Background Patellofemoral pain syndrome (PFPS) is the most common overuse injury in distance runners. A kinematic study found runners with a history of PFPS exhibit increased rear-foot eversion and reduced talocrural dorsiflexion compared to healthy controls during level treadmill running . This study investigates the possibility that similar differences could be established in a clinical setting.
Objectives To ascertain whether clinical measures of static foot posture, knee mobility, ankle mobility and leg length could reveal differences in female runners with and without PFPS.
Methods Nine female runners with a previous history of PFPS and ten healthy female runners (controls) participated in the study. Gonoimetric measurements of knee flexion, extension and ankle dorsiflexion were taken. Leg length was measured from the anterior superior iliac spine to the floor. The Foot Posture Index (FPI) was used to assess the feet. The FPI consists of talar head palpation, malleolar curvature, inversion/eversion of the calcaneus, bulging in the region of talo-navicular joint, medial arch congruence and abduction/adduction of the forefoot on rearfoot. Disaggregating the component scores provides richer information about the various segments/planes.
Results Effect size was calculated due to the low number of subjects in each group.
Goniometry: No difference in knee flexion was noted. Both groups demonstrated knee hyperextension, the PFPS group less than the control group. Both groups demonstrated comparable ankle dorsiflexion with the knee extended. The mean score of 7 degrees for both groups is less than what is considered necessary for normal gait. With the knee flexed, the PFPS group demonstrated greater dorsiflexion than the controls, indicating that the reduced dorsiflexion in this group was due to soft tissue shortening. The effect size of all these measurements was, however, negligible or small.
The main difference in FPI between the two groups was an increased malleolar curvature and increased eversion of calcaneus of both affected and unaffected legs of the PFPS group. The effect size was moderate.
The difference in FPI between the affected and unaffected leg within the PFPS goup was more significant. The affected leg showed increased eversion of the talus and adduction of the forefoot on the rearfoot. The effect size is moderate to large.
The mean difference between affected and unaffected leg length in standing was 11 mm with the affected leg being longer.
Conclusions The increased rearfoot eversion observed in the kinematic study was also observed in the clinical measures and additional differences betyween the affected and unaffected leg of the PFPS group were noted. Those differences may be due to compensation for the longer leg length. Further work with trained runners is recommended as this group ran a minimum of 20 miles/week and the results cannot be applied to the general population.
Leitch J, Reilly K, Stebbins J, Zavatsky AB. Lower-limb and Foot Kinematics in Distance Runners with Patellofemoral Pain Syndrome. In Proceedings of the 2nd Patellofemoral Pain Syndrome International Research Retreat: August 2011; Ghent, Belgium.
Disclosure of Interest None Declared
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