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

Pradyumna Gurusamy; Jennifer W Liu; Thomas C Sullivan; Terry A Clyburn; Bradley S Lambert; Stephen J Incavo

doi:10.1016/j.arth.2024.04.057

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

J Arthroplasty. 2024 Apr 26:S0883-5403(24)00380-2. doi: 10.1016/j.arth.2024.04.057. Online ahead of print.

Authors

Pradyumna Gurusamy¹, Jennifer W Liu¹, Thomas C Sullivan¹, Terry A Clyburn¹, Bradley S Lambert¹, Stephen J Incavo²

Affiliations

¹ Houston Methodist Hospital, Houston Methodist Orthopedics & Sports Medicine 6445 Main St. Outpatient Center, Suite 2500, Houston, Texas 77030.
² Houston Methodist Hospital, Houston Methodist Orthopedics & Sports Medicine 6445 Main St. Outpatient Center, Suite 2500, Houston, Texas 77030. Electronic address: sjincavo@houstonmethodist.org.

PMID: 38679348
DOI: 10.1016/j.arth.2024.04.057

Abstract

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 pre-and postoperatively. Patients were categorized by pre-operative (Pre-op) alignment (varus > 0°; valgus < 0°). Pre-op varus patients were then divided as follows based on post-operative alignment: neutral (VAR-NEUT, 0°±2); remaining in varus (VAR-rVAR, ≥3°); cross-over to valgus (VAR-CO, ≤-3°). Similarly, Pre-op valgus patients were divided as follows for post-operative alignment: neutral (VAL-NEUT, 0°±2); remaining in valgus (VAL-rVAL, ≤-3°); cross-over to varus (VAL-CO, ≥3°). The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS Jr.) survey scores were collected at pre-op as well as at 6-weeks, 3-, 6-, and 12-months post-op. Knee ROM was collected at 2 weeks, 6 to 12 weeks, and > 6-months post-op. An analysis of variance (ANOVA) repeated on time followed by a Bonferroni post-hoc test was used to compare outcomes for the postoperative alignment subgroups.

Results: Pre-op Varus patients: Those in the VAR-CO group (overcorrected to -4.03° ± 1.95^valgus) were observed to have lower KOOS Jr. scores at 3-, 6-, and 12-months post-op compared to those in the NEUT group (P < 0.05). This finding was paired with reduced ROM at 6 to 12 weeks post-op in the VAR-CO group compared to VAR-NEUT and VAR-rVAR (P < 0.05). Pre-op Valgus patients: Those in the VAL-rVal group (left in -4.39° ± 1.39^valgus) were observed to have reduced knee flexion at 6 to 12 weeks post-op compared to VAL-NEUT and VAL-CO.

Conclusion: These findings indicate that post-operative 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.

Keywords: Coronal Alignment; Crossover; PROs; Primary TKA.