Patellofemoral Pain Syndrome Modifies the Movement of the Rearfoot, but It Does Not Alter Plantar Pressure Distribution

Abstract

Objective To compare the plantar pressure distribution and the kinematics of the rearfoot on the stance phase of subjects with or without patellofemoral pain syndrome (PFPS). Methods A total of 26 subjects with PFPS and 31 clinically healthy subjects, who were paired regarding age, height and mass, participated in the study. The plantar pressure distribution (peak pressure) was assessed in six plantar regions, as well as the kinematics of the rearfoot (maximum eversion angle, percentage of the stance phase when the maximum angle was reached, and percentage of the stance phase in which the rearfoot was in eversion). The data were analyzed by descriptive and inferential statistics, with a significance level of p ≤ 0.05. Results The pressure on the six plantar regions analyzed and the magnitude of the maximum eversion angle of the rearfoot when walking on flat surfaces did not present differences among the subjects with PFPS. However, the PFPS subjects showed, when walking, an earlier maximum eversion angle of the rearfoot than the subjects on the control group, and stayed less time with the rearfoot in eversion. Conclusion The PFPS seems to be related to modifications on the temporal pattern on the kinematics of the rearfoot.

Keywords: biomechanical phenomena; gait; knee; patellofemoral pain syndrome.

Fig. 1

Position of the markers for the calculation of the rearfoot angle: 1) just above the flat shoe sole; 2) center of the heel, at the insertion of the Achilles tendon; 3) center of the Achilles tendon, at the height of the medial malleolus; 4) 15 cm above the third marker, at the center of the leg.

Fig. 2

Foot divided into six regions according to the mask applied. Abbreviations: CR, central rearfoot; LF, lateral forefoot; LR, lateral rearfoot; M, midfoot; MF, medial forefoot; MR, medial rearfoot.

Fig. 3

Mean and standard deviations of the peak pressure (kPa) in the six plantar regions of both groups during the flat surface gait.

Fig. 1

Posicionamento dos marcadores para o cálculo do ângulo do retropé: 1) logo acima da sola da sapatilha; 2) centro do calcanhar, na inserção do tendão de Aquiles; 3) centro do tendão de Aquiles, na altura do maléolo medial; 4) 15 cm acima do terceiro marcador, no centro da perna.

Fig. 2

Pé dividido em seis regiões, conforme a máscara aplicada. Abreviaturas: AL, antepé lateral; AM, antepé medial; M, médiopé; RC, retropé central; RL, retropé lateral; RM, retropé medial.

Fig. 3

Médias e desvios padrão do pico de pressão (KPa) nas seis regiões plantares durante a marcha em superfície plana dos dois grupos do estudo.