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 May 6;102(9):778-787
doi: 10.2106/JBJS.19.00915. PMID: 32379118

Summary by Emma E. Johnson BA

Periprosthetic joint infection (PJI) is one of the more severe complications that can occur following total hip arthroplaty.¹ In addition to a sustained courses of intravenous antibiotics, PJI is often treated surgically by a 2-stage exchange. The first stage of this procedure entails the removal of the infected implant and placement of a temporary antibiotic spacer. Once the infection is considered cleared, reimplantation occurs in the second stage.² Although this is widely accepted as the mainstay treatment for PJI, the type of antibiotic spacer – static or articulating –  is controversial.^2-4 It has previously been postulated that the articulating spacer would shorten second-stage operative time, as the leg length and soft tissue tension would be preserved.

This study by Nahhas et al. compared perioperative outcomes between patients who received either a static or articulating spacer in a randomized clinical trial. Fifty-two patients across 3 institutions were randomly assigned to either a static (n=23) or an articulating spacer (n=29) and followed for a mean of 3.2 years. The primary outcome was operative time of the second-stage reimplantation. Secondary outcome measures included length of hospital stay, need for blood transfusion, discharge disposition, failure secondary to infection, need for reoperation, other complications, and the Harris Hip Score.

The authors found that operative times of the first-stage and second-stage reimplantation did not significantly differ between the two cohorts. The length of hospital stay was greater in the static cohort after first and second-stage implantation. In the first stage, length of hospital stay was 8.6 days for the static spacer group and 5.4 days for the articulating group (p=0.006). In the second stage, length of hospital stay was 6.3 days in the static spacer group and 3.6 days for the articulating group (p-<0.001). The authors did not find any of the other secondary outcomes to significantly differ between the two groups.

Nahhas et al. concluded that, while overall outcomes did not differ significantly between the two groups, the significantly longer hospital stay observed in the static group may have important economic consequences. This should be weighed against the higher cost of the articulating spacer itself. This study was limited by a small sample size, which was powered for the primary outcome, but none of the secondary outcomes. Further, the antibiotic regimen, implants used at reimplantation, and postoperative rehabilitation were not standardized throughout.

References

1. Perfetti DC, Boylan MR, Naziri Q, Paulino CB, Kurtz SM, Mont MA. Have periprosthetic hip infection rates plateaued? J Arthroplasty 2017;32:2244e7.
2. Jacobs C, Christensen CP, Berend ME. Static and mobile antibiotic-impregnated cement spacers for the management of prosthetic joint infection. J Am Acad Orthop Surg 2009;17:356e68.
3. Hsieh PH, Shih CH, Chang YH, Lee MS, Shih HN, Yang WE. Two-stage revision hip arthroplasty for infection: comparison between the interim use of antibiotic-loaded cement beads and a spacer prosthesis. J Bone Joint Surg Am 2004;86:1989e97.
4. Haddad FS, Muirhead-Allwood SK, Manktelow AR, Bacarese-Hamilton I. Two stage uncemented revision hip arthroplasty for infection. J Bone Joint Surg Br 2000;82:689e94.