Anatomy and biomechanics of the shoulder

Three-dimensional measurements of scapular kinematics: Interrater reliability and validation of a skin marker-based model against an intracortical pin model

A skin marker-based motion capture model providing measures of scapular rotations was recently developed. The aim of this study was to investigate the concurrent validity and the interrater reliability of the model. Shoulder range of motion (RoM) and activities of daily living (ADL) were tested in healthy volunteers with reflective markers on the scapula and thorax. To investigate the validity, the model was compared to simultaneous data collection from markers on a scapular intracortical pin. The interrater reliability was tested by comparing the skin marker-based protocol performed by two investigators. The mean root mean square error (RMSE) and the intraclass correlation coefficient (ICC(2,1)) were calculated to determine the validity and the interrater reliability, respectively. Eight subjects were included in the validity test: female/male = 2/6, mean (SD) age 35.0 (3.0) and BMI 23.4 (3.3). The mean RMSE of all scapular rotations ranged 2.3-6.7° during shoulder RoM and 2.4-7.6° during ADL. The highest errors were seen during sagittal and scapular plane flexions, hair combing and eating. The reliability test included twenty subjects: female/male = 8/12, mean (SD) age 31.4 (4.9) and BMI 22.9 (1.7). The ICC(2,1) for measuring protraction ranged 0.07-0.60 during RoM and 0.27-0.69 for ADL, for upward rotation the corresponding ICC(2,1) ranged 0.01-0.64 and 0.38-0.60, and anterior tilt 0.25-0.83 and 0.25-0.62. The validity and interrater reliability of the model are task dependent, and interpretation should be made with caution. The model provides quantitative measurements for objective assessment of scapular movements and can potentially supplement the clinical examination in certain motion tasks.

The Role of Arthroscopy in Contemporary Glenoid Fossa Fracture Fixation

Glenoid fossa fractures are rare injuries accounting for 10 to 29% of all intra-articular scapula fractures. They are usually the result of high-energy trauma, and concomitant injuries are not uncommon. Patients with glenoid fractures are admitted with shoulder pain and restricted range of motion. Although shoulder plain radiographs could establish the diagnosis, a computed tomography scan is necessary to adequately define the fracture pattern and characteristics. The most commonly used classification system is that of Ideberg (modified by Goss), which includes five glenoid fossa fracture types according to the location, extension, and complexity of the lesion. Articular surface displacement and step-off are the most important factors that should be taken under consideration when deciding for conservative or surgical management. Operative treatment includes open reduction and internal fixation through a posterior or anterior approach depending on fracture morphology and displacement. However, open surgical techniques are related to extensive soft-tissue disruption, risk of neurovascular injury, and inadequate exposure of the entire glenoid cavity. Introduction of arthroscopy could facilitate better visualization of the glenoid articular surface and improved fracture reduction. However, it is a technically demanding procedure with many challenges and pitfalls. The aim of this review is to summarize the current evidence regarding the treatment of glenoid fossa fractures and present the beneficial effect of arthroscopy in improving the quality of fracture fixation and overall functional outcomes.

Relationship between pectoralis major stiffness and shoulder extension range of motion

This study aimed to investigate the correlation between the passive muscle stiffness of the pectoralis major muscle pars clavicularis (PMc) and shoulder extension range of motion (ROM) in both male and female participants. Thirty-nine (23 male/16 female) physically active and healthy participants volunteered in this study. After a standardized warm-up, the PMc stiffness was tested via shear wave elastography at a slightly stretched position (long muscle length) and in a non-stretched position (short muscle length). Additionally, a custom-made device and 3D motion capture assessed the active shoulder extension ROM. We found a significant moderate and negative relationship between shoulder extension ROM and PMc stiffness at long muscle length (rs = -0.33; p = 0.04) but not at short muscle length (r = -0.23; p = 0.17). Additionally, there was no significant difference between male and female participants in the correlation analyses at both elbow angles. The moderate correlation between PMc stiffness at a slightly stretched position and shoulder extension ROM suggests that additionally, other structures such as nerves/fascia stiffness or even stretch tolerance might be factors that can be related to shoulder extension ROM.

[Shoulder-clinical introduction]

BACKGROUND

Radiological imaging plays a significant role in the diagnostics of shoulder pathologies. Based on a patient's medical history, physical examination and radiological imaging, it is possible to plan the further conservative or surgical treatment.

OBJECTIVES

Common pathologies of the shoulder and the correct radiological imaging are presented.

CONCLUSIONS

A rational and targeted use of radiological imaging, together with the medical history and physical examination allows correct diagnosis of pathologies of the shoulder joint.

[Pathologies of the shoulder joint : Anatomy and examination techniques]

CLINICAL ISSUE

The movements and stability of the human shoulder are a complex dynamic interaction between several joints, muscles and ligaments, which on the one hand enable extensive mobility and on the other hand must provide the necessary stability. Furthermore, the complexity of the shoulder is increased by a large number of normal variants. This article aims to explain the relevant anatomical structures and the radiological examination techniques necessary to visualize them.

STANDARD RADIOLOGICAL PROCEDURES

Various modalities contribute to the examination of the shoulder. These include X‑rays, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound.

METHODOLOGICAL INNOVATION

It is important to use the various procedures appropriately. Especially with MRI arthrography, it is necessary to pay attention to suitable sequences and possibly additional examination positions.

PRACTICAL RECOMMENDATION

The multimodal examination of the shoulder can contribute to the diagnosis of numerous clinical pictures. Anatomical and methodological foundations are essential for this.

Anterior-posterior glenohumeral translation in shoulders with traumatic anterior instability: a systematic review of the literature

Background

Reports of glenohumeral translation in shoulders with traumatic anterior instability have been presented. The aim of this systematic review was to investigate anterior-posterior translation in shoulders with traumatic anterior instability.

Methods

This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies including patients aged ≥15 years with previous traumatic anterior shoulder dislocation or subluxation were included. The outcome was anterior-posterior glenohumeral translation. A search of PubMed, Embase, and Cochrane library was performed on July 17, 2022. Two reviewers individually screened titles and abstracts, reviewed full text, extracted data, and performed quality assessment.

Results

Twenty studies (582 unstable shoulders in total) of varying quality were included. There was a lack of standardization and unity across studies. Radiography, ultrasound, computed tomography, magnetic resonance imaging, motion tracking, instrumentation, and manual testing were used to assess the glenohumeral translation. The glenohumeral translation in unstable shoulders ranged from 0.0 ± 0.8 mm to 11.6 ± 3.7 mm, as measured during various motion tasks, arm positions, and application of external force. The glenohumeral translation was larger or more anteriorly directed in unstable shoulders than in stable when contralateral healthy shoulders or a healthy control group were included in the studies. Several studies found that the humeral head was more anteriorly located on the glenoid in the unstable shoulders.

Conclusion

This systematic review provides an overview of the current literature on glenohumeral translation in traumatic anterior shoulder instability. It was not able to identify a threshold for abnormal translation in unstable shoulders, due to the heterogeneity of data. The review supports that not only the range of translation but also the direction hereof as well as the location of the humeral head on the glenoid seem to be part of the pathophysiology. Technical development and increased attention to research methodology in recent years may provide more knowledge and clarity on this topic in the future.

Safe and Effective Aspirations and Nerve Blocks for the On-Call Orthopaedic Surgeon

The on-call orthopaedic surgeon is faced with a wide array of orthopaedic pathology for which intra-articular aspiration, injection, and/or nerve/hematoma block may be used. Efficient use of these diagnostic and therapeutic modalities affords better patient care and a more effective on-call period. Often, these interventions are the rate limiting factor in a reduction or diagnosis. In this review, we describe joint aspirations, saline load tests, hematoma blocks, and nerve blocks in detail to include their indications, techniques, related pharmacology, pearls, and pitfalls.

Effects of a High-Volume 7-Week Pectoralis Muscle Stretching Training on Muscle Function and Muscle Stiffness

BACKGROUND

There is evidence that high-volume static stretching training of the lower limbs can increase the range of motion (ROM) while decreasing muscles stiffness. However, to date, there is no evidence on the effects of upper limb stretching training or its effect mechanism. Therefore, this study aimed to investigate the effects of a comprehensive 7-week static stretching training program of the pectoralis major muscle (PMa) on glenohumeral joint ROM, muscle force, and muscle stiffness.

METHODS

Thirty-eight healthy, physically active participants (23 male, 15 female) were randomly assigned to either the PMa-static stretching intervention (PMa-SS) group or the control group. The PMa-SS group performed a 7-week intervention comprising three sessions a week for 15 min per session, including three static stretching exercises of the PMa for 5 min each. Before and after the intervention period, shoulder extension ROM, muscle stiffness of the PMa (pars clavicularis), and maximal voluntary isometric contraction (MVIC) peak torque (evaluated at both long (MVIC_long) and short (MVIC_short) muscle lengths) were investigated on a custom-made testing device at 45° shoulder abduction.

RESULTS

In the PMa-SS group, the shoulder extension ROM (+ 6%; p < 0.01; d = 0.92) and the MVIC_long (+ 11%; p = 0.01; d = 0.76) increased. However, there were no significant changes in MVIC_short or in PMa muscle stiffness in the PMa-SS group. In the control group, no changes occurred in any parameter.

CONCLUSION

In addition to the increase in ROM, we also observed an improved MVIC at longer but not shorter muscle lengths. This potentially indicates an increase in fascicle length, and hence a likely increase in sarcomeres in series.

Anterior Bankart Repair With Superior Capsular Plication Causes Increased Mean Tension in Posterior Glenohumeral Capsule

Purpose

The purpose of this study is to investigate if a biomechanical difference exists in the prerepair and postrepair states of the posterior inferior glenohumeral ligament (PIGHL) following anterior Bankart repair with respect to capsular tension, labral height, and capsular shift.

Methods

In this study, 12 cadaveric shoulders were dissected to the glenohumeral capsule and disarticulated. The specimens were loaded to 5-mm displacement using a custom shoulder simulator, and measurements were taken for posterior capsular tension, labral height, and capsular shift. We measured the capsular tension, labral height, and capsular shift of the PIGHL in its native state and following repair of a simulated anterior Bankart lesion.

Results

We found that there was a significant increase in the mean capsular tension of the posterior inferior glenohumeral ligament (Δ = 2.12 ± 2.10 N; P = .005), as well as posterior capsular shift (Δ = .362 ± 0.365 mm; P = .018). There was no significant change in posterior labral height (Δ = 0.297 ± 0.667 mm; P = .193). These results demonstrate the sling effect of the inferior glenohumeral ligament.

Conclusion

Although the posterior inferior glenohumeral ligament is not directly manipulated during an anterior Bankart repair, when the anterior inferior glenohumeral ligament is plicated superiorly, some of the tension is transmitted to the posterior glenohumeral ligament as a result of the sling effect.

Clinical Relevance

Anterior Bankart repair with superior capsular plication results in an increased mean tension of the PIGHL. Clinically, this may contribute to shoulder stability.

Shoulder Dislocation Incidence and Risk Factors-Rural vs. Urban Populations of Poland

(1) Background: The aim of this study was to analyze the incidence of shoulder dislocation and to estimate non-modifiable risk factors in rural and urban subgroups in Poland. (2) Methods: The study covered the entire Polish population, divided into urban and rural subgroups and observed between 1 January 2014 and 31 December 2014. The study population consisted of Polish patients with a diagnosis of shoulder dislocation (S43.0) in accordance with the International Statistical Classification of Diseases and Related Health Problems (ICD-10). Records were obtained from the public health care provider National Health Found (Narodowy Fundusz Zdrowia, NFZ). Based on these data, we assessed shoulder dislocation incidence and risk rates, stratifying the study sample by sex, age and place of residence (rural or urban) using the Central Statistical Office (GUS) personal territorial code (TERYT). (3) The incidence was 25.97/100,000 person-years in rural areas and 25.62/100,000 person-years in urban areas. We did not find significant differences in the incidence between the two subgroups. The highest incidence (75.12/100,000 person-years) and the highest risk for shoulder dislocation were found among subjects 80+ years old living in urban areas. Furthermore, men in the third decade of their life living in urban areas showed the highest risk (OR = 7.8, 95% CI; 6.44-9.45, p < 0.001). In both subgroups, the likelihood of shoulder dislocation was significantly lower for the female sex and among children ≤9 years old. However, girls living in rural areas presented with a significantly higher likelihood for dislocation compared with their peers living in urban environments. (4) Conclusions: No significant difference in the incidence rate of shoulder dislocation between Polish residents living in rural and urban areas emerged. The highest incidence was observed among female subjects 80+ years old living in urban environments. The highest risk was found among men in the third decade of their life living in urban areas. In addition, girls in the first decade of their life living in rural areas had more shoulder dislocations than girls living in urban environments. Shoulder dislocation is dominant in female subjects aged 70-79 living in rural areas and in females 80+ years old living in urban areas.

Feasibility of High-Intensity Resistance Training Sessions in Cancer Survivors

ABSTRACT

Schlüter, K, Schneider, J, Rosenberger, F, and Wiskemann, J. Feasibility of high-intensity resistance training sessions in cancer survivors. J Strength Cond Res 36(9): 2643-2652, 2022-Moderate-intensity resistance training (MIRT) is regarded as safe in cancer survivors (CS), but for high-intensity resistance training (HIRT), evidence is lacking. Hence, in the current exploratory analyses, single sessions of HIRT are compared with MIRT regarding safety and feasibility. Twenty-three of 24 included CS (14 breast and 10 prostate CS, 61.6 ± 9.5 years, body mass index 27.0 ± 4.3 kg·m -2 , 6-52 weeks after end of primary therapy) started a 12-week resistance training (RT) with a daily undulating periodization model including HIRT (90% of 1 repetition maximum [1RM]) and MIRT (67% 1RM) sessions. Parameters of safety (adverse events [AEs] and training-related pain), feasibility (physical and mental exhaustion, sensation of effort, enjoyment, and dropout rate), and adherence were assessed. An alpha level of 0.05 was applied for analyses. Nineteen of 23 training starters (83%) completed all sessions. Fourteen minor AEs occurred. A significantly higher increase for physical exhaustion appeared in HIRT ( p < 0.001). For 18% (HIRT) and 19% (MIRT) of the sessions, training-related pain was reported with no significant difference between intensities. In total, 34% of HIRT and 35% of MIRT sessions were perceived as overstraining or partly overstraining with no significant difference between intensities, but enjoyment (median and quartiles on a 1-7 scale) was high for both (HIRT = 5 [5;6] and MIRT = 5 [4,6]). Our analysis indicates that HIRT sessions do not differ from MIRT sessions concerning safety or feasibility, but training-related pain should be monitored. RT protocols incorporating high-intensity training loads can be applied safely in breast and prostate CS.

Quantitative Muscle Analysis in FSHD Using Whole-Body Fat-Referenced MRI: Composite Scores for Longitudinal and Cross-Sectional Analysis

BACKGROUND AND OBJECTIVES

Facioscapulohumeral muscular dystrophy (FSHD) is a rare, debilitating disease characterized by progressive muscle weakness. MRI is a sensitive assessment of disease severity and progression. We developed a quantitative whole-body (WB) musculoskeletal MRI (WB-MSK-MRI) protocol analyzing muscles in their entirety. This study aimed to assess WB-MSK-MRI as a potential imaging biomarker providing reliable measurements of muscle health that capture disease heterogeneity and clinically meaningful composite assessments correlating with severity and more responsive to change in clinical trials.

METHODS

Participants 18 to 65 years, genetically confirmed FSHD1, clinical severity 2 to 4 (Ricci's scale, range 0-5), and ≥1 short tau inversion recovery (STIR)-positive lower extremity muscle eligible for needle biopsy enrolled at 6 sites; imaged twice 4 - 12 weeks apart. Volumetric analysis of muscle fat infiltration (MFI), muscle fat fraction (MFF), and lean muscle volume (LMV) in 18 (36 total) muscles from bilateral shoulder, proximal arm, trunk, and legs was performed after automated atlas-based segmentation followed by manual verification. A WB composite score, including muscles at highest risk for progression, and functional cross-sectional composites for correlation with relevant functional outcomes including timed up and go (TUG), FSHD-TUG, and reachable workspace (RWS) were developed.

RESULTS

Seventeen participants;16 follow-up MRIs performed at 52 days (range 36 to 85). Functional cross-sectional composites (MFF and MFI) showed moderate to strong correlations: TUG (rho=0.71, rho=0.83), FSHD-TUG (rho=0.73, rho=0.73), and RWS (left arm: rho=-0.71, rho=-0.53; right arm: rho=-0.61, rho=-0.65). WB composite variability:LMV_tot, coefficient of variation (CV) 1.9% and 3.4%; MFF_tot, within-subject standard deviation (S_w) 0.5% and 1.5%; MFI_tot, (S_w), 0.3% and 0.4% for normal and intermediate muscles respectively. CV and S_w were higher in intermediate (MFI≥0.10; MFF<0.50) than in normal (MFI<0.10, MFF<0.50) muscles.

DISCUSSION

We developed a WB-MSK-MRI protocol and composite measures that capture disease heterogeneity and assess muscle involvement as it correlates with FSHD-relevant clinical endpoints. Functional composites robustly correlate with functional assessments. Stability of the WB composite shows it could be an assessment of change in therapeutic clinical trials.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that quantitative WB-MSK-MRI findings associate with FSHD1 severity measured using established functional assessments.

A Gravity-Compensated Upper-Limb Exoskeleton for Functional Rehabilitation of the Shoulder Complex

In the last decade, several exoskeletons for shoulder rehabilitation have been presented in the literature. Most of these devices focus on the shoulder complex and limit the normal mobility of the rest of the body, forcing the patient into a fixed standing or sitting position. Nevertheless, this severely limits the range of activities that can potentially be simulated during the rehabilitation, preventing the execution of occupational therapy which involves the execution of tasks based on activities of daily living (ADLs). These tasks involve different muscular groups and whole-body movements, such as, e.g., picking up objects from the ground. To enable whole-body functional rehabilitation, the challenge is to shift the paradigm of robotic rehabilitation towards machines that can enable wide workspaces and high mobility. In this perspective, here we present Float: an upper-limb exoskeleton designed to promote and accelerate the motor and functional recovery of the shoulder joint complex following post-traumatic or post-surgical injuries. Indeed, Float allows the patient to move freely in a very large workspace. The key component that enables this is a passive polyarticulated arm which supports the total exoskeleton weight and allows the patient to move freely in space, empowering rehabilitation through a deeper interaction with the surrounding environment. A characterization of the reachable workspace of both the exoskeleton and the polyarticulated passive arm is presented. These results support the conclusion that a patient wearing Float can perform a wide variety of ADLs without bearing its weight.

Acute effects of doorway stretch on the glenohumeral rotational range of motion and scapular position in high-school baseball players

Background

Pectoralis minor tightness has been thought to affect the scapular position. Despite the wide implementation of doorway stretch in clinical practice owing to its apparent effectiveness in stretching the pectoralis minor, limited studies have investigated its influence on the glenohumeral rotational range of motion (ROM). This study aimed to examine the acute effects of doorway stretch on the glenohumeral rotational ROM and the correlation between the scapular position and ROM.

Materials and Methods

In total, 34 male high-school baseball players participated in this study. Outcomes included the pectoralis minor muscle length, glenohumeral rotational ROM, and scapular position. The distance between the sternocostal joint of rib 4 and the coracoid process was measured as the pectoralis minor length. Internal and external rotation ROM with the shoulder abducted at 90° were measured. The scapular position was defined by the following two measurements: the distance between the surface and the posterolateral corner of the acromion as well as the scapular index. The participants performed doorway stretch by abducting and externally rotating the shoulder at 90° and flexing the elbow at 90°. The outcomes were compared before and after stretching. Furthermore, the correlation between these changes was investigated.

Results

Pectoralis minor muscle length and glenohumeral internal rotation ROM was significantly higher after stretching than before, and the scapular position also significantly changed (P < .01 for both). A moderate correlation was found between the degree of change in the glenohumeral internal rotational ROM and scapular position (r = 0.44, P < .01).

Discussion

Our results indicated that doorway stretch significantly increased the pectoralis minor muscle length and glenohumeral internal rotation ROM and significantly altered the scapular position. Furthermore, a significant correlation between the degree of change in the scapular position and glenohumeral internal rotation ROM was observed. These results suggest that doorway stretch could be beneficial for improving the scapular position and glenohumeral internal rotation ROM, which are considered the cause of throwing injuries. Furthermore, the glenohumeral ROM may be affected by the scapular position.

The validity of using one force platform to quantify whole-body forces, velocities, and power during a plyometric push-up

Background

Previous studies have typically measured velocity and power parameters during the push-up, either using one or two force platforms. The purpose of the study was to compare the force, velocity, and power parameters between the one-force-platform method and the two-force-platform method during plyometric push-ups.

Methods

Thirty-four physically active young adults participated in the study to perform the plyometric push-up. For the two-force-platform calculation method, the forces applied to the feet and hands were both measured. For the one-force-platform calculation method, the forces applied to the feet were assumed to be constant, while the forces applied to hands were measured by one force platform. Whole-body linear velocities were calculated based on the impulse and momentum theorem. Whole-body power was calculated as the product of the whole-body forces and velocities.

Results

The one-force-platform method overestimated the whole-body velocities and power compared with the two-force-platform method (1.39 ± 0.37 m/s vs. 0.90 ± 0.23 m/s, Cohen’s d = 1.59, p < 0.05; 1.63 ± 0.47 W/body weight vs. 1.03 ± 0.29 W/body weight, Cohen’s d = 1.49, p < 0.05). These differences were caused by the decreased forces applied to the feet compared to the initial value throughout most of the push-up phase. Large to perfect correlations (r = 0.55 – 0.99) were found for most variables between the two-force-platform and one-force-platform methods. Previous findings of push-up velocities and power using the two-force-platform and one-force-platform methods should be compared with caution. While the two-force-platform method is recommended, linear regression equations may be used to predict velocities and power parameters obtained from one force platform.

Conclusions

For those professionals who need to accurately quantify kinetic variables during the plyometric push-up, the two-force-platform method should be considered.

Design and Development of an Upper Limb Rehabilitative Robot with Dual Functionality

The design of an upper limb rehabilitation robot for post-stroke patients is considered a benchmark problem regarding improving functionality and ensuring better human–robot interaction (HRI). Existing upper limb robots perform either joint-based exercises (exoskeleton-type functionality) or end-point exercises (end-effector-type functionality). Patients may need both kinds of exercises, depending on the type, level, and degree of impairments. This work focused on designing and developing a seven-degrees-of-freedom (DoFs) upper-limb rehabilitation exoskeleton called ‘u-Rob’ that functions as both exoskeleton and end-effector types device. Furthermore, HRI can be improved by monitoring the interaction forces between the robot and the wearer. Existing upper limb robots lack the ability to monitor interaction forces during passive rehabilitation exercises; measuring upper arm forces is also absent in the existing devices. This research work aimed to develop an innovative sensorized upper arm cuff to measure the wearer’s interaction forces in the upper arm. A PID control technique was implemented for both joint-based and end-point exercises. The experimental results validated both types of functionality of the developed robot.

Reliability and Validity of a Clinical Assessment Tool for Measuring Scapular Motion in All 3 Anatomical Planes

CONTEXT

A single clinical assessment device that can be used to objectively measure scapular motion in each anatomical plane is not currently available. The development of a novel electric goniometer would allow scapular motion in all 3 anatomical planes to be quantified.

OBJECTIVE

To investigate the reliability and validity of an electric goniometer for measuring scapular motion in each anatomical plane during upper extremity elevation.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Sixty participants (29 women, 31 men; age = 30 ± 14 years, height = 1.73 ± 0.10 m, mass = 75.32 ± 16.90 kg) recruited from the general population.

INTERVENTION(S)

An electric goniometer was used to record clinical measurements of scapular position at rest and total arc of motion (excursion) during active upper extremity elevation in 2 testing sessions separated by several days. Measurements were recorded independently by 2 examiners. In 1 session, scapular motion was recorded simultaneously using a 14-camera, 3-dimensional optical motion-capture system.

MAIN OUTCOME MEASURE(S)

Reliability analysis included examination of clinical measurements for scapular position at rest and excursion during each condition. Both the intrarater reliability between testing sessions and the interrater reliability recorded in the same session were assessed using intraclass correlation coefficients (ICCs [2,3]). The criterion validity was examined by comparing the mean excursion values of each condition recorded using the electric goniometer and the 3-dimensional optical motion-capture system. Validity was assessed by evaluating the average difference and root mean square error.

RESULTS

The between-sessions intrarater reliability was moderate to good (ICC [2,3] range = 0.628-0.874). The within-session interrater reliability was moderate to excellent (ICC [2,3] range = 0.545-0.912). The average difference between total excursion values recorded using the electric goniometer and the 3-dimensional optical motion-capture system ranged from -7° to 4°, and the root mean square error ranged from 7° to 10°.

CONCLUSIONS

The reliability of scapular measurements was best when a standard operating procedure was used. The electric goniometer provided an accurate measurement of scapular excursions in all 3 anatomical planes during upper extremity elevation.

"Current concepts and expert practice report: Augmentation of rotator cuff repairs"

Rotator cuff tears are common shoulder injuries expected to increase with the growth of the aging population. Although a small subset of patients with low functional demands can be treated nonoperatively, surgical intervention is a cost-effective solution, which can restore shoulder function and help patients return to activity sooner. While multiple surgical options are available, rotator cuff repair is a highly utilized procedure with varying success. Due to a large proportion of rotator cuff repairs still failing to completely heal, this procedure requires careful planning to achieve anatomical and biomechanically stability. New technology and techniques are being explored to help increase the success of rotator cuff repairs with an increasing focus on augmentation. The current article gives a brief overview of pertinent anatomy, treatment options, and challenges in healing of rotator cuff repairs. Thereafter, the merits of different types of rotator cuff repair augmentation available will be discussed as well as the authors' experience in utilizing biologic augmentation and surgical technique.

Use of Gracile and semi-tendinosus tendons (GRAST) for the reconstruction of irreparable rotator cuff tears

Background

Irreparable rotator cuff tears are common and difficult to treat. Techniques for “filling the loss of substance” require fixation to the rotator cuff stump (tendon augmentation) or to the glenoid (superior capsular reconstruction), which are complicated by the narrow working zone of the subacromial space. The main objective of this study was to determine whether a braided graft of gracilis (GR) and semitendinosus (ST) could fill a loss of tendon substance from an irreparable rupture of the supra- and infraspinatus, by fixing the graft to the greater tuberosity and the spine of the scapula.

Methods

This was a cadaveric study with the use of ten specimens. The GRA and ST tendons were harvested, braided and reinforced with suture. An experimental tear of the supraspinatus (SS) and upper infraspinatus (IS) retracted at the glenoid was made. The GRAST transplant was positioned over the tear. The transplant was attached to the greater tuberosity by two anchors and then attached to the medial third of the scapular spine by trans-osseous stitching. The percentage of filling obtained was then measured and passive mobility of the shoulder was assessed. We proceeded to the same technique under arthroscopy for a 73 years old patient whom we treated for a painful shoulder with irreparable cuff tear. We inserted a GRAST graft using arthroscopy.

Results

The Braided-GRAST allowed a 100% filling of the loss of tendon substance. Mobility was complete in all cases.

Conclusion

This technique simplifies the medial fixation and restores the musculo-tendinous chain where current grafting techniques only fill a tendinous defect. The transplant could have a subacromial “spacer” effect and lower the humeral head. The donor site morbidity and the fate of the transplant in-vivo are two limits to be discussed. This anatomical study paves the way for clinical experimentation.

Dispersion of shoulder helical axes during upper limb movements after muscle fatigue

Shoulder complex control of motion is influenced by neuromuscular function and can be quantified through the analysis of helical axes (HAs) dispersion. Muscle fatigue is a variable able to influence neuromuscular control, altering muscle activation timing and proprioception. The aim of the study was to describe shoulder complex HAs dispersion after muscle fatigue during upper limb movements of young healthy subjects. Thirty healthy right-handed volunteers (age 23.2 ± 2.6 years) were asked to perform a test made up of 15 humerothoracic flexion and rotation movements using both upper limbs in two different recording sessions. After each session, muscles of the tested movement were fatigued in isometric condition at dominant side. After fatigue, subjects repeated the test. Kinematics was recorded by an optoelectronic system and HAs dispersion was computed using Mean Distance (MD) and Mean Angle (MA) for the entire Range of Motion (RoM) and in portions of RoM. After fatigue of shoulder flexion muscles, greater MD (p = 0.001) and MA (p = 0.019) were found on the dominant side. After fatigue of shoulder rotation muscles, greater MD and MA were found on the dominant (p = 0.002 for MD; p = 0.047 for MA) and non-dominant (p = 0.038 for MD; p = 0.019 for MA) sides. Independently of fatigue, greater MA was found in portions of RoM with higher external resistance torque in flexion and rotation tasks. Muscle fatigue increases shoulder complex HAs dispersion, probably due to alteration in neuromuscular control. This data should be considered when exercise involving upper arms are proposed to subjects undergoing fatigue.

Helical axis analysis to quantify humeral kinematics during shoulder rotation

Information pertaining to the helical axis during humeral kinematics during shoulder rotation may be of benefit to better understand conditions such as shoulder instability. The aim of this study is to quantify the behavior of humeral rotations using helical axis (HA) parameters in three different conditions. A total of 19 people without shoulder symptoms participated in the experiment. Shoulder kinematics was measured with an optoelectric motion capture system. The subjects performed three different full range rotations of the shoulder. The shoulder movements were analyzed with the HA technique. Four parameters were extracted from the HA of the shoulder during three different full-range rotations: range of movement (RoM), mean angle (MA), axis dispersion (MDD), and distance of their center from the shoulder (D). No significant differences were observed in the RoM for each condition between left and right side. The MA of the axis was significantly lower on the right side compared to the left in each of the three conditions. The MDD was also lower for the right side compared to the left side in each of the three conditions.The four parameters proposed for the analysis of shoulder kinematics showed to be promising indicators of shoulder instability.

Reliability of Clinical Assessment Methods to Measure Scapular Upward Rotation: A Critically Appraised Topic

Clinical Scenario: Assessing movement of the scapula is an important component in the evaluation and treatment of the shoulder complex. Currently, gold-standard methods to quantify scapular movement include invasive technique, radiation, and 3D motion systems. This critically appraised topic focuses on several clinical assessment methods of quantifying scapular upward rotation with respect to their reliability and clinical utility. Clinical Question: Is there evidence for noninvasive methods that reliably assess clinical measures of scapular upward rotation in subjects with or without shoulder pathologies? Summary of Key Findings: Four studies were selected to be critically appraised. The quality appraisal of diagnostic reliability checklist was used to score the articles on methodology and consistency. Three of the 4 studies demonstrated support for the clinical question. Clinical Bottom Line: There is moderate evidence to support reliable clinical methods for measuring scapular upward rotation in subjects with or without shoulder pathology. Strength of Recommendation: There is moderate evidence to suggest there are reliable clinical measures to quantify scapular upward rotation in patients with or without shoulder pathology.

Overuse Injuries of the Shoulder

This article discusses the most common and important overuse injuries of the shoulder with attention to MR imaging and ultrasound findings. Pathologic conditions occurring in athletes and nonathletes are included, with review of relevant anatomy, predisposing factors, and treatment considerations. Specific overuse injuries involving the rotator cuff, long head of the biceps tendon, and subacromial-subdeltoid bursa are reviewed. Impingement syndromes of the shoulder, Little Leaguer's shoulder, and stress-induced distal clavicular osteolysis are also discussed.

Dispersion of helical axes during shoulder movements in young and elderly subjects

The shoulder complex (SC) consists of joints with little congruence and its active and passive structures ensure its stability. Stability of the SC rotation centre during upper arm movements can be estimated through the analysis of Helical Axes (HAs) dispersion. The aim of this study was to describe shoulder HAs dispersion during upper limb movements performed with dominant and non-dominant arms by young and elderly subjects. Forty subjects participated in the study (20 young: age 24.8 ± 2.8 years and 20 elderly: age 71.7 ± 6.3 years). Subjects were asked to perform four cycles of 15 rotations, flexions, elevations and abductions with one arm at a time at constant speed. Reflective markers were placed on participants' arms and trunk in order to detect movements and the HAs dispersion with an optoelectronic system. Mean Distance (MD) from the HAs barycenter and Mean Angle (MA) were used as HAs dispersion indexes. Young subjects showed significant lower MD compared to the elderly during all motion ranges of rotation, flexion and elevation (p < 0.001). Moreover, the MD was lower in the dominant arm compared to the contralateral for rotation (p = 0.049) and flexion (p = 0.019). The results may be due to joint degeneration described in elderly subjects and differences in neuromuscular control of SC stability.

MR arthrographic characterization of posterior capsular folds in shoulder joints

METHODS:

This was a retrospective study of 604 consecutive shoulder MR images and MR arthrograms obtained from April 2010 to January 2018. Extension in the vertical-oblique plan of the posterior synovial fold on MR arthrography was identified according to the posterosuperior, posteroinferior, superoposterior, and inferoposterior portions. The morphologies of the posterior synovial folds on MR arthrography were divided three subtypes. Morphologic appearances of the posterior labrocapsular complex on conventional MR images were described with four subtypes.

RESULTS:

A posterior synovial fold in the shoulder joint was identified in 35 of 604 (5.8%) MR arthrography patients. 8 of 35 posterior synovial fold identified on MR arthrography were confirmed at arthroscopy. The most common MR arthrographic type of the posterior synovial fold was triangular-this was detected in 17 of 35 (48.6%) patients. The most common MRI morphology of the posterior labrocapsular complex was doubled posterior labrum. This was detected in 15 of 35 (42.9%) patients. 17 % of patients with posterior synovial folds who were diagnosed with MR arthrography had normal MRI features. The most common localization of the posterior synovial fold was posterosuperior and posteroinferior portions of the posterior labrocapsular structures. The mean of the shortest distance between the posterior synovial fold and the posterior labrum was significantly higher in the positive arthroscopic synovial fold group than in the negative arthroscopic synovial fold group (p = 0.047).

CONCLUSION:

Posterior synovial folds, normal capsular anatomic variants, are seen rarely on MR arthrography, and tend to be in the posterosuperior and posteroinferior portions of the posterior capsule. Some types of the posterior synovial fold can mimic a posterior labral tear in conventional MRI.

ADVANCES IN KNOWLEDGE:

On a direct MR arthrographic image, a posterior capsular synovial fold may be a normal anatomic variant. A fold is more commonly occur in the posterosuperior and posteroinferior capsular portions. The results of our study may allow differentiation of normal variations from abnormalities in patients with symptomatic shoulder joint.

Biomechanics of posterior shoulder instability - current knowledge and literature review

Posterior instability of the shoulder is a rare condition and represents about 10% of shoulder instability. It has become more frequently recognized in the last year, even though it is more difficult to diagnose than anterior shoulder instability. As this form of shoulder pathology is somewhat rare, biomechanical knowledge is limited. The purpose of our study was to perform an extensive literature search, including PubMed and Medline, and to give an overview of the current knowledge on the biomechanics of posterior shoulder instability. The PubMed/Medline databases were utilized, and all articles related to posterior shoulder instability and biomechanics were included to form a comprehensive compilation of current knowledge. A total of 93 articles were deemed relevant according to our inclusion and exclusion criteria. As expected with any newly acknowledged pathology, biomechanical studies on posterior shoulder instability remain limited in the literature. Current biomechanical models are performed in a static manner, which limits their translation for explaining a dynamic pathology. Newer models should incorporate dynamic stabilization of both the rotator cuff and scapulothoracic joint. There is a current lack of knowledge with regards to the pathomechanism of posterior shoulder instability, with no consensus on appropriate treatment regimens. Further investigation is therefore required at both basic science and clinical levels.

Axillary Sonography of the Shoulder: An Adjunctive Approach

Sonography of the shoulder is widely used to assess various disorders, including tendinous diseases of the rotator cuff and the long head of the biceps brachii muscle. The shoulder is commonly explored through anterior, superior, and posterior approaches, but the inferior axillary approach is rarely considered in the literature. However, this technique allows the direct visualization of relevant anatomic structures. The aim of this pictorial essay is, first, to technically describe this approach and the normal musculoskeletal sonographic anatomy of the region and, second, to present the sonographic findings of shoulder disorders that may be helpfully explored this technique.

Improved RBF network torque control in flexible manipulator actuated by PMAs

A Pneumatic Muscle Actuator (PMA) is a new pneumatic component sharing similar characteristics with biological muscles, and the flexible manipulator actuated by PMAs can better reflect the flexibility of the mechanism. First and foremost, based on the study of the characteristics of human shoulder joints, the configuration design of the flexible manipulator is analyzed, and its kinematics and dynamics models are established. Furthermore, with regard to the nonlinearity, time-invariance and uncertainty of the control system, three aspects of improvement are proposed, which are based on the Radial Basis Function (RBF) network torque control algorithm. The Genetic Algorithm is used to optimize the initial values of RBF network parameters; RBF network parameters are adjusted dynamically by using the additional momentum method; the Levenberg--Marquardt (LM) algorithm, instead of the gradient descent method, is adopted to adjust Proportion Integration Differentiation (PID) parameters online in real time. At last, to test the effects that the improved algorithm exerts on the flexible manipulator control system, some physical platform experiments are carried out. It turns out that the control accuracy and robustness of the improved algorithm are well improved, and the mechanism can be controlled better to track the circular arc trajectory. It lays fundamental importance to the practical application for the working environment.

Traumatic Instability: Treatment Options and Considerations for Recurrent Posttraumatic Instability

Recurrent traumatic glenohumeral instability is a complex problem with multiple variables to consider, but patient demographics, activities, as well as clinical and radiographic findings provide significant information to help choose the best treatment option. Although nonoperative treatment is a viable option for primary glenohumeral instability and in-season instability, recurrent instability exhibits anatomic factors which render nonsurgical treatment limited in scope. A proper patient history, clinical examination, and standard and advanced imaging are necessary in the assessment of patients with recurrent traumatic instability. Age, activity, hypermobility, tissue quality, glenoid and humeral head bone stock, and any prior surgical treatment are factors that must be considered for surgical planning. Open and arthroscopic Bankart repairs are good surgical options when bone loss is not an issue but increasing glenoid or humeral osseous deficiency in this setting frequently warrants additional procedures which address bony insufficiency. Controversy remains concerning the threshold value for glenoid bony deficiency and combined, bipolar defects, but this critical number may be less than previously suspected. Despite this controversy, successful surgical treatment of recurrent glenohumeral instability is possible when properly assessed and the correct surgery applied.

Time to peak torque and acceleration time are altered in male patients following traumatic shoulder instability

BACKGROUND

Numerous authors have evaluated the strength of the rotator cuff muscles in patients with shoulder instability. However, only limited data are available with regard to neuromuscular control in patients with traumatic anterior shoulder instability, in particular at 90° of abduction. This study was designed to assess muscle strength and neuromuscular control ability using time to peak torque and acceleration time in nonathletic patients with traumatic anterior shoulder instability.

METHODS

Isokinetic muscle performance testing was performed in 20 male nonathletic anterior shoulder instability patients compared with 20 side-matched asymptomatic volunteers. Isokinetic muscle performance testing was performed at an angular velocity of 180°/s with 90° of shoulder abduction. Muscle strength and neuromuscular control (time to peak torque and acceleration time) of the internal rotators (IRs) and external rotators (ERs) were measured.

RESULTS

There were no significant differences in muscle strength of the IRs and ERs between the 2 groups. The injured shoulder showed delayed neuromuscular control in both the IRs and ERs in the instability patients compared with the normal control subjects (time to peak torque, P = .023 for IRs and P = .020 for ERs; acceleration time, P = .035 for IRs and P = .021 for ERs).

CONCLUSION

The neuromuscular control of both the IRs and ERs was decreased in male nonathletic patients with traumatic anterior shoulder instability even though muscle strength was not altered. Therefore, clinicians and therapists should implement exercises that aim to restore neuromuscular control in the rehabilitation of nonathletic patients with anterior shoulder instability.

Thoracic Outlet Syndrome: Biomechanical and Exercise Considerations

Thoracic outlet syndrome (TOS) describes a group of disorders that are due to a dynamic compression of blood vessels or nerves, between the clavicle and first rib or cervical vertebral nerve roots. Individuals with TOS typically experience upper limb pain, numbness, tingling, or weakness that is exacerbated by shoulder or neck movement. The causes of TOS vary, and can include abrupt movements, hypertrophy of the neck musculature, and anatomical variations in which the brachial plexus roots pass through this musculature, edema, pregnancy, repeated overhead motions, the blockage of an artery or vein, or abnormal posture. To understand the complexity of this condition, an analysis of shoulder anatomy and mechanics are needed to help describe limitations and the subsequent pathophysiology of TOS. Several treatment options are available, including surgery, medications, and exercise. A comprehensive study of shoulder anatomy and biomechanics, and knowledge of the benefits of exercise, may help clinicians and healthcare practitioners determine the most appropriate treatment plan for an individual with TOS.

Anatomical and biomechanical framework for shoulder arthroplasty rehabilitation

This article provides an anatomical and biomechanical framework for the postoperative management and progression of treatment for shoulder arthroplasty. The clinical relevance of normal shoulder anatomy, biomechanics, and pathomechanics related to this surgery is emphasized to provide the reader with an understanding of the rationale for treatment. We review the rehabilitation implications of surgical indications and technique for both traditional total shoulder arthroplasty and reverse total shoulder arthroplasty procedures with an emphasis on biomechanical considerations. Relevant factors that affect rehabilitation outcomes are discussed along with supporting evidence from the literature. Principles to guide and progress treatment are highlighted with a discussion on return to sports with the ultimate objective of providing a comprehensive approach for successful rehabilitation.

Comparison of the Efficiency of Ultrasound-Guided Injections of the Rhomboid Major and Trapezius Muscles in Myofascial Pain Syndrome: A Prospective Randomized Controlled Double-blind Study

OBJECTIVES

We aimed to investigate the effect of ultrasound (US)-guided injections of the rhomboid major (deep) and trapezius (superficial) muscles on pain, disability, and quality of life in patients with myofascial pain syndrome.

METHODS

In this prospective randomized controlled double-blind study, 65 patients with a diagnosis of myofascial pain syndrome were randomized into 2 groups. In group 1 (n = 33), US-guided rhomboid major muscle injection was performed, and in group 2 (n = 32), US-guided trapezius muscle injection was performed. The patients were assessed by a visual analog scale for pain, the Pressure Pain Threshold, the Neck Pain and Disability Scale, and Short Form 12. Data were obtained before treatment (week 0), the second week after treatment, and the fourth week after treatment.

RESULTS

In both groups, significant improvements were observed for all parameters at both weeks 2 and 4 compared to pretreatment values (P < .05). A comparison of the groups showed significantly superior results in group 1 for all parameters at week 2 (P < .05) and for all parameters but the Physical Component Scale of Short Form 12 at week 4 (P < .05).

CONCLUSIONS

We think that US-guided deep injection of the rhomboid major muscle was more effective than superficial injection of the trapezius muscle for pain, disability, and quality of life in patients with myofascial pain syndrome.

Effect of flexibility deficit on scapular asymmetry in individuals with and without shoulder pain

BACKGROUND

Many studies have investigated the relationship between soft tissue tightness and shoulder kinematics. However, there is a lack of information on the dynamic properties responsible for side-to-side differences such as scapular asymmetry.

OBJECTIVE

To determine the relationship between a deficit in soft tissue flexibility and scapular asymmetry.

METHODS

A total of 58 individuals (29 patients with shoulder pain and 29 asymptomatic participants) were enrolled. Bilateral shortening of the pectoralis minor muscle and posterior shoulder tightness were assessed. Additionally, side-to-side flexibility deficit was calculated. Scapular kinematics were measured with an electromagnetic tracking device while individuals were standing in a resting position and during arm elevation. The symmetry angle was calculated to quantify scapular asymmetry.

RESULTS

The pectoralis minor and the posterior capsule flexibility deficit showed a significant positive relationship with the symmetry angle in the resting position separately for both asymptomatic (r=0.47, r=0.37 relatively) and symptomatic groups (r=0.58, r=0.38 relatively), indicating that the increased deficit in the pectoralis minor and posterior capsule flexibility were associated with increased scapular asymmetry. However, no significant relationship was found between flexibility deficit and scapular asymmetry during arm elevation and lowering for both asymptomatic and symptomatic groups.

CONCLUSION

The findings of the study provided information on the relationship of a flexibility deficit on the scapular position and orientation in asymptomatic and symptomatic populations.

Development of the human shoulder joint during the embryonic and early fetal stages: anatomical considerations for clinical practice

Although several studies have been published regarding the morphology and anatomical variations of the human shoulder joint, most have dealt with adult individuals. Those looking into the development of the joint have been focused on specific structures or have observed specimens in advanced gestational stages. The goal of this paper is to perform a complete analysis of the embryonic and early fetal development of the elements in the shoulder joint, and to clarify some contradictory data in the literature. In our study, serial sections of 32 human embryos (Carnegie stages 16-23) and 26 fetuses (9-13 weeks) were analyzed. The chondrogenic anlagen of the humerus and the medial border of the scapula can be observed from as early as Carnegie stage 17, whereas that of the rest of the scapula appears at stage 18. The osteogenic process begins in week 10 for the humeral head and week 11 for the scapula. At stage 19 the interzone becomes apparent, which will form the glenohumeral joint. In the next stage the glenohumeral joint will begin delaminating and exhibiting a looser central band. Denser lateral bands will join the humeral head (caput humeri) and the margins of the articular surface of the scapula, thus forming the glenoid labrum, which can be fully appreciated by stage 22. In 24-mm embryos (stage 21) we can observe, for the first time, the long head of the biceps tendon (which is already inserted in the glenoid labrum by week 9), and the intertubercular sulcus, whose depth is apparent since week 12. Regarding ligamentous structures, the coracohumeral ligament is observed at the end of Carnegie stage 23, whereas the primitive glenohumeral ligament already appeared in week 10. The results of this study provide a detailed description of the morphogenesis, origin and chronological order of appearance of the main intrinsic structures of the human shoulder joint during late embryonic and early fetal development. We expect these results to help explain several functional aspects of the shoulder joint, and to clarify some contradictory data in the literature regarding this complex anatomical and biomechanical structure, helping future researchers in their efforts.

Dynamic and static shoulder strength relationship and predictive model

Static strength is typically used to standardize occupational tasks in an effort to limit over-exertion injuries; however, workplace tasks are commonly dynamic in nature. The purpose of this investigation was to assess factors influencing isokinetic shoulder strength and to develop predictive equations for isokinetic shoulder flexion and extension strength using isometric strength. Fifteen women performed a set of concentric isokinetic and isometric shoulder flexion and extension maximal exertions across a series of movement planes, angular velocities, and grip types. Data were used to generate two stepwise multiple regression models for predicting isokinetic shoulder flexion and exertion strength across the various exertion parameters. The final regression models explained a high degree of variance in predicting isokinetic shoulder flexion (R² = 0.59) and extension (R² = 0.67) with a subset of four and five inputs, respectively. The predictive equations can help establish acceptable force limits for workplace tasks requiring dynamic actions using more easily attainable static forces.

Electromyographic Analysis of the Shoulder Girdle Musculature During External Rotation Exercises

Background:

Implementation of overhead activity, a key component of many professional sports, requires an effective and balanced activation of the shoulder girdle muscles, particularly during forceful external rotation (ER) motions.

Purpose:

To identify activation strategies of 16 shoulder girdle muscles/muscle segments during common shoulder ER exercises.

Study Design:

Descriptive laboratory study.

Method:

Thirty healthy subjects were included in this study, and 16 shoulder girdle muscles/muscle segments were investigated (surface electrode: anterior, middle, and posterior deltoid; upper, middle, and lower trapezius; serratus anterior; teres major; upper and lower latissimus dorsi; and upper and lower pectoralis major; fine wire electrodes: supraspinatus, infraspinatus, subscapularis, and rhomboid major) using a telemetric electromyography (EMG) system. Five ER exercises (standing ER at 0° and 90° of abduction, with underarm towel roll, prone ER at 90° of abduction, side-lying ER with underarm towel) were studied. Exercise EMG amplitudes were normalized to EMG at maximum ER force in a standard position. Univariate analysis of variance and post hoc analysis applied on EMG activity of each muscle were used to assess the main effect of the exercise condition.

Results:

Muscular activity differed significantly among the ER exercises (P < .05 to P < .001). The greatest activation for anterior and middle deltoid, supraspinatus, upper trapezius, and serratus anterior occurred during standing ER at 90° of abduction; for posterior deltoid, middle trapezius, and rhomboid during side-lying ER with underarm towel; for lower trapezius, upper and lower latissimus dorsi, subscapularis, and teres major during prone ER at 90° of abduction; and for the clavicular and sternal part of the pectoralis major during standing ER with underarm towel.

Conclusion:

Key glenohumeral and scapular muscles can be optimally activated during specific ER exercises, particularly in positions that stimulate athletic overhead motions.

Clinical Relevance:

These results enable sports medicine professionals to target specific muscles during shoulder rehabilitation protocols while minimizing the effect of others, providing a foundation for optimal evidence-based exercise prescription. They also provide information for tailored muscle training and injury prevention in overhead sports.

Upper extremity 3-dimensional reachable workspace analysis in dystrophinopathy using Kinect

INTRODUCTION

An innovative upper extremity 3-dimensional (3D) reachable workspace outcome measure acquired using the Kinect sensor is applied toward Duchenne/Becker muscular dystrophy (DMD/BMD). The validity, sensitivity, and clinical meaningfulness of this novel outcome measure are examined.

METHODS

Upper extremity function assessment (Brooke scale and NeuroQOL questionnaire) and Kinect-based reachable workspace analyses were conducted in 43 individuals with dystrophinopathy (30 DMD and 13 BMD, aged 7-60 years) and 46 controls (aged 6-68 years).

RESULTS

The reachable workspace measure reliably captured a wide range of upper extremity impairments encountered in both pediatric and adult, as well as ambulatory and non-ambulatory individuals with dystrophinopathy. Reduced reachable workspaces were noted for the dystrophinopathy cohort compared with controls, and they correlated with Brooke grades. In addition, progressive reduction in reachable workspace correlated directly with worsening ability to perform activities of daily living, as self-reported on the NeuroQOL.

CONCLUSION

This study demonstrates the utility and potential of the novel sensor-acquired reachable workspace outcome measure in dystrophinopathy.

Three-dimensional analysis versus goniometric measurement of total active elevation in normal subjects

BACKGROUND

Multiple planes of motion have been reported for shoulder elevation performed by visual inspection with a goniometer. It is typically measured by a clinician who is standing or sitting at the side of the patient. Instead, accurate assessment of shoulder elevation must be performed by using a plane of reference that is perpendicular to the plane of motion being measured.

METHODS

Three repetitions of humeral elevation in the sagittal, scapular, and coronal planes were performed in a random order and measured by goniometry and three-dimensional (3D) electromagnetic sensors. A guide bar was used to control the initial plane of motion for the sagittal and coronal planes. The plane of motion at 90° and at peak elevation was recorded for each of the 3 defined planes. A goniometer was used to measure the range of maximal elevation performed in each plane, for each subject, by visual inspection.

RESULTS

The 3D data revealed that subjects consistently moved toward scaption as the extremity moved above 90° of elevation, regardless of the initial plane of motion. Significant differences were seen in the goniometric data for the plane of motion at 90° (P = .00) in flexion, abduction, and scaption. Goniometric measurements revealed greater maximum elevation angles in comparison to the 3D kinematic measurements.

CONCLUSIONS

Maximal glenohumeral elevation occurred near the plane of the scapula in all subjects, regardless of the plane in which elevation was initiated. Goniometric measurement of total elevation resulted in greater range of motion measurements than actually occurred because the observer was not routinely positioned in a plane perpendicular to the plane of actual elevation of the upper extremity.

Morphology of the humeral insertion of the supraspinatus and infraspinatus tendons: Application to rotator cuff repair

In shoulder surgery, a precise understanding of anatomical relationships is required for accurate reconstruction. Reports in recent literature have challenged the traditional definitions of the humeral footprints of the supraspinatus and infraspinatus tendons. This study aims to precisely delineate these footprints. The rotator cuffs of 54 shoulders from 27 Australian Caucasoid donor cadavers were examined. The tendinous portions were dissected down to their region/footprint of attachment upon the humerus. Measurements of those footprints, upon the greater and lesser tuberosities, were made. Those measurements were statistically analyzed for any association with age, sex, height, or side. Twenty-seven cadavers had an average age at death of 74.9 (± 12.8), 56% were male, average height was 168 (± 8.6) cm. Due to premorbid fracture, or degeneration, 11 shoulders were excluded. The footprint of the supraspinatus was triangular, with a medial, anteroposterior length of 20.4 ± 4.2 mm. Its lateral anteroposterior length was 6.3 ± 1.6 mm and its maximal mediolateral width was 6.6 ± 2.7 mm. Its calculated area was 122.0 ± 66.6 mm(2). The footprint of the infraspinatus was trapezoidal, with a medial anteroposterior length 22.6 ± 3.0 mm. Its lateral anteroposterior length was 25.4 ± 3.3mm and its maximal mediolateral width was 12.0 ± 2.7 mm. Its calculated area was 294.9 ± 74.1 mm(2). There was no statistical correlation between size of the footprint and age, sex, side, or height. The humeral footprints of the supraspinatus and infraspinatus tendons upon the greater tuberosity were distinct. The lateral border of the infraspinatus' humeral attachment extended much farther anteriorly upon the highest facet of the greater tuberosity than in traditional descriptions.

The external rotation immobilisation does not reduce recurrence rates or improve quality of life after primary anterior shoulder dislocation: a systematic review and meta-analysis

PURPOSE

Conducting a systematic review and meta-analysis of prospective randomised controlled trials directly comparing (1) the rates of recurrence and (2) patient-based quality-of-life assessments after the external rotation (ER) or internal rotation (IR) immobilisation after primary anterior shoulder dislocation.

METHODS

PubMed, EMBASE, the Cochrane Library and ISI Web of Science were searched up to January 2013, using the Boolean operators as follows: (bankart lesion OR shoulder anterior dislocation) AND ((external rotation AND internal rotation) OR immobilisation). All prospective randomised controlled trials directly comparing recurrence rate and patient-based quality-of-life assessments between the ER and IR immobilisations were retrieved. No limitation of the language or publication year existed in our analysis.

RESULTS

Seven of 896 studies involving 663 patients were included, 338 in the ER group and 325 in the IR group. No significant difference was observed in the recurrence rate at all ages (risk ratio (RR)=0.65; 95% confidence interval, 0.41-1.03; p=0.067), at the age stratum of ≤30 years (RR=0.70; 95% confidence interval, 0.38-1.29; p=0.250) and >30 years (RR=0.86; 95% confidence interval, 0.38-1.97; p=0.722). Four trials adopted quality-of-life assessments, using the Constant-Murlay functional scoring system, the Rowe scoring system, the Western Ontario Shoulder Instability index (WOSI), the Disabilities of arm, shoulder and hand (DASH) and the American Shoulder and Elbow Surgeons evaluation form (ASES). Only one trial demonstrated borderline statistical significance (p=0.05) and probable superiority of the ER group based on the ASES. No significant difference was observed in other three trials.

CONCLUSION

Based on the results of our analysis, the ER immobilisation could not reduce the rates of recurrence after primary anterior shoulder dislocation or improve the quality of life compared with the IR immobilisation. More rigorous and adequately powered prospective randomised controlled trials with long-term follow-ups are required to elucidate a more objective outcome.

Morphometric analysis of the association of primary shoulder reconstruction procedures with scapular growth in obstetric brachial plexus paralysis patients

BACKGROUND

Obstetric brachial plexus paralysis (OBPP) has been associated with shoulder deformities, scapular growth, and shoulder function impairment. The absence of balanced muscular forces acting on the scapula has been considered responsible for scapula dysplasia and impaired growth as compared with the normal side. Scapula growth impairment may also lead to shoulder and upper extremity dysfunction. This study aims at showing the association of primary nerve reconstruction with the restoration of scapular bone growth potential.

METHODS

This is a retrospective review of 73 patients with OBPP who underwent primary shoulder reconstruction. Patients were categorized for assessment and analysis into group A, global paralysis; group B, Erb's palsy; and group C, Erb's palsy with C7 root involvement. Scapular posteroanterior and lateral X-rays were obtained in which four scapula dimensions were manually measured. The growth discrepancy depending on the applied treatment was investigated.

RESULTS

The highest improvement was noted in scapular height in the Erb's palsy group who underwent simultaneous neurotization of the suprascapular and axillary nerves. The oblique axis was more improved in the Erb's palsy group while both big and small widths were more improved in the Erb's palsy with C7 root involvement group in patients who underwent concomitant neurotization of the suprascapular and the axillary nerves. Functional improvement correlated positively with growth improvement in all groups and scapular dimensions.

CONCLUSION

Scapula growth and shoulder function improvement were higher in patients with Erb's palsy. Simultaneous axillary and suprascapular nerve neurotization provided the best outcome in both functional and growth restoration.

Morphometric analysis of the effect of scapula stabilization on obstetric brachial plexus paralysis patients

BACKGROUND

Scapular position and size deficiency is evident in obstetric brachial plexus paralysis (OBPP) patients due to the absence of balanced muscular forces acting on the scapula. Scapula stabilization (SS) procedures aim to restore a balanced musculature and anatomic position and to augment shoulder function and enhance developmental potential.

METHODS

Retrospective chart review of 106 patients with OBPP between March 1979 and March 2007 was performed. Forty-one female and 27 male were included in the study. In 38 patients, the paralysis was global, 13 had Erb's paralysis with C7 root involvement; in 18 patients, the lesion was limited to C5 and C6. X-rays were evaluated, and scapula dimensions were manually measured at several stages. Shoulder abduction (SA) and external rotation (SER) outcomes were also recorded.

RESULTS

Mean improvement was 85.68° in shoulder abduction and 36.74° in shoulder external rotation. SA and SER improvement was significantly better in those who underwent SS procedures compared to those who did not (mean improvement was increased by 9.15° and 8.54°, respectively). Improvement was noted in all scapular dimensions, in all groups, postoperatively. However, the mean improvement in scapular height, big width, small width, and oblique axis discrepancies was 4.92, 14.04, 12.66, and 13.89 %, respectively, higher in patients who underwent SS procedures compared to those who did not.

CONCLUSION

Dimensional discrepancies and functional outcomes are improved by SS procedures. Maximal results are attained in patients who have undergone both primary and secondary shoulder reconstruction before age 2.