personal injuries sustained on public property (and teh LAW!!)

i fell on a bit of broken sidewalk the other day and hurt my ankle. according to the cop who helped me at the time, a lot of people had accidents at the same spot but the city hasn't done anything about it (i'm assuming complaints were filed and that's easy enough to find out). i'm normally not the litigious type and a sprained ankle probably isn't anything to sue over, but given the city's negligence, might i have a case here? maybe a class-action suit?

nyc ambulance chaser site says this:

If you are hurt because of an unsafe condition, and the owner or company in charge of the property either created that unsafe condition, knew of it, or had time to find out about the unsafe condition, they can be held responsible for your injury.

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In New York City we have what is known as the "pothole" law. This is a "prior actual written notice statute" which was enacted during Mayor Koch's administration. This means that to hold The City of New York responsible for an accident due to a broken sidewalk or street, the City must have received written notice of that defect at least 15 days before the date of your accident. If not, you will not recover against the City, except if the City actually created the defect.