Effect of individual distal femoral valgus resection in total knee arthroplasty for patients with valgus knee: A retrospective cohort study

Abstract

Background: Proper limb alignment and implant positioning are important for successful total knee arthroplasty (TKA). It remains unknown whether any differences exist in the restoration of limb alignment for valgus knees between fixed and individual femoral valgus correction angle (VCA) for distal femoral resection.

Methods: A total of 63 patients (66 knees) had fixed 4° VCA (fixed group), and 55 patients (59 knees) had individual VCA (individual group). We compared the VCA, mechanical femorotibial (MFT) angle, femoral component angle (α), and tibial component angle (β) between the two groups.

Results: There were statistically significant differences in postoperative MFT angle between the two groups (2.0° ± 1.2° versus 2.8° ± 1.6°, p < 0.002). A total of 51 (77.3%) patients in the individual group had postoperative alignment deviation within ±3° compared with that of 32 (54.2%) patients in the fixed group (p = 0.006). We found better postoperative alignment accuracies in the individual group for grade II knee valgus deformities (1.8° ± 1.2° versus 2.8° ± 1.5°, p = 0.00). There was a significant difference in α angle deviations between the two groups (1.7° ± 1.3° versus 2.5° ± 1.8°, p = 0.00). The number of patients with postoperative femoral coronal component alignment deviations within ±3° in the individual group was higher compared to that in the control group (87.8% versus 67.8%, p = 0.006).

Conclusions: This radiological study showed that individual VCA for distal femoral resection could achieve better postoperative alignment accuracy and fewer outliers of limb and femoral component malalignment in the coronal plane.

Keywords: Mechanical alignment; Total knee arthroplasty; Valgus correction angle; Valgus knee.