Comparison of the effects of shoe orthotics on the replacement of center of pressure in patients with severe medial compartment knee osteoarthritis
Background and aim: Osteoarthritis of knee is the most common joint disorder, accounting for a large rate of disability in elderly that affected both genders equally. The patients with severe knee osteoarthritis complain of considerable pain and immobility and functional limitations. The medial compartment of the knee affected more often than lateral compartment. One of the conservative treatments proposed for this disorder is the lateral wedge insole. The aim of this study was to compare the effect of different insoles (in-shoe and out-shoe wedges) with the height of 7mm on the replacement of foot’s center of pressure in patients with severe medial knee osteoarthritis.
Materials &Methods: 40 female patients with severe knee OA (severity of OA was 3, 4 in kallegrane & larense index, varus angle >182 and Mean age of 56.52±9.38) participated in this interventional study. The volunteers are evaluated at two positions included single limb stance and double limb stance during wearing seven different in-sole and out-sole wedges; in-shoe lateral heel wedge, in-shoe full length lateral wedge, in-shoe lateral heel wedge with medial arc support, in-shoe full length wedge with medial arc support, out-shoe lateral heel wedge, out-shoe full length lateral wedge and, without any wedge. Foot scan setting was used for evaluating and data collection. Repeated Measures ANOVA test was used to analyze the data.
Results: Different in-shoe and out-shoe wedges had different effects on the displacement of the center of pressure (P<0.0001). The comparison across different lateral wedges with height of 7mm suggested that out-shoe full length Lateral wedge has the most effect in lateralization of foot center of pressure followed by in-shoe lateral heel wedge with medial arc support, in-shoe lateral heel wedge, in-shoe full length wedge and in-shoe full length wedge with medial arch support.
Conclusion: Among the investigated in-sole and out-sole wedges the lateral full length out-shoe wedge has the greatest effect on the lateral displacement of foot center of pressure.
Key words: knee osteoarthritis, Insole, center of pressure.