A "1.5-Stage" Spacer Construct Using Revision Components for the Management of Periprosthetic Joint Infection of the Knee.

Background: The two-stage surgical protocols used for the treatment of periprosthetic joint infection following total knee arthroplasty are associated with marked patient morbidity. As such, alternatives, such as durable "1.5-stage" spacer constructs, have gained popularity. We sought to describe the outcomes of a novel "1.5-stage" spacer construct utilizing revision stemmed-tibia implants.

Methods: Patients who underwent a "1.5-stage" for the management of a knee periprosthetic joint infectionat our institution were screened for inclusion. A "1.5-stage" was defined as a spacer placed with the intent of not performing a second stage, without the use of press-fit stems or cemented intramedullary fixation as is often done during a single-stage protocol. Procedures were categorized into two groups based on construct type: (1) hand-made constructs utilizing all-polyethylene tibial components; or (2) constructs utilizing stemmed-revision components precoated with cement before insertion. Patient demographics, comorbidities, and surgical details were collected and reported. The two-year Kaplan-Meier survival estimates for all-cause revision, revision for spacer loosening, and revision due to infection recurrence were reported. In total, 46 "1.5-stage" procedures were identified, including 12 handmade and 34 stemmed-revision constructs.

Results: The stemmed-revision cohort was less likely to undergo reoperation for any reason (17.6 versus 50.0%, P = 0.028) or a revision for spacer loosening (0.0 versus 25.0%, P = 0.003) compared to the hand-made cohort. There were no differences with respect to infection recurrence or time to revision. The 2-year survival from revision for loosening was higher in the stemmed cohort compared to the handmade cohort though not statistically different (100%, 95% CI [confidence interval]: 2.5 to 100.0 versus 72.9%, 95% CI: 26.3 to 96.6%, P = 0.330).

Conclusions: A "1.5-stage" spacer construct using stemmed-revision components was associated with promising short-term results. Durable spacer constructs may be a viable option for select patients; however, longer-term follow-up is needed to identify patients who stand to benefit the most from this technique.