Foot orthoses for forefoot pressure reduction and the hypothesized role in calf muscle stretching : a systematic review highlighting an evidence gap

Abstract

Background: Excessive forefoot plantar pressures are associated with pain, ulceration risk, and functional limitations in both healthy individuals and those with pathologies such as rheumatoid arthritis (RA). Limited ankle dorsiflexion, often related to gastrocnemius–soleus tightness, may contribute to forefoot overload. Although foot orthoses (FOs) are widely used to redistribute plantar loads, it remains unclear whether the existing evidence includes orthotic interventions designed to promote posterior chain flexibility.

Objective: To systematically evaluate the effectiveness of foot orthoses in reducing forefoot plantar pressure and pressure-time integral (PTI), and to identify whether current evidence addresses orthoses specifically intended to facilitate calf muscle stretching.

Methods: A systematic review was conducted in accordance with PRISMA 2020 guidelines. Five databases were searched up to December 2024. Inclusion criteria encompassed adult populations, studies reporting plantar pressure outcomes, and interventions involving foot orthoses. Methodological quality was assessed using RoB 2 and ROBINS-I tools. Due to substantial clinical and methodological heterogeneity, a meta-analysis was not undertaken and findings were synthesized narratively.

Results: Twelve studies involving 456 participants met the inclusion criteria. No eligible studies directly evaluated orthoses designed to stretch the triceps surae. All included studies reported reductions in peak plantar pressure (PPP) and/or pressure-time integral (PTI). Descriptively, PPP reductions were greater in healthy cohorts (unweighted mean 20.2%) compared to RA populations (14.5%), whereas PTI reductions were descriptively higher in RA participants (22.2% vs. 14.7%). Interventions incorporating metatarsal pads and soft contoured orthoses showed consistent reductions in forefoot loading across studies.

Conclusions: Foot orthoses appear to be consistently associated with reductions in forefoot plantar loading across populations, particularly in individuals with inflammatory or structural pathology. The absence of studies specifically evaluating posterior chain flexibility represents a clear evidence gap. Future research should explore whether orthotic designs combining forefoot offloading with mechanisms that may influence ankle dorsiflexion or posterior chain mechanics could have biomechanical relevance.