A couple of years after getting two side by side implants I noticed a lump on the gums above them. Advice?

While it is recommended to see your dentist on a regular schedule, it is even more important to continue seeing your dentist before a joint replacement. The bump above the implants should be evaluated by a dentist, be it the one who placed the implants, the one who placed the crowns or another new dentist of your choice. The dentist you see will determine if you need a pre-med for your appointment. 

Grammi26 --
Go see the dentist who placed those implants. There are a number of things which could be causing the bump, but until you see a dentist, it's impossible to predict which of them is happening to you.
Call that dentist (who placed your implants) and advise their office that you've had a hip replacement and your orthopaedic surgeon is recommending antibiotic premedication.  It's more than likely that your dentist will see you at that first appointment for an exam and to diagnose what's happening.  
Good luck!Kevin Fitzpatrick, DDS, MS