The purpose of this study was to evaluate the
change in sagittal tibiotalar alignment after total ankle arthroplasty (TAA)
for osteoarthritis and to investigate factors affecting the restoration
of alignment. This retrospective study included 119 patients (120 ankles) who
underwent three component TAA using the Hintegra prosthesis. A total
of 63 ankles had anterior displacement of the talus before surgery
(group A), 49 had alignment in the normal range (group B), and eight
had posterior displacement of the talus (group C). Ankles in group
A were further sub-divided into those in whom normal alignment was
restored following TAA (41 ankles) and those with persistent displacement
(22 ankles). Radiographic and clinical results were assessed. Pre-operatively, the alignment in group A was significantly more
varus than that in group B, and the posterior slope of the tibial
plafond was greater (p <
0.01 in both cases). The posterior slope
of the tibial component was strongly associated with restoration
of alignment: ankles in which the alignment was restored had significantly
less posterior slope (p <
0.001). An anteriorly translated talus was restored to a normal position
after TAA in most patients. We suggest that surgeons performing
TAA using the Hintegra prosthesis should aim to insert the tibial
component at close to 90° relative to the axis of the tibia, hence
reducing posterior soft-tissue tension and allowing restoration
of normal tibiotalar alignment following surgery. Cite this article:
The purpose of this study was to obtain anatomical measurements of the distal tibia and talus of Korean ankles and to evaluate, based on those measurements, the compatibility of the HINTEGRA prostheses in the context of total ankle replacement (TAR). We measured the length, width, height, and angles of the distal tibia and talus of 51 cadavers and compared these measurements with the corresponding dimensions of the HINTEGRA prostheses. The male ankles were larger than the female ones as was expected, but their overall shapes did not differ, which fact validates use of the prostheses irrespective of patients' sex. The dimensions of the talus itself did not differ significantly from those previously reported for American whites and blacks and South African whites. This might suggest a possibility that the HINTEGRA prostheses, being used in these countries, would be compatible to Korean ankles, too. In fact, the length range of the talar components was generally compatible with those derived from cadaveric measurements of the trochlea. However, the widths of the tibial and talar components were not completely compatible to Korean ankles. Above all, the length of the large-sized tibial components was much longer than the largest ankles, which would confine the choice of prosthesis mainly to small-sized ones for arthroplasty in Korea. Even though these prostheses are currently used, some modifications are needed to extend their usability in Korea, such as shortening and width/length ratio adjustment of the tibial component, and of the talar component accordingly.
