Relationship Between the Knee and Hindfoot Axes in Patients With Severe Knee Osteoarthritis

Abstract

Objective: To evaluate the correlation between knee axis and hindfoot axis in patients with advanced gonarthrosis, and the association between ankle function and angular deformities. Methods: 72 patients were enrolled in the study: 66% were women, and mean age was 58.7 years. The anatomical axis of the knee and hindfoot were measured by short knee radiographs and long axial view of the hindfoot. Results: Among the study group, 79.2% presented varus knee (mean 15º ± 7.69º) and 20.8% valgus (mean 15.9º ± 7.7º). 63.9% had hindfoot varus (mean 8.5º ± 6.07º) and 36.1% valgus (mean 3.9º ± 3.92º) (p < 0.05). The mean value for the American Orthopaedic Foot and Ankle Society (AOFAS) score was 74.26 points, and values were significantly higher among patients with hindfoot varus (p < 0.05). We found no correlation between gender or AOFAS score and knee and hindfoot axes, nor between deformities in the knee and hindfoot axes (p > 0.05). The subgroup genu valgum - hindfoot varus presented a moderate correlation (r = 0.564; p < 0.05). Conclusion: We found no association between the anatomical axes of the knee and hindfoot. Patients with gonarthrosis and hindfoot varus presented a better ankle function. Level of Evidence II, Prognostic Studies - Investigating the Effect of a Patient Characteristic on the Outcome of Disease.