The association of rotator cuff muscle morphology and glenoid morphology in primary glenohumeral osteoarthritis.

Background: This retrospective study investigated associations of rotator cuff muscle atrophy (MA) and fatty infiltration (FI) with glenoid morphology.

Methods: Patients with primary glenohumeral osteoarthritis who presented to Penn State Bone and Joint Institute's orthopaedic clinic from September 2002 to December 2019 as total shoulder arthroplasty (TSA) candidates were evaluated. MA was determined by the cross-sectional area of each rotator cuff muscle on pre-operative MR and CT scans.

Use of a factor analysis to assess biomechanical factors of American Sign Language in native and non-native signers.

Prior studies suggest that native (born to at least one deaf or signing parent) and non-native signers have different musculoskeletal health outcomes from signing, but the individual and combined biomechanical factors driving these differences are not fully understood. Such group differences in signing may be explained by the five biomechanical factors of American Sign Language that have been previously identified: ballistic signing, hand and wrist deviations, work envelope, muscle tension, and "micro" rests. Prior work used motion capture and surface electromyography to collect joint kinematics and muscle activations, respectively, from ten native and thirteen non-native signers as they signed for 7.

Risk Reduction of Concussion in Athletes: Do Neck Size or Neck Strength Make a Difference?

Medical provider's ability to detect, diagnose, and treat sport-related concussion has greatly improved in recent years. Although more is known about the biomechanical forces involved in concussion, it is still uncertain whether there are preventative measures athletes can take to prevent a sport-related concussion from occurring. The objective of this review was to determine if either neck size or neck strength is related to a decreased risk of sustaining a sport-related concussion.

Focused ultrasound as an alternative to dry needling for the treatment of tendinopathies: A murine model.

Tendinopathies account for 30% of 102 million annual musculoskeletal injuries occurring annually in the United States. Current treatments, like dry needling, induce microdamage to promote healing but produce mixed success rates. Previously, we showed focused ultrasound can noninvasively create microdamage while preserving mechanical properties in ex vivo murine tendons.

Treatment and Management of Work-Related Mild Traumatic Brain Injury in Physical Medicine and Rehabilitation.

The purpose of this narrative review was to assess work-related mild traumatic brain injury treatment approaches and outcomes. Literature indicates that incidence of work-related mild traumatic brain injury is high. Ability to return to work after injury is variable, with differences identified across industry sector, mechanisms of injury, sex, and timely treatment and referral.

The role of physical arm function and demographic disparities in breast cancer survivors' ability to return to work.

Purpose: Ability to return to work (RTW) is an important aspect of breast cancer that is limited for many survivors. With 90% survivorship in the USA, it is imperative that focus shifts toward the improvement of physical arm function to improve survivors' ability to RTW. This narrative review discusses the role of physical arm function and demographic disparities in breast cancer survivor RTW.

Therapeutic Ultrasound and Shockwave Therapy for Tendinopathy: A Narrative Review.

Tendon injury is prevalent and costly in the United States, comprising 45% of the 66 million musculoskeletal injuries and costing $114 billion annually. Surgical and therapeutic methods, such as arthroscopic surgery, dry needling, and physical therapy, produce mixed success in reintroducing a healing response in tendinopathy due in part to inconsistent dosing and monitoring. Ultrasound is one therapeutic modality that has been shown to noninvasively induce bioeffects in tendon that may help promote healing.

Automated Tissue Strain Calculations Using Harris Corner Detection.

The elastic modulus, or slope of the stress-strain curve, is an important metric for evaluating tissue functionality, particularly for load-bearing tissues such as tendon. The applied force can be tracked directly from a mechanical testing system and converted to stress using the tissue cross-sectional area; however, strain can only be calculated in post-processing by tracking tissue displacement from video collected during mechanical testing. Manual tracking of Verhoeff stain lines pre-marked on the tissue is time-consuming and highly dependent upon the user.

Effects of focused ultrasound and dry needling on tendon mechanical properties.

Tendon injuries are extremely common, resulting in mechanically weaker tendons that could lead to tendon rupture. Dry needling (DN) is widely used to manage pain and function after injury. However, DN is invasive and high inter-practitioner variability has led to mixed success rates.

Upper extremity biomechanics in native and non-native signers.

Background: Individuals fluent in sign language (signers) born to non-signing, non-deaf parents (non-natives) may have a greater injury risk than signers born to signing, deaf parents (natives). A comprehensive analysis of movement while signing in natives and non-natives has not been completed and could provide insight into the greater injury prevalence of non-natives.

Objective: The objective of this study was to determine differences in upper extremity biomechanics between non-natives and natives.

Comparison between dry needling and focused ultrasound on the mechanical properties of the rat Achilles tendon: A pilot study.

In the U.S., approximately 14 million tendon and ligament injuries are reported each year.

Upper extremity and trunk body segment parameters are affected by BMI and sex.

Although body mass index (BMI) relates to body segment parameters (BSPs), unknowns persist over whether: 1) BSPs relate to BMI group classifications, 2) sex influences BMI/BSP relationships, and 3) simple anthropometric measures sufficiently predict BSPs. Dual energy X-ray absorptiometry (DXA) scans and anthropometric measures were obtained from 76 participants (33M, 43F) of varying body composition. Trunk, neck and head (TNH), arm, forearm and hand masses were obtained from DXA scans and center of mass locations (COM) estimated from geometric models.

The Modified Strain Index: A Composite Measure of Injury Risk for Signers.

Up to 81% of individuals who are fluent in sign language (signers) report pain. Non-native signers (with non-signing, non-deaf parents) report greater pain than natives (≥1 signing, deaf parent). The goal of this study was to develop a composite measure of injury risk (the modified Strain Index for signers) based on previously identified biomechanics unique to signers and examine scores across sub-groups of natives and non-natives.

A simple joint control pattern dominates performance of unconstrained arm movements of daily living tasks.

A trailing joint control pattern, during which a single joint is rotated actively and the mechanical effect of this motion is used to move the other joints, was previously observed during simplified, laboratory-based tasks. We examined whether this simple pattern also underlies control of complex, unconstrained arm movements of daily activities. Six tasks were analyzed.

The influence of mastectomy and reconstruction on residual upper limb function in breast cancer survivors.

Purpose: Breast cancer survivorship is common (90% of women survive 5 or more years), but many women are not able to return to full function and well-being after treatment due to functional limitations, persistent pain, and inability to perform daily activities. Since each surgical reconstructive option (e.g.

Trends and advancements in shoulder biomechanics research.

The 12th International Shoulder Group (ISG) Conference was held at Mayo Clinic in Rochester, Minnesota, USA, from August 12-13, 2018, and was hosted by Dr. Melissa (Missy) Morrow of Mayo Clinic and Dr. Meghan Vidt of Pennsylvania State University.

Muscle compensation strategies to maintain glenohumeral joint stability with increased rotator cuff tear severity: A simulation study.

Rotator cuff tear (RCT) in older adults may cause decreased muscle forces and disrupt the force balance at the glenohumeral joint, compromising joint stability. Our objective was to identify how increased RCT severity affects glenohumeral joint loading and muscle activation patterns using a computational model. Muscle volume measurements were used to scale a nominal upper limb model's peak isometric muscle forces to represent force-generating characteristics of an average older adult male.

Workstation configuration and container type influence upper limb posture in grocery bagging.

Introduction: Repetitive movements and awkward postures are two persistent injury risk factors for grocery store cashiers. Due to the recent rise in popularity of environmentally-friendly grocery bagging options, current recommendations for cashiers are likely outdated. Correspondingly, the objective of this study was to examine the effects of cashier-specific work demands, workstation configuration, and container type on upper limb postures during typical job activities.

Scapular Kinematics by Sex Across Elevation Planes.

Scapular kinematics are important indicators of dyskinesis, often suggesting underlying shoulder pathology, but the influence of sex is unknown. This study's objective was to examine scapular kinematics in healthy males and females. Positions of surface-mounted reflective markers were tracked during arm elevation movements in 0°/30°/40°/60°/90°/120° planes.

Shoulder Strength Requirements for Upper Limb Functional Tasks: Do Age and Rotator Cuff Tear Status Matter?

Understanding upper limb strength requirements for daily tasks is imperative for early detection of strength loss that may progress to disability due to age or rotator cuff tear. We quantified shoulder strength requirements for 5 upper limb tasks performed by 3 groups: uninjured young adults and older adults, and older adults with a degenerative supraspinatus tear prior to repair. Musculoskeletal models were developed for each group representing age, sex, and tear-related strength losses.