Effects of Lateral Wedge Insoles on Knee Adduction Moment and Frontal Alignment in Individuals with Genu Varum Deformity: A Narrative Review

Background and Objectives:

Genu varum (GV) is a serious musculoskeletal impairment that has become increasingly prevalent among young populations as well as individuals with knee osteoarthritis (KOA). This deformity alters the kinetic chain, thereby increasing the mechanical loading on the medial compartment of the knee. The objective of this narrative review was to critically analyze the biomechanical evidence regarding the effects of medial and lateral wedge insoles on the knee adduction moment (KAM) and frontal alignment of the lower limb in individuals with GV deformity.

Methodology: A comprehensive search was conducted across PubMed, ScienceDirect, Scopus, and Web of Science databases without any timeframe restrictions, utilizing a combination of keywords: Orthopedic insole (“Foot Orthoses” OR “Orthoses, Foot” OR “Foot Orthosis” OR “Orthosis, Foot”); Genu Varum (“Bow Leg” OR “Bow Legs” OR “Genu Varum” OR “Knee Varus”); and Biomechanics (“Kinematics” OR “Kinetics” OR “Knee Adduction Moment” OR “KAM”). Studies evaluating the effects of insoles on the kinematic and kinetic parameters of individuals with GV were included, while case reports, conference proceedings, and book chapters were excluded. A total of 10 studies meeting the inclusion criteria were analyzed.

Results: Evidence indicated that lateral wedge insoles may reduce the knee adduction moment by shifting the center of pressure laterally; however, the efficacy of these insoles decreases in cases of severe GV deformity and in patients with concomitant KOA. Conversely, combining insoles with corrective braces appears to yield greater positive effects on restoring mechanical loading.

Conclusion: In conclusion, wedge insoles may be effective in managing mild-to-moderate structural genu varum; however, in severe conditions or when accompanied by KOA, the closed kinetic chain appears to require a larger corrective moment, which can be achieved through the simultaneous application of both insoles and braces.