Do implants expand in LENGTH when pumped?

Because otherwise it seems like the penis would need to be stretch to full erect length, even when flaccid, to accommodate the length of the implant.

I had a radical prostatectomy in October, and I'm dealing with issues of ED and incontinence. I've tried vacuum pumps but was completely unsatisfied with the results. I'm scheduled to see my urologist next week to try injections. I just wanted to say hello, and hopefully get more acquainted over time.