We compared the incidence of capsular contracture in an implant (Bioplasty Misti Gold II) which has a textured surface and is filled with polyvinyl-pirrolidone (PVP)-hydrogel, with that in saline-filled implants with textured surfaces when the implants are placed subcutaneously during immediate reconstruction after subcutaneous mastectomy. In 41 patients, mean age 55 years (range 30-81), with breast cancer that was not suitable for breast conservation, 20 patients had 22 Misti Gold II prostheses inserted (two patients bilaterally) and 21 patients had saline-filled prostheses (one patient bilaterally). The development of capsular contracture was assessed using Baker's classification and applanation tonometry. Fourteen patients with Misti Gold II implants were classified one year postoperatively as Baker 2 and 3 compared with five with saline-filled implants (p = 0.01). On applanation tonometry 16 of the Misti Gold II group had an operative:postoperative ratio of < or = 0.75, compared with 50% in the saline-filled group (p = 0.096). In the 12 Misti Gold II prostheses that were removed because of capsular contracture between 13-40 months postoperatively, the volume in the prostheses had increased by 48%. The poor results obtained with the Misti Gold II prosthesis can be explained by the volume that they gained after implantation as a result of osmosis.