How to sanitize raw SQL in Rails 4

In Rails 3 I could use sanitize_sql_array to sanitize raw SQL for those occassional moments where a raw SQL query is needed. But this appears to have been removed in Rails 4, or not so much removed, but moved to ActiveRecord::Sanitization. However, I can not figure out how to call sanitize_sql_array now, so what's the best way to sanitize raw SQL in Rails 4?

I want to clarify that I am talking about a full raw SQL query here, not using Rail's models. I'm aware that this is not best practice, this is just what I have to do for this specific query since it can't be represented by Rails's nice ActiveRecord interface (Trust me, I've tried).

Here is a sample call, which is obviously simpler than what my query actually looks like:

query = "SELECT * FROM users 
LEFT OUTER JOIN posts ON users.id=posts.user_id
AND posts.topic_id = '#{topic.id}'" 
# ^- Obviously bad and very vulnerable, this is what we're trying to fix
ActiveRecord::Base.connection.select_all(query)