Talonavicular joint mobilization and foot core strengthening in patellofemoral pain syndrome: a single-blind, three-armed randomized controlled trial

BACKGROUND: Patellofemoral pain syndrome (PFPS) is defined as pain around the patella while performing activities such as squats, running, and climbing steps. One of the inherent risk factors for PFPS is an excessively pronated foot posture. The aim of this study was to investigate the effect of foot intervention, talonavicular joint mobilization (TJM) and foot core strengthening (FCS), on PFPS. METHODS: Forty-eight patients with PFPS (mean age, 21.96 ± 2.34 years; BMI, 22.77 ± 2.95 kg/m(2)) were enrolled in the study. Participants were randomly assigned in a 1:1:1 ratio to three groups, and received 12 sessions of TJM, FCS, and blended intervention at university laboratory for 4 weeks. The primary outcomes were pain while the secondary outcomes were lower extremity function, valgus knee, foot posture, and muscle activity ratio measured at baseline, after 12 sessions, and at the 4-week follow-up. RESULTS: The two-way repeated-measures ANOVA revealed significant interactions in all groups (p < 0.05). TJM reduced pain more than the FCS at post-test (mean difference, − 0.938; 95% Confidence interval [CI], − 1.664 to − 0.211; p < 0.05), and blended intervention improved lower extremity function (mean difference, 6.250; 95% CI, 1.265 to 11.235; p < 0.05) and valgus knee (mean difference, − 11.019; 95% CI, − 17.007 to − 5.031; p < 0.05) more than the TJM at 4 weeks follow-up. TJM was more effective in post-test (mean difference, − 1.250; 95% CI, − 2.195 to − 0.305; p < 0.05), and TJM (mean difference, − 1.563; 95% CI, − 2.640 to − 0.485; p < 0.05) and blended intervention (mean difference, − 1.500; 95% CI, − 2.578 to − 0.422; p < 0.05) were more effective in foot posture than the FCS in 4 weeks follow-up. Blended intervention displayed greater improvement in muscle activity than the TJM (mean difference, 0.284; 95% CI, 0.069 to 0.500; p < 0.05) and the FCS (mean difference, 0.265; 95% CI, 0.050 to 0.481; p < 0.05) at 4 weeks follow-up. CONCLUSIONS: Our study is a novel approach to the potential impact of foot interventions on patellofemoral pain. Foot intervention including TJM and FCS is effective for pain control and function improvement in individuals with PFPS. TRIAL REGISTRATION: KCT0003176, 16/08/2018 (retrospectively registered). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-022-05099-x.