Alignment in Total Knee Arthroplasty: Avoid Crossing over from Varus to Valgus

Background: Ideal target limb alignment remains a debated topic in total knee arthroplasty (TKA). We aimed to determine the effect of limb alignment correction on patient-reported outcomes and knee range of motion (ROM) following TKA. Methods: In this retrospective analysis, patients (N = 409) undergoing primary TKA at a single institution were studied. Using full leg-length radiographs, limb alignment was measured preoperatively and postoperatively. Patients were categorized by preoperative (Preop) alignment (varus > 0 degrees; valgus < 0 degrees). Preop varus patients were then divided as follows based on postoperative alignment: neutral (VAR-NEUT, 0 degrees +/- 2), remaining in varus (VAR-rVAR, >= 3 degrees), and cross-over to valgus (VAR-CO, <=-3 degrees). Similarly, Preop valgus patients were divided as follows for postoperative alignment: neutral (VAL-NEUT, 0 degrees +/- 2), remaining in valgus (VAL-rVAL, <=-3 degrees), and cross-over to varus (VAL-CO, >= 3 degrees). The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement survey scores were collected at preoperatively as well as at 6 weeks, 3, 6, and 12 months postoperatively. Knee ROM was collected at 2 weeks, 6 to 12 weeks, and >6 months postoperatively. An analysis of variance repeated on time followed by a Bonferroni post hoc test was used to compare outcomes for the postoperative alignment subgroups. Results: Preop Varus patients: Those in the VAR-CO group (overcorrected to -4.03 degrees +/- 1.95(valgus)) were observed to have lower Knee Injury and Osteoarthritis Outcome Score for Joint Replacement scores at 3, 6, and 12 months postoperatively compared to those in the NEUT group (P < .05). This finding was paired with reduced ROM at 6 to 12 weeks postoperatively in the VAR-CO group compared to VAR-NEUT and VAR-rVAR (P < .05). Preop Valgus patients: Those in the VAL-rVal group (left in -4.39 degrees +/- 1.39(valgus)) were observed to have reduced knee flexion at 6 to 12 weeks postoperatively compared to VAL-NEUT and VAL-CO. Conclusions: These findings indicate that postoperative valgus alignment via either crossing over to valgus (VAR-CO) or remaining in valgus (VAL-rVAL) alignment may result in less preferable outcomes than correction to neutral or slightly varus alignment. (c) 2024 Elsevier Inc. All rights reserved.