Complications and Outcomes Associated With Two-Stage Treatment of Periprosthetic Knee Infection

Recent studies have focused on morbidity during the interstage and early post reimplantation periods of two-stage treatment for periprosthetic joint infection, suggesting that single-stage treatment may alleviate high complication rates. To understand the possibly cohort-specific nature of complications associated with two-stage treatment, we compared morbidity in an independent cohort using the same methods as a comparison study.

We retrospectively analyzed medical chart data for 98 infected knees undergoing two-stage treatment at our academic referral center. The results were compared to the outcomes of 134 infected knees in a comparison study performed at a specialized periprosthetic joint infection center. Outcomes included reoperations and medical complications during the interstage period and within 1 year of reimplantation, along with final patient dispositions at the latest mean follow-up of 49.0 months.

In the current sample, 82% of patients achieved successful reimplantation without reoperation within a year compared to 56% in the comparison study. There were 99% of patients, compared to 91.8%, who progressed to the second stage of treatment, with concomitantly fewer instances of long-term spacer retention (0 versus 4.5%). Interstage reoperations were similar, although there were fewer reoperations within a year of reimplantation in the current cohort. Medical complication rates were higher in the current study, which comprised ostensibly sicker patients. There were no deaths during the interstage period or within a year of reimplantation, compared to six deaths in the comparison study.

Observed differences may reflect the inherent complexity of this patient group, as well as perioperative and surgical protocol differences, and not the two-stage treatment itself. The cohort-specific nature of morbidity associated with two-stage treatment should be considered in discussions about the relative morbidity of two-stage versus single-stage treatment for knee infection.