Chang SH, Abdelatif NMN, de Cesar Netto C, et al. - This study was undertaken to investigate the available clinical and radiographic evidence for incorporation of a gastrocnemius recession or tendo-Achilles lengthening into the surgical correction of adult-acquired flatfoot deformity. PubMed, Embase, Cochrane, CINAHL, and Google Scholar were applied to conduct a systematic review of the literature. The data revealed that support for lengthening procedures is largely based on expert opinion or case series and is difficult to distinguish from the clinical contribution of associated corrective procedures, although gastrocnemius-soleus complex contractures have certainly been demonstrated to coexist with adult-acquired flatfoot deformity.