Johnson & Johnson (NYSE:JNJ) is buying Swiss medical devices company Synthes Inc. for 19 billion francs (U.S. $21.6 billion). This is J&J’s largest acquisition, giving them a boost in the orthopedic market. J&J will be paying 159 Swiss francs in cash and stock for each share of Synthes. This is an 8.5% premium on Synthes’ closing share price as of Tuesday. The acquisition is likely to be closed in the first half of 2012. Synthes posted $3.7 billion in 2010 revenues. Synthes is best known for making nails, screws, plates, and artificial spine discs for broken bones. The deal was approved by the Wyss family, who owns 40% of Synthes.