Periprosthetic joint infection risk is comparable between unicompartmental knee arthroplasty to total knee arthroplasty conversion and primary total knee arthroplasty: A systematic review and meta-analysis.
Maximilian Budin, Matthew De Ruyter, Zachary Christopher Lum et al.
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In 30 seconds
This systematic review and random-effects meta-analysis compared periprosthetic joint infection (PJI) after conversion of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) with PJI after primary TKA. Six retrospective studies included 456 conversion procedures and 719 primary TKAs. PJI rates were similar: 0.66% after conversion and 0.70% after primary TKA (OR 1.21, 95% CI [0.27, 4.46]; p = 0.91). Conversion was associated with greater use of augments and stems, indicating increased surgical complexity.
Key findings
- PJI occurred in 0.66% of UKA-to-TKA conversions and 0.70% of primary TKAs (OR 1.21, 95% CI [0.27, 4.46]; p = 0.91).
- Augments were used more often in conversion than primary TKA (15.6% vs. 3.9%; OR 8.71, 95% CI [1.29, 58.80]; p = 0.03).
- Stems were used more often in conversion than primary TKA (36.6% vs. 1.7%; OR 45.83, 95% CI [9.53, 220.55]; p < 0.00001).
Why it matters
The findings help contextualise infection risk when a UKA requires conversion to TKA: the pooled evidence did not show a higher PJI rate than with primary TKA. However, the greater use of revision-specific components signals that conversion may involve more complex reconstruction, an important consideration when interpreting procedural demands and planning care.
What to keep in mind
The evidence came from six retrospective studies, and the confidence interval around the PJI odds ratio was wide.