In the study by Widuchowski et al(14), some type of chondral lesion was found in 60% of the knees operated, of which 67% were classified as osteochondral or chondral lesions, 29% as osteoarthritis, 2% as osteochondritis dissecans and 1% as other types.
Your account balance, also referred to as your current balance, is the total balance on your account, including any activity since your last statement. That last bit of the definition is probably the best way to differentiate the pair.
A current account surplus indicates that the value of a country's net foreign assets (i.e. assets less liabilities) grew over the period in question, and a current account deficit indicates that it shrank. Both government and private payments are included in the calculation.