The success of closed reduction in the treatment of complex developmental dislocation of the hip.

The purpose of our study was to determine the efficacy of closed reduction in the treatment of complex developmental dislocation of the hip. We identified two factors, the cone of stability and the limbus type, through the use of arthrography and gentle examination under anesthesia, which are useful guidelines in the management of complex developmental dislocation of the hip. We feel as a result of this study we can select those cases of complex developmental dislocation of the hip that are amenable to closed reduction and separate them from those other cases for which we recommend open reduction.

Effect of vacuum mixing on the mechanical properties of antibiotic-impregnated polymethylmethacrylate bone cement.

Polymethylmethacrylate bone cement, containing either no added antibiotic, 0.5 g of Vancomycin, 1.0 g of Vancomycin, or 1.0 g of Tobramycin, was mixed either in air or a vacuum chamber. Following storage in a water bath at 37 degrees C for 48 h, the specimens were tested in four-point bending. The porosity of the specimens was assessed radiographically, and their antibacterial activity was monitored for 21 days. The bending strength of the vacuum mixed specimens containing no antibiotic was 40% greater than that of similar air-mixed specimens. However, there were no significant differences in the bending strength of either the air- or vacuum-mixed specimens when any of the antibiotic dosages were added. The bending modulus of the vacuum-mixed specimens, containing no antibiotic, was significantly greater than the moduli of all the other specimen groups which did not differ from each other. Vacuum mixing reduced the apparent porosity of the specimens fivefold, and while the addition of antibiotic did not effect porosity of the air-mixed specimens, that of the vacuum-mixed specimens was doubled. Although initial rapid decreases were seen, leaching of antibiotic from the cement and antibacterial activity continued through the 21-day monitoring period.

Ankle arthroscopy: neurovascular and arthroscopic anatomy of standard and trans-achilles tendon portal placement.

Ankle arthroscopy is an accepted method of evaluating ankle disorders. Accurate arthroscopic portal placement is essential because of the proximity of superficial and deep neurovascular and tendinous structures of the ankle. In order to define this anatomy as it pertains to safe portal placement, five fresh frozen cadaver ankles were dissected after standard arthroscopic portals were placed anteriorly and posteriorly. All structures were identified. The distances to these structures from the most lateral portals were recorded. Five other ankles were arthroscoped using standard portals and evaluated. In addition, a trans-achilles tendon (TAT) approach was evaluated for portal use. Ankle arthroscopy can be performed in a safe, reproducible manner when the following recommendations are followed: (a) outline tendinous structures, and remain parallel to them with the knife blade to avoid laceration of underlying structures; (b) penetrate only the skin with the knife to avoid laceration of superficial nerves in the subcutaneous tissue; (c) perform pre- and postneurovascular examination; and (d) understand that anterocentral and posteromedial portals are potentially hazardous to their respective neurovascular bundles. The TAT approach, based only on cadaver studies, appears anatomically safe and offers the potential advantage of an additional posterior portal.