Abstract
Mechanically aligned total knee arthroplasty (MATKA) aims to make alignment of the
hip, knee, and ankle straight unexceptionally. However, emerging evidence suggests
that unexceptional straightening the mechanical axis of the lower limb may lead to
clinical and radiological problems of the ankle joint. By contrast, kinematically
aligned total knee arthroplasty (KATKA) strives to restore the articular surface of
the prearthritic knee. In this study, we examined results from KATKA and MATKA to
determine which surgery restores the ankle joint orientation closer to the native
ankle joint in bipedal stance and hypothesized that KATKA, rather than MATKA, would
be more effective. Data from long-leg standing radiographs of 60 healthy adults (control
group, n = 120 knees), patients who underwent MATKA (n = 90 knees), and patients who underwent KATKA (n = 90 knees) were retrospectively reviewed. The hip–knee–ankle angle, orientation
of the tibial plafond and the talar dome relative to the ground (G-plafond and G-talus,
respectively), and orientation of the plafond relative to the mechanical axis of the
limb (M-plafond and M-talus, respectively) were measured and analyzed for comparison.
Results show that bipedal stance alignment in patients who underwent KATKA (G-plafond:
−0.65 ± 3.03 and G-talus: −1.72 ± 4.02) were not significantly different to native
ankle joint alignment indicated by the control group. Compared with the native ankle
joint measured in the control group (G-plafond: −0.76 ± 2.69 and G-talus: −1.30 ± 3.25),
the tibial plafond and talar dome significantly tilted laterally relative to the ground
in ankle joints after MATKA (G-plafond: −2.32 ± 3.30 and G-talus: −2.97 ± 3.98, p = 0.001 and p = 0.004, respectively). Thus, postoperative ankle joint line orientation after KATKA
was horizontal to the floor and closer to that of native ankle joints than those after
MATKA. The level of evidence is Level III.
Keywords
knee - ankle - joint - arthroplasty
