Is there improvement in plantar pressures patterns following total ankle replacement? – A prospective novel 1 year follow up study

S. Hakeem, J. Ramaskandhan, S. Galloway, K. Smith, M. Siddique

Introduction: The aim of this study was to investigate plantar pressures changes with gait in patients presenting with ankle arthritis pre and post TAR.

Methods: 11 patients were recruited to this study. Patients who were listed for a primary TAR with a 3 component mobile bearing prosthesis were included. Exclusion criteria included refusal of consent, previous surgery to foot, h/o infection, peripheral vascular disease, neurological disease and other LL joint replacements. Gait analysis was carried out using TekscanTM plantar pressure analysis system and plantar pressures were recorded pre-operatively and 1 year post-operatively. Gait asymmetries were recorded in Percentage for ST parameters.

Results: 11 patients were recruited. Mean age were 70.5 years. Improvement centre of pressure pattern restoration and Force percentage curve (FP) patterns from pre-op to 1 Year. Improvement in foot progression angle was seen in 6 out of 11 patients (54.5%). Plantar pressure analysis showed deviation from reference ranges for 1) differences in centre of pressure (COP) 2) changes to hindfoot vs. forefoot loading ratio 3) change in loading pattern at heel in KPa (p0.565) for pain, difficulty with walking/ standing and difficulty with social activities. Gait asymmetries improved significantly (p<0.05) from pre-op to 1 year for step velocity (76.1 to 93.4 in 6/11 patients) and mid stance time (76.04 to 93.5% in 8/11patients).

Conclusion: This study has shown that TAR surgery helps in restoring centre of pressure, force percentage curve patterns and reduces asymmetries in step velocity and mid stance times during gait at 1 year post surgery. Plantar pressure analysis is a useful tool to study improvement in function in this patient group.