Browsing by Subject "shoulder"
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Item Clinical Diagnosis and Functional Implications of Shoulder Multidirectional Instability(2017-12) Staker, JustinBackground: Shoulder injuries are a common musculoskeletal complaint. Shoulder multidirectional instability (MDI) is thought to be a common cause of symptoms especially in athletes such as competitive swimmers. Clinical laxity tests such as the anterior/posterior drawer and sulcus tests are commonly used to identify excessive glenohumeral translations commonly associated with the diagnosis of MDI. However, the ability of these tests to identify individuals with MDI and to determine if excessive glenohumeral translations are present compared to controls without MDI has not been established. Therefore, the overall purpose of this study was to determine how laxity test findings relate to glenohumeral translations and if differences in joint stability exist dynamically during scapular plane abduction for swimmers diagnosed with MDI and matched controls. Methods: Direct tracking of glenohumeral motion was performed with bone-fixed pins or single plane fluoroscopic imaging. The kinematic inter-examiner repeatability of the laxity tests was determined by ICC calculations in individuals diagnosed with shoulder impingement (n=11). The relationship of the average laxity test score (composite laxity score) from the anterior/posterior drawer and sulcus tests to the root-mean-square average (composite translation) of the laxity test translations was performed with a regression analysis. The differences in joint translations during laxity tests and joint stability during dynamic movement between swimmers diagnosed with MDI and healthy controls without MDI were examined arthrokinematically and osteokinematiclly (n=44). Results: Good inter-examiner kinematic repeatability was demonstrated between examiner for two of three laxity tests. A strong and moderate linear relationship was demonstrated between the composite laxity score and composite translations for the laxity tests. No differences were observed between groups for contact path length or helical parameter descriptions of joint stability during scapular plane abduction. Conclusions: Clinical laxity tests demonstrate good repeatability between examiners. Combining laxity tests in a single score has capability to identify subtle differences in overall joint translations. Composite laxity scores of joint laxity tests may be able to identify differences individuals with overall joint laxity consistent with the diagnosis of MDI. To detect dynamic joint instability between groups, test movements must be sufficiently challenging to elicit signs of joint instability.Item Movement-Related Pathogenesis of Rotator Cuff Disease in Persons with Shoulder Pain: Effects of Decreased Scapulothoracic Upward Rotation(2018-05) Lawrence, RebekahBackground: Shoulder pain is a common musculoskeletal complaint that is often associated with rotator cuff injury and abnormal scapular movement. In particular, decreased scapulothoracic upward rotation has been theorized to increase an individual’s risk for subacromial rotator cuff compression. However, the effect of abnormal shoulder motion on mechanisms of rotator cuff injury remains unclear. Further, the ability to accurately and non-invasively quantify shoulder complex kinematics is limited. Objectives: The objectives of this thesis are: 1) Develop and validate a protocol for using single-plane fluoroscopy and 2D/3D shape-matching to quantify shoulder complex kinematics; 2) Determine the impact of decreased scapulothoracic upward rotation on subacromial proximities; and 3) Identify the kinematic mechanisms by which sternoclavicular and acromioclavicular motion contributes to scapulothoracic upward rotation. Methods: A protocol for using single-plane fluoroscopy and 2D/3D shape-matching to quantify shoulder complex kinematics was validated using radiostereometric analysis in four cadaveric specimens. Shoulder complex kinematics were quantified in 60 participants with and without shoulder pain during scapular plane abduction using the validated protocol. Subject-specific 3D bone models reconstructed from MR images were animated with each participant’s glenohumeral kinematics. Subacromial proximities were calculated between the coracoacromial arch and rotator cuff insertion. The effect of decreased scapulothoracic upward rotation on subacromial proximities was assessed. The relative contribution of sternoclavicular and acromioclavicular motion to scapulothoracic upward rotation was calculated using two derived coupling functions. Results: Single-plane fluoroscopy and 2D/3D shape-matching can accurately quantify static shoulder complex kinematics. Subacromial proximities were generally smallest below 90° humerothoracic elevation. The normalized minimum distance for participants in the low scapulothoracic upward rotation group was significantly smaller (35%) than those in the high scapulothoracic upward rotation group at the minimum position. Scapulothoracic upward rotation can be estimated from acromioclavicular upward rotation, sternoclavicular posterior rotation, and sternoclavicular elevation. Conclusions: Decreased scapulothoracic upward rotation shifts the range of motion in which normalized minimum distances are smallest to lower angles. Acromioclavicular upward rotation and sternoclavicular posterior rotation are the predominant component motions of scapulothoracic upward rotation.Item Osteoarthritis of the glenohumeral joint(2009-08-19) Ou-Yang, DavidIt is estimated that osteoarthritis of the shoulder affects over 30% of patients over the age of sixty, and it can lead to pain, crepitus, loss of motion, and loss of function. Multiple treatment options are available, both surgical and nonsurgical. The following is a patient education tool dedicated to osteoarthritis of the glenohumeral joint.Item Scapular Mechanisms of Movement-Related Shoulder Dysfunction(2024) Saini, GauraBackground: Shoulder pain and dysfunction, including rotator cuff tears, are highly prevalent and can limit an individual’s ability to perform basic activities of daily living, work-related tasks, and recreational activities. Repetitive deformation of the rotator cuff tendons is one hypothesized mechanism of tear formation. Shoulder motion, particularly at the scapula, directly affects the position of the rotator cuff tendons with respect to surrounding structures during motion and may impact rotator cuff tendon deformation. To date, research around abnormal scapular motion has generally not investigated impacts of specific patterns of abnormal scapular motion. Additionally, there is a lack of research guiding clinicians with regard to underlying muscle activation patterns within specific movement patterns. The links between scapular movement abnormalities, muscle activation, and rotator cuff deformation remain unclear, limiting the development of precise, individualized treatment of each patient. Objectives: The overall objectives for this project were to (i) identify muscle activation in two specific scapular movement groups (excessive scapular anterior tilt, scapular lateralization), and (ii) identify rotator cuff deformation caused by surrounding structures in the same two scapular movement groups.Methods: Participants with shoulder pain were classified into the two movement patterns based on clinical exam measurements during overhead reaching, and movement patterns were confirmed using 2D/3D shape-matching. Highly accurate shoulder bone motion was obtained from biplane video radiography in three motions: abduction, flexion, and unrestricted overhead reaching. Participant-specific bone and supraspinatus (rotator cuff) tendon models were derived from magnetic resonance imaging. The bone models were projected onto and aligned with the radiography images (2D/3D shape-matching) to output the 3D joint positions throughout motion. Muscle activity was recorded simultaneously with the radiography collections using electromyography. Muscle activity of key scapulothoracic muscles were compared between groups. The proximity of the supraspinatus tendon to the coracoacromial arch and glenoid was calculated throughout motion by recreating each participant’s arm motion using models of their humerus, scapula, and supraspinatus tendon and their specific arm raising kinematics. Results: Significant interactions of group and motion type and group and range of motion interval were found for the anterior deltoid, ratio of lower trapezius/serratus anterior, and ratio of lower trapezius/anterior deltoid. Both groups had increasing anterior deltoid muscle activity as humerothoracic elevation increased, and the anterior tilt group increased across intervals to a greater extent than the lateralization group. In abduction and flexion, the anterior tilt group had a higher ratio of lower trapezius/serratus anterior compared to the lateralization group indicating relatively increased lower trapezius activity or relatively decreased serratus anterior activity in the anterior tilt group. In abduction and flexion, both groups generally had a ratio >1 indicating relatively more lower trapezius activity than serratus anterior. In unrestricted reaching, both groups had less lower trapezius activity compared to serratus anterior (ratio <1), and this occurred to a greater degree in the anterior tilt group. The anterior tilt group had a higher ratio of lower trapezius/anterior deltoid compared to the lateralization group from 31¬–60 of humerothoracic elevation. Groups were similar from 61–90°, then, though both groups had increasing ratios, the lateralization group progressively increased to a greater extent. The minimum distance between the supraspinatus tendon and the coracoacromial arch was significantly smaller in the anterior tilt group than the lateralization group. All participants experienced contact between the tendon and the glenoid regardless of movement pattern grouping. Conclusions: Individuals with a scapular anterior tilt movement pattern have differences in muscle activity of key shoulder muscles compared to individuals with a scapular lateralization pattern. The supraspinatus tendon is in closer proximity to the coracoacromial arch in people with the anterior tilt pattern, indicating that this might be a movement pattern of concern that warrants further investigation.Item What is an acromioclavicular separation?(2010-07-22) Rosenkvist, JessicaA patient’s guide to acromioclavicular separation injuries, including information about symptoms and various forms of treatment. The choice between surgical and conservative treatment depends on the severity of the injury and the functional goals of the patient. Therefore it is important for patients to work with their health care providers to determine the best course of treatment for their injury.