Anoop K. Prasad, Jaimee H.S. Tan, Hany S. Bedair, Sebastian Dawson-Bowling, Sammy A. Hanna
4 min
As the demand for total knee arthroplasty (TKA) increases, particularly among younger, more active patients, surgeons are re-evaluating the optimal method for implant fixation. While cemented fixation remains the gold standard, cementless fixation—which relies on biological osseointegration—has seen a resurgence in interest due to advancements in implant design and manufacturing. This study aimed to determine if cementless fixation provides comparable long-term durability and functional outcomes to traditional cemented techniques.
The authors conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing cemented and cementless primary TKA. After searching MEDLINE and EMBASE, they identified six high-quality studies (Jadad score ≥ 3) that met their strict inclusion criteria. The final cohort included 755 knees (356 cemented, 399 cementless) with a mean follow-up period of 8.4 years, ranging up to 16.6 years. The primary outcome was the all-cause revision rate, while secondary outcomes included patient-reported functional scores.
The meta-analysis revealed no statistically significant difference in revision rates between the two groups (p = 0.64). Furthermore, functional outcomes, assessed via the Knee Society Score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), showed no significant differences between cemented and cementless cohorts. Although some studies noted a trend toward higher early post-operative pain in the cementless group—likely due to initial prosthetic migration before complete biological fixation—this difference typically resolved within the first year.
This study provides evidence that modern cementless fixation is not inferior to cemented fixation in terms of long-term survival and function. For younger patients, who may face higher risks of aseptic loosening with cement, these findings support the use of cementless implants as a viable alternative that preserves bone stock and avoids potential cement-related complications. However, the authors caution that implant design varies significantly, and surgeons should remain selective, as historical failures of certain cementless models underscore the importance of ongoing monitoring.
Sam: [direct, acknowledging the limitation] That is the most important critique of this paper. The meta-analysis pools studies spanning different generations of implant design. Early cementless models that struggled with poor geometry are being averaged together with modern, high-performance prostheses. That heterogeneity almost certainly masks the true performance of current technology — meaning the "no difference" finding is likely a conservative estimate of what modern cementless implants can actually achieve, not a ceiling.
Alex: [summarizing, checking understanding] So we are looking at a composite of historical failures and modern successes. If you could isolate the latest generation, do you think that parity would hold, or would we see a divergence? [[RP_SECTION:future-of-patient-stratification|Future of patient stratification]]
Sam: [measured, weighing the evidence] It is genuinely difficult to say. What the current evidence supports is that for the average patient, either method is a safe, durable choice. But the more interesting clinical question may be about patient stratification rather than technique superiority. If bone quality could be reliably characterized — through advanced imaging, say — you might preferentially offer cementless fixation to patients with robust bone stock, where long-term biological integration is a realistic expectation, while reserving cemented fixation for lower bone density cases where immediate mechanical interlock is the priority.
Alex: [reflective] So the field is moving away from a population-level "one size fits all" answer, even though the meta-analysis suggests that on average, both paths lead to the same destination.
Sam: [quiet conviction, concluding] Precisely. The parity we see today is a starting point for more nuanced decision-making, not a final verdict on technique superiority. The productive question for the next decade of research isn't which method is better in aggregate — it is identifying which patient-specific factors determine whether biological or mechanical fixation will serve a given individual best. That is where the real clinical signal is likely buried.