Analysis of Ankle Mobility and Dynamic Valgus Knee in Runners With and Without Patellofemoral Pain Syndrome

Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal complaints among recreational runners, who commonly engage in various athletic activities. Thus, there is considerable discussion surrounding its risk factors, including dynamic knee valgus (DKV), as well as ankle dorsiflexion restriction (ADR) in a closed kinetic chain. To date, no scientific studies have investigated both ADR and DKV during the execution of the Step-Down Lateral Test (SDLT) in female runners with and without PFPS.

To measure ankle dorsiflexion mobility and determine differences in the magnitude and frequency of dynamic knee valgus during the SDLT in recreational female runners with and without patellofemoral pain syndrome.

This was an analytical, observational, cross-sectional study involving 40 amateur street runners, aged between 18 and 45 years, divided into a symptomatic group (SG) and asymptomatic group (AG), with allocation performed by a blinded researcher uninvolved in data collection and video analysis. The presence of patellofemoral pain was used to define group allocation and was assessed by an orthopedic surgeon specialized in knee disorders, based on clinical history and physical examination. The outcome measures included the Weight-Bearing Lunge Test to assess ankle dorsiflexion in a closed kinetic chain, as well as two-dimensional analysis of dynamic knee valgus during the SDLT. The statistical approach was descriptive and analytical, using the Shapiro-Wilk test, Mann-Whitney U test, or Student's t-test, as appropriate.

The final sample consisted of 40 runners, with 22 participants in the AG, while the SG had a total of 18 participants, with homogeneity between groups with respect to age, sex, height and body mass index. The mean DKV in the SG was 17.23° in the symptomatic limb, while in the asymptomatic limb it was 17.35°, from the same group; and in the group without it was 16.01° in the dominant limb. The mean dorsiflexion range of motion for the symptomatic group was 4.40 cm in the symptomatic limb, and 3.99 cm in the asymptomatic limb, while the AG demonstrated a mean of 3.78 cm in the dominant limb. Therefore, no statistically significant differences were observed between groups or between limbs (p > 0.05), suggesting that ankle dorsiflexion mobility and dynamic knee valgus during the SDLT do not differ between recreational female runners with and without PFPS.

The findings of this study indicate that there are no significant differences in ankle dorsiflexion mobility or frontal plane knee projection (dynamic valgus) between the studied groups during the SDLT in female recreational runners with and without PFPS.