Aim: This study aimed to compare postoperative alignment using fixed versus individual valgus correction angle (VCA) in primary total knee arthroplasty (TKA) and analyze factors affecting VCA. Material and Methods: This prospective randomized controlled trial was conducted at the Department of Orthopaedics, Noida International Institute of Medical Sciences (NIIMS) Greater Noida, from September 2023 to September 2024. A total of 100 knees from 52 patients were included, with 50 knees in each group: Group A (individual VCA) and Group B (fixed VCA). Patients were selected based on strict inclusion and exclusion criteria and underwent TKA using the modified Insall’s technique. Preoperative and postoperative hip-knee-ankle (HKA) radiographs were analysed. Statistical analysis was conducted using SPSS 26.0, and a p-value <0.05 was considered significant. Results: The mean age of the study population was 64.04 ± 9.41 years, with the majority (38.4%) aged 60–69 years. Females constituted 84.6% of the cohort. The mean BMI was 30.33 ± 5.32, with 53.8% classified as obese. The mean VCA was 6.9°, with 41% of patients having VCA values between 6–6.9° and 37% >7°. Postoperative alignment was significantly better in the individual VCA group (MAD: 1.61 ± 1.63°) compared to the fixed VCA group (MAD: 3.3 ± 1.60°, p = 0.000). Group B had a higher proportion of patients with alignment deviation ≤1° (48%) compared to Group A (12%). Conclusion: Individual VCA resulted in significantly better postoperative limb alignment compared to fixed VCA. Factors such as height, weight, BMI, and hip medial offset influence VCA and should be considered during preoperative planning to optimize outcomes in TKA. Tailored VCA measurement ensures precise alignment, particularly in patients with unique anatomical variations.