Normal Shoulder Research Articles

Does Reverse Shoulder Arthroplasty Improve Function and Quality of Life in Patients With Rotator Cuff Tear Arthropathy?

Background This study aims to determine the change in functional capacity and quality of life in patients who underwent reverse shoulder arthroplasty (RSA) due to rotator cuff tear arthropathy (RCTA). Methodology A total of 89 patients who underwent RSA due to RCTA between 2016 and 2022 were included in the study, as examined by the senior author. The Constant-Murley Score (CMS) was used for functional assessment, whereas the Short Form-36 (SF-36) was used for quality-of-life evaluation. The assessment scores before and after the surgery were compared to the reference values of CMS and SF-36 scores, as determined by reference studies, based on age groups. The change in functional capacity and quality of life with RSA was calculated. In addition, the impact of age and body mass index (BMI) on the results was examined. Results No differences were found in demographic data except for BMI (p = 0.026). CMS did not reach the reference values of a normal shoulder during the 12-month postoperative period. However, a significant increase of 156% in comparison to the preoperative values was detected (p < 0.001). In the postoperative period, there was a statistically significant improvement in SF-36 scores compared to preoperative scores, except for social functioning (p = 0.099) and vitality (p = 0.255) (for all other parameters, p < 0.001). In patients under the age of 65 years, all parameters except for physical functioning, physical role, and social functioning statistically reached the reference values. A decrease in CMS scores was noted with an increase in BMI, and the negative correlation further increased in the postoperative period (preoperative: r = -0.274, 12-month postoperative: r = -0.476). Conclusions RSA performed for RCTA leads to an improvement in functional outcomes and quality of life. Although there was a considerable improvement after surgery for CMS compared to preoperatively, it was observed that normal shoulder reference values ​​could not be reached. For SF-36, it was observed that it reached normal shoulder reference values, especially in patients over 65 years of age.

Comparison of isometric strength in rotator cuff and scapulothoracic muscles between elite volleyball athletes versus non-athletes.

Volleyball is an exceptionally popular global sport that involves repetitive, rapid, powerful and wide overhead movements, which can seriously alter normal shoulder kinematics. A recognized hallmark of shoulder muscle balance is the ratio of shoulder external (ER) and internal (IR) rotators. By extension, objective measurement of shoulder muscles' strength could help identify at risk athletes and preempt those injuries by engaging in prescriptive strength training programs. This cross-sectional study measured the isometric strengths of 1) shoulder internal and external rotator muscles, as well as the 2) supraspinatus, 3) rhomboid, and 4) middle and inferior trapezius muscles, in addition to calculation of ER:IR ratios, in professional volleyball players as well as in non-athletes. Measurements were made for dominant- and non-dominant upper limbs, in different position of the body (supine and orthostatic) and in different position of upper limb (adducted and abducted position). Our subject population included 11 male professional volleyball players as well as 14 healthy male orthopedic interns from Orthopedics and Trauma school of University of Milano Bicocca. Strengths were assessed by a handheld dynamometer. Each subject's isometric strength was assessed in triplicate in each limb position through a "make test" procedure; the greatest of each triplicate value was the accepted measure of isometric strength. We observed a gradient in muscle strength in the scapulothoracic complex in both groups; the rhomboid, middle trapezius, and lower trapezius ranked from greatest to least strength, respectively. The data suggest also that intrarotators are stronger in rotation adducted position than in rotation abducted position; however, extrarotators seem to be weaker in rotation adducted position than in rotation abducted position. There is also some indication that force development is enhanced in the supine position compared with the orthostatic position. Our findings indicate a scapulothoracic strength gradient with a rank order of strength of the rhomboid>middle trapezius>lower trapezius. The data further suggest that volleyball players have stronger intrarotation in rotation adducted position than in the rotation abducted position, while extra rotation shows the opposite trend. Finally, our data suggest that force development is greater in the supine position compared to the orthostatic position.

Role of computed tomography in glenohumeral joint deformity following obstetric brachial plexus injury: Proposed radiological classification

Objective: The study aimed to study the usefulness of computed tomography (CT) in the measurement of glenoid version angle, humeral head dislocation, or subluxation and to propose a grading system for the severity of glenohumeral deformity following OBPI. Material and Methods: A prospective study conducted over a period of 3 years. The study group includes 21 children below the age of 12 years presenting with posterior dislocation of the shoulder, with prior history of OBPI. CT of both shoulders was done using a 128-slice CT scanner. The children were assessed clinically by a Modified Mallet Scale and graded by Waters classification. Results: We graded the severity of deformity on the affected side according to Waters et al. The difference between affected and normal shoulder glenoscapular angle (GSA), percentage of humeral head anterior to the scapular line (PHH), scapular height, and scapular width was statistically significant (P &lt; 0.05). We propose grading for severity and assessed joint stability based on the CT parameters. GSA and PHH show a statistically significant difference between the three grades (P &lt; 0.05). We also confirm that the higher the grade of the deformity, the more difficult the shoulder movements leading to worse scores on the Modified Mallet Scale. Conclusion: CT scan identifies glenohumeral deformities such as increased glenoid retroversion, posterior dislocation of the humeral head, smaller humeral head size, and smaller size of the scapula as deviations from normal status and helps in radiological grading.

Assessment of core endurance and shoulder proprioception in dental students with and without forward head posture

BackgroundOne of the most prevalent musculoskeletal issues in dentistry is forward head posture (FHP). Proprioception and core endurance are crucial for maintaining proper posture.ObjectiveThe aim of this study was to compare dental students with and without FHP in terms of their core endurance and shoulder proprioception.MethodsUsing kinovea software, a cross-sectional study was conducted on 30 dental students who had FHP with a craniovertebral angle less than 49 degrees. The control group consisted of 30 additional dental students without FHP. Trunk anterior flexor, posterior extensor, right and left flexors were tested using the McGill method to determine core endurance. The isokinetic Biodex system was used to measure shoulder proprioception.ResultsIndependent t-test results revealed that core endurance was significantly lower in the group with forward head posture compared to the control group (p 0.05), while shoulder proprioception did not differ significantly between groups (p > 0.05).ConclusionIn comparison to dental students without forward head posture, male dental students with FHP have normal shoulder joint proprioception and impaired core endurance holding time. This could be a risk factor for a variety of musculoskeletal issues in dentists.

Supraspinatus muscle atrophy in relation to aging with or without shoulder pathology: A radiographic study

IntroductionSupraspinatus muscle atrophy is commonly associated with shoulder disease, but the effect of ageing on atrophy is not well understood. It was the aim of this study to investigate this effect using MRI scans in older patients. Methods and materialsA retrospective review of MRI scans in patients aged >70 years was performed between Jan 2016–Dec 2018.Both normal and abnormal scans were included in the analysis which included quantifying muscle atrophy of the supraspinatus using Thomazeu's occupation ratio. ResultsThere were 39 normal shoulder MRI scans with a mean age of 75 years (range: 70–88) and 163 abnormal scans with a mean age of 77 years (range: 70–93). The mean supraspinatus occupation ratio for normal MRI scans was 0.57 (range: 0.33–0.86) and abnormal scans 0.35 (range: 0.17–0.90). Occupation ratio was maintained with advancing until the age of 85 years before undergoing a significant declin following this. ConclusionThis study has shown that the occupation ratio is significantly reduced with shoulder disease, but normal shoulders do not undergo significant atrophy of supraspinatus tendon with increasing age. An occupation ratio of <0.32 is unlikely to occur in normal shoulders and this awareness may be useful when planning shoulder surgery, specifically shoulder arthroplasty.

Repair of a Reverse HAGL: A 2-Portal Technique

Background: Glenohumeral joint stability is reliant on a combination of static and dynamic constraints. Humeral avulsion of the posterior band of the inferior glenohumeral ligament (HAGL) is an exceedingly rare injury. These injuries can be difficult to diagnose and can lead to continued pain, dysfunction, and recurrent instability. There is a paucity of literature regarding surgical management of reverse HAGL lesions. Indications: Many intrasubstance reverse HAGL lesions can be managed nonoperatively with rehabilitation focused on improving shoulder stability. Although the incidence of recurrent instability in patients with reverse HAGL lesions is unknown, the acute detached humeral lesions in athletes are often treated surgically to restore normal shoulder. Technique Description: The patient was placed in a standard beach chair position, and the standard portals were made for a diagnostic shoulder arthroscopy. The anterior portal was the primary viewing portal. Using the initial posterior skin incision, instruments were introduced through the defect from the retracted posterior band of the inferior glenohumeral ligament. Using a combination of the 30° and 70° arthroscope, the HAGL was mobilized from the infraspinatus musculature. Two knotless suture devices (1.8-mm suture anchor, 2.6-mm suture anchor) were used to reduce the reverse HAGL lesion to an anatomical position, and the posterior capsule was closed thereafter. Results: Only case studies and a single case series have been published pertaining to reverse HAGL repair techniques and related outcomes. When diagnosed and treated appropriately, arthroscopic repairs yield promising results with a high percentage of patients returning to prior level of activity or returning to prior participation level in sport. However, outcome data are limited given the rare occurrence of this injury pattern. Discussion/Conclusion: Reverse HAGL pathology can be treated effectively with arthroscopic surgical repair to restore the normal capsular anatomy and prevent recurrent instability and persistent posterior shoulder pain. Using a 2-portal approach with posterior capsular closure is a minimally invasive operation that allows for appropriate management of these rare injuries. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Ultrasound assessment of the inferior glenohumeral capsule in normal shoulders—a study of measurement variables and reliability

To establish the reliability of a standardised ultrasound protocol to measure normal inferior glenohumeral capsule (IGHC) thickness and to investigate the effects of age, sex, hand dominance and angles of abduction on the thickness. IGHC images were obtained at 60o, 90o and 180o abduction angles of 151 asymptomatic shoulders in supine position. Following the proposed guidelines, three sonographers blindly measured the IGHC thicknesses for intra- and interrater reliability assessments. The intrarater reliability was excellent (intraclass correlation coefficient value = 0.95; 95% CI = 0.92-0.97). The interrater reliability was moderate (intraclass correlation coefficient value = 0.74; 95% CI = 0.60-0.83). The mean IGHC thickness values in mm ± SD at 60o, 90o and 180o abduction angles for males were 3.3 ± 0.93, 3.0 ± 0.80 and 2.6 ± 0.55 and those for females were 2.7 ± 0.86, 2.4 ± 0.7 and 2.0 ± 0.56 respectively. Although males had thicker IGHC, the rate at which the thickness reduced with increased abduction was same in both males and females. Age and hand dominance had no effect. The normal IGHC thickness varies with sex and the abduction angle of the arm at which it is measured. A large variation of IGHC thickness exists in the normal population. The results of this study discourage the use of a single value of IGHC thickness and emphasise the importance of comparing the thickness of the symptomatic side to that of the asymptomatic side of the same subject at the same abduction level. The guidelines provided in this study can be used in clinical practice and in future research studies.

Mid-term comparative study between the glenoid and humerus lateralization designs for reverse total shoulder arthroplasty: which lateralization design is better?

IntroductionThe complications of the conventional medialized design for reverse total shoulder arthroplasty (RSA) are increased scapular notching, and decreased external rotation and deltoid wrapping. Currently, lateralization design RSA, which avoid scapular notching and improve impingement-free range of motion, is commonly used. Especially, humeral lateralization design was most commonly used and glenoid lateralization design was preferred for glenoid abnormities. We compared mid-term clinical and radiologic outcomes of glenoid and humeral lateralization RSA in an Asian population in this study.Materials and MethodsWe enrolled 124 shoulders of 122 consecutive patients (mean age 73.8 ± 6.8 years) who received glenoid or humeral lateralization RSA from May, 2012 to March, 2019. We divided these patients into two groups according to RSA using either glenoid or humeral lateralization design. These different designs were introduced consecutively in Korea. The clinical and radiological results of 60 glenoid lateralization RSA (Group I, 60 patients) and 64 humeral lateralization RSA (Group II, 62 patients) were retrospectively evaluated and also were compared between the two groups. All patients were followed for mean 3 years.ResultsThe clinical and radiologic outcomes of the two groups did not differ significantly, including scapular notching (p = 0.134). However, humeral lateralization RSA showed a larger glenoid-tuberosity (GT) distance (p = 0.000) and less distalization shoulder angle (DSA) (p = 0.035). The complication rate did not differ significantly either. But, revision surgery was performed for 2 humeral loosening in the Group II.ConclusionThe clinical and radiologic outcomes of the two groups did not differ significantly, including scapular notching at mid-term follow-up. However, humeral lateralization design showed larger GT distance and less DSA. Humeral lateralization design RSA could preserve the normal shoulder contour due to a larger GT distance (more lateralization) and provide less deltoid tension due to less DSA (less distalization of COR).

Investigation of the Effect of Conventional Treatment on Postural Stability and Balance in Individuals with Shoulder Pain

Background: The stability provided by the trunk is needed for normal shoulder function. This is also related to balance. Objectives: To examine the postural stability and balance status of individuals with shoulder pain and the relations of these parameters to each other. In addition, to investigate the effects of conventional shoulder pain treatment on postural instability and balance parameters. Methods: Twenty patients with shoulder pain and twenty healthy individuals included in the study were assigned to the treatment (n = 20) and control group (n = 20). A conventional physiotherapy program was applied 3 times a week to individuals with shoulder pain in the treatment group for 8 weeks (24 sessions). Pain, shoulder range of motion, and balance were evaluated at the end of the program. Results: A statistically significant improvement was observed in the pre-and post-treatment values of pain and range of motion in the treatment group at the end of 8 weeks (P = 0.00; P = 0.02). In addition, statistically significant differences were found in all values in the results of the balance assessment between the groups, except for the dynamic balance scores of the medial-lateral balance (P = 0.014; P = 0.016). Conclusions: Postural stability and balance status of individuals with shoulder pain were evaluated, and no statistically significant difference was found between them and healthy individuals. It was observed that therapeutic agents applied in addition to exercise in individuals with shoulder pain prove to be a safe method that can be implemented to improve the parameters of pain, mobility, balance, and postural stability.

Refractory shoulder injury related to vaccine administration: correlation with culture presence of Cutibacterium acnes

Shoulder pain following intramuscular administration of vaccine is common. However, a small number of patients experience prolonged pain and dysfunction atypical to normal transient postvaccination shoulder pain. Shoulder Injury Related to Vaccine Administration (SIRVA) remains incompletely understood, whether a robust immune response to vaccine antigen or inappropriate injection technique with needle placement in synovial or bursal tissue, or some combination of the two. Symptoms overlap with those of Cutibacterium acnes (C. acnes) infection but the relationship between the two, if any, has not been evaluated. Clinical case files were reviewed for 3 cases of SIRVA with positive cultures for C. acnes were reviewed. Presentation, treatment, and clinical outcomes were compared. In all cases, patients were thin (body mass index < 23), females, who had high injection placement of a vaccine, all patients had positive magnetic resonance imaging findings of increased signal in the subacromial bursa, and/or greater tuberosity. All patients underwent arthroscopic débridement and culture harvest and cultures were positive for C. acnes. A combination of oral and intravenous antibioticswas used, and all patients demonstrated clinical improvement from the preoperativestate. This case series presents 3 patients with refractory SIRVA who ultimately underwent arthroscopic irrigation and débridement with culture biopsy. Each case had culture results positive for C.acnes and all responded, at least partially, to arthroscopic débridement and intravenous antibiotic therapy. The purpose of this manuscript is to raise awareness of potential coexistence of SIRVA and C.acnes which may be of assistance to surgeons treating refractory cases of SIRVA.

Correction of Static Posterior Shoulder Subluxation by Restoring Normal Scapular Anatomy Using Acromion and Glenoid Osteotomies: A Case Report.

A 40-year-old man presented with progressive shoulder pain, associated with static posterior subluxation and mild eccentric glenohumeral osteoarthritis. Compared with a mean statistical shape model of a normal shoulder, the patient's acromion was abnormally high and horizontal, and the glenoid abnormally inclined inferiorly and minimally retroverted. Restoration of normal scapular anatomy using 3-dimensional planned acromial and glenoid osteotomies led to recentering of the joint and full shoulder function up to 24 months postoperatively. The correction of associated acromial and glenoid malformation can revert early static posterior subluxation of the shoulder. Whether successful recentering prevents progression of osteoarthritis remains to be established.

Biphasic Interpositional Allograft for Rotator Cuff Repair Augmentation Is Safe in an Ovine Model

This study is a preclinical histological assessment of a biphasic acellular interpositional cancellous allograft in an ovine model of rotator cuff repair (RCR) designed to better understand its safety profile and effects on tendon healing after rotator cuff repair. Thirty skeletally mature sheep with clinically normal shoulders with an artificially created degenerative infraspinatus tendon (IST) tear were randomized to control and treatment groups. Animals were euthanized at 3-weeks, 6-weeks, and 12-weeks. After gross dissection, rotator cuff specimens were fixed with formalin and polymerized for sectioning and staining. Blinded histological scores evaluated inflammatory cell infiltrates, signs of degradation, particulate debris, collagen arrangement, neo-vascularization, and enthesis qualitative measures. There were no treatment specimens that exhibited histological signs of a significant infection, inflammatory infiltrate, or foreign body reaction such as granuloma or fibrous capsule formation. Histological scores in all categories were not significantly different at all time points, including the primary endpoint mean cumulative inflammatory score (control: 3.66 ± 1.21 versus treated: 4.33 ± 1.51, p = 0.42), when comparing the treatment and control RCR groups. In general, the degree of tendon healing and host tissue response was essentially equivalent between the two groups with observation of low overall levels of inflammation and progressive improvements in collagen organization, reduced tenocyte activity, and fibrocartilaginous enthesis reformation. This histological study demonstrated the use of a biphasic interpositional allograft for rotator cuff repair augmentation in an ovine model does not generate an inflammatory response or foreign body reaction. Use of the biphasic interpositional allograft resulted in a histological profile that was essentially equivalent to that of a standard RCR at 3-, 6-, and 12-week post-operative timepoints. These findings suggest that a biphasic interpositional allograft is safe for further clinical investigation in humans before broader clinical application. Patch augmentation of RCR is a popular technique that has shown clinical success in improving the likelihood of a successful repair in patients at elevated risk for retear. Newer augmentation technologies are being developed to address the biology at the interface between the bone and soft tissue where failure typically occurs.

Complete excision of giant clavicular hydatid cyst: a case report

BackgroundEchinococcosis, also known as hydatid disease, is a zoonotic parasitic disease prevalent in pastoral areas, mainly involving the liver and lungs, and less frequently the bones and surrounding soft tissues. Diagnosis and treatment of bone hydatid disease is a challenge, and because of the insidious course of the disease, the lesions are often widely disseminated by the time patients seek medical attention.Case presentationA 29-year-old woman presented with a painless mass that was gradually increasing in size in the cervical thorax. Imaging revealed an enlarged clavicle with multiple bone cortical defects and the existence of cysts in the soft tissues surrounding the clavicle, for which complete excision of the clavicle and the attached cysts was performed. There was no recurrence of the cyst within one year after the operation, and the patient felt well and had normal shoulder joint movement.ConclusionsBone hydatid may appear in bones throughout the body, and cysts that leak from the bone into the surrounding soft tissues may spread at a relatively rapid rate. Prompt surgical removal of the affected bone and surrounding cysts is necessary for treatment.

Avoidance behaviours while circumventing to the left or right of someone with different shoulder widths and facing directions: How do side, width, or orientation matter?

BackgroundCollision avoidance during locomotion is influenced by a variety of situational factors. When circumventing around an inanimate object, the amount of clearance is dependent on the side of avoidance. When avoiding other pedestrians, individuals most often choose to walk behind a moving pedestrian, and avoid people differently depending on their body size. However, side of avoidance has not been evaluated with human obstacles, nor facing direction of a stationary pedestrian, nor the size of a single pedestrian. Therefore, the aim of this study is to evaluate these knowledge gaps concurrently. Research questionHow do people avoid a collision to the left-side or right-side of a single stationary pedestrian (interferer) of varying shoulder width and orientation? MethodsParticipants (n = 11) walked along a 10 m pathway towards a goal, while a stationary interferer stood 6.5 m from the start. The interferer faced one of three directions relative to the participant (orientation); forward, leftward, or rightward, with either their normal shoulder width or enlarged width created by wearing football shoulder pads. Participants were explicitly instructed as to which side of the interferer to avoid (forced-left vs forced-right). Each participant completed 32 randomized avoidance trials. Centre of Mass separation at the time of crossing was used to examine individual's avoidance behaviours. ResultsResults revealed no effect of interferer width, but a significant side of avoidance effect, where the centre of mass separation between the participant and interferer at the time of crossing was smallest when participants avoided to their left. SignificanceFindings suggest that changing the facing direction or artificially increasing the shoulder width of a stationary interferer will not affect one's avoidance behaviours. However, an asymmetry in side of avoidance is maintained similar to that observed in obstacle avoidance behaviours.

Evaluation of the coracoid bone tunnel placement on Dog Bone™ button fixation for acromioclavicular joint dislocation: a cadaver study combined with finite element analysis

BackgroundDog Bone™ button fixation is frequently used to treat acromioclavicular joint (ACJ) dislocation. However, various studies have reported complications after fixation.ObjectiveTo investigate the effect of the coracoid bone tunnel location on the treatment of ACJ dislocation through single-tunnel coracoclavicular (CC) ligament fixation with the Dog Bone™ button.MethodsSix cadaveric shoulders were used. Each specimen was subjected to five testing conditions in the following order: (1) normal ACJ (Gn); (2) acromioclavicular and CC ligaments were removed (G0); (3) CC ligament reconstruction was performed using the Dog Bone™ technique, and the coracoid bone tunnel was at the center of the coracoid base (G1); (4) reconstruction was performed at 5 mm distal from the G1 site, along the axis of the coracoid (G2); (5) reconstruction was performed at 10 mm distal from the G1 site, along the axis of the coracoid (G3). The angles of pronation and supination of the clavicle under the same load (30 N) were measured. Next, a finite element (FE) model was created using computed tomography (CT) images of the normal shoulder. Model 1 (M1), model 2 (M2), and model 3 (M3) correspond to G1, G2, and G3, respectively. A force of 70 N was applied as a vertical upward load to the distal clavicle. Subsequently, the von Mises stress, the strain LE along the FiberWire, and the displacement nephogram of the three models were obtained.ResultsAfter single-tunnel CC ligament fixation using the Dog Bone™ technique, the clavicle in the G2 group (20.50 (19.50, 21.25) °, 20.00 (18.75, 21.25) °) had the best rotational stability. The peak von Mises stress, the strain LE along the FiberWire, and the maximum displacement were smaller in M2 than in M1 and M3.ConclusionsWhen the coracoid bone tunnel was located 5 mm anterior to the center of the coracoid base (along the axis of the coracoid), the clavicle showed greater rotational stability.

Association of Shoulder Dysfunction with Mobility Limitation Among Older Adults in the Baltimore Longitudinal Study of Aging.

Association between lower extremity dysfunction and mobility limitation in older adults is well-established; whereas, the impact of upper extremity dysfunction on mobility remains unclear. Since lower extremity dysfunction does not explain all mechanisms that contribute to mobility limitation, more holistic hypotheses that explain reduced mobility in older populations are needed. The shoulders facilitate dynamic stability for ambulation, but the impact of shoulder dysfunction on mobility is poorly understood. This study examined the cross-sectional association of restricted shoulder elevation and external rotation range of motion (ROM) with poor lower extremity function and walking endurance capacity among 613 older adults aged 60 years and older in the Baltimore Longitudinal Study of Aging. Results showed that persons with abnormal shoulder elevation or external rotation ROM were 2.5 to 4.5 times more likely to perform poorly on the expanded Short Physical Performance Battery (p < .050) and the fast-paced 400 m walk test (p < .050), relative to participants with normal shoulder ROM. These findings provide nascent preliminary evidence that shoulder dysfunction is associated with mobility limitation and suggest that future studies are needed to clarify its impact on mobility and to develop novel interventions to improve prevention or mitigation of age-related declines in mobility.

Subacromial Content to Subacromial Space Ratio in Neutral Position of the Arm as Diagnostic Criteria of Subacromial Impingement Syndrome.

Shoulder impingement syndrome is one of the main causes of shoulder disability of working-class individuals. Currently, dynamic sonography of the shoulder is the modality of choice for the evaluation of shoulder impingement syndrome. The ratio of subacromial contents (SAC) and subacromial space (SAS) in neutral arm position could be used as a diagnostic parameter for the subacromial impingement syndrome (SIS), especially in patients who have difficulties in the elevation of their shoulders due to pain. To use the SAC to SAS ratio as a sonographic criterion for the diagnosis of SIS. SAC and SAS of 772 shoulders were vertically measured in coronal view with linear transducer 7-14MHz of Toshiba Xario Prime ultrasound unit, while the patient arm was kept in the neutral position. The ratio of both the measurements was calculated, to be used as a diagnostic parameter of the SIS. The mean SAS was 10.79 ± 1.94 mm and SAC was 7.65 ± 1.43 mm. SAC-to-SAS ratio for normal shoulders was a focused value with narrow standard deviation (0.66 ± 0.03). However, shoulder impingement is confirmed by any value falls out of the range of ratio for normal shoulders. Area under the curve at 95% confidence interval was 96%, while the sensitivity at 95% confidence interval was 99.25% (97.83%-99.85%), and specificity was 80.86% (76.48%-84.74%). SAC-to-SAS ratio in neutral arm position is a relatively more accurate sonographic technique for the diagnosis of SIS.

Implant selection for successful reverse total shoulder arthroplasty.

Reverse total shoulder arthroplasty (RTSA) emerged as a new concept of arthroplasty that does not restore normal anatomy but does restore function. It enables the function of the torn rotator cuff to be performed by the deltoid and shows encouraging clinical outcomes. Since its introduction, various modifications have been designed to improve the outcome of the RTSA. From the original cemented baseplate with peg or keel, a cementless baseplate was designed that could be fixed with central and peripheral screws. In addition, a modular-type glenoid component enabled easier revision options. For the humeral component, the initial design was an inlay type of long stem with cemented fixation. However, loss of bone stock from the cemented stem hindered revision surgery. Therefore, a cementless design was introduced with a firm metaphyseal fixation. Furthermore, to prevent complications such as scapular notching, the concept of lateralization emerged. Lateralization helped to maintain normal shoulder contour and better rotator cuff function for improved external/internal rotation power, but excessive lateralization yielded problems such as subacromial notching. Therefore, for patients with pseudoparalysis or with risk of subacromial notching, a medial eccentric tray option can be used for distalization and reduced lateralization of the center of rotation. In summary, it is important that surgeons understand the characteristics of each implant in the various options for RTSA. Furthermore, through preoperative evaluation of patients, surgeons can choose the implant option that will lead to the best outcomes after RTSA.

Morphology of Humeral Head and Glenoid in Normal Shoulder of Indonesian Population.

Shoulder prostheses designed and used around the world may not fit an Asian shoulder. Normal shoulder morphology in Asian population had been reported, ie, Chinese, Indian, Japanese, and Thai populations, but no data from the Indonesian population. The aim of this study was to evaluate the three-dimensional (3D) morphology of the glenohumeral joint in the normal Indonesian population, identify its normal values, and compare them with those of other populations in the literature. Images for analysis were computed tomography (CT) scans of 85 normal shoulders from 71 patients who had CT scans for another diagnosis. Morphometry of the humeral head and glenoid were measured using 3D reconstruction. Gender differences and correlations between age, height, and glenohumeral morphometry were evaluated. Indonesians' glenohumeral morphometry was compared with those of other populations in the literature. In the normal Indonesian population, the mean of humeral head inclination (HHI), height (HHH), diameter in sagittal plane (DS), diameter in frontal plane (DF), radius of curvature in sagittal plane (RS), and radius of curvature in frontal plane (RF) were 134.1°, 15.6mm, 39.3mm, 41.3mm, 20.4mm, and 21.4mm, respectively. The glenoid height (GH), upper width (GUW), lower width (GLW), inclination (GI), and version (GV) mean values were 34.2mm, 18.4mm, 24.5mm, 74.0mm, and 12.3mm, respectively. There was a significant difference in HHH, DS, DF, RS, RF, GH, GUW, GLW between males and females. Except for HHI and GI, glenohumeral morphometry was correlated with patient height. Age was not correlated with any glenohumeral morphometry. In the Indonesian population, males had a larger humeral head and glenoid than females, and the size of the humeral head and glenoid was correlated to body height. Indonesians' humeral head and glenoid sizes were smaller than those of Western populations, but close to those of other Asian populations.

Angle measurement stability and cycle counting accuracy of hours-long duration IMU based arm motion tracking with application to normal shoulder ADLs

BackgroundInertial measurement units are increasing used for monitoring joint motion, but there is a need to demonstrate their suitability during hours-long continuous use, as well as a need for validated methods to count arm cycles and provide descriptions of typical cycles. Research questionDo IMU sensors and rainflow counting have sufficient accuracy for tracking and cycle counting of hours-long continuous arm motion? If so, what are the cycle rates of normal arm ADL and is there a representative cycle that can serve as a ‘gait cycle’ for the arm? MethodsIMU sensors continuously tracked a robot performing 8 h of simulated cyclic arm motion. Error in the angle measurements was regressed against time to determine the rate of error and the total accumulated error. Additionally, the cycle count accuracy of rainflow, peak/valley, and Fourier transform counting methods was evaluated. ResultsOver 8 h the IMU measurements accumulated a maximum 0.473° of error and the rainflow method counted cycles with less than 1% error. Applying rainflow counting to normal shoulder ADL resulted in an average rate of 533 elevation cycles per day.Tabulating the ADL cycles by mean and range values into a matrix and calculating the centroid, the single best values representing arm elevation cycles were a mean of 22.4° and a range of 21.6°. SignificanceIMU sensors can track arm motion for 8 h with little increase in error, though during longer durations error may reach unacceptable levels. For normal arm ADL, the rainflow determined count of arm elevation full-cycles differed from previous estimates based on peak/valley counting. From the rainflow counting, a single cycle representation of cycle mean and range was determined that can be used as a ‘gait cycle’ for the shoulder