Custom-made total knee arthroplasty with mechanical alignment achieves 94% patient satisfaction at mid-term follow-up

Purpose: A notable proportion of patients remain dissatisfied following a total knee arthroplasty (TKA), often due to issues like prosthetic implant overhang, overstuffing, ligament imbalance and paradoxical motion. Custom made implants (CMI) aim to improve this condition by providing patient-specific solutions tailored to individual knee joint characteristics. The purpose of this prospective study is to evaluate the clinical and radiological outcomes of patients undergoing CMI TKA. Methods: This prospective study evaluated clinically and radiologically 31 patients (33 knees) undergoing TKA with custom-made prostheses implanted using mechanical alignment. Pre- and post-operative assessments included patient-reported outcome measures (PROMs), radiographic evaluations, and analysis of intraoperative and postoperative data. The mean follow-up period was of 39 ± 22.6 months (range: 9–66 months). Results: Clinical outcomes, including functional scores and range of motion, showed significant improvements over time. Specifically, at a mean follow-up of three years after the custom TKA, the Oxford Knee Score (OKS) improved from a preoperative value of 24.3 ± 8.5 to a postoperative value of 41.2 ± 5.9 (p < 0.01), and the Knee Society Score (KSS) (functional) increased from 54.4 ± 14.2 to 89.8 ± 14.6 (p < 0.01). Similarly, it was observed an increase in the Forgotten Joint Score (FJS), reaching an average value of 85.8 ± 27.0 (range: 15–100) three years post-surgery. The radiographic analysis showed an increase in the mechanical Lateral Distal Femoral Angle (mLDFA) from 89.2 ± 4.4 to 90.6 ± 2.5 (p = 0,03). No significant complications were observed, with the exception of one patient who was diagnosed with aseptic loosening. The overall satisfaction rate was 94%. Conclusions: CMI demonstrate good clinical and radiological outcomes at mid-term follow-up, encouraging further studies to support the potential implementation of this type of implant. Level of Evidence: Level II, prospective cohort study.