BACKGROUND:Acellular dermal matrices are increasingly used to reinforce the lower pole of the breast during tissue expander/implant breast reconstruction. Although a low complication rate and good aesthetic outcome have been reported, meticulous technique is important for success. This retrospective study compared the clinical course and postoperative outcome of women who underwent breast reconstruction using AlloDerm or Strattice in the authors' practice and highlights key technical considerations that are important for optimizing outcomes. METHODS:Patient records were reviewed for demographic data, operative parameters (length and volume of drainage), and type and frequency of postoperative complications, which were compared between the AlloDerm and Strattice groups. Biopsy specimens of acellular dermal matrices were taken for histologic analyses. RESULTS:Ninety-six patients (126 reconstructions) received AlloDerm, and 90 (144 reconstructions) received Strattice. Total complications were significantly higher with AlloDerm (21.4 percent versus 6.3 percent; p = 0.0003) and were driven by a significantly higher seroma rate (12.7 percent versus 1.4 percent; p = 0.0003). All other complications were similar between the groups. The capsular contracture rate (grade 1 or 2) was 2.4 percent with AlloDerm and 2.8 percent with Strattice, indicating that both may play a role in capsule formation. This was supported by histologic analyses indicating an absence of synovia-like metaplasia at the acellular dermal matrix/tissue expander interface. CONCLUSIONS:: Complications in this series were of low severity, which, together with consistent clinical outcomes seen in the authors' practice, justifies the cost associated with the use of acellular dermal matrices in breast reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE:Therapeutic: III.