Key Points • The normal knee anatomy varies widely, and the more extreme ones may be inherently biomechanically inferior which may have deleterious effects on the TKA biomechanics and wear patterns. • The restricted kinematic alignment protocol (rKA) has been developed as an alternative solution to the "true" KA technique in situations of patients with atypical knee anatomy. • The rKA protocol limits the femoral and tibial prosthesis coronal alignment to within ±5° of neutral, with the overall

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... ombined lower limb coronal orientation within ±3° of neutral. • 50% of patients fit within the rKA safe range allowing a pure KA technique.