Which radial head fractures are best treated surgically?

Despite the common occurrence of radial head fractures, there is still a lack of consensus on which radial head fractures should be treated surgically. The radial head is an important secondary stabilizer in almost all directions. An insufficient radial head can lead to increased instability in varus-valgus and posterolateral rotatory directions, especially in a ligament-deficient elbow.

Persistent elbow dislocation.

Acute elbow dislocation is a common injury with an incidence in the general population estimated at around 5/100,000. Persistent (or static) elbow dislocation is a relatively rare problem but might occur due to inappropriate assessment or treatment of acute simple or complex elbow dislocations. Persistent elbow dislocation can be an invalidating and painful condition with a more ominous prognosis than an acute elbow dislocation with appropriate treatment.

Management of the stiff elbow: a literature review.

The elbow is prone to stiffness due to its unique anatomy and profound capsular reaction to inflammation. The resulting movement impairment may significantly interfere with a patient's activities of daily living. Trauma (including surgery for trauma), posttraumatic arthritis, and heterotopic ossification (HO) are the most common causes of elbow stiffness.

Physosmotic Induction of Chondrogenic Maturation Is TGF-β Dependent and Enhanced by Calcineurin Inhibitor FK506.

Increasing extracellular osmolarity 100 mOsm/kg above plasma level to the physiological levels for cartilage induces chondrogenic marker expression and the differentiation of chondroprogenitor cells. The calcineurin inhibitor FK506 has been reported to modulate the hypertrophic differentiation of primary chondrocytes under such conditions, but the molecular mechanism has remained unclear. We aimed at clarifying its role.

Osmolarity determines the in vitro chondrogenic differentiation capacity of progenitor cells via nuclear factor of activated T-cells 5.

Introduction: Previous studies have shown that human articular chondrocytes in vitro are osmolarity-responsive and increase matrix synthesis under cartilage-specific physiological osmolarity. The effects of increased osmolarity on chondrogenesis of progenitor cells in vitro are largely unknown. We therefore aimed to elucidate whether hyperosmolarity facilitates their chondrogenic differentiation and whether Nfat5 is involved.

Inhibiting calcineurin activity under physiologic tonicity elevates anabolic but suppresses catabolic chondrocyte markers.

Objective: The physiologic interstitial tonicity of healthy articular cartilage (350-480 mOsm) is lowered to 280-350 mOsm in osteoarthritis (OA). This results in loss of tissue prestress, altered compressive behavior, and, thus, inferior tissue properties. This study was undertaken to determine whether physiologic tonicity in combination with the inhibition of calcineurin (Cn) activity by FK-506 has synergistic effects on human articular chondrocytes and explants in vitro.

Physiological tonicity improves human chondrogenic marker expression through nuclear factor of activated T-cells 5 in vitro.

Introduction: Chondrocytes experience a hypertonic environment compared with plasma (280 mOsm) due to the high fixed negative charge density of cartilage. Standard isolation of chondrocytes removes their hypertonic matrix, exposing them to nonphysiological conditions. During in vitro expansion, chondrocytes quickly lose their specialized phenotype, making them inappropriate for cell-based regenerative strategies.

Calcineurin inhibitors promote chondrogenic marker expression of dedifferentiated human adult chondrocytes via stimulation of endogenous TGFbeta1 production.

In vitro chondrocyte expansion is required for several cell-based approaches for the repair of chondral lesions. During expansion, loss of chondrogenic phenotype takes place (dedifferentiation). The objective of this study was to investigate calcineurin (Cn) as a potential target to improve chondrocyte phenotype for cartilage repair purposes.

Can platelet-rich plasma enhance tendon repair? A cell culture study.

Background: Autologous platelet-rich plasma (PRP) application appears to improve tendon healing in traumatic tendon injuries, but basic knowledge of how PRP promotes tendon repair is needed.

Hypothesis: Platelet-rich plasma has a positive effect on cell proliferation and collagen production and induces the production of matrix-degrading enzymes and endogenous growth factors by human tenocytes.

Study Design: Controlled laboratory study.