Progressive collapsing foot deformity: an instructional review.

Progressive collapsing foot deformity (PCFD) is an acquired condition characterised by collapse of the medial longitudinal arch, hindfoot valgus and forefoot abduction. This condition predominantly affects middle-aged and older patients and can lead to significant pain and functional impairment. Clinical assessment is key to identifying a flexible versus rigid foot deformity. The Johnson and Strom classification provides a framework for staging the disease process and guides management. Treatment can involve non-operative measures such as orthoses, or operative measures tailored to the components of deformity present. An understanding of the pathophysiology and biomechanical drivers is key to individualising treatment. Recent advances include a better understanding of peritalar subluxation as a causative factor, and a focus on motion-preserving surgical techniques.