Immediate effect of neuromuscular activation on knee joint dynamics in women with patellofemoral pain: a randomized clinical trial

Abstract

Introduction: Patellofemoral pain (PFP) is a general term used to describe the painful sensation on the anterior faces and in the adjacent regions around the knee joint. Weakness and lack of neuromuscular control of the hip and knee muscles can lead to changes in the dynamics of the joints of the lower limbs during movements, as is evident in tasks such as one-legged posture and one-legged squat. As a countermeasure to this clinical condition, neuromuscular exercises have been widely applied as a therapeutic approach for PFP, with consistent evidence of its effectiveness. However, which types of neuromuscular exercises are most suitable for this condition are still debatable. Objective: The objective of the study was to investigate the immediate effect of neuromuscular exercises on the dynamic valgus of the knee and the sensation of pain in a sample of women with PFP. Methods: A convenience sample of 19 women participated in this randomized clinical trial. Based on the exercise performed, the participants were allocated to a clamshell group (N = 4), lunge Squat (N = 7) or hip abduction (N = 8). Before and after these exercises, participants performed (1) a single leg squat test and (2) a box drop test. In both tasks, video recordings and pain reports were made. The videos were used to estimate the angular and linear displacement of the knee joint in the frontal plane to estimate the peak of the valgus angle. Changes in pain reporting were analyzed using the chi-square test. The delta values (post-minus pre-intervention) for the knee angle were calculated and used for comparison between groups (Kruskal-Wallis) and comparison with zero reference value (one-sample t-test), assuming alpha equal to 5 %. Results: Eight participants (42% of the sample) showed changes in the report of pain sensation after the exercises, with 6 of them (2 in each group) changing their response from "presence of pain" to "absence of pain"; no group effect was found (P = 0.254). The delta-intervention values for the peak valgus angle showed no differences between groups (P> 0.781) or differences from zero (P> 0.148). Conclusion: Different types of exercises result in a small but similar change in the report of the sensation of pain, with no differences about the peak of the valgus angle during dynamic tasks.