ALTERATIONS OF PLANTAR PRESSURE DISTRIBUTION IN POSTTRAUMATIC END-STAGE ANKLE OSTEOARTHRITIS

Abstract

Background: While several studies in the last years tried to identify clinical limitations of patients suffering from end-stage ankle osteoarthritis (OA), very few attempted to assess foot and ankle function in a more objective biomechanical way, especially using dynamic pedobarography. The aim of the study was therefore to explore plantar pressure distribution characteristics in a large cohort of posttraumatic end-stage ankle OA.

Method: 120 patients (female, 54; male, 66; 120 cases) suffering from posttraumatic end-stage ankle OA were included. The clinical examination consisted of assessment of the AOFAS hindfoot score, a pain score, the range of motion (ROM) for ankle dorsiflexion and plantar flexion, and the body mass index (BMI, kg/m2). Radiological parameters included the radiological tibiotalar alignment and the radiological ankle OA grading. Plantar pressure distribution parameters were assessed using dynamic pedobarography.

Results: Intra-individual comparison between the affected and the opposite, asymptomatic ankle revealed significant differences for several parameters: maximum pressure force and contact area were decreased in the whole OA foot, such was maximum peak pressure in the hindfoot and toes area. No correlations could be found between clinical parameters, such as AOFAS hindfoot score, VAS for pain, and ROM, and the pedobarographic data. However, there was a positive correlation between dorsiflexion and the pedobarographic parameters for the hindfoot area.

Conclusion: In conclusion, posttraumatic end-stage ankle OA leads to significant alterations in plantar pressure distribution. These might be interpreted as an attempt of the patient to reduce the load on the painful ankle. Other explanations might be bony deformity and ankle malalignment as a consequence of either the initial trauma or of the degenerative process itself, pain related disuse atrophy of surrounding muscles, and scarred soft tissue.