Sentence 1 is the correct version. Simple way to identify the use of as well as is to replace it with 'In addition to
For example: the above sentence can be reworded as
In addition to breaking his leg, he hurt his arm.
As well as is usually
followed by an infinitive if the main clause has an infinitive or it is followed by by an -ing as in sentence1.
My First Blog on my GMAT Journey
Arise, Awake and Stop not till the goal is reached