Total and Distributed Plantar Loading in Subjects With Stage II Tibialis Posterior Tendon Dysfunction During Terminal Stance

Abstract

Background:

In subjects with stage II tibialis posterior tendon dysfunction (TPTD), the function of the tibialis posterior muscle is altered and may be associated with a change in total and distributed loading.

Methods:

Thirty subjects with a diagnosis of stage II TPTD and 15 matched control subjects volunteered to participate in a study to examine the total and distributed plantar loading under the foot during the terminal stance phase of gait. Plantar loading, measured as the subject walked barefoot, was assessed using instrumented flexible insoles. A secondary analysis was done to explore the contribution of flatfoot kinematics to plantar loading patterns.

Results:

Overall, there was reduced total plantar loading in subjects with stage II TPTD compared with controls. Accounting for differences in total loading, the presence of clinically measured weakness in subjects with TPTD was associated with reduced lateral forefoot loading. Medial longitudinal arch height was significantly correlated with loading patterns but explained only 21% of the variance in observed loading patterns.

Conclusion:

Subjects with TPTD who are strong exhibited loading patterns similar to controls. Changes in total and distributed loading during terminal stance suggest there are altered ankle mechanics at push-off during the functional task of gait.

Clinical Relevance:

Strength, in the presence of TPTD, may be important to stabilize the midfoot during gait and might be important in rehabilitation protocols.