Coronal Plane Alignment After TKA And Its Influence On Outcome

Background: Appropriate positioning of total knee arthroplasty (TKA) components is a key concern of surgeons. Post-operative varus alignment has been associated with poorer clinical outcome scores and increased failure rates. However, obtaining neutral alignment can be challenging in cases with significant pre-operative varus deformity Questions: 1) In patients with pre-operative varus deformities, does residual post-operative varus limb alignment lead to increased revision rates or poorer outcome scores compared to correction to neutral alignment? 2) Does placing the tibial component in varus alignment lead to increased revision rates and poorer outcome scores? 3) Does femoral component alignment affect revision rates and outcome scores? 4) Do these findings change in patients with at least 10 degrees of varus alignment pre-operatively? Patients and Methods: 553 patients undergoing TKA for varus osteoarthritis were identified from a prospective database. Patients were divided into those with residual post-operative varus and those with neutral post-operative alignment. Revision rates and clinical outcome scores were compared between the two groups. Revision rates and outcome scores were also assessed based on post-operative component alignment. The analysis was repeated in a subgroup of patients with at least 10 degrees of pre-operative varus. Results: At a mean follow-up of 5.7 years (range: 2 to 19.8 years), residual varus deformity did not yield significantly increased revision rates or poorer outcome scores. Varus tibial component alignment and valgus femoral component alignment were associated with poorer outcome scores. Results were similar in the significant varus subgroup. Conclusions: Residual post-operative varus deformity after TKA does not yield poorer clinical results in patients with pre-operative varus deformities, providing tibial component varus is avoided.