Personalized knee replacement approach shows strong long-term success
A new surgical technique that customizes knee implants to each patient's anatomy achieved durable results over seven years, with high patient satisfaction and low revision rates. The finding could reshape orthopedic surgery standards and reduce costly repeat procedures, benefiting both healthcare systems and device manufacturers.
Originaltitel: Unrestricted kinematic alignment for total knee arthroplasty
Aims: Kinematic alignment (KA) offers a personalized approach by restoring each patient's pre-arthritic joint lines. Unrestricted KA (urKA) removes alignment boundaries defined by restricted KA concept, but concerns regarding reproducibility and clinical success persist. This study evaluates mid- to long-term survivorship and functional outcomes of urKA total knee arthroplasty (urKA-TKA) performed using a manual surgical technique by a single surgeon, with a minimum follow-up of three years. Methods: We prospectively reviewed 229 consecutive urKA-TKAs performed between March 2014 and October 2019 using a medial pivot design TKA and calipered measured resection (mean follow-up 87 months (36 to 136)). Patella was not routinely resurfaced. No restrictions were applied regarding preoperative limb alignment. Outcomes included survivorship (revision and reoperation), radiological alignment, and patient-reported outcomes: Knee Injury and Osteoarthritis Outcome Score (KOOS), Forgotten Joint Score (FJS), and Numerical Rating Scale (NRS) for pain. Survivorship was calculated using Kaplan-Meier analysis. Results: Preoperative and postoperative hip-knee-ankle (HKA) axis ranged respectively from -20.4° to 25.2° and -9.4° to 10.6°. The mean KOOS improved from 28.8 (SD 10.3) preoperatively to 75.8 (SD 16.6) postoperatively (p < 0.001). FJS was 87.6 (SD 17.7) at final follow-up, while NRS pain scores averaged 1.6 (SD 2.4), with 60% reporting no pain. At nine years (n = 32 at risk), implant survivorship was 97% free from revision for any reason and 96% free from reoperation, with no cases of aseptic loosening. Patients with preoperative alignment outliers (>± 5° HKA) demonstrated greater improvements in KOOS and FJS than neutral knees. Outcomes and implant survival were similar between knees within or outside restricted alignment boundaries. A trend towards higher rates of secondary patellar resurfacing was observed in valgus phenotypes, although this finding was not statistically significant. Conclusion: UrKA TKA provides excellent mid- to long-term survivorship and significant functional improvement without compromising safety in all knee phenotypes including patients with extreme preoperative alignment.