Background:
Anatomical tissue expanders are widely used in two-stage breast reconstruction following mastectomy. In recent years, microtextured implant surfaces have largely replaced macrotextured devices in order to reduce the risk of capsular contracture while maintaining tissue integration. However, rotation of anatomical expanders remains a clinically relevant complication that may compromise reconstructive outcomes. Comparative data regarding the rotational stability of different microtextured surfaces are limited.

Methods:
This retrospective cohort study included patients who underwent mastectomy followed by two-stage breast reconstruction using anatomical tissue expanders between January 2017 and December 2024 at two hospitals. Microtextured expanders from Mentor (Siltex surface) and Polytech (POLYtxt surface) were compared. The primary endpoint was expander rotation ≥45°, assessed intraoperatively at the time of expander exchange. Secondary endpoints included reconstruction outcomes, complications, and potential risk factors such as radiotherapy, chemotherapy, smoking status, and body mass index (BMI).

Results:
A total of 164 patients with 181 reconstructed breasts were included (74 Siltex, 107 POLYtxt). Rotation ≥45° occurred significantly more frequently in the Siltex group (33.8%) than in the POLYtxt group (11.2%) (χ²(1)=13.7, p=0.0002). The relative risk of rotation with Siltex expanders was 3.01 (95% CI 1.62–5.61). Patient demographics and expander volumes were comparable between groups. Despite a higher rate of adjuvant radiotherapy in the POLYtxt group, rotation remained less frequent than in the Siltex group. Smoking and chemotherapy were associated with higher rotation rates in the Siltex group, whereas no comparable increase was observed in the POLYtxt group. Other complication rates were similar between groups.

Conclusions:
Siltex microtextured expanders demonstrated a significantly higher rate of clinically relevant rotation compared with POLYtxt expanders. These findings suggest that microarchitectural differences between surfaces classified as microtextured may influence rotational stability. When Siltex expanders are used, additional stabilization measures such as fixation tabs should be considered.