Article
Static and dynamic hindfoot alignment in ankle and TTC arthrodesis
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Published: | October 21, 2010 |
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Objective: The Saltzman hindfoot alignment view (HAV) is considered the gold standard for assessing the axis from hindfoot to tibia. However, it is unclear how static alignment influences dynamic alignment during gait. This study aimed at evaluating the static and dynamic hindfoot alignment in ankle (AA) and tibiotalocalcaneal (TTC) arthrodesis.
Methods: 98 patients (AA=56, TTC=42) with an average follow-up of 4.1±1.3 years were assessed clinically with AOFAS- and SF-36 scores, visual hindfoot alignment, HAV, dynamic pedobarography using a 5-step method and a mask with 11 divisions (novel emed m/e). For comparison, 70 normal feet were evaluated.
Results and conclusions: The HAV-angle was –0.75±7.83 degrees for ankle, –1.19±6.92° for TTC arthrodesis. Visual alignment only predicted the corresponding HAV-angle in 48%. The HAV-angle had significant correlations to several final pedobarographic load parameters (r=0.35–0.53, p=0.02 to <0.0001). Static alignment did not influence subjective outcome. To reproduce the dynamic load pattern of normal subjects, an HAV-angle of 0 to >10° of valgus was needed.
Intra-operative positioning of the hindfoot by visual means resulted in a relatively large standard deviation of ±7–8° and a slight varus position. Visual judgment was not accurate enough as it only corresponded to the HAV-angle in 48%. The static alignment had a strong correlation to the dynamic load pattern; however, it did not influence subjective outcome. To reproduce the dynamic load pattern of normal subjects, a neutral to >10° of valgus position was needed in the HAV.