Conference Coverage

Functionally Aligned Robotic TKA Outcomes Better Than Mechanically Aligned

Edited by:
Brian McCurdy

Key Highlights

  • Functional alignment produced higher Forgotten Joint Scores at 1 and 2 years, while early outcomes showed no clinically meaningful differences.
  • WOMAC results favored functional alignment across several domains, but KOOS and EQ-5D scores remained comparable.
  • Surgical time was longer with functional alignment, averaging 114.6 versus 104.8 minutes.

In a prospective, double-blinded randomized trial, functionally aligned robotic total knee arthroplasty (TKA) yielded better results on selected patient-reported outcomes at 1 and 2 years than mechanically aligned robotic TKA. Early recovery outcomes were comparable, although functional alignment required longer surgical time. The study received the James A. Rand, MD, Young Investigator’s Award at the 2026 American Association of Hip and Knee Surgeons (AAHKS) Annual Meeting in Dallas.

Investigators compared the approaches since interest in functional alignment has increased while comparative randomized evidence remains limited. The trial enrolled 100 patients undergoing primary robotic TKA and randomized them equally to mechanically aligned or functionally aligned surgery. Baseline characteristics and preoperative patient-reported outcome measures were comparable.

Assessments occurred at 6 weeks, 6 months, 1 year, and 2 years. Measures included the Oxford Knee Score, Forgotten Joint Score (FJS), visual analog scale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and EQ-5D. Perioperative assessments included surgical time, length of stay, physiotherapy sessions, and opioid consumption.

Study Findings

No clinically meaningful between-group differences were observed at 6 weeks or 6 months. At 1 year, functional alignment produced a higher FJS than mechanical alignment—76.9 ± 21.2 versus 67.4 ± 23.9 (P = .041). WOMAC stiffness (P = .022), function (P = .044), and total scores (P = .048) also favored functional alignment. At 2 years, FJS remained higher with functional alignment: 79.9 ± 21.9 versus 70.2 ± 23.1 (P = .042). WOMAC pain (P = .024), stiffness (P = .003), function (P = .007), and total scores (P = .004) favored functional alignment at that assessment.

KOOS and EQ-5D scores were comparable at every time point. The groups did not differ in length of stay, opioid consumption, or most perioperative variables. Surgical time was longer with functional alignment, at 114.6 ± 27.0 minutes versus 104.8 ± 20.7 minutes with mechanical alignment (P = .023).

Clinical Implications

The authors suggest functional alignment may offer incremental clinical benefit after robotic TKA without compromising perioperative safety. They characterized the findings as improved patient-reported outcomes at mid-term follow-up without differences in perioperative recovery, while emphasizing the need for longer-term follow-up.

Expert Commentary

“These findings suggest that functional alignment may provide incremental clinical benefit without compromising perioperative safety, although longer-term follow-up is required,” the researchers concluded.

Reference

Fontalis A, Kayani B, Haddad FS, et al. Functionally aligned vs. mechanically aligned robotic TKA: a double-blinded randomized trial. James A. Rand, MD, Young Investigator’s Award. Presented at the American Association of Hip and Knee Surgeons Annual Meeting, November 5–8, 2026, Dallas, TX.