BUZZ-Smith & Nephew: guidance cut spurs worst day in 9 years
** Europe's biggest artificial hip and knee maker slumps 6.1 pct, biggest one-day drop since March 2009
** Co cuts forecast for 2018 underlying revenue growth and profit margin after some markets softened and its bioactives business slowed
** Co says underlying revenue for the year to rise by 2-3 pct, less than the 3-4 pct it predicted in Feb.
** Smith & Nephew (Frankfurt: 502816 - news) says now expects a mid-single digit percentage decline in revenue from bioactives business in 2018
** YTD: up ** Stock bottom of FTSE 100, third-top faller on Stoxx 600 (RM (LSE: RM.L - news) : justin.varghese.thomsonreuters.com@reuters.net)