Free man
Karlena is a feminine elaboration of Karl, which is the Germanic form of Charles. It carries the historical meaning of a free person who was not of noble birth but held legal rights. The suffix '-ena' adds a rhythmic, Latinate flair to the traditional root.
Less common today
Karlena isn't in the latest US Top 1000. It last peaked at #6,417 in 1992.
US births per 5-year period, 1990βpresent (SSA data).