Muscle activity pattern of the shoulder external rotators differs in adduction and abduction: an analysis using positron emission tomography.

Background: The muscle activity pattern during shoulder external rotation has not been fully clarified. This study aimed to determine the activities involved in external rotation in the adducted and abducted positions using positron emission tomography (PET).

Methods: Seven healthy volunteers underwent PET examinations after performing external rotation using an elastic band at both 0° and 90° of shoulder abduction in the frontal plane.

Differences in muscle activities during shoulder elevation in patients with symptomatic and asymptomatic rotator cuff tears: analysis by positron emission tomography.

Background: Differences in muscle activity patterns between patients with symptomatic and asymptomatic full-thickness rotator cuff tears have not yet been fully clarified. The purpose of this study was to investigate the muscle activity pattern by use of positron emission tomography (PET) in patients with symptomatic and asymptomatic rotator cuff tears.

Methods: Ten shoulders of 9 patients with full-thickness rotator cuff tears were divided into 2 groups by a numerical pain rating scale (0-10), symptomatic (≥2) and asymptomatic (0 or 1), with 5 shoulders each.

Is protecting the healing ligament beneficial after immobilization in external rotation for an initial shoulder dislocation?

Background: Immobilization in external rotation is one of the treatment options for an initial dislocation of the shoulder. However, it remains unclear how long it takes for a Bankart lesion to heal.

Hypothesis: Protection of a healing Bankart lesion from stretching would promote the healing process and decrease the recurrence rate after an initial dislocation of the shoulder.

Postoperative anemia following posterior decompression surgery for lumbar spinal canal stenosis.

The incidence of lumbar spinal canal stenosis (LSCS) is increasing in Japan. Posterior lumbar decompression surgery, wide fenestration and laminectomy, for LSCS is a common treatment modality. Compared with posterior fusion surgery, posterior decompression surgery has been considered as less invasive.

Humeral head osteonecrosis in an adolescent amateur swimming athlete: a case report.

Osteonecrosis of the humeral head in an adolescent without clear pathogenesis has not been reported in the literature. In this case report, we present such a case of humeral head osteonecrosis in a 15-year-old adolescent. The lesion was located at the subchondral area of the medial part of the humeral head with characteristic appearances on MRI.

Reliability and validity of the Western Ontario Shoulder Instability Index (WOSI) in the Japanese population.

Background: The Western Ontario Shoulder Instability Index (WOSI) questionnaire is a disease-specific self-evaluated measurement tool used for patients with shoulder instability. The purpose of this study was to evaluate the reliability and validity of the WOSI Japanese version for the Japanese population.

Methods: The WOSI Japanese version was prepared by use of several steps including translation, back translation, and verification by the author and owner of the WOSI.

Anatomical and functional segments of the deltoid muscle.

Previous studies showed that the insertion of the intramuscular tendons of the deltoid muscle formed three discrete lines. The purpose of the present study was to establish a new dividing method of the deltoid muscle into various anatomical segments based on the distribution of the intramuscular tendons with their insertions (anatomical study). We further hoped to clarify the relationship between the anatomical segments and their activity pattern assessed by positron emission tomography with [¹⁸F]-2-fluoro-deoxyglucose (FDG-PET; PET study).