Influence of patellofemoral pain syndrome on plantar pressure in the foot rollover process during gait

Abstract

Background: Patellofemoral Pain Syndrome is one of the most common knee disorders among physically active young women. Despite its high incidence, the multifactorial etiology of this disorder is not fully understood.

Objectives: To investigate the influence of Patellofemoral Pain Syndrome on plantar pressure distribution during the foot rollover process (i.e., the initial heel contact, midstance and propulsion phases) of the gait.

Materials and methods: Fifty-seven young adults, including 22 subjects with Patellofemoral Pain Syndrome (30 ± 7 years, 165 ± 9 cm, 63 ± 12 kg) and 35 control subjects (29 ± 7 years, 164 ± 8 cm, 60 ± 11 kg), volunteered for the study. The contact area and peak pressure were evaluated using the Pedar-X system (Novel, Germany) synchronized with ankle sagittal kinematics.

Results: Subjects with Patellofemoral Pain Syndrome showed a larger contact area over the medial (p = 0.004) and central (p = 0.002) rearfoot at the initial contact phase and a lower peak pressure over the medial forefoot (p = 0.033) during propulsion when compared with control subjects.

Conclusions: Patellofemoral Pain Syndrome is related to a foot rollover pattern that is medially directed at the rearfoot during initial heel contact and laterally directed at the forefoot during propulsion. These detected alterations in the foot rollover process during gait may be used to develop clinical interventions using insoles, taping and therapeutic exercise to rehabilitate this dysfunction.

Figure 1

Synchronization between the Pedar-X System and the ankle electrogoniometer through the synchronizer box of the Pedar-X System.

Figure 2

Subphases of the gait stance obtained from ankle sagittal angular variation: the initial heel contact occurred between A and B, the midstance phase occurred between B and C, and the propulsion phase occurred between C and D. Positive values denote ankle flexion, and negative values denote extension.

Figure 3

Mean values of the contact area (cm²) in six plantar areas (MR = medial rearfoot, CR = central rearfoot, LR = lateral rearfoot, M = midfoot, MF = medial forefoot and LF = lateral forefoot) during initial contact, midstance and propulsion. (CG = control group, PFPS = patellofemoral pain syndrome, * p<0.05, # p < 0.1).

Figure 4

Mean values of the peak pressure (kPa) in six plantar areas (MR = medial rearfoot, CR = central rearfoot, LR = lateral rearfoot, M = midfoot, MF = medial forefoot and LF = lateral forefoot) during initial contact, midstance and propulsion. (CG = control group, PFPS = patellofemoral pain syndrome, * p<0.05).