Finite element-based evaluation of the supraspinatus tendon biomechanical environment necessitates better clinical management based on tear location and thickness.

Partial-thickness rotator cuff tears are a common cause of pain and disability and are central to developing full-thickness rotator cuff tears. However, limited knowledge exists regarding the alterations to the mechanical environment due to these lesions. Computational models that study the alterations to the mechanical environment of the supraspinatus tendon can help advance clinical management to avoid tear progression and provide a basis for surgical intervention.

Disparities in Rotator Cuff Tear Progression Definitions and Rates: A Systematic Review.

Background: While rotator cuff tears are prevalent in the general population, the natural history of this disease is unclear. Understanding rotator cuff tear progression is crucial for refining surgical indications and evaluating the necessity of early interventions. This study presents an in-depth analysis of the existing literature on the definitions and progression rates of rotator cuff tears, aiming to enhance clinical decision making and patient outcomes.

Effect of Tear Size and Location on Supraspinatus Tendon Strain During Activities of Daily Living and Physiotherapy.

The supraspinatus tendon plays a crucial role in shoulder abduction, making it one of the common structures affected by injury. Clinically, crescent-shaped tears are the most commonly seen tear shape. By developing six specimen-specific, three-dimensional, supraspinatus-infraspinatus finite element model with heterogeneous material properties, this study aimed to examine the changes in tissue deformation (maximum principal strain) of the supraspinatus tendon due to specimen-specific material properties and rotator cuff tear size.

Successive tendon injury in an rat overload model induces early damage and acute healing responses.

Tendinopathy is a degenerative condition resulting from tendons experiencing abnormal levels of multi-scale damage over time, impairing their ability to repair. However, the damage markers associated with the initiation of tendinopathy are poorly understood, as the disease is largely characterized by end-stage clinical phenotypes. Thus, this study aimed to evaluate the acute tendon responses to successive fatigue bouts of tendon overload using an in vivo passive ankle dorsiflexion system.

A Passive Ankle Dorsiflexion Testing System for an In Vivo Model of Overuse-induced Tendinopathy.

Tendinopathy is a chronic tendon condition that results in pain and loss of function and is caused by repeated overload of the tendon and limited recovery time. This protocol describes a testing system that cyclically applies mechanical loads via passive dorsiflexion to the rat Achilles tendon. The custom-written code consists of pre- and post-cyclic loading measurements to assess the effects of the loading protocol along with the feedback control-based cyclic fatigue loading regimen.

A passive ankle dorsiflexion testing system to assess mechanobiological and structural response to cyclic loading in rat Achilles tendon.

Tendinopathy is thought to be caused by repeated overload of the tendon with insufficient recovery time, leading to an inadequate healing response and incomplete recovery of preinjury material strength and function. The etiology of tendinopathy induced by mechanical load is being explored with a variety of mechanical load scenarios in small animals. This study establishes a testing system that applies passive ankle dorsiflexion to a rat hindlimb, estimates the force applied to the tendon during cyclic loading and enables the assessment of subsequent structural and biological changes.

Effect of intraarticular pressure on glenohumeral kinematics during a simulated abduction motion: a cadaveric study.

Background: The current understanding of glenohumeral joint stability is defined by active restrictions and passive stabilizers including naturally-occurring negative intraarticular pressure. Cadaveric specimens have been used to evaluate the role of intraarticular pressure on joint stability, although, while the shoulder's negative intraarticular pressure is universally acknowledged, it has been inconsistently accounted for.

Hypothesis: During continuous, passive humeral abduction, releasing the native intraarticular pressure increases joint translation, and restoring this pressure decreases joint translations.

A Validated Three-Dimensional, Heterogenous Finite Element Model of the Rotator Cuff and The Effects of Collagen Orientation.

Continuum mechanics-based finite element models of the shoulder aim to quantify the mechanical environment of the joint to aid in clinical decision-making for rotator cuff injury and disease. These models allow for the evaluation of the internal loading of the shoulder, which cannot be measured in-vivo. This study uses human cadaveric rotator cuff samples with surface tendon strain estimates, to validate a heterogeneous finite element model of the supraspinatus-infraspinatus complex during various load configurations.

Minimally invasive, sustained-release relaxin-2 microparticles reverse arthrofibrosis.

Substantial advances in biotherapeutics are distinctly lacking for musculoskeletal diseases. Musculoskeletal diseases are biomechanically complex and localized, highlighting the need for novel therapies capable of addressing these issues. All frontline treatment options for arthrofibrosis, a debilitating musculoskeletal disease, fail to treat the disease etiology-the accumulation of fibrotic tissue within the joint space.

Lateral release associated with MPFL reconstruction in patients with acute patellar dislocation.

Objective: Medial patellofemoral ligament (MPFL) injury occurs in the majority of the cases of acute patellar dislocation. The role of concomitant lateral retinaculum release with MPFL reconstruction is not clearly understood. Even though the lateral retinaculum plays a role in both medial and lateral patellofemoral joint stability in MPFL intact knees, studies have shown mixed clinical outcomes following its release during MPFL reconstruction surgery.

Recommended musculoskeletal and sports ultrasound terminology: a Delphi-based consensus statement.

The current lack of agreement regarding standardised terminology in musculoskeletal and sports ultrasound presents challenges in education, clinical practice and research. This consensus was developed to provide a reference to improve clarity and consistency in communication. A multidisciplinary expert panel was convened consisting of 18 members representing multiple specialty societies identified as key stakeholders in musculoskeletal and sports ultrasound.

Recommended Musculoskeletal and Sports Ultrasound Terminology: A Delphi-Based Consensus Statement.

Objectives: The current lack of agreement regarding standardized terminology in musculoskeletal and sports ultrasound presents challenges in education, clinical practice, and research. This consensus was developed to provide a reference to improve clarity and consistency in communication.

Methods: A multidisciplinary expert panel was convened consisting of 18 members representing multiple specialty societies identified as key stakeholders in musculoskeletal and sports ultrasound.

Lateral Release With Tibial Tuberosity Transfer Alters Patellofemoral Biomechanics Promoting Multidirectional Patellar Instability.

Purpose: The purpose of this study was to develop and validate a finite element (FE) model of the patellofemoral (PF) joint to characterize patellofemoral instability, and to highlight the effect of lateral retinacular release in combination with tibial tuberosity transfer with respect to contact pressures (CP), contact area (CA), and kinematics during knee flexion.

Methods: A comprehensive, dynamic FE model of the knee joint was developed and validated through parametric comparison of PF kinematics, CP, and CA between FE simulations and in vitro, cadaveric experiments. Using this FE model, we characterized the effect of patellar instability, lateral retinacular release (LR), and tibial tuberosity transfer (TTT) in the setting of medial patellofemoral ligament injury during knee flexion.

Tendinopathy and tendon material response to load: What we can learn from small animal studies.

Tendinopathy is a debilitating disease that causes as much as 30% of all musculoskeletal consultations. Existing treatments for tendinopathy have variable efficacy, possibly due to incomplete characterization of the underlying pathophysiology. Mechanical load can have both beneficial and detrimental effects on tendon, as the overall tendon response depends on the degree, frequency, timing, and magnitude of the load.

Evolution of knowledge on meniscal biomechanics: a 40 year perspective.

Background: Knowledge regarding the biomechanics of the meniscus has grown exponentially throughout the last four decades. Numerous studies have helped develop this knowledge, but these studies have varied widely in their approach to analyzing the meniscus. As one of the subcategories of mechanical phenomena Medical Subject Headings (MeSH) terms, mechanical stress was introduced in 1973.

Imaging of Acute Shoulder Trauma.

Acute injuries to the shoulder girdle are common and frequently encountered by the practicing radiologist. The type of injury is highly dependent on the age of the patient and mechanism of trauma with injuries occurring at the site of greatest mechanical weakness. In this review, we discuss the main clinical features and key imaging findings for the most common shoulder injuries.

Comparison of Patellofemoral Kinematics and Stability After Medial Patellofemoral Ligament and Medial Quadriceps Tendon-Femoral Ligament Reconstruction.

Background: There is a lack of evidence regarding the optimum extensor-sided fixation method for medial patellofemoral ligament (MPFL) reconstruction. There is increased interest in avoiding patellar drilling via soft tissue-only fixation to the distal quadriceps, thus reconstructing the medial quadriceps tendon-femoral ligament (MQTFL). The biomechanical implications of differing extensor-sided fixation constructs remain unknown.

Effect of rotator cuff muscle activation on glenohumeral kinematics: A cadaveric study.

Healthy shoulder function requires the coordination of the rotator cuff muscles to maintain the humeral head's position in the glenoid. While glenohumeral stability has been studied in various settings, few studies have characterized the effect of dynamic rotator cuff muscle loading on glenohumeral translation during shoulder motion. We hypothesize that dynamic rotator cuff muscle activation decreases joint translation during continuous passive abduction of the humerus in a cadaveric model of scapular plane glenohumeral abduction.

Implant cut-out following cephalomedullary nailing of intertrochanteric femur fractures: Are helical blades to blame?

Introduction: Implant cut-out remains a common cause of cephalomedullary nail (CMN) failure and patient morbidity following surgical treatment of intertrochanteric femur fractures. Recent studies have suggested an increased rate of CMN cut-out with helical blades as opposed to lag screws. We compared rates of overall cut-out between helical blades and lag screws and used bivariate and multivariate analysis to determine the role of proximal fixation method among other variables on risk for cut-out.

Shoulder biomechanics of RC repair and Instability: A systematic review of cadaveric methodology.

Background: Numerous biomechanical studies have addressed normal shoulder function and the factors that affect it. While these investigations include a mix of in-vivo clinical reports, ex-vivo cadaveric studies, and computer-based simulations, each has its own strengths and limitations. A robust methodology is essential in cadaveric work but does not always come easily.

Rehabilitation following meniscal repair: a systematic review.

Objective: To review existing biomechanical and clinical evidence regarding postoperative weight-bearing and range of motion restrictions for patients following meniscal repair surgery.

Methods And Data Sources: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline, we searched MEDLINE using following search strategy: (((("Weight-Bearing/physiology"[Mesh]) OR "Range of Motion, Articular"[Mesh]) OR "Rehabilitation"[Mesh])) AND ("Menisci, Tibial"[Mesh]). Additional articles were derived from previous reviews.

Evaluating Nonoperative Treatments for Adhesive Capsulitis.

Patients commonly present with shoulder complaints to the primary care and orthopaedic setting. The differential includes rotator cuff tears, subacromial impingement, osteoarthritis, and adhesive capsulitis, also known as frozen shoulder. Despite the prevalence of adhesive capsulitis, it is commonly misdiagnosed and management remains unclear.

Double Oblique Osteotomy: A Technique for Correction of Posttraumatic Deformities of the Distal Femur.

Objective: To evaluate the outcomes of a double oblique osteotomy for the management of distal femoral malunions and a combination malunion/nonunion.

Design: Case series.

Setting: Level 1/2 hospital.

Comparison of Anterior and Posterior Cortico-steroid Injections for Pain Relief and Functional Improvement in Shoulder Impingement Syndrome.

Subacromial impingement syndrome (SIS) is the most common cause of shoulder pain. Treatment options for SIS include conservative modalities such as use of nonsteroidal anti-inflammatory drugs, physical therapy, and subacromial corticosteroid injections (CSIs). Although studies have found improvement in pain, function, and range of motion after CSI, the effect of injection route (anterior or posterior) on shoulder pain in patients with SIS has not been investigated.