Spotted over at FT Alphaville we have this extract from Jeffries Fixed Income (emphasis mine) :

Although encouraging that Q4 UK GDP was revised up from a rise of only 0.1% to 0.3%, arthritically this was largely the result of general government expenditure (see chart below). General government expenditure rose by 1.2% (not annualized) during the period, the strongest rise since 2003. This boosted GDP by almost 0.3 percentage points. Looked at another way, excluding general government expenditure GDP was effectively flat on quarter.

Growth may indeed have been arthritic but I assume the spell checker chose that over arithmetically. Whilst spell check can be useful it is more often a source of amusement.