Outcomes of Image-Free Robotic Assisted Total Knee Arthroplasty in Patients Who Have Valgus Knee Deformities

Background Valgus knee deformities pose a unique challenge in total knee arthroplasty (TKA) due to the complexity of achieving ligamentous balance and satisfactory alignment compared to varus or neutral deformities. Robotic-assisted (RA) TKA could aid in achieving improved component alignment and balance. Methods We retrospectively evaluated a matched cohort of patients to compare image-free RA-TKA (n = 44) versus conventional manual (CM) TKA (n = 30) techniques in patients who have valgus deformity of 5 to 15 degrees, including radiographic and patient-reported outcomes measures (PROM) over a 3-year period. The patient reported outcome measures (PROMs) studied to determine outcomes were: Western Ontario McMaster University Arthritis Index (WOMAC), Knee Society Score-Function Score (KSS-FS), and Short Form 12-item Survey (SF-12). Results Overall, the RA-TKA cohort showed faster improvement in PROMs (37.16 ±1 8.8 versus 25.74 ± 17.7, P = 0.02), shorter length of stay (1.41 versus 2.29 days, P = 0.02), and shorter operating room (OR) times (120.79 versus 123.67 minutes, P = 0.02) than CM-TK). Additionally, there was no difference in the use of primary versus varus-valgus constrained polyethylene liners between the cohorts. Conclusion In this investigation, RA-TKA yielded a slightly faster patient recovery, more objective measurements of ligamentous balance, and proved non-inferior PROMs compared to CM-TKA for pre-operative valgus knee deformities.