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ArthroplastyRCT

Functional alignment robotic‐assisted TKA improves clinical outcomes compared with conventional mechanical alignment TKA: A single‐surgeon randomised controlled non‐inferiority trial with 2‐year follow‐up

Knee Surgery Sports Traumatology Arthroscopy · 11 Sept 2026

Rigour64/100
Clinical54/100
Impact†49/100

† Impact is the editorial-priority score. All scores are out of 100. Clinical is a stored clinical-importance score from the earlier method; it has not been recalculated.

Why it matters

This adds single-surgeon RCT data to the ongoing debate about whether robotic functional alignment TKA meaningfully improves patient-reported outcomes over conventional mechanically-aligned TKA, a question directly relevant to whether surgeons should adopt costly robotic platforms.

The evidence

This single-centre RCT randomised 180 patients undergoing primary TKA to either robotic-assisted total knee arthroplasty using a functional-alignment (kinematic-based) technique (FA-RATKA) or conventional mechanically-aligned TKA (MA-CTKA), following them for 2 years with a battery of knee scores. FA-RATKA showed statistically significant but small improvements over time in several patient-reported outcomes, including KSS Function (p<0.001, r=0.173), KSS Satisfaction (p<0.001, r=0.214), KSS Symptoms (p=0.004, r=0.138), Oxford Knee Score (p<0.001, r=0.185), VAS pain (p<0.001, r=0.188) and EQ-5D index (p=0.006, r=0.141), while other measures (KSS Expectations, LEAS, FJS-12, EQ-5D VAS) showed no difference. No revisions, deep infections or periprosthetic fractures occurred in either group by 2 years.

A coherent primary effect estimate is unavailable. Clinical relevance does not estimate treatment benefit.

Why this rigour score?

RCTDesign starting point: 59.5

64/ 100

Raised the score

  • Adequately powered+6
  • Concealed allocation+5.1

Lowered the score

  • Unblinded assessment of a subjective outcome−9.3
  • Per-protocol analysis only−6

Methods at a glance

Recorded assessment
  • Outcome assessors blindedNot met
  • Allocation concealedMet
  • Random sequence generatedMet
  • Intention-to-treat analysisNot met
  • Adequate statistical powerMet
  • Prospective registrationMet

Not reported does not mean not done. Checks have different weights; this is not a count of boxes ticked.

See the full score breakdown
Study design starting point
59.5
Concealed allocation
+5.1
Random sequence generation
+2.5
Compared against current standard of care
+3.4
Unblinded assessment of a subjective outcome
−9.3
Per-protocol analysis only
−6
24-month follow-up
+3.4
9% loss to follow-up
−1.1
Adequately powered
+6
Prospectively registered
+5.1
A positive result from a single centre
−4.3
Final rigour score rounded
64 / 100

Study design sets the starting point and a ceiling of 96. Recorded methods then adjust the score. Points are shown to one decimal place; the final score uses unrounded values.

Checklist from the stored appraisal. “Not met” describes the recorded criterion; it does not always produce a deduction. This overview supports reading the full study.

For journal club

1.If the observed differences (effect sizes r=0.12-0.21) are statistically significant but below typical MCID thresholds for KSS and OKS, should surgeons change their alignment philosophy based on these results alone?

2.Given that a larger, multicentre, blinded RASKAL trial found no differences between functional and mechanical alignment, how should a surgeon weigh a single high-volume operator's favourable results against that contrasting multicentre evidence when counselling patients about robotic TKA?

Original publication title

Functional alignment robotic‐assisted TKA improves clinical outcomes compared with conventional mechanical alignment TKA: A single‐surgeon randomised controlled non‐inferiority trial with 2‐year follow‐up

Read original paper