Should we rely on frozen section during the reimplantation stage of revision knee arthroplasty?

Objective: To compare Frozen Section (FS) results during the reimplantation stage of revision knee arthroplasty, in patients without clinical signs of infection but with preoperative inconclusive serum inflammatory markers.

Methods: Sections were revisited the day after surgery. Intraoperative FS (iFS) was accepted as positive when the presence of >5 polymorphonuclear neutrophils (PMNLs) in 5 separate high-power fields was determined according to the consensus criteria of the International Consensus on Musculoskeletal Infection. The clinical outcomes, cultures and diagnostic values of iFS and review FS (rFS) were analyzed.

Results: No complications developed after reimplantation in 66 (84.6%) of the 78 evaluated patients. Complications developed in 12 patients, six of whom were treated with re-explantation, four with arthrodesis and two with above-the-knee amputation. Both iFS and rFS yielded insignificant sensitivity and specificity (25% and 45.5%, 25% and 45%, respectively). There was no statistically significant difference between definitive culture and iFS and rFS.

Conclusion: iFS evaluation is insufficient to exclude recovery from periprosthetic joint infection (PJI). Diagnosis of recurrence of infection in patients with indefinite serum inflammatory markers between the explantation and reimplantation interval remains challenging due to massive fibrosis that makes proper tissue sampling difficult. The attending physician should closely monitor clinical findings.