Abstract
BackgroundThis study aimed to investigate the risk factors for mechanical failure of cement spacers and the impact on hip function after two-stage exchange arthroplasty for periprosthetic joint infection (PJI).MethodsThirty-one patients (19 males and 12 females) with hip PJIs underwent resection arthroplasty and implantation of cement spacers from January 2014 to December 2015. Patients who encountered spacer-associated mechanical complications in the interim period (14 of 31) were compared with those without complications (17 of 31). Complications were defined as spacer dislocation, spacer fracture, spacer fracture with dislocation, and femoral fracture during or following spacer implantation. Hip functional outcome was assessed using the Harris hip score (HHS). Treatment success was defined according to the following criteria: (1) no symptoms or signs indicative of infection; (2) no PJI-related mortality; and (3) no subsequent surgical intervention for infection after reimplantation surgery. Multivariate logistic regression and Kaplan-Meier survival curves were used for analysis.ResultsFourteen patients (14/31 = 45%) suffered at least one spacer-related complication within the interim period. The development of spacer complications was associated with a younger age (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.83–1.00, p = 0.045) and chronic PJI (OR 14.7, 95% CI 1.19–182, p = 0.036). Patients with spacer complications also had a lower median HHS (37 vs. 60, p < 0.001) before reimplantation in comparison to those without spacer complications. After reimplantation, the two groups had a similar median HHS (90 vs. 89, p = 0.945). Two patients did not undergo reimplantation due to extensive comorbidities, and subsequently retained the antibiotic spacer for definitive treatment. The 2-year treatment success rate was 84.6% in the spacer-complication group and 87.5% in the non-spacer-complication group (p = 0.81).ConclusionThere was a high complication rate for articulating PMMA spacers during the interim period of two-stage revision total hip arthroplasty. A young age and chronic infection were the primary risk factors associated with mechanical complications. Patients at high risk of spacer-related mechanical complications should be advised accordingly by surgeons. Knowing the possible risk factors, surgeons should educate patients thoroughly to avoid spacer complications, thereby increasing patient satisfaction in the interim stage.Level of evidencePrognostic Level III.
Highlights
This study aimed to investigate the risk factors for mechanical failure of cement spacers and the impact on hip function after two-stage exchange arthroplasty for periprosthetic joint infection (PJI)
The gold standard for treating PJI after total hip arthroplasty (THA) is via two-stage revision arthroplasty, which involves initial removal of the prosthesis and insertion of an articulating polymethylmethacrylate (PMMA) spacer
Articulating PMMA spacers have been shown to eliminate infection at a rate similar to cement beads [4]; articulating spacers are advantageous in comparison with beads, in that they provide temporary soft tissue tension and improved hip scores, and allow for increased functional capacity [2]
Summary
This study aimed to investigate the risk factors for mechanical failure of cement spacers and the impact on hip function after two-stage exchange arthroplasty for periprosthetic joint infection (PJI). The gold standard for treating PJI after THA is via two-stage revision arthroplasty, which involves initial removal of the prosthesis and insertion of an articulating polymethylmethacrylate (PMMA) spacer. Articulating PMMA spacers have been shown to eliminate infection at a rate similar to cement beads [4]; articulating spacers are advantageous in comparison with beads, in that they provide temporary soft tissue tension and improved hip scores, and allow for increased functional capacity [2]. Application of an articulating spacer is relatively straight-forward during reimplantation surgery [7], and results in a lower dislocation rate postoperatively in comparison to antibiotic beads [4]. In comparison, preformed spacers provide similar infection eradication rates to articulating spacers, as well as good mechanical stability [3, 12]; the cost of preformed spacers is much higher than that of articulating PMMA spacers
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