Recurrence of varus/valgus deformity after TKR at 3 years' follow-up

We assessed 30 patients with a cemented TKR implant (Interax ISA®, Stryker Orthopaedics) at 1 and 3 years follow-up. We wanted to ascertain whether knee alignment was maintained during the critical period of follow-up in meniscal-bearing PCL-retaining TKR patients and test if correlations exist between alignment variations in the coronal plane and preoperative varus/valgus deformity or tibial component position and migration with respect to the tibia. Lower limb alignment was evaluated by measuring the angle between the tibia and femur anatomical axis directly from the antero-posterior radiographs and the tibial component position with respect to the tibial anatomical axis. The tibial component varus/valgus migration in the tibia was measured by roentgen stereophotogrammetric analysis. The results showed that at 3 years follow-up 40% of patients presented an alignment variation of over 3°. The recurrent deformity was not correlated with the preoperative deformity, nor with the tibial component position with respect to the tibial shaft nor with its migration. After total knee arthroplasty coronal axial variation is a common finding and it depends on the overall limb muscles and ligaments adaptation to prosthetic constraints.