Background: It has been shown that total knee arthroplasty (TKA) can correct the alignment of the lower limb, not only correcting the knee axis, but also affecting the alignment of the hindfoot. However, there is still not a significant amount of work in the literature.
Methods: A prospective study was carried out in which 72 patients were radiographically (long axial view of the hindfoot) and clinically (American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale) evaluated before and 3 months after TKA. We investigated whether there were any significant associations between measurements of the axes, hindfoot angle, and AOFAS score with the type of deviation of the patient's axis.
Results: For the subgroups "hindfoot valgus-knee valgus," "hindfoot valgus-knee varus," and "hindfoot varus-knee valgus," a reduction in angle after surgery was observed; for the cases "hindfoot varus-knee varus," an increase in angle after surgery was observed. However, the Wilcoxon test showed that only the changes in the hindfoot axis of the "hindfoot varus-knee valgus" subgroup are statistically significant (P < .05). After surgery, the Wilcoxon test showed that the AOFAS score changes are statistically significant for all subgroups for which it was possible to perform the test (P < .05).
Conclusion: TKA promotes changes in the postoperative hindfoot axis, significantly in patients with knee valgus and hindfoot varus. In addition, TKA provides significant improvement in the postoperative AOFAS score.
Level of evidence: IIB.
Keywords: TKA; alignment; hindfoot; knee; long axial view.
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