Characterizing 24-Hour Skeletal Muscle Gene Expression Alongside Metabolic and Endocrine Responses Under Diurnal Conditions.

Context: Skeletal muscle plays a central role in the storage, synthesis, and breakdown of nutrients, yet little research has explored temporal responses of this human tissue, especially with concurrent measures of systemic biomarkers of metabolism.

Objective: To characterize temporal profiles in skeletal muscle expression of genes involved in carbohydrate metabolism, lipid metabolism, circadian clocks, and autophagy and descriptively relate them to systemic metabolites and hormones during a controlled laboratory protocol.

Methods: Ten healthy adults (9M/1F, [mean ± SD] age 30 ± 10 years; BMI 24.

Finding Your Job in Orthopaedic Trauma: A Survey Revealing the Cold Hard Facts.

Objectives: Finding a first job after fellowship can be stressful due to the uncertainty about which resources to use, including fellowship program directors, residency faculty, and other sources. There are more than 90 orthopaedic trauma fellows seeking jobs annually. We surveyed orthopaedic trauma fellows to determine the job search process.

Single-Incision, Four-Compartment Fasciotomy and Application of Negative Pressure Dressing for Compartment Syndrome of the Leg.

The video described by this article presents a safe and effective technique for single-incision, 4-compartment fasciotomy of the leg in a patient with a tibial plateau fracture and clinically diagnosed compartment syndrome. We also demonstrate a technique for the application of a negative pressure wound dressing when delayed closure or coverage is planned.

Dorsal Impaction Injuries of the Distal Radius: Operative Technique Through Dorsal Approach to the Wrist.

Distal radius fractures vary widely in fracture pattern and displacement. Impaction injuries involving the dorsal articular surface of the distal radius can present challenges when anatomic reduction and fixation is attempted through a standard volar approach. Dorsal approach to the distal radius can provide direct visualization of these fracture patterns, greatly facilitating anatomic reduction and stabilization.

Phosphate Loading Does not Improve 30-km Cycling Time-Trial Performance in Trained Cyclists.

Phosphate is integral to numerous metabolic processes, several of which strongly predict exercise performance (i.e., cardiac function, oxygen transport, and oxidative metabolism).

Elbow Trauma: An Evidence-Based Approach to Improving Outcomes.

The management of elbow fractures remains difficult and controversial. The failure rate of surgical intervention in elbow fractures remains higher than that seen with other fractures, and there remains significant room for improvement in the care of these injuries. Evidence-based management strategies for elbow fractures and how to prevent and manage complications following elbow fracture surgery have been described.

Recommendations on the use of virtual interviews in the orthopaedic trauma fellowship match: A survey of applicant and fellowship director perspectives.

Objective: The aim of this study was to assess applicant and fellowship director (FD) perspectives on virtual interviewing based on the 2019 to 2020 orthopaedic trauma fellowship interview experience and to develop recommendations for future application cycles.

Methods: Web-based surveys were distributed to all matched applicants and orthopaedic trauma FDs after the 2019 and 2020 orthopaedic trauma fellowship match. Thirty-one applicants and 23 FDs completed the survey-response rates of 34% and 38%, respectively.

Retrograde Intramedullary Nail for Distal Femur Fracture, Through a Total Knee Arthroplasty.

Distal femur fractures are common in the elderly population. The risk of sustaining a distal femur fracture is increased with the presence of total knee arthroplasty components. Fixation with a retrograde intramedullary nail is a viable option for treatment of these injuries.

Examination Under Anesthesia for Evaluation of Hip Stability in Posterior Wall Acetabulum Fractures.

Posterior wall fractures of the acetabulum are the most common acetabular fracture pattern. Stable, congruous hips are amenable to nonoperative management, whereas any instability in the hip is an indication for operative management of the posterior wall fracture. Stability cannot adequately be predicted by static imaging alone.

Modern Implant Options for the Treatment of Distal Femur Fractures.

Distal femur fractures occur in a periarticular fracture pattern and disproportionately afflict an aging population. Although the goals of treatment have not changed, the emergence of new surgical techniques and devices has recently been developed and refined to treat this challenging fracture pattern. Treatment options include open reduction and internal fixation with periarticular locking plates, intramedullary nails, or distal femur replacement.

Inhibition of p38 mitogen-activated protein kinase signaling reduces fibrosis and lipid accumulation after rotator cuff repair.

Background: The repair of rotator cuff tears is often complicated by fatty degeneration, which is the combination of lipid accumulation, fibrosis, inflammation, and muscle weakness. A signaling molecule that plays a central role in these processes is p38 mitogen-activated protein kinase (MAPK). The purpose of this study was to evaluate the ability of a small molecule inhibitor of p38 MAPK, SB203580, to reduce fatty degeneration in a preclinical model of rotator cuff injury and repair.

Inhibition of 5-LOX, COX-1, and COX-2 increases tendon healing and reduces muscle fibrosis and lipid accumulation after rotator cuff repair.

Background: The repair and restoration of function after chronic rotator cuff tears are often complicated by muscle atrophy, fibrosis, and fatty degeneration of the diseased muscle. The inflammatory response has been implicated in the development of fatty degeneration after cuff injuries. Licofelone is a novel anti-inflammatory drug that inhibits 5-lipoxygenase (5-LOX), as well as cyclooxygenase (COX)-1 and COX-2 enzymes, which play important roles in inducing inflammation after injuries.

Simvastatin reduces fibrosis and protects against muscle weakness after massive rotator cuff tear.

Background: Chronic rotator cuff tears are a common source of shoulder pain and disability, and patients with chronic cuff tears often have substantial weakness, fibrosis, inflammation, and fat accumulation. Identifying therapies to prevent the development of these pathologic processes will likely have a positive impact on clinical outcomes. Simvastatin is a drug with demonstrated anti-inflammatory and antifibrotic effects in many tissues but had not previously been studied in the context of rotator cuff tears.

Reduced muscle fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears.

Background: A persistent atrophy of muscle fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that muscles from patients with chronic rotator cuff tears have reduced muscle fiber force production, disordered myofibrils, and an accumulation of fat vacuoles.

Muscle fibers are injured at the time of acute and chronic rotator cuff repair.

Background: Rotator cuff tears are a common source of shoulder pain and disability. Even after surgical repair, some patients continue to have reduced function and progression of fatty degeneration. Because patients with chronic cuff tears often experience muscle shortening, it is possible that repairing the tendon to its anatomic footprint induces a stretch-induced muscle injury that could contribute to failures of the repair and perhaps ongoing pain.

Elevation in circulating biomarkers of cartilage damage and inflammation in athletes with femoroacetabular impingement.

Background: Femoroacetabular impingement (FAI) is one of the most common causes of early cartilage and labral damage in the nondysplastic hip. Biomarkers of cartilage degradation and inflammation are associated with osteoarthritis. It was not known whether patients with FAI have elevated levels of biomarkers of cartilage degradation and inflammation.

Changes in circulating biomarkers of muscle atrophy, inflammation, and cartilage turnover in patients undergoing anterior cruciate ligament reconstruction and rehabilitation.

Background: After anterior cruciate ligament (ACL) reconstruction, there is significant atrophy of the quadriceps muscles that can limit full recovery and place athletes at risk for recurrent injuries with return to play. The cause of this muscle atrophy is not fully understood.

Hypothesis: Circulating levels of proatrophy, proinflammatory, and cartilage turnover cytokines and biomarkers would increase after ACL reconstruction.

MMP inhibition as a potential method to augment the healing of skeletal muscle and tendon extracellular matrix.

The extracellular matrix (ECM) of skeletal muscle and tendon is composed of different types of collagen molecules that play important roles in the transmission of forces throughout the body, and in the repair and regeneration of injured tissues. Fibroblasts are the primary cells in muscle and tendon that maintain, repair, and modify the ECM in response to mechanical loading, injury, and inactivity. Matrix metalloproteinases (MMPs) are enzymes that digest collagen and other structural molecules, which are synthesized and excreted by fibroblasts.

Rotator cuff tear reduces muscle fiber specific force production and induces macrophage accumulation and autophagy.

Full-thickness tears to the rotator cuff can cause severe pain and disability. Untreated tears progress in size and are associated with muscle atrophy and an infiltration of fat to the area, a condition known as "fatty degeneration." To improve the treatment of rotator cuff tears, a greater understanding of the changes in the contractile properties of muscle fibers and the molecular regulation of fatty degeneration is essential.

Transforming growth factor-beta induces skeletal muscle atrophy and fibrosis through the induction of atrogin-1 and scleraxis.

Introduction: Transforming growth factor-beta (TGF-β) is a well-known regulator of fibrosis and inflammation in many tissues. During embryonic development, TGF-β signaling induces expression of the transcription factor scleraxis, which promotes fibroblast proliferation and collagen synthesis in tendons. In skeletal muscle, TGF-β has been shown to induce atrophy and fibrosis, but the effect of TGF-β on muscle contractility and the expression of scleraxis and atrogin-1, an important regulator of muscle atrophy, were not known.