Paper of the Week: A Randomized Trial of Static and Articulating Spacers for the Treatment of Infection Following Total Knee Arthroplasty

Nahhas CR, Chalmers PN, Parvizi J, Sporer SM, Berend KR, Moric M, Chen AF, Austin MS, Deirmengian GK, Morris MJ, Della Valle CJ
J Bone Joint Surg Am. 2020 Feb 20. doi: 10.2106/JBJS.19.00915

Summary by Steven Yacovelli MD

Periprosthetic joint infection (PJI) remains one of the most difficult to treat complications after total knee arthroplasty (TKA). While 2-stage exchange using an interim spacer remains one of the mainstays of treatment, there is no clear consensus with regards to which type of spacer, static or articulating, should be used. Proponents of the static spacer argue that immobilization of the periarticular soft tissues provides stability and is easier to place when compared to an articulating spacer. Those who support the use of an articulating spacer state that mobilization improves long-term knee function and that their use actually facilitates surgical exposure at the time of reimplantation. As such, the authors sought to compare articulating and static spacers in patients undergoing 2-stage exchange arthroplasty. This multicenter study randomized 68 patients undergoing 2-stage exchange arthroplasty to receive either a static (32 patients) or articulating (36 patients) spacer. They subsequently compared a number of postoperative outcomes and found that those in that static spacer group had greater hospital length of stay (6.1 vs 5.1 days p=0.032), more limited range of motion (100.2° vs 113.0° p=0.001), lower Knee Society Scores (69.8 vs 79.4 points p=0.043), and greater need for extensile exposure at the time of reimplantation (16.7% vs 4.0% p=0.189) when compared to those who received an articulating spacer. Although the cohort size was limited and found to be underpowered to detect potential differences in a number of variables in the study, this data strongly supports the use of articulating spacers during 2-stage exchange arthroplasty when the patient’s anatomy allows for it.