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Tomasz Poboży

Robotic Total Knee Arthroplasty — Cemented or Cementless Fixation?

Autor:

Tomasz Poboży

Robotic assistance can improve planning and execution of component positioning, but it does not answer whether a total knee arthroplasty should be cemented or cementless. A recent meta-analysis found no reliable clinical advantage for either fixation method in revision risk, manipulation for stiffness, operative time or length of stay. Certainty of evidence was very low for all pooled outcomes.

Why is this study interesting?

Use of robotic-assisted total knee arthroplasty is increasing, as is interest in cementless fixation. The two technologies are often presented as complementary: robotic assistance may improve bone preparation and implant positioning, while biological ingrowth may provide durable fixation. The clinically relevant question, however, is whether this combination actually reduces revision risk or improves recovery.

Research question and methods

The authors performed a prospectively registered systematic review and meta-analysis comparing cementless and cemented fixation in robotic-assisted total knee arthroplasty. PubMed, Embase, Web of Science and CENTRAL were searched through 29 July 2026. Ten studies, reported in 11 publications, were included. The evidence was observational rather than randomized.

A random-effects model with Hartung–Knapp adjustment was used. Risk of bias was assessed with ROBINS-I and certainty of evidence with GRADE. Adjusted registry and institutional estimates were considered separately from simple unadjusted event rates.

Results

  • All-cause revision: RR 0.63; 95% CI 0.09–4.53; three studies. The confidence interval is compatible with both substantial benefit and clinically important harm.
  • Manipulation under anaesthesia for stiffness: RR 1.03; 95% CI 0.09–11.74; three studies. The estimate is extremely imprecise.
  • Operative time: mean difference −12.91 minutes; 95% CI −36.38 to 10.55. Heterogeneity was very high (I² 94.4%).
  • Length of stay: mean difference −0.24 days; 95% CI −3.67 to 3.19.

Adjusted analyses of implant survival were inconsistent. Certainty of evidence for all pooled outcomes was rated very low.

Clinical interpretation for an orthopaedic surgeon

The most defensible conclusion is a negative one: current evidence does not allow fixation to be selected on the expectation of superior implant survival or a lower risk of stiffness. Absence of a statistically significant difference is not evidence of equivalence. Event numbers were small, follow-up and patient characteristics varied, and the confidence intervals remained wide.

In practice, fixation choice should still take account of bone quality, age and activity level, implant design, surgeon and team experience, and credible long-term survivorship data. Robotic assistance does not remove these variables.

Limitations

  • no randomized trials and potential selection of younger or healthier patients for cementless fixation;
  • few clinically important events;
  • different robotic systems, implants, perioperative pathways and follow-up durations;
  • very high heterogeneity for operative time;
  • insufficient evidence for firm conclusions about long-term osseointegration and implant survival.

What may change in practice — and what does the study not prove?

The study is useful as a reminder that new technology should not automatically be equated with a better clinical result. It supports individualized fixation choice and the need for registries and comparative studies with longer follow-up.

The meta-analysis does not prove that the two fixation methods are equivalent, that cementless fixation shortens surgery, or that robotic assistance improves implant survival. It evaluated fixation within robotic TKA, not robotic versus conventional TKA.

Source

Lu X, et al. Cementless versus cemented fixation in robotic-assisted total knee arthroplasty: a systematic review and meta-analysis. Journal of Robotic Surgery. Published online 10 September 2026. DOI: 10.1007/s11701-026-03858-9. PubMed PMID 42720876.

PROSPERO: CRD420261446055.

For Doctors and Physiotherapists · Polish version

Content prepared by: Tomasz Poboży - orthopaedic surgeon.

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