The goal of this thesis is to use biomechanical data describing shoulder motion to determine optimal parameters to assist in the design of a 5 DOF active shoulder exoskeleton. This thesis will provide a proof of concept on optimization techniques using motion data using a simplified 3 DOF model to facilitate future work implementing a full 5 DOF model. Optimization will be performed to determine the link lengths and, consequently, the locations of the joints of the exoskeleton by considering the human's workspace to maximize range of motion and promote user safety by minimizing collisions of the exoskeleton with the user and with the exoskeleton itself. The thesis will detail the development of computational models of the human and proposed exoskeleton, the processing of experimental data used to estimate the human's capabilities, optimization, and future work. This work will contribute to a large-scale NSF-funded project of building an upper body exoskeleton emulator. The emulator will promote the widespread adoption of exoskeletons in industry by providing a test-bed to streamline the rapid design of various assistance profiles for various users and tasks. / Master of Science / An exoskeleton is a robotic assistive device used in industrial and rehabilitative settings. This thesis will use data describing how the human shoulder moves during certain tasks to help design an exoskeleton to assist with theses tasks. A model of the human shoulder and a model of the exoskeleton will be developed and used in an optimization to figure out the best dimensions of the exoskeleton links to support the human's movements.

Shoulder-to-helmet (STH) impacts have been shown to cause approximately twenty percent of concussions in football, yet little research has investigated shoulder pad design and STH impacts. While shoulder pads are designed to protect the player wearing them, they have the potential to better protect the struck player in STH collisions. This study aimed to characterize STH impacts and identify the effect of shoulder pad stiffness on the struck head kinematics. Additional padding was added to a shoulder pad as means to reduce the overall stiffness of the system, and an unmodified shoulder pad acted as the control. Participants performed a series of impact tests with two shoulder pad variations to identify if additional padding in the shoulder pads could reduce head kinematics. Participants struck a helmeted Hybrid III dummy with a National Operating Committee on Standards for Athletic Equipment (NOCSAE) on the side, replicating a lateral STH impact. Linear and rotational kinematics of the struck head were recorded for each impact, and impact speed was derived from high-speed video. Peak kinematics were compared between shoulder pad configurations to identify differences in pad performance. Impact response corridors were developed from this study that could be used to inform future controlled laboratory test setups that replicate STH impacts. A controlled test setup would allow for future testing at higher impacts speeds to evaluate concussive level impacts. Overall, this study aimed to identify if shoulder pad design can affect the struck head kinematics in STH impacts, which would open a new avenue of player safety research and development. / Master of Science / Shoulder-to-helmet (STH) impacts have been shown to cause approximately twenty percent of concussions in football, yet little research has investigated shoulder pad design and STH impacts. While shoulder pads are designed to protect the player wearing them, they have the potential to better protect the struck player in STH collisions. This study aimed to characterize STH impacts and identify the effect of shoulder pad stiffness on the struck head kinematics. Participants performed a series of impact tests with two shoulder pad variations to identify if additional padding in the shoulder pads could reduce head kinematics. Participants struck the side of a crash test dummy head with their shoulder to replicate a STH impact. Linear and rotational kinematics were recorded for each impact, and impact speed was derived from high-speed video. Values that are used to quantify head injury were compared between shoulder pad configurations to identify differences in pad performance. This study defined impact response corridors that could be used to inform future controlled lab test setups that replicate STH impacts. A controlled test setup would allow for future testing at higher impacts speeds to evaluate concussive level impacts. Overall, this study aimed to identify if shoulder pad design can affect the struck head kinematics in STH impacts, which would open a new avenue of player safety research and development.

No / Computed tomography (CT) arthrography of the shoulder is an imaging modality of great diagnostic accuracy with regard to glenohumeral instability and in particular labral lesions. Interpretation of the scans is made difficult by the frequent occurrence of normal anatomic variants and the complexity of injuries to the bone and soft tissues. We selected a continuous sample of 50 CT arthrograms of the shoulder and they were reported by two consultant musculoskeletal radiologists. The results were collated and analysed for the level of agreement. Hill¿Sachs showed Kappa (K) statistic to be 0.37 (fair agreement), soft tissue Bankart 0.32 (fair agreement), bony Bankart 0.61 (substantial agreement), anterior capsular laxity 0.41 (moderate agreement) and glenohumeral osteoarthritis 0.20 (slight agreement). All the results were significant with a p value of <0.05. Nine (18%) of the 50 scans were in complete agreement. The results demonstrate that there can be considerable interobserver variation (IOV) in the reports of a CT arthrogram of a shoulder. They highlight the potential difficulties in reporting such images and suggests ways in which the report could be more focussed to provide a clinically reliable report and one which matches the surgical findings accurately.

Stationary (static) shoulder friction stir welding (SSFSW) is a variant of conventional friction stir welding (FSW) that was originally invented to improve the quality of welds produced with titanium alloys. Its predominant advantage is a reduction of the severe through thickness temperature gradients seen in conventional FSW, when welding low thermal conductivity alloy. However, SSFSW has rarely been utilised as a method to weld aluminium alloys because it is generally thought that in conventional FSW the rotating shoulder plays an essential role in the heat generation and, due to the high thermal conductivity of aluminium alloys, a rotating shoulder is beneficial for the welding process. In the work presented, the advantages of SSFSW have been examined when welding a typical high strength aluminium alloy AA7050-T7651. The process window for each approach has first been determined, and the optimum welding conditions were systematically evaluated, using power-rotation rate curves. Direct comparison of the two processes was subsequently carried out under these optimum conditions. It has been demonstrated that SSFSW can dramatically improve the quality of a weld's surface finish. Under optimum conditions it has also been shown that SSFSW was able to weld with approximately a 30% lower heat input than FSW and the stationary shoulder led to a narrower heat affected zone (HAZ). As a result, the through thickness properties of SSFSW were much better and more homogeneous than that for FSW, in terms of grain sizes, hardness and cross-weld mechanical properties. Uniaxial tensile tests proved that the average tensile strength of SSFSW samples was around 500 MPa, which was about 100 MPa larger than that of the FSW sample. Also, it was shown that during tensile testing the deformation zones, which correspond to minima in the hardness distribution of SSFSW welds, were about half the size of those found in FSW welds under the same traverse speed. The mechanisms that give rise to these advantages have been investigated systematically, focusing on directly comparing the SSFSW and FSW processes, and are discussed aided by finite element modelling (FEM) of the heat distribution in welds produced by each process and microstructural investigations.

INTRODUÇÃO - A literatura mostra a utilização da radiofreqüência como alternativa em casos de redundância ou frouxidão de tecido, podendo ser empregada como solução em alguns casos de instabilidade de ombro. O presente estudo avalia os efeitos mecânicos da radiofreqüência em cápsulas anteriores de ombros de coelhos vivos. MÉTODOS O estudo é comparativo e randomizado, tendo sido realizado em trinta e sete ombros de coelhos, machos, da raça Nova Zelândia, na faixa etária de 4 meses 6 meses, com peso médio de 3kg 250mg, criados para o projeto e mantidos no Biotério Central da Universidade Federal de Pelotas UFPEL - RS. O trabalho consta de dezoito ombros do grupo controle sendo estes abertos para gerar instabilidade e não submetidos ao procedimento de radiofreqüência; e dezenove ombros do grupo experimento (radiofreqüência), abertos para gerar instabilidade e submetidos a radiofreqüência com tempo fixado em 7segundos numa temperatura fixa de 650C, com tecido embebido em solução salina. Após cinqüenta dias de pós operatório, os animais foram levados à eutanásia. O material foi mantido em -21,40C por quinze dias e, após transportado para o Laboratório de Investigação Medica 21 da Universidade de São Paulo USP - SP, para avaliação de nove variáveis: altura, comprimento inicial sem carga, área da cápsula, força máxima, deformação máxima, tensão máxima, deformação relativa, rigidez e módulo de elasticidade. RESULTADOS Foram encontradas diferenças estatisticamente significantes entre os grupos controle e o grupo radiofreqüência, para as variáveis força máxima e rigidez (p<0,05), sendo maiores em média, no grupo controle. CONCLUSÃO Desse modo a força máxima e a rigidez da cápsula anterior de ombros de coelhos vivos, submetidas à radiofreqüência em um único ponto, diminui após cinqüenta dias / INTRODUTION literature presents radiofrequency as an alternative tool to be used in redundancy or tissue looseness cases, and to be employed as a potencial solution for shoulder instability. The present study evaluated the mechanical effects of radiofrequency usage in anterior shoulder capsules of living rabbits. METHODS - the study is comparative and randomized, it was carried out with thirty seven shoulders of male rabbits (New Zealand breed), with ages between 4 to 6 months, weighing on average 3kg250g that were raised for the project and kept at Central Biotery from Federal University of Pelotas RS. The study groups encompassed eighteen shoulders as a control group that were operated to generate instability but were not submitted to radiofrequency procedure; and nineteen shoulders as intervention group (radiofrequency), that underwent the same operation procedure but were submitted to radiofrequency by the period of seven seconds at a steady temperature of 650C, the tissue was Embedded in salt solution. Fifty days after surgery the rabbits were taken to euthanasia. The material was kept at - 21,40C for fifteen days and later was taken to the São Paulo University-USP Medical Investigation Laboratory(#21), for the assessment of nine variables: height, unloaded inicial length, capsule area, maximum strength, maximum deformation, maximum tension, relative deformation, stiffness and elasticity module. RESULTS Statistical differences were observed between groups concerning maximum strength and stiffness(p<0.05), that were higher on average in the contrl group. CONCLUSION Maximum strength and stiffness of the anterior shoulder capsule in living rabbits, submitted to radiofrequency in a single spot, decreases after fifty days

Reverse shoulder arthroplasty (RSA) is performed to decrease pain and improve function and range of motion (ROM) primarily for patients with rotator cuff arthropathy, an arthritis of the shoulder secondary to rotator cuff insufficiency. However, RSA has suffered from high early to mid-term rates of complication, with instability being one of the most common. The shoulder biomechanics post-RSA depend on multiple factors such as implant geometry, positioning, and cuff integrity. This study built upon prior finite element (FE) analysis of RSA to investigate the effects of glenoid lateralization and retentive liner design on shoulder stability. A previously validated FE model was extended to model shoulder external rotation (ER) after implantation of the Zimmer Trabecular Metal RSA system. The FE model included the scapula bone with an implanted glenosphere implant, the humerus bone with implanted humeral sections of the RSA implant, and muscle tendons representing the subscapularis, infraspinatus, and deltoid. Six different models matched glenospheres in three cases of lateralization (2mm, 4mm, and 10mm) with two humeral poly liner designs (normal: 150° neck shaft angle or retentive: 155° neck shaft angle). Using Abaqus/Explicit FE software, the proximal ends of the soft tissues were pulled to their anatomical positions, and then fixed in space while the humerus was externally rotated 80° about the humeral long axis from a neutral position with the shoulder abducted 25°. The displacements, deltoid and subscapularis forces, impingement-free ROMs, and subluxation gap distances were recorded. Although greater glenosphere lateralization was associated with higher impingement-free ROM, larger deltoid and subscapularis forces developed. Deltoid tension contributes to shoulder stability and control, but elevated amounts of deltoid tension may contribute to scapular fractures and greater stress at impingement sites post-RSA. Further analysis such as inclusion of more anatomical features and additional motions may offer greater insight to orthopedic surgeons when planning for RSA insertion.

The aim of this thesis was to study different aspects of the soft tissues of the shoulder joint. The variation in the quality of the tendons and ligaments can be explained by genetic factors. To test the hypothesis that collagen 1 α1 Sp1 polymorphism is related to the occurrence of cruciate ligament ruptures and shoulder dislocations, a total of 358 patients (233 patients with cruciate ligament ruptures and 126 with shoulder dislocations) were included in the study. We found a decreased risk of these injuries associated with collagen type 1 α1 Sp1 polymorphism. To study the mechanical properties of a better type of fixation of soft tissue to bone, 10 skeletally mature New Zealand white rabbits were operated bilaterally on the knees. The medial collateral ligaments were fixed by two types of plates one with a flat undersurface and the other with a pegged undersurface. After 4 weeks the force at failure, stiffness and energy uptake was almost double in the knees operated with the pegged plates. The prevalence and dysfunction of rotator cuff tears was investigated in 106 subjects who had never sought for their shoulder complaints, using Constant score, ultrasound and plain x-ray. The prevalence of full-thickness cuff tears was 30% (21% of all shoulders). The Constant score was lower in subjects with full-thickness tears. Partial-thickness tears and acromioclavicular joint osteoarthritis had no impact on shoulder complaints or Constant score. The subacromial index was lower for shoulders with full-thickness tears. Forty-eight patients with median age 56 years underwent subacromial decompression with or without acromioclavicular joint resection, investigated with MRI pre- and 3 months postoperatively. The Constant score and subjective shoulder value were measured preoperatively and at 3 and 6 months after surgery and even 2 years for subjective shoulder value. Two raters investigated the MRI. The results showed poor inter-rater reliability for MRI. However, both Constant score and subjective shoulder value improved over time. MRI is not a reliable method to study the capsular reaction after subacromial decompression due to high subjectivity of the radiologists.

In this cross-sectional study, the sensibility, reliability, and validity of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire were assessed in patients who underwent neck dissection for head and neck cancer. A sensibility questionnaire was used to assess face and content validity. Test-retest reliability was tested by re-mailing the questionnaire; validity, by evaluating differences in scores between patients undergoing different types of neck dissections and by correlating DASH scores with Neck Dissection Impairment Index (NDII) scores. The DASH was considered sensible by both patients and surgeons. The DASH was reliable with an intraclass coefficient of 0.91. The DASH showed differences between patients who underwent accessory nerve-sacrifice and nerve-sparing neck dissection. DASH scores strongly correlated with NDII scores. Thus, the DASH is a sensible, reliable, and valid instrument for assessing shoulder impairments and activity limitations following neck dissection.

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic at the Durban Institute of Technology, 2008. / Purpose Cricket fast bowlers are prone to the development of Myofascial pain syndrome and in particular active myofascial trigger points in their rotator cuff muscles of the shoulder joint (Scott, et al. 2001). This is due to the severe stresses placed upon the muscles, bones and joints of the shoulder as a result of the high velocity throwing action (Bartlett, et al.1996). In muscles containing active myofascial trigger points a decrease in the stretch range of motion as well as the maximal contractile force is noted, these two factors may negatively affect the speed at which a fast bowler deliver the ball (Travell, Simons and Simons, 1999). Dry needling is viewed as the most effective means of deactivating myofascial trigger points leading to in increase in both the contractile force and range of motion of the affected muscle, which could increase the speed at which the bowler delivers the ball (Wilks, 2003). The aim of the study was to determine the immediate effect of dry needling active myofascial trigger points of the rotator cuff on bowling speed in action cricket fast bowlers. Method The study consisted of 40 participants (randomly split into two equal groups of 20) each with shoulder pain of a myofascial origin. Group A (intervention group) received the dry needling intervention in their most tender active myofascial trigger point. While participants in Group B (control group) received no treatment. Bowling speeds were measured both before and after the intervention, to determine its effect on bowling speed. IV Data was entered into MS Exel spreadsheet and imported into SPSS version 15 (SPSS Inc.,Chicago, Iiiinois, USA), which was used for data analysis. Paticipants were evaluated on bowling speed, Algometer readings and Numerical pain rating Scale (NRS) both pre and post intervention. Participants were also asked if they believed the intervention increased, decreased or had no effect on their bowling speeds. Two sample t-test was used to compare baseline values between the groups. A repeated measure ANOVA was used to compare the rate of change of each outcome over time in the two groups. Pearson’s correlation analysis (intra-group) was used to assess the strength and magnitude of correlations of the changes in the outcomes. The McNemar – Bowker test and Weighted Cohen’s kappa statistics were calculated to assess agreement between perceived and actual levels of change. Results A significant treatment effect was observed in the intervention group were an increase in bowling speed, algometer readings as well a decrease in Numerical pain rating scale(NRS) scores was observed. There was also a perceived increase in the speed the participants delivered the ball in the intervention group. No significant changes were observed in the control group. The findings of this study indicate that dry needling as a treatment modality would be beneficial to fast bowlers in not only increasing their speeds but also the pain experienced as a result of active myofascial trigger points.

In this cross-sectional study, the sensibility, reliability, and validity of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire were assessed in patients who underwent neck dissection for head and neck cancer. A sensibility questionnaire was used to assess face and content validity. Test-retest reliability was tested by re-mailing the questionnaire; validity, by evaluating differences in scores between patients undergoing different types of neck dissections and by correlating DASH scores with Neck Dissection Impairment Index (NDII) scores. The DASH was considered sensible by both patients and surgeons. The DASH was reliable with an intraclass coefficient of 0.91. The DASH showed differences between patients who underwent accessory nerve-sacrifice and nerve-sparing neck dissection. DASH scores strongly correlated with NDII scores. Thus, the DASH is a sensible, reliable, and valid instrument for assessing shoulder impairments and activity limitations following neck dissection.