Floating Inferior Glenohumeral Ligament: A Case Report.

A humeral avulsion of the glenohumeral ligament (HAGL lesion) is a relatively rare pathology seen in patients with traumatic anterior shoulder instability. A HAGL lesion combined with a Bankart lesion is called a floating inferior glenohumeral ligament (IGHL) and is rare. We report a case of floating IGHL that could not be diagnosed before surgery.

Changes in the Articular Cartilage Thickness in Patients with Symptomatic Rotator Cuff Tears: A Prospective Study with a Mean 5-Year Follow-Up.

The purpose of this study was to prospectively investigate the progression of cartilage thinning in patients with symptomatic rotator cuff tears using MRI. Two hundred twenty-five consecutive patients with symptomatic rotator cuff tears visited our institute between 2009 and 2019. Of these, 28 shoulders of 27 patients (mean age, 65 years) who underwent at least two magnetic resonance imaging (MRI) examinations were prospectively enrolled.

Glenoid track revisited.

The risk of Hill-Sachs lesion (HSL) to cause instability depends not only on the HSL but also on the glenoid size. Clinically, the only method to assess the risk of instability considering the dynamic interaction of both, the HSL together with the glenoid bone loss, is the glenoid track concept. Since it was introduced in a cadaveric study, its clinical efficacy and validity have been reported in the literature.

Glenoid track and subcritical Hill-Sachs lesion.

Background: We have proposed the concept of glenoid track ("on-track/off-track" lesion) to evaluate the risk of engagement of the Hill-Sachs lesion with the glenoid after arthroscopic Bankart repair. This concept has been widely used and many clinical validation studies have been reported. To measure the glenoid track width, we have recommended to use 3-dimensional computed tomography (CT) images.

Location and size of the reverse Hill-Sachs lesion in patients with traumatic posterior shoulder instability.

Background: In patients with traumatic posterior shoulder instability, little is known about the precise location and size of the reverse Hill-Sachs lesion.

Methods: Forty-nine shoulders of 47 patients with traumatic posterior instability were included in this study based on the following inclusion criteria: (1) a primary or recurrent traumatic posterior shoulder dislocation and (2) the initial event being caused by trauma. Patients were excluded if they had (1) no history of trauma, (2) prior shoulder surgery, (3) no computed tomographic (CT) examination, or (4) were seizure cases.

When and how much does the muscle strength recover after arthroscopic superior capsular reconstruction?

Background: Recently, arthroscopic superior capsular reconstruction (SCR) has been performed for irreparable large to massive rotator cuff tears and excellent clinical results have been reported. Although the muscle strength is reported to recover, it has not yet been clarified when and how much it recovers. The purpose of this study was to determine the recovery pattern of muscle strength after SCR.

TiNbSn stems with gradient changes of Young's modulus and stiffness reduce stress shielding compared to the standard fit-and-fill stems.

Background: The difference between Young's moduli of the femur and the stem causes stress shielding (SS). TiNbSn (TNS) stem has a low Young's modulus and strength with gradient functional properties during the change in elastic modulus with heat treatment. The aim of this study was to investigate the inhibitory effect of TNS stems on SS and their clinical outcomes compared to conventional stems.

Non-operative management of shoulder osteoarthritis: Current concepts.

Glenohumeral osteoarthritis (OA) is one of the most common causes of shoulder pain. Conservative treatment options include physical therapy, pharmacological therapy, and biological therapy. Patients with glenohumeral OA present shoulder pain and decreased shoulder range of motion (ROM).

A stabilizing role of the glenoid labrum: the suction cup effect.

Background: The glenoid labrum acts as a bumper, deepening glenoid concavity and amplifying the concavity-compression mechanism, and serves as the scapular attachment for glenohumeral ligaments. The role of the posterosuperior labrum in anteroinferior glenohumeral stability, and the role of the anterior labrum in posterior stability has been debated. The purpose of this study was to quantify the contribution of anteroinferior and posterosuperior labral tears to loss of glenohumeral stability in multiple directions.

Effect of shoulder immobilization position and activities of daily living on the stiffness of the repaired supraspinatus tendon.

Background: Although tension on the supraspinatus tendon may be increased by wearing an abduction brace in an improper position or activities of daily living with the operated arm in the brace, the amount of tension has not been objectively evaluated.

Methods: Eighteen patients who underwent arthroscopic rotator cuff repair were enrolled. The stiffness of the repaired supraspinatus tendon was measured with ultrasound elastography to estimate the tension on the repaired tendon.

Effect of Anterior Glenoid Chondrolabral Defects on Anterior Glenohumeral Stability: A Biomechanical Study.

Background: It is well known that glenoid osseous defects >13.5% of the glenoid width critically destabilize the shoulder, as do labral tears. Chondrolabral defects often occur with anterior dislocation of the shoulder.

How much force is acting on the shoulder joint to create a Hill-Sachs Lesion or reverse Hill-Sachs Lesion?

Background: It has not been clarified yet how much force is acting on the shoulder joint to create Hill-Sachs/reverse Hill-Sachs lesions which are commonly observed in patients with anterior or posterior shoulder instability. The purpose of this study was to determine the magnitude of force to create these bony lesions using cadaveric shoulders.

Methods: Fourteen fresh-frozen cadaveric shoulders were used.

The quantification of muscle activities during arm elevation following reverse shoulder arthroplasty or superior capsular reconstruction for irreparable rotator cuff tears using positron emission tomography.

Background: Reverse shoulder arthroplasty (RSA) and superior capsular reconstruction (SCR) are recognized as surgical options for an irreparable rotator cuff tear. However, the postoperative changes of the muscle activity patterns remain unclear. The purpose of this study was to investigate the quantified muscle activities on shoulder elevation in patients treated with RSA or SCR using fluorine-18-labelled fluorodeoxyglucose-positron emission tomography.

RSPO3 is a novel contraction-inducible factor identified in an "in vitro exercise model" using primary human myotubes.

The physiological significance of skeletal muscle as a secretory organ is now well known but we can only speculate as to the existence of as-yet-unidentified myokines, especially those upregulated in response to muscle contractile activity. We first attempted to establish an "insert-chamber based in vitro exercise model" allowing the miniature but high cell-density culture state enabling highly developed contractile human myotubes to be readily obtained by applying electric pulse stimulation (EPS). By employing this in vitro exercise model, we identified R-spondin 3 (RSPO3) as a novel contraction-inducible myokine produced by cultured human myotubes.

Reliable interobserver and intraobserver agreement of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification system of rotator cuff tears.

Objective: The ISAKOS Shoulder Committee developed a new comprehensive classification system aimed to describe all rotator cuff tears. The five characteristics of the tears included are pattern (P), extension (E), fatty atrophy (A), retraction (R), and location (L), conforming to the acronym "PEARL." The objective of this study is to assess if the ISAKOS Rotator Cuff Tear Classification System is reliable by measuring the intraobserver and interobserver multirater reliability.

Antibacterial Activity of an Anodized TiNbSn Alloy Prepared in Sodium Tartrate Electrolyte.

In this study, we anodized a TiNbSn alloy with low Young's modulus in an electrolyte of sodium tartrate with and without hydrogen peroxide (HO). The photo-induced characteristics of the anodized alloy were analyzed for crystallinity and electrochemical conditions with comparisons to the effect with the addition of HO. The antibacterial activity was evaluated using methicillin-resistant and other pathogenic bacteria according to ISO 27447, and time decay antibacterial tests were also conducted.

Morphology of Glenoid Cartilage Defects in Anteroinferior Glenohumeral Instability.

Background: Glenoid cartilage defects may contribute to anterior shoulder instability recurrence and progression to osteoarthritis, but their morphology remains unknown.

Purpose/hypothesis: The purpose was to determine the shape, size, and location of glenoid cartilage defects and the prevalence and risk factors for cartilage defects in the setting of anterior glenohumeral instability. It was hypothesized that glenoid cartilage defects would be common, would be associated with recurrence of dislocation, and would share similar morphology with glenoid osseous defects.

Feeder-supported in vitro exercise model using human satellite cells from patients with sporadic inclusion body myositis.

Contractile activity is a fundamental property of skeletal muscles. We describe the establishment of a "feeder-supported in vitro exercise model" using human-origin primary satellite cells, allowing highly-developed contractile myotubes to readily be generated by applying electrical pulse stimulation (EPS). The use of murine fibroblasts as the feeder cells allows biological responses to EPS in contractile human myotubes to be selectively evaluated with species-specific analyses such as RT-PCR.

Mid-term results of a new femoral prosthesis using Ti-Nb-Sn alloy with low Young's modulus.

Background: This study was performed to investigate the mid-term results of Ti-Nb-Sn (TNS) alloy stem with a low Young's modulus.

Methods: This study was a multicenter prospective cohort study. A total of 40 primary total hip arthroplasties performed between April 2016 and September 2017 was enrolled in this study.

Editorial Commentary: It Is Not the Size, But the Location of Hill-Sachs Lesion That Matters.

The risk of a Hill-Sachs lesion (HSL) to engage the anterior glenoid rim depends on the location of the medial margin of the HSL relative to the anterior rim of the glenoid. The same-sized HSL can be engaging or nonengaging depending upon the size of the glenoid. In order to assess these bony lesions (bipolar lesion) together, the glenoid track concept has been introduced: an on-track lesion (stable) and an off-track lesion (unstable).

Long-term effect of immobilization in external rotation after first-time shoulder dislocation: an average 18-year follow-up.

Background: Immobilization in external rotation (ER) after a first-time shoulder dislocation was introduced to reduce the risk of recurrence compared with immobilization in internal rotation (IR), but its efficacy remains controversial. The purpose of this study was to determine the long-term effect of immobilization in ER after a first-time shoulder dislocation.

Methods: Between October 2000 and March 2004, 198 patients with a first-time anterior dislocation of the shoulder (average age 37) were randomly assigned to immobilization in ER (ER group = 104 shoulders) or IR (IR group = 94 shoulders) for 3 weeks.