CLINICAL IMPACT OF TIBIAL MALALIGNMENT

Tibial and distal femoral component malalignment has been specifically associated with adverse clinical events. In a study of 2,125 patients (3,152 knees) undergoing TKA between the years of 1983– 2000, it was found that tibial and distal femoral malalignment was a strong predictor of the need for revision, with more than 3° of tibial and distal femoral component varus alignment increasing the odds of implant failure by roughly 17x (Hazard Ratio = 17.2, p < 0.0001). This same study found that the combination of tibial and distal femoral malalignment and obesity indicated an especially strong risk for revision, with a relative risk of approximately 168 (p < 0.0001), suggesting that a well-aligned tibial and distal femoral component could significantly reduce revision rate among obese patients.⁴⁰

Given that approximately 87% of Canadian TKA patients are obese or overweight⁴¹ (with the U.S. likely sharing similar statistics), achieving accurate tibial and distal femoral component alignment is particularly important.

Moreover, relatively little clinical research has been done regarding posterior-slope alignment (an angle which the KneeAlign® 2 system enables the surgeon to measure and set), with available data suggesting that the prevalence of malalignment in this dimension may even be worse than varus/valgus malalignment.⁴²