Loss of spatial organization and destruction of the pericellular matrix in early osteoarthritis in vivo and in a novel in vitro methodology.

Objectives: Current repair procedures for articular cartilage (AC) cannot restore the tissue's original form and function because neither changes in its architectural blueprint throughout life nor the respective biological understanding is fully available. We asked whether two unique elements of human cartilage architecture, the chondrocyte-surrounding pericellular matrix (PCM) and the superficial chondrocyte spatial organization (SCSO) beneath the articular surface (AS) are congenital, stable or dynamic throughout life. We hypothesized that inducing chondrocyte proliferation in vitro impairs organization and PCM and induces an advanced osteoarthritis (OA)-like structural phenotype of human cartilage.

The effects of shoulder laxity on upper extremity blood flow in professional baseball pitchers.

Background: The repetitive overhand throwing can potentially cause physiologic or pathologic changes in musculoskeletal and vascular structures. The purpose of this study was to investigate the effects of throwing on upper extremity arterial blood flow before and after a controlled pitching session. The hypothesis is that pitchers with physical signs of shoulder laxity would demonstrate differential changes in upper extremity blood flow as compared to those without laxity.

The effects of concentric versus eccentric isokinetic strength training of the rotator cuff in the plane of the scapula at various speeds.

This study compares the effects of three modes of isokinetic resistance training at the shoulder--concentric, eccentric, and a combination of both concentric and eccentric, with a group that received no training at all. Twenty-eight healthy volunteers (male and females), 18 to 36 years of age, with no history of shoulder pathology, were randomly assigned to one of four groups; concentric training, eccentric training, a combination of both concentric and eccentric training, or control (no training). Testing and training of the dominant shoulder was performed on an isokinetic dynamometer.

Nonoperative treatment for minimally and nondisplaced lateral humeral condyle fractures in children.

The radiographic and clinical records of 95 children with nondisplaced or minimally displaced fractures of the lateral humeral condyle treated on a nonoperative protocol were reviewed. Acute nondisplaced or minimally displaced fractures were defined as < 24 h old on initial evaluation and displaced < 2 mm in three radiographic planes (anteroposterior, lateral, and internal oblique). Closed treatment and close follow-up in a long-arm cast or splint resulted in a union rate of 98% in 3-7 weeks.