EMG) was used to assess muscle activity before and after the intervention. RESULTS: The experimental group had a significant increase in PM activity after the intervention (p=0.0002; ES=2.6), while the control group did not show any significant change (p=0.14). The activity of AD and TB remained relatively stable across both groups and time points. CONCLUSIONS: These findings indicate that focused resistance training can improve PM involvement in the bench press, potentially optimizing muscle excitation patterns and performance.

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Background: The radial nerve, originating from the posterior cord of the brachial plexus, traverses the posterior humerus. Incidences of radial nerve injury have been noted following surgical interventions like fracture fixation and exploration in this area. There's a paucity of literature detailing soft tissue anatomical cues for radial nerve dissection. This study aimed to identify reliable soft tissue and bony landmarks (triceps aponeurosis and deltoid tuberosity) that can be of substantial importance in dissecting the radial nerve and reducing iatrogenic nerve injury utilizing the posterior approach. Methods: Thirty-two fresh-frozen cadaver specimens underwent dissection using a posterior triceps-splitting approach to expose the radial nerve. The distance between the apex of the triceps aponeurosis and the radial nerve was measured, alongside noting the radial nerve's position relative to the deltoid tuberosity. Results: Of the cadavers, 78% were female, and 22% were male, with a mean age of 76 (range: 62-85). The average distance between the aponeurosis apex and the radial nerve was 40.3 mm (range: 28-60). The radial nerve was consistently found in all specimens, situated posteriorly at the humerus's mid-axial level at the distal part of the deltoid tuberosity. Conclusion: The triceps aponeurosis and distal deltoid tuberosity serve as reliable and practical landmarks for dissecting and exploring the radial nerve during posterior humeral approaches. These landmarks prove especially valuable when fractures obscure conventional anatomical cues.

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In this study, we report the functional and perceived outcomes of 51 posterior deltoid-to-triceps transfers in patients with tetraplegia. With a minimum follow-up of 12 months, patients were divided into two subcategories based on preoperative posterior deltoid strength: Medical Research Council (MRC) 3 and MRC 4/5. At 12-month follow-up, all patients achieved antigravity elbow extension. Patients with a stronger posterior deltoid (MRC 4/5) attained an elbow extension with a strength grade MRC 3.7 (SD 0.6), while those with a weaker posterior deltoid (MRC 3) reached an elbow extension of MRC 3.1 (SD 0.6). Patient-reported outcome measure was evaluated using the Canadian Occupational Performance Measure (COPM) and demonstrated a significant improvement for both performance and satisfaction. No difference in the COPM scores could be found between the two subcategories. This study indicates that tetraplegic patients with a posterior deltoid strength grade of both MRC 4/5 as well as MRC 3 benefit from the procedure.Level of evidence: III.

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We report three cases of young athletes with symptomatic ossicles of the medial malleolus who underwent arthroscopic resections of the ossicle combined with deltoid ligament repair. A differential diagnosis of the ossicles beneath the medial malleolus, accessory ossification center, avulsion fracture resulting in pseudoarthrosis, and accessory bone such as os subtibiale has been proposed. However, it is difficult to differentiate them clearly. Most of these ossicles are asymptomatic, although they can cause chronic medial ankle pain, especially in young athletes who require surgical treatment. All three patients had pain in the distal part of the medial malleolus, which restricted their sports activities. Plain radiographs of all three cases revealed a well-defined, round-shaped bony lesion beneath the medial malleolus. Ultrasonographic imaging, magnetic resonance imaging, and arthroscopic findings revealed that ligament attachment to the ossicle varies in volume and type according to the cases. In other words, the mechanisms through which the existence of the ossicles affects the stability of the ankle joint and foot alignment are different in each case, indicating that deltoid ligament repair is necessary according to the cases. In all three cases, we performed arthroscopic resections of ossicles combined with deltoid ligament repairs, achieving favorable short-term clinical outcomes.

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Background: A deltoid rupture can result in significant losses of shoulder function, and in the setting of a rotator cuff tear, the deltoid serves as the sole abductor of the shoulder. Deltoid ruptures can be secondary to trauma, a consequence of massive rotator cuff tears, or a result of postoperative complications. There is a paucity of literature on the management of deltoid ruptures. In this systematic review, we aim to report on the incidence of deltoid ruptures, the surgical treatment options, and the outcomes following operative treatment. Methods: A literature search was conducted on February 1, 2023 on MEDLINE and Google Scholar. Titles and abstracts were screened and the full text versions of articles that met criteria were reviewed. Criteria for inclusion included peer-reviewed studies evaluating the outcomes following surgical treatment of deltoid ruptures (direct repair, mobilization, reconstruction, and pedicled pectoralis transfer, with or without a reverse total shoulder arthroplasty). Secondary outcomes included incidence and causes of deltoid ruptures. Results: A total of 101 studies were retrieved. After review and additional studies identified from reference lists, a total of 14 studies were included in the review. The incidence of deltoid ruptures ranged from 0.3% to 7%, and large, full-thickness rotator cuff tears were found to be a significant risk factor. Surgical treatment options for deltoid ruptures include direct repair, rotationplasty, and pedicelled muscle-tendon transfers; and when indicated, these procedures can be paired with a reverse total shoulder replacement. Postoperatively, the operative extremity should be immobilized in the position of least tension (forward flexion and abduction, 30°-70°) for 4-8 weeks. Most patients in this systematic review who underwent surgical treatment of their deltoid rupture had significant improvements in pain and mean postoperative forward elevation and abduction above 90°. Discussion: The current available literature demonstrates that direct deltoid repair, rotationplasty, or reconstruction (muscle tendon transfer) with or without a concomitant reverse total shoulder arthroplasty can be an acceptable treatment option in patients with deltoid defects and massive rotator cuff tear. The average shoulder flexion and abduction increased postoperatively with improvements in pain.

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Immobilization following trauma or surgery induces skeletal muscle atrophy, and improvement in the muscle atrophy is critical for successful clinical outcomes. The purpose of this study is to evaluate the effect of electrical muscle stimulation (EMS) on muscle atrophy. The study design is a controlled laboratory study. Eighty rats (56 to establish the deltoid muscle atrophy [DMA] model and 24 to evaluate the effect of EMS on the model) were used. DMA was induced by completely immobilizing the right shoulder of each rat by placing sutures between the scapula and humeral shaft, with the left shoulder as a control. After establishing the DMA model, rats were randomly assigned into three groups: low-frequency EMS (L-EMS, 10 Hz frequency), medium-frequency EMS (M-EMS, 50 Hz frequency), and control (eight rats per group). After 3 weeks, the deltoid muscles of each rat were harvested, alterations in gene expression and muscle cell size were evaluated, and immunohistochemical analysis was performed. DMA was most prominent 3 weeks after shoulder immobilization. Murf1 and Atrogin were significantly induced at the initial phase and gradually decreased at approximately 3 weeks; however, MyoD expressed an inverse relationship with Murf1 and Atrogin. IL6 expression was prominent at 1 week. The time point for the EMS effect evaluation was selected at 3 weeks, when the DMA was the most prominent with a change in relevant gene expression. The M-EMS group cell size was significantly larger than that of L-EMS and control group in both the immobilized and intact shoulders (all p < 0.05), without significant differences between the L-EMS and control groups. The M-EMS group showed significantly lower mRNA expressions of Murf1 and Atrogin and higher expressions of MyoD and Col1A1 than that of the control group (all p < 0.05). In immunohistochemical analysis, similar results were observed with lower Atrogin staining and higher MyoD and Col1A1 staining in the M-EMS group. DMA model was established by complete shoulder immobilization, with the most prominent muscle atrophy observed at 3 weeks. M-EMS improved DMA with changes in the expression of relevant genes. M-EMS might be a solution for strengthening atrophied skeletal muscles and facilitating rehabilitation after trauma or surgery.

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Introduction: This study aimed to compare the efficacy of three methods for isolated greater tuberosity fractures of the humerus. Methods: A retrospective review of patients with isolated humeral greater tuberosity fractures between January 2013 and June 2021 in our institution. We recorded data on patient demographics, injury characteristics, preoperative and postoperative imaging findings, length of incision, operative time, and intraoperative blood loss. Results: A total of 107 patients met the inclusion criteria and were divided into three groups. 50 patients in group A were administered a proximal humeral internal locking system (PHILOS) plate fixed using the deltopectoral approach, 26 patients in group B were administered a PHILOS plate fixed using the deltoid-splitting approach, and 31 patients in group C were administered a novel anatomical plate fixed using the deltoid-splitting approach. No significant differences were identified in sex, age, injury mechanism, type of fracture, dominant side limb, or shoulder anterior joint dislocation. However, the operative time, blood loss, and the length of incision was shorter than in Group C. Moreover, pain was evaluated on the third and fifth days after surgery; pain was lower in Group C, and pain at the last follow-up was not different between the groups. No significant differences were identified in the Constant score, DASH score, and ROM at the last follow-up. 2 patients were diagnosed with subacromial impingement, 1 in Group A one in Group B, and 1 patient in Group B experienced axillary nerve injury after surgery. Conclusion: The novel anatomical plate fixed using the deltoid-splitting approach can achieve good results in the treatment of isolated humeral greater tubercle fractures with less blood loss, shorter operative time, and shorter surgical incisions, and can relieve pain in the early postoperative period.

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The deltoid muscle and rotator cuff tissue are structural components that maintain the dynamic stability of the shoulder joint. However, atrophy of the deltoid muscle may affect the stability of the shoulder joint, which in turn alters the mechanical distribution of rotator cuff tissue. Currently, the effect of muscle volume changes in the deltoid muscle on reducing the load on the rotator cuff tissue is still unknown. Therefore, this paper intends to analyze the mechanical changes of rotator cuff tissue by deltoid muscle atrophy through finite elements. Based on previously published finite element shoulder models, the deltoid muscle was modeled by constructing deltoid muscle models with different degrees of atrophy as, 100% deltoid muscle (Group 1), 80% deltoid muscle (Group 2), and 50% deltoid muscle (Group 3), respectively. The three models were given the same external load to simulate glenohumeral joint abduction, and the stress changes in the rotator cuff tissue were analyzed and recorded. In all three models, the stress in the rotator cuff tissue showed different degrees of increase with the increase of abduction angle, especially in the supraspinatus muscle. At 90° of glenohumeral abduction, supraspinatus stress increased by 58% and 118% in Group 2 and Group 3, respectively, compared with Group 1; In the subscapularis, the stress in Group 3 increased by 59% and 25% compared with Group 1 and Group 2, respectively. In addition, the stress of the infraspinatus muscle and teres minor muscle in Group 2 and Group 3 were higher than that in Group 1 during the abduction angle from 30° to 90°. Deltoid atrophy alters the abduction movement pattern of the glenohumeral joint. During glenohumeral abduction activity, deltoid atrophy significantly increases the stress on the rotator cuff tissue, whereas normal deltoid volume helps maintain the mechanical balance of the rotator cuff tissue.

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PURPOSE: Residual symptoms can be observed after ankle lateral ligament repairs commonly due to hyperlaxity, severe ankle instability or a failed stabilization. In order to increase joint stability, ligament or capsular-ligament plication has been used in other joints. Given that the anterior portion of the deltoid is a stabilizer against anterior talar translation, it could be used as an augmentation to restrict anterior talar translation. The aim of this study was to describe an arthroscopic anterior deltoid plication with a bony anchor as an augmentation to the lateral stabilization. The results in a series of eight patients were presented. METHODS: Eight patients (seven males, median age 31 [range, 22-43] years) presented residual instability after arthroscopic all inside lateral collateral ligament repair. Arthroscopic anterior deltoid ligament plication was performed in these patients. Median follow-up was 22 (range, 15-27) months. Using an automatic suture passer and a knotless anchor, the anterior deltoid was arthroscopically plicated to the anterior aspect of the medial malleolus. RESULTS: During the arthroscopic procedure, only an isolated detachment of the anterior talofibular ligament was observed without any deltoid open-book injury in any case. All patients reported subjective improvement in their ankle instability after the arthroscopic all-inside ligament repair and the anterior deltoid plication with a bony anchor. On clinical examination, the anterior drawer test was negative in all patients. The median American Orthopedic Foot and Ankle Society score increased from 68 (range, 64-70) preoperatively to 100 (range, 90-100) at final follow-up. CONCLUSION: The arthroscopic anterior deltoid plication is a feasible procedure to augment stability and control anterior talar translation when treating chronic ankle instability in cases of residual excessive talar translation. LEVEL OF EVIDENCE: Level IV.

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HYPOTHESIS AND BACKGROUND: Fragility fracture of the proximal humerus is a common occurrence. Current literature suggests that poor local bone density is a significant predictor of surgical fixation failure. The deltoid tuberosity index (DTI) is a simple radiographic tool that strongly correlates with local humeral bone mineral density (BMD), aiding surgical planning to consider adjuncts or arthroplasty. However, there is a lack of data in the reliability of assessment of DTI, as well as its correlation to systemic osteoporosis. Our study investigates the reliability of DTI as a predictor of systemic osteoporosis. METHODS: A retrospective cohort of patients with proximal humeral fracture (PHF) treated at a trauma center in Singapore from August 2017 to July 2018 were recruited. Four raters at different levels of varying clinical seniority measured DTI using shoulder radiographs. The dual-energy x-ray absorptiometry (DEXA) BMD scan of the hip and lumbar spine was used to diagnose osteoporosis. Area under the receiver operating characteristic curve analysis was calculated to study the diagnostic utility of DTI for predicting the risk of osteoporosis. RESULTS: Our study sample had 87 patients comprising 18 men and 69 women, mainly of Chinese ethnicity (84%), and with a mean age of 69.7 years (standard deviation 9.52, range 39-92). For assessment of DTI, there was good intrarater reliability among 4 raters (correlation coefficient range 0.805-0.843) and excellent interrater reliability between all raters (intraclass correlation coefficient 0.898, 95% confidence interval [CI] 0.784-0.950, P < .001). Based on the BMD, 55.2% (n = 48) had osteoporosis, with a T score <2.5. The highest correlation of DTI to BMD was with femoral neck density at 0.580. The DTI cutoff of 1.6 had the highest combined sensitivity and false positive rate, with areas under the curve of 0.682 (95% CI 0.564-0.799) for the overall population and 0.706 (95% CI 0.569-0.842) for patients aged <75 years. CONCLUSION: The DTI is a simple and reliable tool and has a strong applicability in clinical practice to enhance preoperative planning in the surgical fixation of PHF. DTI with a cutoff of 1.6 may help prompt clinicians to initiate workup and thus manage underlying osteoporosis.

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Stage IV adult acquired flatfoot deformity (AAFD) with secondary chronic deltoid ligament insufficiency is a challenging deformity to treat, with minimal consensus in the literature concerning its surgical management. Many surgical treatment options have been described, including joint-sparing techniques, fusions, osteotomies, and even arthroplasties. However, questions remain as to what, if any, treatment is optimal. This contribution reviews studies on surgical treatments for stage IV AAFD with deltoid ligament failure and provides a critical analysis regarding the quality of outcomes reported for those different treatment options. PubMed and Google Scholar databases were searched between June 1, 2022, and August 15, 2022, for studies published between 1990 and 2022 that describe the treatment of stage IV AAFD with deltoid ligament insufficiency. Articles included in the study focused on subjects with stage IV AAFD and associated deltoid ligament insufficiency undergoing surgical correction. Exclusion criteria included stage I, II, and III AAFD, as well as deltoid ligament repair following acute injury/rupture. Nine studies covering five different treatment options for patients with stage IV AAFD and chronic deltoid insufficiency were included, with minimal overlap in outcome measures used to assess the efficacy of the procedure. Triple arthrodesis with deltoid ligament reconstruction resulted in a 62.5% (5/8) success rate with a residual tibiotalar (TT) angulation of 2° (success defined as <3°). Tibiotalar arthrodesis of four patients resulted in an average post-operative tibiotalar angulation of 4.8° with all patients showing progressive destabilization of the hindfoot complex at 12-18 year follow-ups. Deltoid arthroscopic laminoplasty (Brostrom) resulted in an increased American Orthopaedic Foot and Ankle Society (AOFAS) score from 49.7 pre-op to 91.9 post-op. There was no long-term follow-up of these patients. Deltoid ligament reconstruction using autografts of the peroneus longus resulted in a post-operative valgus of 2.1° in one study and <5° in another. Deltoid ligament reconstruction using an anterior tibial tendon autograft resulted in a gain of 126.4 + 40.2% in stiffness compared to an intact ligament. Twinfix suture anchors resulted in a post-operative hindfoot angle averaging 5.3°. Combined deltoid and spring ligament reconstruction resulted in a 5.1° valgus angulation. There is currently no standard of care or clinical consensus regarding surgical treatment for stage IV AAFD with deltoid insufficiency. Several studies imply that mild valgus malalignment around the tibiotalar joint can result in satisfactory outcomes. A few studies even deemed <5° of valgus tilt post-operatively successful. However, it has been described that any imbalance in tibiotalar tilt is a significant risk factor for progressive arthritis and future ligamentous failure. No treatment option was able to correct valgus tilt to an anatomical standard (i.e., to normal anatomy). These varied findings, along with the lack of consensus on post-surgical measures to assess efficacy, are worrisome and emphasize the need for better surgical options. Moreover, there is a critical need for additional research on the long-term outcomes following stage IV AAFD and deltoid insufficiency repair, particularly, as over five million people in the United States and 10% of the geriatric population are affected by AAFD with a risk of progressing to stage IV.

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Background: Reverse total shoulder arthroplasty (RSA) significantly impacts deltoid length, tension, and structure. Studies have extensively investigated various modifications in deltoid characteristics, such as perfusion, elasticity, caliber, histological changes, and strength post-RSA. However, to date, there is a notable absence of research evaluating changes in bone mineral density (BMD) at the deltoid muscle origin after the RSA procedure. Methods: A retrospective analysis of a consecutive series of RSAs performed between May 2011 and May 2022 was conducted. Inclusion criteria comprised primary RSAs with both preoperative and last follow-up shoulder CT scans and a minimum follow-up of 12 months. Trabecular attenuation measured in Hounsfield units (HU) was calculated using a rapid region-of-interest (ROI) method. BMD analysis involved segmenting three ROIs in both pre- and postoperative CT scans of each patient: the acromion, clavicle, and spine of the scapula. Results: A total of 44 RSAs in 43 patients, comprising 29 women and 14 men, were included in this study. The mean follow-up duration was 49 ± 22.64 months. Significant differences were observed between preoperative and postoperative HU values in all analyzed regions. Specifically, BMD increased in the acromion and spine, while it decreased in the clavicle (p-values 0.0019, <0.0001, and 0.0088, respectively). Conclusions: The modifications in shoulder biomechanics and, consequently, deltoid tension post-implantation result in discernible variations in bone quality within the analyzed regions. This study underscores the importance of thorough preoperative patient planning. By utilizing CT images routinely obtained before reverse shoulder replacement surgery, patients at high risk for fractures of the acromion, clavicle, and scapular spine can be identified.

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PURPOSE: The anatomy of the deltoid ligament is complex. There is agreement on the presence of superficial and deep layers but the number and frequency of fascicles remains controversial. Identifying injuries to specific components of the deltoid ligament may inform decision-making on their management. The anatomy was reviewed to establish the number and dimension of fascicles visible with three-dimensional (3D) volumetric magnetic resonance images (MRI). METHODS: Twenty ankles from asymptomatic healthy volunteers were imaged with 3D volumetric MRI. The presence of individual fascicles was recorded and measured in 3D. RESULTS: The median age of participants was 26 years (range: 20-37) of which 13 (65%) were female. All 20 ankles had a deltoid ligament formed of four fascicles in two layers: three fascicles in the superficial layer; tibionavicular (mean dimensions 22.5 × 10.0 × 2.4 mm), tibiospring (16.6 × 6.7 × 1.9 mm) and tibiocalcaneal (23.8 × 4.6 × 1.8 mm) and a deep layer consisting of the tibiotalar fascicle, which could be divided into two parts: anterior tibiotalar (mean dimensions 10 × 5.6 × 4.1 mm) and the significantly larger posterior tibiotalar (14.2 × 13.8 × 17.5 mm, p < 0.01). There were no additional fascicles observed. CONCLUSIONS: The deltoid ligament complex was consistently visualised as four fascicles (tibionavicular, tibiospring, tibiocalcaneal, tibiotalar) in two layers (superficial and deep) in all 20 ankles. The posterior part of the tibiotalar fascicle was the thickest of all the fascicles in the deltoid ligament. It is, therefore, possible to accurately identify the components of the deltoid ligament, and 3T MRI can be used to assess fascicle-specific injury, which will guide treatment and rehabilitation. LEVEL OF EVIDENCE: Level III.

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The rotator cuff tear effects on glenohumeral joint tissues, such as superior labrum anterior-posterior (SLAP) lesions, have been studied experimentally or numerically in various cases. In relation to these studies, and as a novel feature of our study, infraspinatus (INF) muscle tear effects on other muscle force variations and stress and strain increases on glenoid labrum (GL), glenoid cartilage (GC) tissues, and a SLAP pathology were investigated. The ITK-SNAP Software (ISS) was used to segment the humerus and glenoid bone. The surface entities were segmented and exported to SolidWorks 2019, where the finite element model (FEM) was completed. Static optimizations of the muscle forces were calculated using a generic model in OpenSim 4.1 for the 0-3.88 s time interval to perform our finite element analyses (FEAs) in ANSYS 19.3 for the intact, partial torn, and fully torn INF muscle. The FEAs were also conducted for the specified time interval. The stress and strain increases on the GL, and GC tissues were determined to be critical when compared with yield strengths. In the case of fully torn INF, the GL and cartilage interfacial principal stress was calculated to be 3.3856 MPa. In the case of the fully torn INF, the principal stress that occurred on the GC tissue was calculated to be 42.465 MPa. In the case of the intact INF, the principal stress that occurred on the labrum was obtained as 4.257 MPa. These results showed that there was no detachment or disorder on the designated tissues caused by the INF muscle tear when the shoulder functioned at 60° of external rotation at 11° of abduction. Nonetheless, a minor amount of external force could cause severe pathological effects on the specified tissues.

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Introduction Acromioplasty is a widely performed procedure for various rotator cuff pathologies with good outcomes and high patient satisfaction. However, few studies have focused on its potential complications. Previous cadaveric studies have demonstrated that a considerable portion of the deltoid muscle is detached from its acromial origin following arthroscopic acromioplasty, but the clinical relevance of this muscle detachment has not been investigated. The goal of our research was to examine the influence of arthroscopic acromioplasty on abduction strength and to assess whether acromial anatomy plays a role in any potential effect. Methods From a preliminary sample of 87 individuals who were diagnosed with isolated impingement syndrome and underwent arthroscopic acromioplasty, 74 patients who met the inclusion criteria were ultimately included in the study. The patients were divided into two groups according to their acromion morphology: Bigliani type 2 (33 patients) and type 3 (41 patients). The isometric abduction strength of the two groups was measured by a handheld dynamometer (Isobex®; Cursor AG, Berne, Switzerland) at different abduction angles preoperatively and at the first, third, and sixth months following surgery and was statistically compared. Results Both groups showed reduced abduction strength postoperatively; however, the strength of abduction in the Bigliani type 3 group returned to near preoperative values in the third month. Although increased mean abduction strength was recorded at 30° abduction in the sixth month, this difference was not statistically significant (p=0.78). In the Bigliani type 2 group, compared with those in the sixth-month group, the preoperative abduction strength decreased from 8.32 kg to 6.0 kg (p = 0.047), 6.57 kg to 5.15 (p = 0.025), and 6.1 kg to 4.56 kg (p = 0.006) at 30, 60, and 90° abduction, respectively.  Conclusions Arthroscopic acromioplasty decreased isometric abduction strength in patients with a Bigliani type 2 acromion. Patients should be counseled about this loss, which might be especially important for professional athletes and heavy manual workers.

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The deltoid ligament plays a key role in ankle stability. Ankle fractures involving the medial ligamentous complex are evaluated on the basis of medial-sided tenderness and the Ottawa ankle rules. Evolution in our understanding of this ligament over the last three decades has shown that, within this medial ligamentous complex, it is the deep deltoid ligament that confers mechanical stability. The latest evolution in this understanding, and the learning point of this report, is that only a distinct component of the deep deltoid ligament - specifically the discreet posterior third - the rear attachment of the deep deltoid ligament (RAD) - confers mechanical value. The RAD is responsible for providing the medial ligamentous component of ankle stability - specifically talar shift, tilt, and importantly rotational stability. This knowledge is of key importance in the assessment and management of ankle fractures with associated deltoid ligament injuries. In this technical report, we highlight the biomechanical contribution of the RAD, which will help surgeons and physiotherapists to accurately manage ankle injuries.

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In this case report, a unique instance of delayed isolated anterior branch axillary nerve injury following shoulder dislocation is highlighted. The patient, a 55-year-old manual laborer, presented with severe deltoid wasting and reduced power 18 months postdislocation, necessitating a specialized treatment approach. The use of axillary nerve neurolysis and an innovative upper trapezius to anterior deltoid transfer via a subacromial path posterior to the clavicle, facilitated by an autologous semitendinosus graft, resulted in significant improvement with 160 degrees of abduction and Grade 4+ power Medical Research Council grading (MRC) at the 5-year follow-up.

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BACKGROUND: In end-stage arthritis indicated for total ankle arthroplasty (TAA), full-thickness cartilage damage, subchondral bone defect/shaving, and fluttering of the talar dome occur, shortening the distance between the tibial and talar insertions of ligaments and leading to laxity of ligaments surrounding the ankle joint. Under such conditions, medial ligaments (including the deltoid ligament) would not be expected to function properly. To stabilize the ankle joint during the stance phase, medial ligament function under tension is important. This study therefore examined whether TAA contributes to lengthening of the medial tibio-talar joint as evaluated radiographically, as a preferable method for achieving tensile effects on medial ligaments. MATERIALS AND METHODS: Twenty-four feet with end-stage varus deformity of the ankle joint that underwent TAA were retrospectively investigated, excluding cases with any malleolar osteotomy or fracture. Distance between proximal and distal insertions of medial ligaments, lateralization of the talus, and talar tilt angle under valgus/varus stress condition were evaluated pre- and postoperatively. RESULTS: Distance between proximal and distal insertions of medial ligaments was significantly elongated after TAA. At the same time, the talus showed significant lateralization. Furthermore, talar tilt under valgus/varus stress conditions was also significantly reduced after TAA. CONCLUSION: TAA affects distal translation and lateralization of the talus in cases of varus ankle deformity. These effects might contribute to re-providing tensile force on lax medial ligaments, improving ligament function.

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