Does transosseous-equivalent rotator cuff repair biomechanically provide a "self-reinforcement" effect compared with single-row repair?

Background: Transosseous-equivalent (TOE) rotator cuff repair has been theorized to be "self-reinforcing" against potentially destructive and increasing tendon loads. The goal of this study was to biomechanically verify and characterize the effect of increasing tendon load on frictional resistance over a repaired footprint for single-row (SR) and TOE repair techniques.

Methods: In 10 fresh frozen human shoulders, TOE and SR supraspinatus tendon repairs were performed in each specimen.

Spatially-resolved hydraulic conductivity estimation via poroelastic magnetic resonance elastography.

Poroelastic magnetic resonance elastography is an imaging technique that could recover mechanical and hydrodynamical material properties of in vivo tissue. To date, mechanical properties have been estimated while hydrodynamical parameters have been assumed homogeneous with literature-based values. Estimating spatially-varying hydraulic conductivity would likely improve model accuracy and provide new image information related to a tissue's interstitial fluid compartment.

The lung corps' approach to reducing health disparities in respiratory disease.

Health disparities are prevalent across diseases of the respiratory system, and are major sources of morbidity and mortality among disadvantaged populations in the United States. The American Thoracic Society (ATS) aims to reduce disparities that are both avoidable and unjust. In meeting this goal, the ATS is committed to creating the Lung Corps, a diverse group of senior, mid-level, and junior clinicians, trainees, researchers, and public health practitioners to help achieve health equality.

The role of pectoralis major and latissimus dorsi muscles in a biomechanical model of massive rotator cuff tear.

Background: Superior migration of the humeral head after massive rotator cuff tear (mRCT) is thought to lead to cuff tear arthropathy. Previous biomechanical studies have demonstrated the ability of the pectoralis major and latissimus dorsi (PM/LD) muscles to resist this migration. This study examined the role of PM/LD muscles on glenohumeral joint forces and acromiohumeral contact pressures in a mRCT model.

Biomechanical effects of humeral neck-shaft angle and subscapularis integrity in reverse total shoulder arthroplasty.

Background: The variability in functional outcomes and the occurrence of scapular notching and instability after reverse total shoulder arthroplasty remain problems. The objectives of this study were to measure the effect of reverse humeral component neck-shaft angle on impingement-free range of motion, abduction moment, and anterior dislocation force and to evaluate the effect of subscapularis loading on dislocation force.

Methods: Six cadaveric shoulders were tested with 155°, 145°, and 135° reverse shoulder humeral neck-shaft angles.

A large humeral avulsion of the glenohumeral ligaments decreases stability that can be restored with repair.

Background: Humeral avulsion of the glenohumeral ligaments (HAGL) has become a recognized cause of recurrent shoulder instability; however, it is unknown whether small and large HAGL lesions have similarly destabilizing effects and if large lesion repair results in restoration of stability.

Questions/purposes: In a cadaver model, we evaluated the effect of small and large HAGL lesions and large HAGL lesion repair on glenohumeral ROM, translation, and kinematics.

Methods: We measured rotational ROM, humeral head translation under load, and humeral head apex position in eight cadaveric shoulders.

Role of the superior shoulder capsule in passive stability of the glenohumeral joint.

Background: The shoulder capsule is the main static stabilizer of the glenohumeral joint. However, few studies specifically address the function of the superior shoulder capsule, which is usually damaged in patients with complete rotator cuff tears. Therefore, the purpose of this study was to determine the biomechanical contribution of the superior shoulder capsule to passive stability of the glenohumeral joint.

3D multislab, multishot acquisition for fast, whole-brain MR elastography with high signal-to-noise efficiency.

Purpose: To develop an acquisition scheme for generating MR elastography (MRE) displacement data with whole-brain coverage, high spatial resolution, and adequate signal-to-noise ratio (SNR) in a short scan time.

Theory And Methods: A 3D multislab, multishot acquisition for whole-brain MRE with 2.0 mm isotropic spatial resolution is proposed.

Biomechanical characteristics of the horizontal mattress stitch: implication for double-row and suture-bridge rotator cuff repair.

Background: We investigated the effects of bite-size horizontal mattress stitch (distance between the limbs passed through the tendon) on the biomechanical properties of the repaired tendon.

Methods: We anchored 20 bovine Achilles tendons to bone using no. 2 high-strength suture and 5-mm titanium suture anchors in a mattress-suture technique.

The influence of partial subscapularis tendon tears combined with supraspinatus tendon tears.

Background: With the advent of arthroscopy, more partial subscapularis tears are being recognized. The biomechanical effects of partial subscapularis tears are unknown, and there is no consensus as to their treatment. Therefore, the objective of this study was to evaluate and to quantify the changes in range of motion and glenohumeral kinematics for isolated subscapularis partial tears, combined subscapularis and supraspinatus tears, supraspinatus repair, and combined supraspinatus and subscapularis repair.

The biomechanical effect of increased valgus on total knee arthroplasty: a cadaveric study.

The effects of valgus load on cadaveric knees following total knee arthroplasty (TKA) were investigated using a custom testing system. TKAs were performed on 8 cadaveric knees and tested at 0°, 30°, and 60° knee flexion in both neutral and 5° valgus. Fuji pressure sensitive film was used to quantify contact areas and pressures and MCL strain was determined using a Microscribe digitizing system.

Normalization of sweat chloride concentration and clinical improvement with ivacaftor in a patient with cystic fibrosis with mutation S549N.

The cystic fibrosis (CF) protein forms an anion channel in epithelial cells, and the absence or defective function of this channel results in the clinical manifestations of CF. CF is an autosomal recessive disorder, and its many disease-causing mutations divide into five or six classes. There are 10 known class 3 gating mutations, the most common of which is G551D.

Biomechanical effects of a 2 suture-pass medial inter-implant mattress on transosseous-equivalent rotator cuff repair and considerations for a "technical efficiency ratio".

Background: Rotator cuff repair involving fewer tendon suture passes without compromising biomechanical performance would represent a technical advancement. An inter-implant "medial pulley-mattress" transosseous-equivalent (MP-TOE) repair requiring fewer tendon suture-passes was hypothesized to provide equivalent biomechanical characteristics compared to the control.

Methods: In 6 human cadaveric shoulders, a transosseous-equivalent (TOE) repair (control) was performed utilizing 2 separate medial mattresses resulting in 4 tendon-bridging sutures.

Anterior capsulolabral lesions combined with supraspinatus tendon tears: biomechanical effects of the pathologic condition and repair in human cadaveric shoulders.

Purpose: Our purpose was to investigate the effect of supraspinatus tendon tear combined with anterior capsulolabral injury on glenohumeral joint biomechanics and to identify which structures should be repaired when both pathologic conditions are present.

Methods: Eight cadaveric shoulders were tested on a custom system. Five conditions were tested: intact supraspinatus full-thickness tear, supraspinatus tear combined with Bankart lesion, supraspinatus repair, and supraspinatus repair combined with Bankart repair.

Simultaneous anatomic reconstruction of the acromioclavicular and coracoclavicular ligaments using a single tendon graft.

Purpose: The purpose of this study was to introduce a novel surgical technique for simultaneous anatomic reconstruction of the acromioclavicular and coracoclavicular ligaments using a single tendon graft and to compare its biomechanical characteristics to those of a coracoid cerclage reconstruction of the coracoclavicular ligaments.

Methods: Six matched pairs of human acromioclavicular joints with an average age of 54.8 ± 7.

Including spatial information in nonlinear inversion MR elastography using soft prior regularization.

Tissue displacements required for mechanical property reconstruction in magnetic resonance elastography (MRE) are acquired in a magnetic resonance imaging (MRI) scanner, therefore, anatomical information is available from other imaging sequences. Despite its availability, few attempts to incorporate prior spatial information in the MRE reconstruction process have been reported. This paper implements and evaluates soft prior regularization (SPR), through which homogeneity in predefined spatial regions is enforced by a penalty term in a nonlinear inversion strategy.

Biomechanical characteristics of osteochondral defects of the humeral capitellum.

Background: The repetitive, excessive compression forces in the radiocapitellar joint caused by elbow valgus stresses during throwing motions can result in osteochondritis dissecans (OCD) of the humeral capitellum in adolescent athletes.

Purpose: To assess the effect of elbow valgus torque on contact pressure in the radiocapitellar joint and that of central and lateral capitellar osteochondral defects on radiocapitellar joint contact pressure, elbow valgus laxity, and ulnar collateral ligament (UCL) strain.

Study Design: Controlled laboratory study.

Expression of the secondary granule proteins major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX) is required for eosinophilopoiesis in mice.

Eosinophil activities are often linked with allergic diseases such as asthma and the pathologies accompanying helminth infection. These activities have been hypothesized to be mediated, in part, by the release of cationic proteins stored in the secondary granules of these granulocytes. The majority of the proteins stored in these secondary granules (by mass) are major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX).

Silicone breast phantoms for elastographic imaging evaluation.

Purpose: Breast cancer is a major public health issue for women, and early detection significantly increases survival rate. Currently, there is increased research interest in elastographic soft-tissue imaging techniques based on the correlation between pathology and mechanical stiffness. Anthropomorphic breast phantoms are critical for ex vivo validation of emerging elastographic technologies.

Kinematic effect of MGHL incorporation into Bankart repair.

Surgical treatment for traumatic shoulder instability has progressed in tandem with the evolution of the current understanding of the anatomy and biomechanics of the shoulder. Proponents of incorporating the middle glenohumeral ligament (MGHL) in Bankart repair believe this technique could increase repair strength. The purpose of this biomechanical study was to compare the range of motion and humeral head kinematic changes that result from including the MGHL in a Bankart repair in an effort to identify possible changes in shoulder biomechanics as a result of this addition in surgical repair.

Contribution of osseous and muscular stabilizing effects with the Latarjet procedure for anterior instability without glenoid bone loss.

Background: The Latarjet procedure is used to treat anterior shoulder instability. Authors contend that the main concept of the operation is using the conjoined tendon as a sling to lower the subscapularis, reinforcing the anteroinferior capsule. The effects of the "sling," as well as stability and range of motion (ROM), after the Latarjet procedure have not been documented.

Local mechanical properties of white matter structures in the human brain.

The noninvasive measurement of the mechanical properties of brain tissue using magnetic resonance elastography (MRE) has emerged as a promising method for investigating neurological disorders. To date, brain MRE investigations have been limited to reporting global mechanical properties, though quantification of the stiffness of specific structures in the white matter architecture may be valuable in assessing the localized effects of disease. This paper reports the mechanical properties of the corpus callosum and corona radiata measured in healthy volunteers using MRE and atlas-based segmentation.

Biomechanical comparison of single-row, double-row, and transosseous-equivalent repair techniques after healing in an animal rotator cuff tear model.

The transosseous-equivalent (TOE) rotator cuff repair technique increases failure loads and contact pressure and area between tendon and bone compared to single-row (SR) and double-row (DR) repairs, but no study has investigated if this translates into improved healing in vivo. We hypothesized that a TOE repair in a rabbit chronic rotator cuff tear model would demonstrate a better biomechanical profile than SR and DR repairs after 12 weeks of healing. A two-stage surgical procedure was performed on 21 New Zealand White Rabbits.