Factors Affecting Transtibial Prosthetic Socket Fit: A Clinical Review of Residual-limb Volume Dynamics and Preventive Accommodation Strategies

Introduction: Prosthesis users consistently rank socket fit as the leading determinant of comfort, function, and continued prosthesis use. A transtibial socket, however, is made to fit a residual limb of one specific size, captured at a single moment. The limb itself gains and loses volume over minutes, hours, days, and years. Even small changes in the limb-to-socket relationship can compromise fit and place the skin at risk. Methods: This clinical review synthesizes the primary factors that influence residual-limb volume change. It draws on the peer-reviewed prosthetics and rehabilitation literature and on approximately four and a half decades of clinical experience in transtibial prosthetics. The review organizes these factors into five clinically actionable domains that allow targeted intervention: diurnal and fluid-volume dynamics; dietary, metabolic, and body-weight factors; environmental and climatic factors; activity and lifestyle; and medical and physiological determinants. Results: Each domain changes limb volume in a characteristic direction and over a characteristic time course, from the fluid shifts that follow doffing within minutes to the remodeling of early residual-limb maturation over months. For each domain, evidence-supported accommodation strategies are available. They include sock-ply regulation, adjustable socket design, suspension selection, moisture and thermal control, patient education and behavioral counseling, and coordinated management of systemic comorbidities. Conclusions: Volume management is not a single intervention but a layered clinical strategy. Recognizing the direction and time course of each contributing factor allows the clinician to anticipate fit problems rather than react to them and to distinguish transient, accommodatable change from change that warrants socket replacement.