The formal grammar demands that numbers be written out as words at the beginning of a sentence. I have a paragraph like the one below and I am not sure how best to re-phrase it so as to conform to the academic grammars. General suggestions on writing this type of sentences (sentences with "complex numbers") are especially welcome. (I intentionally put all numbers at the beginning of all sentences to highlight the issue)
4165 cases of respondents reported pain in knee joints, hand joints or wrists. 60.77% of them reported only knee pain whereas 64.71% reported pain in hand and wrist joints. 74.89% of the patients with osteoarthritis complained knee pain while 87.64% of the patients with rheumatoid arthritis complained hand and wrist pain. 69.55% of the patients 60 years old and above showed signs of knee pain while 46.78% of the patients 40 years old and younger showed similar signs. 69.24% of the patients 40 years old and younger complained about hand and wrist pain and 62.50% of the patients 60 years old and above have a similar complaint.