-
Journal of Shoulder and Elbow Surgery Feb 2021The rotator cuff (RC) and the deltoid muscle are 2 synergistic units that enable the functionally demanding movements of the shoulder. A number of biomechanical studies...
BACKGROUND
The rotator cuff (RC) and the deltoid muscle are 2 synergistic units that enable the functionally demanding movements of the shoulder. A number of biomechanical studies assume similar force contribution of the force couple (RC and deltoid) over the whole range of motion, whereas others propose position-dependent force distribution. There is a lack of in vivo data regarding the deltoid's contribution to shoulder flexion and abduction strength. This study aimed to create reliable in vivo data quantifying the deltoid's contribution to shoulder flexion and abduction strength throughout the range of motion.
METHODS
Active range of motion and isometric muscle strength of shoulder abduction and flexion in 0°, 30°, 60°, 90°, and 120° of abduction/flexion as well as internal and external rotation in 0° and 90° of abduction were obtained in 12 healthy volunteers on the dominant arm before and after an ultrasound-guided isolated axillary nerve block. Needle electromyography was performed before and after the block to confirm deltoid paralysis. Radiographs of the shoulder and an ultrasonographic examination were used to exclude relevant shoulder pathologies.
RESULTS
Active range of motion showed a minimal to moderate reduction to 94% and 88% of the preintervention value for abduction and flexion. Internal and external rotation amplitude was not impaired. The abduction strength was significantly reduced to 76% at 0° (P = .002) and to 25% at 120° (P < .001) of abduction. The flexion strength was significantly reduced to 64% at 30° (P < .001) and to 30% at 120° (P < .001) of flexion. The strength reduction was linear, depending on the flexion/abduction angle. The maximal external rotation strength showed a significant decrease to 53% in 90° (P < .001) of abduction, whereas in adduction no strength loss was observed (P = .09). The internal rotation strength remained unaffected in 0° and 90° of abduction (P = .28; P = .13).
CONCLUSION
The deltoid shows a linear contribution to maximal shoulder strength depending on the abduction or flexion angle, ranging from 24% in 0° to 75% in 120° of abduction and from 11% in 0° to 70% in 120° of flexion, respectively. The overall contribution to abduction strength is higher than to flexion strength. The combination of deltoid muscle and teres minor contributes about 50% to external rotation strength in 90° of abduction. The internal rotation strength is not influenced by a deltoid paralysis. This study highlights the position-dependent contribution of the shoulder muscles to strength development and thereby provides an empirical approach to better understand human shoulder kinematics.
Topics: Biomechanical Phenomena; Deltoid Muscle; Humans; Range of Motion, Articular; Rotation; Rotator Cuff; Shoulder; Shoulder Joint
PubMed: 32540315
DOI: 10.1016/j.jse.2020.05.023 -
BMC Musculoskeletal Disorders Jun 2020With the rapid aging of the population, the incidence of proximal humeral fracture (PHF) has increased. However, the optimal method for open reduction and internal... (Comparative Study)
Comparative Study
BACKGROUND
With the rapid aging of the population, the incidence of proximal humeral fracture (PHF) has increased. However, the optimal method for open reduction and internal fixation (ORIF) remains controversial.
METHODS
We performed a retrospective analysis of patients with PHF who underwent locking plate internal fixation at our institution from January 2016 to December 2018. Patients were divided into two groups based on the surgical approach used: an expanded deltoid-split approach group (ORIF group) and minimally invasive deltoid-split approach group (minimally invasive percutaneous plate osteosynthesis, [MIPPO] group). The groups were compared in terms of demographic and perioperative characteristics, and clinical outcomes.
RESULTS
A total of 115 cases of PHF were included in our study, of which 64 cases were treated using the minimally invasive deltoid-split approach and 51 using the extended deltoid-split approach. Fluoroscopy was performed significantly less frequently in the ORIF group and the surgical duration was shorter. However, the postoperative visual analogue scale (VAS) pain score and duration of postoperative hospital stay were significantly higher compared to the MIPPO group. Moreover, secondary loss was significantly less extensive in the ORIF group compared to the MIPPO group, while there was no significant group difference in fracture healing time, Constant shoulder score, or complications at the last follow-up visit.
CONCLUSIONS
The clinical outcomes associated with both the minimally invasive and extended deltoid-split approaches were satisfactory. The data presented here suggest that the extended deltoid-split approach was superior to the minimally invasive deltoid-split approach in terms of operational time, fluoroscopy, and secondary loss of reduction, while the minimally invasive approach was superior in terms of postoperative pain and hospital stay. Accordingly, neither procedure can be considered definitively superior; the optimal surgical procedure for PHF can only be determined after full consideration of the situation and requirements of the individual patient.
Topics: Aged; Bone Plates; Case-Control Studies; Deltoid Muscle; Female; Fracture Fixation, Internal; Fracture Healing; Humans; Male; Middle Aged; Minimally Invasive Surgical Procedures; Operative Time; Shoulder Fractures; Treatment Outcome
PubMed: 32593311
DOI: 10.1186/s12891-020-03417-9 -
Frontiers in Physiology 2023Scapular dyskinesis is commonly associated with subacromial pain syndrome (SAPS). Addressing scapular dyskinesis is widely accepted as an important component of...
Scapular dyskinesis is commonly associated with subacromial pain syndrome (SAPS). Addressing scapular dyskinesis is widely accepted as an important component of shoulder rehabilitation. Our previous randomized controlled trial showed that Yi Jin Bang (YJB) exercises could effectively manage SAPS, but scapular motions and muscle activity during YJB exercises remain unknown. This study examined scapular kinematics synchronously with scapular muscle activation during YJB exercises. Thirty healthy participants with no shoulder complaints were enrolled in this study. Three-dimensional (3D) scapular kinematics and electromyography (EMG) activation of the upper trapezius, middle trapezius, lower trapezius, serratus anterior, anterior deltoid, middle deltoid, and posterior deltoid were synchronously measured during nine YJB movements. During all YJB movements, the scapula was upwardly rotated and anteriorly tilted, with more upward rotation and a similar or less anterior tilt than the mean resting scapular angle. Column rotation, arm crossover, shoulder support circle, and armpit support high lift generated more internal rotation than the mean resting scapular angle, with the angles of internal rotation significantly greater than the other five movements ( < 0.001). Regarding EMG activity, all YJB movements elicited low activity (1.42%-19.19% maximal voluntary isometric contraction [MVIC]) from the upper trapezius and posterior deltoid and low to moderate activity (0.52%-29.50% MVIC) from the middle trapezius, lower trapezius, serratus anterior, anterior deltoid, and middle deltoid. YJB exercises could be useful in the middle to later phases of shoulder rehabilitation. For patients with insufficient external rotation, some YJB movements should be prescribed with caution.
PubMed: 37362425
DOI: 10.3389/fphys.2023.1169092 -
JSES International Jun 2020Reverse shoulder arthroplasty (RSA) is an increasingly popular treatment modality for glenohumeral joint arthritis in association with rotator cuff arthropathy. A...
BACKGROUND AND HYPOTHESIS
Reverse shoulder arthroplasty (RSA) is an increasingly popular treatment modality for glenohumeral joint arthritis in association with rotator cuff arthropathy. A prolonged hospital stay following joint arthroplasty risks increased complications for patients plus financial implications for institutions. We hypothesized that RSA could be safely and effectively carried out as an outpatient procedure with reduced risks to patients and institutional costs.
METHODS
Patients attending our institution for RSA during March 2015 to August 2018 were reviewed preoperatively for consideration for RSA as an outpatient procedure. The inclusion criteria were arthritis of the shoulder having failed conservative management, age older than 50 years, and intact deltoid muscle function. Patients were excluded if they underwent RSA for trauma or for revision following previous total shoulder replacement or hemiarthroplasty. Overall health, social circumstances, and individual wishes were considered.
RESULTS
A total of 21 patients underwent RSA as an outpatient procedure. The mean age was 74 years (range, 59-84 years). There were 8 male and 13 female patients. No overnight stays were required in patients in whom outpatient surgery was planned. The Oxford Shoulder Score increased from a mean of 16 (range, 4-30) preoperatively to a mean of 31 (range, 7-35) at 6 months postoperatively; it was a mean of 36 (range, 7-48) at 12 months postoperatively. Of the patients, 88% were "very satisfied" or "satisfied" with the service and 81% would undergo the surgical procedure again as a day-case procedure.
CONCLUSION
RSA as an outpatient procedure can be carried out effectively with high patient satisfaction rates in carefully selected patients.
PubMed: 32490433
DOI: 10.1016/j.jseint.2020.01.001 -
Current Reviews in Musculoskeletal... Oct 2020Reverse shoulder arthroplasty (RSA) is commonly considered as one of the options for surgical management of the functionally irreparable rotator cuff tear (FIRCT). This... (Review)
Review
PURPOSE OF THE REVIEW
Reverse shoulder arthroplasty (RSA) is commonly considered as one of the options for surgical management of the functionally irreparable rotator cuff tear (FIRCT). This article reviews tips and tricks to optimize the outcome of RSA when performed specifically for this indication.
RECENT FINDINGS
RSA has been reported to provide satisfactory outcomes in a large proportion of patients with FIRCTs. However, subjective satisfaction is lesser in patients with well-maintained preoperative motion as well as those with isolated loss of active external rotation. The popularity of implants that provide some degree of global lateralization continues to increase. Optimizing the outcome of RSA for FIRCTs requires a careful balance between minimizing perimeter impingement and enhancing the function of intact muscles, in particular the deltoid and any remaining rotator cuff. Controversy continues regarding the benefits and disadvantages of subscapularis repair at the time of RSA. Tendon and muscle transfers performed at the time of RSA have the potential to optimize the outcome in selected patients with profound weakness in external rotation or those with severe deltoid dysfunction. When RSA is considered for patients with a FIRCT without arthritis, careful attention to indications and technical pearls may contribute to optimize outcomes.
PubMed: 32488624
DOI: 10.1007/s12178-020-09655-7 -
JSES International Nov 2022After latissimus dorsi transfer (LDT), an increase in scapulothoracic (ST) contribution in thoracohumeral (TH) elevation is observed when compared to the asymptomatic...
BACKGROUND
After latissimus dorsi transfer (LDT), an increase in scapulothoracic (ST) contribution in thoracohumeral (TH) elevation is observed when compared to the asymptomatic shoulder. It is not known which shoulder muscles contribute to this change in shoulder kinematics, and whether the timing of muscle recruitment has altered after LDT. The aim of the study was to identify which shoulder muscles and what timing of muscle recruitment are responsible for the increased ST contribution and shoulder elevation after LDT for a massive irreparable posterosuperior rotator cuff tear (MIRT).
METHODS
Thirteen patients with a preoperative pseudoparalysis and MIRT were recruited after LDT with a minimum follow-up of 1 year. Three-dimensional electromagnetic tracking was used to assess maximum active elevation of the shoulder (MAES) in both the LDT and the asymptomatic contralateral shoulder (ACS). Surface electromyography (EMG) tracked activation (% EMG max) and activation timing of the latissimus dorsi (LD), deltoid, teres major, trapezius (upper, middle and lower) and serratus anterior muscles were collected. MAES was studied in forward flexion, scapular abduction and abduction in the coronal plane.
RESULTS
In MAES, no difference in thoracohumeral motion was observed between the LDT and ACS, = .300. However, the glenohumeral motion for MAES was significantly lower in LDT shoulders F(1,12) = 11.230, = .006. The LD % EMG max did not differ between the LDT and ACS in MAES. A higher % EMG max was found for the deltoid F(1,12) = 17.241, = .001, and upper trapezius F(1,10) = 13.612, = .004 in the LDT shoulder during MAES. The middle trapezius only showed a higher significant difference in % EMG max for scapular abduction, = .020 (LDT, 52.3 ± 19.4; ACS, 38.1 ± 19.7).The % EMG max of the lower trapezius, serratus anterior and teres major did not show any difference in all movement types between the LDT and ACS and no difference in timing of recruitment of all the shoulder muscles was observed.
CONCLUSIONS
After LDT in patients with a MIRT and preoperative pseudoparalysis, the LD muscle did not alter its % EMG max during MAES when compared to the ACS. The cranial transfer of the LD tendon with its native %EMG max, together with the increased %EMG max of the deltoid, middle and upper trapezius muscles could be responsible for the increased ST contribution. The increased glenohumeral joint reaction force could in turn increase active elevation after LDT in a previous pseudoparalytic shoulder.
PubMed: 36353427
DOI: 10.1016/j.jseint.2022.07.008 -
JSES International Jul 2022Shoulder movements that involve unilateral and bilateral flexion, extension, abduction, and asymmetrical flexion-extension cause the activity of trunk muscles. There has...
BACKGROUND
Shoulder movements that involve unilateral and bilateral flexion, extension, abduction, and asymmetrical flexion-extension cause the activity of trunk muscles. There has not been a fixed consensus on the onset of deep trunk muscle activities including the psoas major (PM), quadratus lumborum (QL), transversus abdominis (TrA), and lumbar multifidus (MF) during shoulder movements. The purpose of this study was to measure the onset of electromyographic activity of the deep trunk muscles during rapid shoulder movements and clarify the coordinated activity pattern of the deep trunk muscles during 11 shoulder movements.
METHODS
Thirteen men participated in this study. The onset of activity of the right deep trunk muscles (PM, QL, TrA, and MF) were measured using fine-wire electrodes, and those of the right and left deltoid (anterior, middle, and posterior) and right superficial trunk muscles (rectus abdominis, external oblique [EO], and internal oblique [IO]) were measured using surface electrodes as participants performed 6 types of unilateral, 3 types of bilateral, and 2 types of asymmetrical rapid shoulder movements. We defined feedforward activation as the onset of activity of trunk muscle before or within +50 ms onset of the deltoid muscle and feedback activation as that after +50 ms. A 1-way analysis of variance was performed to compare the onset of activity of each muscle during each shoulder movement.
RESULTS
The mean onset of activity of the PM (26.0 ms), QL (13.1 ms), TrA (-19.7 ms), and MF (20.4 ms) muscles demonstrated feedforward activation during left shoulder flexion. The onset of activity of the TrA (1.6-48.7 ms), rectus abdominis (-1.7 to 17.3 ms), and EO (5.6-40.8 ms) muscles demonstrated feedforward activation during left, right, and bilateral shoulder extension. The onset of activity of the PM (22.9 ms), QL (23.0 ms), TrA (18.9 ms), and EO (15.4 ms) demonstrated feedforward activation during left shoulder abduction, while that of the IO (4.4-10.9 ms) only demonstrated feedforward activation during right and bilateral shoulder abduction. The onset of activity of the TrA (-27.6 ms) and IO (-23.9 ms) demonstrated feedforward activation during left shoulder flexion-right shoulder extension, and that of the MF (33.4 ms) and EO (-17.2 ms), during left shoulder extension-right shoulder flexion.
CONCLUSION
Rapid shoulder movements occur with coordinated muscle activation of the deep trunk muscles depending on the direction of shoulder movements. Feedforward activation of single or combined deep trunk muscles may facilitate rapid shoulder movements.
PubMed: 35813146
DOI: 10.1016/j.jseint.2022.04.003 -
Scientific Reports Jan 2022Current US Centers for Disease Control and Prevention intramuscular injection needle length guidelines for injection fo the deltoid muscle are based on weight and...
Current US Centers for Disease Control and Prevention intramuscular injection needle length guidelines for injection fo the deltoid muscle are based on weight and gender. The aims of this study are (1) to evaluate whether other biometric data (age, gender, height, weight and body mass index (BMI)) are better predictors of the thickness of the deltoid subcutaneous fat pad (DSFP) than weight and gender and (2) to evaluate the performance of the CDC weight-based needle length guidelines. This was a retrospective single center cohort study of 386 patients who underwent surveillance PET/CT between 01/01/2020 and 04/01/2021. Patient age, gender, height, weight, BMI and CT measurements of the DSFP were evaluated. DSFP was positively correlated with weight and BMI in men (r = 0.67, P < 0.001; r = 0.74, P < 0.001) and women (r = 0.69, P < 0.001; r = 0.75, P < 0.001) respectively. DSFP was negatively correlated with age in women (r = - 0.19, P = 0.013). Age and BMI were better predictors of DSFP than weight. The best model to predict the DSFP is: [Formula: see text] A 1-inch needle is expected to reach the deltoid in 85.3% of women less than 200 pounds, and 98.6% of men less than 260 pounds. This rate differed between genders (P < 0.001, odds ratio (OR) 0.08, 95% CI (0.02, 0.29)). A 1.5-inch needle is expected to reach the deltoid in 76.7% of women greater than 200 pounds, and 75.0% of men greater than 260 pounds. Current CDC deltoid intramuscular injection needle length guidelines result in women and obese individuals being more likely to receive subcutaneous injections. Age and BMI based guidelines for needle length selection are more accurate.
Topics: Adipose Tissue; Adult; Aged; Aged, 80 and over; Biometry; Body Height; Body Mass Index; Cohort Studies; Deltoid Muscle; Female; Humans; Injections, Intramuscular; Injections, Subcutaneous; Male; Middle Aged; Models, Statistical; Needles; Obesity; Retrospective Studies; Skin; Subcutaneous Fat; Subcutaneous Tissue
PubMed: 35058499
DOI: 10.1038/s41598-022-05020-5 -
Diagnostics (Basel, Switzerland) Feb 2020Papillary thyroid cancer (PTC) is the most common type of thyroid malignancy and is characterized by slow growth and an indolent biological behavior. Papillary thyroid... (Review)
Review
Papillary thyroid cancer (PTC) is the most common type of thyroid malignancy and is characterized by slow growth and an indolent biological behavior. Papillary thyroid microcarcinoma is the PTC with the maximum size of the tumor <1cm, considered the most indolent form of thyroid cancer. PTC is usually metastasizes in cervical lymph nodes, lungs and bones and, less commonly, in brain or liver. Skeletal muscle metastases from PTC are extremely rare, a retrospective review of the literature revealed only 13 case reports. Among them, six cases are solitary skeletal muscle metastases, and seven are multiple metastases, most of them being associated with lung lesions. It seems that PTC is prone to metastasizing to the erector spinae and thigh muscles groups with unique cases located in trapezoid, biceps, deltoid, gastrocnemius and rectus abdominis muscles. Although extremely rare, one must bear in mind the fact that muscle metastasis from PTC is possible, and that is the reason we would like to discuss the existing clinical cases and to add a unique case of solitary skeletal muscle metastasis from papillary microcarcinoma.
PubMed: 32059570
DOI: 10.3390/diagnostics10020100 -
Revue Medicale de Liege Oct 2023In this article, we present a rare type of acute compartment syndrome affecting the deltoid muscle, which occurred after a crush syndrome in a patient discovered at home...
In this article, we present a rare type of acute compartment syndrome affecting the deltoid muscle, which occurred after a crush syndrome in a patient discovered at home in a stuporous state. Although compartment syndromes are not rare, certain circumstances cause unusual consequences and localizations, shoulder impotence in the present case. The importance of an early diagnosis is obvious to avoid the risk of irreversible lesions. We describe predisposing circumstances and provide a brief review of the pathophysiology of this syndrome.
Topics: Male; Humans; Compartment Syndromes; Acute Disease
PubMed: 37830316
DOI: No ID Found