NEW YORK (AP) â¿¿ Smith & Nephew PLC said Friday it is pulling from the market a metal liner used in hip replacements. The London company said the device is the optional metal liner for its R3 Acetabular System hip devices. Smith & Nephew said it is "not satisfied with the clinical results" of the liner, but did not explain why it was not satisfied. Smith & Nephew did not immediately respond to a request for further comment. Smith & Nephew said the liner was introduced in 2009 and about 7,700 have been implanted in patients. Most of them were used in stemmed total hip replacements. The company reported $4.27 billion in revenue in 2011, and it said less than 1 percent of that revenue came from procedures involving the recalled component. Shares of Smith & Nephew lost $1.37, or 2.9 percent, to $45.29 in midday trading.