Superior patient-reported clinical outcomes after patient-individual total knee arthroplasty compared with off-the-shelf robotic-assisted total knee arthroplasty in valgus knee phenotypes.

PURPOSE: To compare early patient-reported clinical outcomes of patient-individual total knee arthroplasty (TKA) with individualized trochlear design versus robotic-assisted TKA using off-the-shelf implants in patients with valgus knee phenotypes and pronounced femoral valgus (lateral distal femoral angle [LDFA] < 85°) at 3 and 12 months postoperatively in a prospective matched case-control study.

METHODS

This prospective matched case-control study based on predefined anatomical criteria included 42 patients who underwent primary TKA between October 2021 and October 2023. Twenty-one patients received patient-individual posterior-stabilized implants. Twenty-one matched controls underwent robotic-assisted TKA with off-the-shelf implants. All procedures followed restricted kinematic alignment (KA) principles with valgus undercorrection. Primary outcomes were patient-reported scores (Forgotten Joint Score [FJS], Kujala Score, Oxford Knee Score [OKS] and the Western Ontario and McMaster Universities Arthritis Index [WOMAC]), assessed preoperatively and at 3 and 12 months.

RESULTS

Both groups demonstrated comparable preoperative clinical status and comparable degrees of preoperative valgus deformity, with no significant differences in hip-knee-ankle angle (HKA, 185.6 ± 6.3° vs. 188.8 ± 4.1°; p = 0.060) or mechanical LDFA (84.0 ± 0.9° vs. 83.7 ± 1.2°; p = 0.261). At 3 and 12 months, patient-individual total knee arthroplasty (pTKA) demonstrated significantly better scores across all patient-reported outcome measures (PROMs) (p < 0.05). The largest difference was observed in the Kujala score at 12 months (79.5 ± 12.8 vs. 59.7 ± 19.0, p = 0.001). FJS improved more rapidly in the pTKA group (from 9.0 to 49.1 at 3 months, and 52.5 at 12 months) compared to robotic-assisted total knee arthroplasty (rTKA) (26.9 and 36.0, respectively). One revision for suspected infection occurred in the pTKA cohort; none were reported after rTKA.

CONCLUSIONS

Patient-individual TKA with individualized trochlear design achieved superior early functional outcomes compared to robotic-assisted TKA with standard implants in severe valgus morphotypes. Individualized trochlear orientation may improve patellofemoral mechanics and facilitate faster recovery in patients with severe femoral valgus.

LEVEL OF EVIDENCE: Level III.