Possible Sprain in front leg

Hi there. One of the neighbourhood cats came today limping but putting minimal weight on the affected leg and the leg is swollen from the "elbow" up. He came in and ate, drank water, moved around and let me pet him and feel his leg without real fuss. This is just one of 3 cats that come by daily. Any suggestions on whether it could be a break or what to do to speed the recovery of a swollen sprain???