The ulnar nerve on the inner side of the elbow and forearm can get pinched or compressed causing problems. One way to treat this condition is by removing part or all of the bone along the inside of the elbow. The operation is called an epicondylectomy.
It sounds like you may have had a minimal or partial epicondylectomy. Elbow pain, finger numbness, and loss of elbow flexion are common after this operation. In most cases these symptoms resolve or go away on their own. You should see a gradual improvement from 30 days to three months.
Elbow pain and function is often better after this operation but many patients still report mild to moderate pain even years later.