Long-term outcome of periprosthetic joint infection following unicompartmental knee arthroplasty: A single-centre case series.

PURPOSE

Periprosthetic joint infection (PJI) following unicompartmental knee arthroplasty (UKA) is a rare but serious complication. The data available on this topic are heterogeneous and limited, particularly in regard to long-term survival and patient-reported outcomes (PROs). Therefore, the aim of the present study was to analyse the long-term survival and functional outcome of a case series of PJI following primary UKA at a tertiary referral centre.

METHODS

Eighteen knees treated for acute or chronic PJI after primary UKA between 2001 and 2020 with a minimum follow-up of 2 years were retrospectively identified and evaluated in the present study. Surgical treatment included debridement, antibiotics and implant retention (DAIR) in 10 patients, and two-stage arthroplasty in 8 patients. Implant survival analysis was conducted using the Kaplan-Meier estimator. Patient-reported outcome measures (PROMs) were used to assess clinical outcomes.

RESULTS

Overall implant survival free from any revision at 10 years was 83% (95% confidence interval [CI]: 57%-94%). Three DAIR procedures failed due to persistent infection with partially major complications, resulting in a 10-year revision-free implant survival of 73% (95% CI: 37%-90%). No reoperation was required in the group that underwent staged treatment. There were no long-term revisions due to aseptic loosening or degeneration of other compartments in either group. Both groups demonstrated promising median Oxford Knee Scores, with no significant difference (>0.05) between the DAIR (42, range 11-45) and two-stage exchange arthroplasty (43, range 19-46) groups.

CONCLUSIONS

Two-stage revision procedure offers excellent long-term survival and high patient satisfaction. The DAIR procedure represents a valid treatment option for acute PJI but carries a certain risk of treatment failure that surgeons should be aware of. Successful treatment of PJI in UKA can provide excellent functional outcomes and long-term survival without an increased risk of low-grade infection and aseptic loosening.

LEVEL OF EVIDENCE

Level IV.