Lower Limb Alignment Shifts Toward Varus a Decade After Knee Replacement

Total knee arthroplasty remains the definitive intervention for end-stage knee osteoarthritis, with data indicating higher prosthetic survival rates compared to unicompartmental procedures over follow-up periods of five years or more [1]. While surgeons traditionally target a neutral mechanical axis, the relationship between the knee and the hindfoot is dynamic; for example, correcting a varus deformity (an inward angulation of the distal segment of a bone) can trigger compensatory changes in the hindfoot alignment [2]. Clinical recovery is often limited by persistent functional deficits, as patients may retain significant weakness in the quadriceps and hip abductors for up to three years postoperatively [3]. Although robotic-assisted techniques can achieve a lower hip-knee-ankle angle deviation (mean difference -0.99; 95% confidence interval [-1.24, -0.74]; p < 0.00001) compared to conventional methods, the longitudinal stability of these alignments is not well established [4]. A new study now examines how femoral geometry and limb alignment shift over a ten-year period following primary total knee arthroplasty.