Capsular contracture (CC) is the most common complication of breast augmentation and reconstruction with implants. [1][2][3][4] The original classification scheme, developed by Spear and Baker, 5 is the most broadly adopted and provides a straightforward metric for evaluating CC in countless studies that have shaped our understanding of outcomes in breast implant surgery. The Baker classification (Table 1) considers physician and patient perceptions of implant palpability, visibility, breast firmness, and pain to generate a score ranging from I to IV. 5 By strict definition, though, CC refers specifically to morphologic and physiomechanical changes to the fibrous capsule that forms around breast implants. 4 Although the palpability, visibility, firmness, and pain that develop around a breast implant can result exclusively from contracture of the periprosthetic capsule, there are myriad factors that may influence this. Despite a thoughtful modification of the Baker grade to evaluate CC following Background: Breast implants are the most commonly used medical devices in plastic surgery, and capsular contracture (CC) is one of the most common complications. However, our assessment of CC is based largely on Baker grade, which is problematically subjective and affords only four possible values. Methods: The authors performed a systematic review concluding in September of 2021 in compliance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. It identified 19 articles that propose approaches to measuring CC. Results: In addition to Baker grade, the authors identified several modalities reported to measure CC. These included magnetic resonance imaging, ultrasonography, sonoelastography, mammacompliance measuring devices, applanation tonometry, histologic evaluation, and serology. Capsule thickness and other measures of CC inconsistently correlated with Baker grade, whereas the presence of synovial metaplasia was consistently associated with Baker grade I and II, but not III and IV capsules. Conclusions: There remains no particular method to reliably and specifically measure the contracture of capsules that form around breast implants. As such, we would recommend that research investigators use more than one modality to measure CC. Other variables that can impact breast implant stiffness and associated discomfort beyond CC need to be considered when evaluating patient outcomes. Given the value placed on CC outcomes in assessing breast implant safety, and the prevalence of breast implants overall, the need for a more reliable approach to measuring this outcome persists.
