From what Ive heard over the years, and understand, a "string implant" would look like a ball of wound up string. It slowly unravels inside, irritating more tissue and causing more fluid to be produced and make the boobs keep growing and growing. Larger amounts of string would cause more swelling over time. Many women had horrible complications like greatly uneven growth between their left and right breasts, and some women growing way too fast, requiring removal. The idea got canned because there was no consistent, and safe, outcome. Chelsea and the other few girls that still have them are the lucky ones that didnt experience complications. But even Chelsea has been getting uneven growth over the last 10 years or so with her nipples pointing outwards now.
Chelsea getting them removed after this long will probably be a massive undertaking as well. Who knows how things have grown around the insides of her breasts as they've gotten bigger and bigger. Only a doctor with some proper xrays and ultrasounds would be able to tell whats going on in there. I doubt they could just poke a hole and deflate them like a normal implant. It would probably require alot of tissue removal and reconstructive surgery. I cant imagine she'll want to lug them around much longer, but hopefully people help her out when that time comes.