A novel 3D MRI-based approach for assessing supraspinatus muscle length.

Rotator cuff (RC) tears are a common source of pain and decreased shoulder strength. Muscle length is known to affect muscle strength, and therefore evaluating changes in supraspinatus muscle length associated with RC pathology, surgical repair, and post-operative recovery may provide insights into functional deficits. Our objective was to develop a reliable MRI-based approach for assessing supraspinatus muscle length.

Investigating the multifactorial etiology of supraspinatus tendon tears.

The purpose of this study was to develop a multivariable model to determine the extent to which a combination of etiological factors is associated with supraspinatus tendon tears. Fifty-four asymptomatic individuals (55 ± 4 years) underwent testing of their dominant shoulder. Diagnostic ultrasound was used to assess for a supraspinatus tendon tear.

Correspondence between scapular anatomical coordinate systems and the 3D axis of motion: A new perspective on an old challenge.

Several scapular anatomical coordinate systems have been reported in the literature to describe shoulder kinematics. Unfortunately, the use of different conventions hinders comparison across studies. Further, inconsistencies between a coordinate system and the scapula's 3D axis of motion means that scapular motion will be incorrectly attributed to axes about which it did not rotate.

Intervertebral kinematics during neck motion 6.5 years after fusion and artificial disc replacement.

Background: Arthroplasty with artificial disc replacement for surgical treatment of cervical spine degeneration was introduced with the notion that motion-preserving approaches would prevent development of adjacent segment disease. Though clinical outcomes favor arthroplasty over the commonly used anterior cervical discectomy with fusion approach, clinical studies confirming the biomechanical basis of these results are lacking. The aim of this study was to compare intervertebral kinematics between arthroplasty and fusion patients 6.

In vivo evaluation of rotator cuff internal impingement during scapular plane abduction in asymptomatic individuals.

Internal impingement-or entrapment of the undersurface of the rotator cuff tendon against the glenoid during overhead activities-is believed to contribute to articular-sided tears. However, little is known about internal impingement outside athletic populations. Therefore, the objectives of this study were to (1) describe glenoid-to-footprint distances and proximity centers during dynamic, in vivo motion in asymptomatic individuals, and (2) determine the extent to which these measures differed between individuals with and without a rotator cuff tear.

Presurgical tear characteristics and estimated shear modulus as predictors of repair integrity and shoulder function one year after rotator cuff repair.

Background: Rotator cuff repair provides pain relief for many patients; however, retears are relatively common and affect approximately 20%-70% of patients after repair. Although magnetic resonance imaging (MRI) offers the ability to assess tissue characteristics such as tear size, retraction, and fatty infiltration, it provides little insight into the quality of the musculotendinous tissues the surgeon will encounter during surgery. However, shear wave elastography (SWE) could provide an indirect assessment of quality (ie, stiffness) by measuring the speed of shear waves propagating through tissue.

Validation of a 3D CT imaging method for quantifying implant migration following anatomic total shoulder arthroplasty.

Glenoid component loosening remains a common complication following anatomic total shoulder arthroplasty (TSA); however, plain radiographs are unable to accurately detect early implant migration. The purpose of this study was to validate the accuracy of a method of postoperative, three-dimensional (3D) computed tomography (CT) imaging with metal artifact reduction (MAR) to detect glenoid component migration following anatomic TSA. Tantalum bead markers were inserted into polyethylene glenoid components for implant detection on 3D CT.

Quantifying shoulder activity after rotator cuff repair: Technique and preliminary results.

Repair tissue healing after rotator cuff repair remains a significant clinical problem, and excessive shoulder activity after surgical repair is believed to contribute to re-tears. In contrast, small animal studies have demonstrated that complete removal of activity impairs tendon healing and have advocated for an "appropriate" level of activity, but in humans the appropriate amount of shoulder activity to enhance healing is not known. As an initial step toward understanding the relationship between postoperative shoulder activity and repair tissue healing, the objectives of this study were to assess the precision, accuracy, and feasibility of a wrist-worn triaxial accelerometer for measuring shoulder activity.

Ultrasound shear wave elastography and its association with rotator cuff tear characteristics.

Background: Approximately 20-60% of rotator cuff repairs fail with higher failure rates in patients with larger or more chronic tears. Although MRI provides an objective estimate of tear size, it can only provide qualitative descriptions of tear chronicity. By contrast, ultrasound shear wave elastography (SWE) may assess tear chronicity by estimating tissue mechanical properties (ie, shear modulus).

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography.

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g.

Variability of glenohumeral positioning and bone-to-tendon marker length measurements in repaired rotator cuffs from longitudinal computed tomographic imaging.

Background: To address the need for more objective and quantitative measures of tendon healing in research studies, we intend to use computed tomography (CT) with implanted radiopaque markers on the repaired tendon to measure tendon retraction following rotator cuff repair. In our small prior study, retraction at 1-year follow-up averaged 16.1± 5.

Instantaneous helical axis estimation of glenohumeral kinematics: The impact of rotator cuff pathology.

The rotator cuff is theorized to contribute to force couples required to produce glenohumeral kinematics. Impairment in these force couples would theoretically result in impaired ball-and-socket kinematics. Although less frequently used than traditional kinematic descriptors (e.

Dynamic foraminal dimensions during neck motion 6.5 years after fusion and artificial disc replacement.

Objective: To compare changes in foraminal motion at two time points post-surgery between artificial disc replacement (ADR) and anterior cervical discectomy and fusion (ACDF).

Methods: Eight ACDF and 6 ADR patients (all single-level C5-6) were tested at 2 years (T1) and 6.5 years (T2) post-surgery.

Three-dimensional scapular morphology is associated with rotator cuff tears and alters the abduction moment arm of the supraspinatus.

Background: Numerous studies have reported an association between rotator cuff injury and two-dimensional measures of scapular morphology. However, the mechanical underpinnings explaining how these shape features affect glenohumeral joint function and lead to injury are poorly understood. We hypothesized that three-dimensional features of scapular morphology differentiate asymptomatic shoulders from those with rotator cuff tears, and that these features would alter the mechanical advantage of the supraspinatus.

Correlation of neural foraminal motion after surgical treatment of cervical radiculopathy with long-term patient reported outcomes.

Background: Post-surgical changes in adjacent segment motion are considered a factor in further development of degeneration and cervical radiculopathy. The objective was to examine the extent of correlations between physiological motion of cervical foramina and long-term patient reported outcomes (PRO).

Methods: Biplane X-ray imaging and CT-based markerless tracking were used to measure 3D static and dynamic dimensions during neck axial rotation and extension from 18 patients treated for C5-6 radiculopathy with fusion or arthroplasty.

Ankle Motion and Offloading in Short Leg Cast and Low and High Fracture Boots.

Background: Short leg casts (SLCs) and fracture boots are used to treat foot and ankle injuries, but the decision to use one device over the other is often subjective. This study compared the impact of SLCs and low and high fracture boots on ankle motion and offloading.

Methods: Twenty healthy adults were prospectively studied.

Asymptomatic Rotator Cuff Tears.

Asymptomatic rotator cuff tears (RCTs) are prevalent in the general population; they are positively associated with age and are common in the contralateral shoulder of individuals who are being treated for shoulder pain or a symptomatic RCT. Asymptomatic RCTs are likely to become symptomatic over time, corresponding with decreased patient-reported function, strength, and range of motion. Previous studies have largely reported inconsistent findings regarding patient-reported outcomes, strength, range of motion, and kinematics in individuals with asymptomatic RCTs.

Shear wave elastography of the healing human patellar tendon following ACL reconstruction.

Purpose: Anterior cruciate ligament (ACL) ruptures are common and are frequently reconstructed using a patellar tendon (PT) autograft. Unfortunately, the time course of PT healing after ACL reconstruction is not particularly well understood. Thus, the primary objective of this study was to use shear wave elastography (SWE) to evaluate the extent to which shear wave speed (SWS) is associated with time after ACL reconstruction.

Clinical utilization of shear wave elastography in the musculoskeletal system.

Shear wave elastography (SWE) is an emerging technology that provides information about the inherent elasticity of tissues by producing an acoustic radiofrequency force impulse, sometimes called an "acoustic wind," which generates transversely-oriented shear waves that propagate through the surrounding tissue and provide biomechanical information about tissue quality. Although SWE has the potential to revolutionize bone and joint imaging, its clinical application has been hindered by technical and artifactual challenges. Many of the stumbling blocks encountered during musculoskeletal SWE imaging are readily recognizable and can be overcome, but progressive advances in technology and a better understanding of image acquisition are required before SWE can reliably be used in musculoskeletal imaging.

Dynamic foraminal dimensions during neck extension and rotation in fusion and artificial disc replacement: an observational study.

Background: Changes in the dimensions of the cervical neural foramina (CNF) are considered to be a key factor in nerve root compression and development of cervical radiculopathy. However, to what extent foraminal geometry differs between patients who underwent anterior cervical discectomy and fusion (ACDF) and those who underwent total disc arthroplasty with an artificial disc (AD) during physiological motion is largely unknown.

Purpose: The objective of this study is to compare CNF dimensions during physiological neck motion between ACDF and AD.

Association Between Years of Competition and Shoulder Function in Collegiate Swimmers.

Background: Shoulder injuries are common among competitive swimmers, and the progression of shoulder pathology is not well understood. The objective of this study was to assess the extent to which years of competitive swim training were associated with physical properties of the supraspinatus muscle and tendon, shoulder strength, and self-reported assessments of shoulder pain and function.

Hypothesis: Increasing years of competition will be associated with declining physical properties of the supraspinatus muscle/tendon and declining self-reported assessments of pain and function.

Effects of age and pathology on shear wave speed of the human rotator cuff.

Rotator cuff tears are common and often repaired surgically, but post-operative repair tissue healing, and shoulder function can be unpredictable. Tear chronicity is believed to influence clinical outcomes, but conventional clinical approaches for assessing tear chronicity are subjective. Shear wave elastography (SWE) is a promising technique for assessing soft tissue via estimates of shear wave speed (SWS), but this technique has not been used extensively on the rotator cuff.

Dynamic measurements of cervical neural foramina during neck movements in asymptomatic young volunteers.

Purpose: Neural foraminal dimensions are considered important in nerve root compression and development of cervical radiculopathy, but baseline data regarding their range during normal motion are not available. An in vivo study of cervical foraminal motion was conducted to characterize normal 3D dynamic foraminal dimensions during physiological neck motion and compare between different tasks and intervertebral segments.

Methods: Biplane X-ray imaging and computed tomography-based markerless tracking were used to measure foraminal height (FH) and width (FW) from five asymptomatic subjects during neck axial rotation and extension.

Effects of asymptomatic rotator cuff pathology on in vivo shoulder motion and clinical outcomes.

Background: The incidence of asymptomatic rotator cuff tears has been reported to range from 15% to 39%, but the influence of asymptomatic rotator cuff pathology on shoulder function is not well understood. This study assessed the effects of asymptomatic rotator cuff pathology on shoulder kinematics, strength, and patient-reported outcomes.

Methods: A clinical ultrasound examination was performed in 46 asymptomatic volunteers (age: 60.