Creation of a Knee Joint-on-a-Chip for Modeling Joint Diseases and Testing Drugs.

The high prevalence of debilitating joint diseases like osteoarthritis (OA) poses a high socioeconomic burden. Currently, the available drugs that target joint disorders are mostly palliative. The unmet need for effective disease-modifying OA drugs (DMOADs) has been primarily caused by the absence of appropriate models for studying the disease mechanisms and testing potential DMOADs.

Human Mesenchymal Stem Cell-Derived Miniature Joint System for Disease Modeling and Drug Testing.

Diseases of the knee joint such as osteoarthritis (OA) affect all joint elements. An in vitro human cell-derived microphysiological system capable of simulating intraarticular tissue crosstalk is desirable for studying etiologies/pathogenesis of joint diseases and testing potential therapeutics. Herein, a human mesenchymal stem cell-derived miniature joint system (miniJoint) is generated, in which engineered osteochondral complex, synovial-like fibrous tissue, and adipose tissue are integrated into a microfluidics-enabled bioreactor.

Graphene oxide-functionalized nanocomposites promote osteogenesis of human mesenchymal stem cells via enhancement of BMP-SMAD1/5 signaling pathway.

Biomaterials that can harness the intrinsic osteogenic potential of stem cells offer a promising strategy to accelerate bone regeneration and repair. Previously, we had used methacrylated gelatin (GelMA)-based scaffolds to achieve bone formation from human mesenchymal stem cells (hMSCs). In this study, we aimed to further enhance hMSC osteogenesis by incorporating graphene oxide (GO)-based nanosheets into GelMA.

Urolithin A Protects Chondrocytes From Mechanical Overloading-Induced Injuries.

Physiological mechanical stimulation has been shown to promote chondrogenesis, but excessive mechanical loading results in cartilage degradation. Currently, the underlying mechanotransduction pathways in the context of physiological and injurious loading are not fully understood. In this study, we aim to identify the critical factors that dictate chondrocyte response to mechanical overloading, as well as to develop therapeutics that protect chondrocytes from mechanical injuries.

Pathogenesis of Osteoarthritis: Risk Factors, Regulatory Pathways in Chondrocytes, and Experimental Models.

As the most common chronic degenerative joint disease, osteoarthritis (OA) is the leading cause of pain and physical disability, affecting millions of people worldwide. Mainly characterized by articular cartilage degradation, osteophyte formation, subchondral bone remodeling, and synovial inflammation, OA is a heterogeneous disease that impacts all component tissues of the articular joint organ. Pathological changes, and thus symptoms, vary from person to person, underscoring the critical need of personalized therapies.

Shoulder functional performance status of Minor League professional baseball pitchers.

Background And Hypothesis: The Overhead Shoulder and Elbow Score (Kerlan-Jobe Orthopaedic Clinic [KJOC] score) among healthy or uninjured professional baseball pitchers is lacking. We hypothesized that shoulder function and performance status measured by the KJOC score among active Minor League professional baseball pitchers were high at pre-participation and that the pitchers who had not been previously treated for a shoulder injury and were playing without arm trouble had significantly higher KJOC scores than their counterparts.

Methods: In this cross-sectional survey, data on pre-participation KJOC scores, along with other study measures, were collected from a cohort of Minor League professional baseball pitchers.

Treatment of partial ulnar collateral ligament tears in the elbow with platelet-rich plasma.

Background: Studies have demonstrated the potential of platelet-rich plasma (PRP) to heal damaged tissue. To date, there are no published reports of clinical outcomes of partial ulnar collateral ligament (UCL) tears of the elbow treated with PRP.

Hypothesis: Platelet-rich plasma will promote the healing of partial UCL tears and allow a return to play.

Anconeus epitrochlearis as a source of medial elbow pain in baseball pitchers.

Medial elbow pain is reported in 18% to 69% of baseball players aged of 9 and 19 years. This is due to the large valgus stresses focused on the medial side of the elbow during overhead activities. In overhead throwers and pitchers, pain can be attributed to valgus extension overload with resultant posteromedial impingement, overuse of the flexor-pronator musculature resulting in medial epicondylitis, or occasional muscle tears or ruptures.

'Batter's shoulder': can athletes return to play at the same level after operative treatment?

Background: Batter's shoulder has been defined as posterior subluxation of the lead shoulder during the baseball swing. However, it is unclear whether or how frequently patients may return to play after treatment of this uncommon condition.

Questions/purposes: We therefore determined the rate of return to play after operative treatment for Batter's shoulder and whether ROM was restored.

Management and outcomes of latissimus dorsi and teres major injuries in professional baseball pitchers.

Background: Very little data exist on latissimus dorsi (LD) and teres major (TM) injuries in professional baseball pitchers.

Purpose: This review was undertaken to report on the management and outcomes of baseball pitchers with injury to 1 or both of these muscles.

Study Design: Case series; Level of evidence, 4.

Outcome of type II superior labral anterior posterior repairs in elite overhead athletes: Effect of concomitant partial-thickness rotator cuff tears.

Background: There are conflicting reports in the literature regarding the outcome of superior labral anterior posterior (SLAP) repairs in overhead athletes and a paucity of data demonstrating ability to return to prior level of competition.

Hypothesis: Kerlan-Jobe Orthopaedic Clinic shoulder and elbow score provides more accurate assessment of shoulder function and ability to return to previous level of athletic competition after SLAP lesion repair than does the conventional American Shoulder and Elbow Surgeons scoring system.

Study Design: Cohort study; Level of evidence, 3.

The development and validation of a functional assessment tool for the upper extremity in the overhead athlete.

Background: There are no validated upper extremity instruments designed specifically to evaluate the performance and function of overhead athletes. Current shoulder and elbow scoring systems may not be sensitive to subtle changes in performance in this high-demand population.

Hypothesis: The scoring system developed in this study will be valid, reliable, and responsive in the evaluation of overhead athletes.

Revision ulnar collateral ligament reconstruction using a suspension button fixation technique.

Background: Revision ulnar collateral ligament reconstruction remains a challenging problem. The objective of this study was to biomechanically evaluate an ulnar collateral ligament reconstruction technique using a suspension button fixation technique that can be used even in the case of ulnar cortical bone loss.

Hypothesis: An ulnar suspension fixation technique for ulnar collateral ligament reconstruction can restore elbow kinematics and demonstrate failure strength comparable to that of currently available techniques.

The effect of pitching biomechanics on the upper extremity in youth and adolescent baseball pitchers.

Background: Increased pitch counts have been linked to increased complaints of shoulder and elbow pain in youth baseball pitchers. Improper pitching mechanics have not been shown to adversely affect the upper extremity in youth pitchers.

Hypothesis: The correct performance of 5 biomechanical pitching parameters correlates with lower humeral internal rotation torque and elbow valgus load, as well as higher pitching efficiency, in youth and adolescent pitchers.

Glenohumeral internal rotation deficits in baseball players with ulnar collateral ligament insufficiency.

Background: The kinetic chain of the throwing motion functions to optimize efficiency of proximal segments to decrease force loads seen at smaller, distal segments such as the ulnar collateral ligament. Several studies have shown that shoulder internal rotation forms the physiologic counter to the valgus torque generated during the late cocking phase of throwing. Previous studies have implicated decreased glenohumeral internal rotation as a cause of shoulder internal impingement.

Revision surgery for failed elbow medial collateral ligament reconstruction.

Background: Although excellent results can be achieved in up to 90% of primary elbow medial ulnar collateral ligament reconstructions, retears of the ligament have been reported. As the number of primary reconstructions continues to increase, one could expect a commensurate increase in the number of revision medial collateral ligament reconstructions performed.

Hypothesis: Given the difficulty associated with revision procedures, the complication rate relative to primary reconstructions would increase while the percentage of athletes returning to their previous level of play would decrease.

Arthroscopic treatment of posterolateral elbow impingement from lateral synovial plicae in throwing athletes and golfers.

Background: Although elbow pain is common in throwing athletes and golfers, posterolateral impingement from a hypertrophic synovial plica is a rare but possibly underdiagnosed condition.

Purpose: To evaluate the clinical results of arthroscopic treatment of symptomatic lateral elbow plicae in this athletic population.

Study Design: Case series; Level of evidence, 4.

An evaluation of the provocative tests for superior labral anterior posterior lesions.

Background: Although our understanding of superior labral anterior posterior lesions has grown, the physical diagnosis remains imperfect.

Study Design: Cohort study (diagnostic); Level of evidence, 2.

Purpose: To determine the most effective provocative maneuver with which to diagnose superior labral anterior posterior lesions.

Isolated electrothermal capsulorrhaphy in overhand athletes.

The purpose of this study was to determine the efficacy of arthroscopic electrothermal capsulorrhaphy for the treatment of instability in overhand athletes. Electrothermal capsulorrhaphy without labral repair was used to treat 20 symptomatic overhand athletes (15 baseball, 3 softball, and 2 volleyball). Nineteen patients were evaluated at a mean of 23 months.

Electrothermal capsulorrhaphy in glenohumeral instability without Bankart tear.

Purpose: The purpose of this study is to review the clinical results of electrothermal capsulorrhaphy (ETC) performed on 23 patients for the treatment of glenohumeral instability at an minimum follow-up of 2 years.

Type Of Study: Retrospective case series.

Methods: Twenty-six patients with symptomatic unidirectional or multidirectional glenohumeral instability without Bankart tear were treated with ETC using a radiofrequency probe.

Ulnar collateral ligament reconstruction in athletes: muscle-splitting approach without transposition of the ulnar nerve.

Eighty-three athletes with medial elbow instability underwent reconstruction of the anterior band of the ulnar collateral ligament with a muscle-splitting approach without transposition of the ulnar nerve. The purposes of this study were to describe postoperative neurologic outcomes in all 83 athletes and to describe the 2-year follow-up in 33 athletes. Postoperatively, 5% of this group had transient ulnar nerve symptoms, all of which resolved with nonoperative management.

Arthroscopy of the elbow: a long-term clinical review.

Purpose: The purpose of this study was to review a large group of patients who had arthroscopy of the elbow to determine the efficacy and relative risks of this procedure.

Type Of Study: We retrospectively reviewed a convenient sample of 172 patients who underwent 187 arthroscopies of the elbow over a 7-year period.

Materials And Methods: All patients had their charts and radiographs reviewed, and 104 of these patients were also contacted for a telephone interview at an average follow-up of 42.

The cyclops lesion: a cause of diminished knee extension after rupture of the anterior cruciate ligament.

Four patients presented with persistent diminution of knee motion after rupture of the anterior cruciate ligament with a novel lesion as the cause. Each had participated in an aggressive rehabilitation program for a minimum of 2 months with emphasis on regaining full range of knee motion. Because chronic impairment of knee extension can be disabling, in those who did not regain full range of motion, arthroscopy of the knee ensued.