Clinical relevance of hindfoot alignment view in total ankle replacement

Alignment is instrumental for success and long-term survival of Total Ankle Replacement (TAR). At this point in TAR, only coronal alignment in the region of the tibiotalar joint or above has been assessed because inframalleolar deformity is difficult to visualize radiographically. The Hindfoot Alignment View (HAV) allows visualization of the hindfoot position relative to the tibia. The purpose of this study was to evaluate the clinical relevance of this view in assessing patients with TAR.

Twenty-eight consecutive patients with a Hintegra-TAR with an average followup of 4.1 ± 1.5 years were followed with (1) AOFAS and SF-36 scores, (2) visual judgment of the hindfoot position, (3) HAV and AP/lateral radiographs, (4) dynamic pedobarography (Novel emed m/E, Munich, Germany).

The HAV position correlated well with different load parameters on heel strike (r = 0.44 to 0.62) but not with the varus-valgus load pattern of the rest of the foot. Visual judgment and TAR joint line did not correlate to radiographic hindfoot alignment or to pedobarographic load distribution. The hindfoot alignment measured by the HAV correlated significantly to the Physical Function and Role Physical of SF-36. No correlation was found to other SF36-qualities or the AOFAS-score.

Inframalleolar alignment, as assessed by the HAV, influenced the dynamic pedobarographic load pattern and clinical outcome. Visual judgment and TAR joint line were not accurate enough to estimate the hindfoot alignment or dynamic load pattern. We believe adjusting the hindfoot correctly with HAV might improve long-term outcome and survival of TAR.