Publications by authors named "William Anderst"

The perceived association between foot type and injury risk has inspired the development of many foot typing methods. The purpose of this study was to determine how well different foot typing methods explained variations in regional foot loading in asymptomatic adults during gait, while considering age, sex, and walking speed as covariates. Six methods were used to determine foot type in 92 asymptomatic adults.

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Cadaveric and computer simulations suggest lateral humeral offset (LHO) and humeral retroversion (HR) are associated with strength and range of motion (ROM) after reverse total shoulder arthroplasty (rTSA), butin vivodata is lacking. This study aimed to evaluate the effects of implant parameters (i.e.

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Quantitative in vivo biomechanical assessments are typically performed with optoelectronic motion capture (MoCap) using retroreflective markers attached to skin. This technique inherently contains measurement errors from both marker placement on palpated bony landmarks and skin motion relative to the underlying bone (i.e.

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Purpose: This study aimed to identify surgical parameters during reverse shoulder arthroplasty (RSA) that predict post-surgical kinematics during the hand-to-head motion (H2H) and to identify associations between kinematics and outcomes. We hypothesized that greater humeral retroversion and lateralization predict kinematics, and that more scapular upward rotation is associated with better PROs and more range of motion (ROM).

Methods: Thirty-five post-RSA patients consented to participate.

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The purpose of this study was to identify side-to-side and sex-based differences in hip kinematics during a unilateral step-up from deep flexion. Twelve (eight men, four women) asymptomatic young adults performed a step ascent motion while synchronized biplane radiographs of the hip were collected at 50 images per second. Femur and pelvis position were determined using a validated volumetric model-based tracking technique that matched digitally reconstructed radiographs created from subject-specific computed tomography (CT) bone models to each pair of synchronized radiographs.

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Article Synopsis
  • The study investigates the movement mechanics of the atlantooccipital joint (occiput-C1) in healthy young adults during various head movements, using high-speed biplane radiographs to capture the motion.
  • Researchers tracked the joint's movements while participants performed flexion/extension, axial rotation, and lateral bending, finding significant variability in flexion/extension compared to more consistent axial and lateral movements.
  • The results reveal key details about the joint's range of motion and axis of rotation during these movements, providing valuable insights for future studies on upper cervical spine biomechanics.
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The objectives of this study were to evaluate the reliability of cartilage T2 relaxation time measurements and to identify focal changes in T2 relaxation on the affected knee from 6 to 24 months after anatomic anterior cruciate ligament reconstruction (ACLR). Data from 41 patients who received anatomic ACLR were analyzed. A bilateral 3.

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Total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) are effective surgeries to treat end-stage knee osteoarthritis. Clinicians assume that TKA alters knee kinematics while UKA preserves native knee kinematics; however, few studies of in vivo kinematics have evaluated this assumption. This study used biplane radiography to compare side-to-side tibiofemoral kinematics during chair rise, stair ascent, and walking in 16 patients who received either TKA or UKA.

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The introduction of women into U.S. military ground close combat roles requires research into sex-specific effects of military training and operational activities.

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This study aimed to characterize ankle and hindfoot kinematics of healthy men and women during overground running using biplane radiography, and to compare these data to those previously obtained in the same cohort during overground walking. Participants ran across an elevated platform at a self-selected pace while synchronized biplane radiographs of their ankle and hindfoot were acquired. Motion of the tibia, talus, and calcaneus was tracked using a validated volumetric model-based tracking process.

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Accurate measurements of hip joint kinematics are essential for improving our understanding of the effects of injury, disease, and surgical intervention on long-term hip joint health. This study assessed the accuracy of conventional motion capture (MoCap) for measuring hip joint center (HJC) location and hip joint angles during gait, squat, and step-up activities while using dynamic biplane radiography (DBR) as the reference standard. Twenty-four young adults performed six trials of treadmill walking, six body-weight squats, and six step-ups within a biplane radiography system.

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Purpose: The aim of this study was to investigate whether the whole tibial spine volume and femoral intercondylar notch volume are risk factors for anterior cruciate ligament (ACL) injury. The hypothesis was that the whole tibial spine volume and femoral notch volume would be smaller in athletes who sustained ACL injury than in athletes with no history of ACL injury.

Methods: Computed tomography scans of both knees were acquired and three-dimensional bone models were created using Mimics to measure whole tibial spine volume and femoral notch volume.

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Background: Cadaver biomechanical testing suggests that the morphology of articulating bones contributes to the stability of the joints and determines their kinematics; however, there are no studies examining the correlation between bone morphology and kinematics of the subtalar joint. The purpose of this study was to investigate the influence of talar and calcaneal morphology on subtalar kinematics during walking in healthy individuals.

Methods: Forty ankles (20 healthy subjects, 10 women/10 men) were included.

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Biplane radiography has emerged as the gold standard for accurately measuring in vivo skeletal kinematics during physiological loading. The purpose of this scoping review was to map the extent, range, and nature of biplane radiography research on humans from 2004 through 2022. A literature search was performed using the terms biplane radiography, dual fluoroscopy, dynamic stereo X-ray, and biplane videoradiography.

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Background: Reaching behind the back is painful for individuals with rotator cuff tears. The objectives of the study were to determine changes in glenohumeral kinematics when reaching behind the back, passive range of motion (RoM), patient reported outcomes and the relationships between kinematics and patient reported outcomes following exercise therapy.

Methods: Eighty-four individuals with symptomatic isolated supraspinatus tears were recruited for this prospective observational study.

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Exercise therapy for individuals with rotator cuff tears fails in approximately 25.0 % of cases. One reason for failure of exercise therapy may be the inability to strengthen and balance the muscle forces crossing the glenohumeral joint that act to center the humeral head on the glenoid.

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The goal of this study was to determine how foot type and activity level affect ankle and hindfoot motion. Dynamic biplane radiography and a validated volumetric registration process was used to measure ankle and hindfoot motion of 20 healthy adults during walking and running. The helical axes of motion (HAM) during stance were calculated at the tibiotalar and subtalar joints.

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Purpose: Bony morphology has been proposed as a potential risk factor for anterior cruciate ligament (ACL) injury. The relationship between bony morphology, knee kinematics, and ACL elongation during high-demand activities remains unclear. The purpose of this study was to determine if bone morphology features that have been associated with ACL injury risk and knee kinematics are also predictive of ACL elongation during fast running and double-legged drop jump.

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Background: Superior capsular reconstruction (SCR) is a procedure purported to restore stability of the glenohumeral joint after an irreparable rotator cuff tear, but the in vivo behavior of the graft is unknown. Previous work has not evaluated the relationship between graft deformation, kinematics, and healing.

Purpose: To (1) determine regional graft elongation after SCR, (2) determine if graft elongation is related to graft healing, and (3) identify associations between graft elongation and changes in kinematics from presurgery to postsurgery.

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Objective: Changes in cartilage contact area and/or contact location after knee injury can initiate and exacerbate cartilage degeneration. Typically, the contralateral knee is used as a surrogate for native cartilage contact patterns on the injured knee. However, symmetry in cartilage contact patterns between healthy knees during high-impact activities is unknown.

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Article Synopsis
  • This study investigated how well different types of cervical orthoses (neck braces) limit neck movements during various motions in a group of healthy adults.
  • It found that while the soft collar was somewhat effective in reducing motion during flexion/extension and axial rotation, it did not restrain lateral bending.
  • The hard collar proved to be more effective than the soft collar across all motions, except for specific segments during axial rotation and lateral bending.
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  • The study investigates how total hip arthroplasty (THA) affects lower back movement during walking in patients with hip-spine syndrome, aiming to understand improvements in back pain.
  • Thirteen patients with severe hip osteoarthritis were analyzed before and six months after THA, using various questionnaires and measurements of spinal and pelvic orientation during walking.
  • Results indicated significant improvements in hip and back pain scores after THA, but no changes in static spinal positioning; however, there were notable changes in lumbar spine movement that may contribute to reduced pain.
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  • Load carriage and forced-marching can negatively impact gait stability and adaptability, contributing to musculoskeletal injuries in military personnel.
  • The study examined how different load magnitudes and locomotion patterns influenced motor variability and stride regulation in recruits during running and forced-marching.
  • Results indicated that as tasks became more challenging with added loads, participants displayed stricter stride regulation and adjusted motor strategies to maintain speed, which may increase injury risk during extended activities.
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Dynamic biplane radiographic (DBR) imaging measures continuous vertebral motion during in vivo, functional tasks with submillimeter accuracy, offering the potential to develop novel biomechanical markers for lower back disorders based on true dynamic motion rather than metrics based on static end-range of motion. Nevertheless, the reliability of DBR metrics is unclear due to the inherent variability in movement over multiple repetitions and a need to minimize radiation exposure associated with each movement repetition. The objectives of this study were to determine the margin of uncertainty (MOU) in estimating the typical intervertebral kinematics waveforms based upon only a small number of movement repetitions, and to determine the day-to-day repeatability of intervertebral kinematics waveforms measured using DBR.

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