Staple vs. subcuticular vicryl skin closure in knee replacement surgery: a spectrophotographic assessment of wound characteristics.

Staple closure is a popular method of skin closure for patients undergoing knee replacement surgery. There are no guidelines regarding spacing of staples and some concern exists with regard to wound oxygenation in knees subject to early movement. We compared cutaneous wound characteristics in terms of blood oxygenation and blood content, using two types of skin closure. Staples or 4/0 subcuticular vicryl were used. We found favourable blood perfusion characteristics when using stapled closure. Our results also suggest that optimum wound oxygenation requires staple spacing of 6 mm or more.

The changing morphology and increasing deceleration of supernova 1993J in M81

Twenty consecutive Very Long Baseline Interferometry images of supernova 1993J from the time of explosion to the present show the dynamic evolution of the expanding radio shell of an exploded star. High-precision astrometry reveals that the supernova expands isotropically from its explosion center. Systematic changes in the images may reflect a pattern of anisotropies and inhomogeneities in the material left over from the progenitor star. As the shock front sweeps up the material in the surrounding medium, it is increasingly decelerated and influenced by the material. After 5 years, the supernova has slowed to half of its original expansion velocity and may have entered the early stages of the adiabatic phase common in much older supernova remnants in the Milky Way Galaxy.