Comparison of infection eradication rate of using articulating spacers containing bio-inert materials versus all-cement articulating spacers in revision of infected TKA: a systematic review and meta-analysis

Effect of Antibiotic Spacer Dosing on Treatment Success in Two-Stage Exchange for Periprosthetic Joint Infection

INTRODUCTION

In two-stage exchange for periprosthetic joint infection (PJI), adding antibiotics to cement spacers is the standard of care; however, little is known about optimal dosage. There is emphasis on using >3.6 g of total antibiotic, including ≥2.0 g of vancomycin, per 40 g of cement, but these recommendations lack clinical evidence. We examined whether recommended antibiotic spacer doses affect treatment success.

METHODS

This was a retrospective review of 202 patients who underwent two-stage exchange for PJI from 2004 to 2020 with at least 1-year follow-up. Patients were separated into high (>3.6 g of total antibiotic per 40 g of cement) and low-dose spacer groups. Primary outcomes were overall and infectious failure.

RESULTS

High-dose spacers were used in 80% (162/202) of patients. High-dose spacers had a reduced risk of overall (OR, 0.37; P = 0.024) and infectious (OR, 0.35; P = 0.020) failure for infected primary arthroplasties, but not revisions. In multivariate analysis, vancomycin dose ≥2.0 g decreased the risk of infectious failure (OR, 0.31; P = 0.016), although not overall failure (OR, 0.51; P = 0.147).

CONCLUSION

During two-stage exchange for PJI, spacers with greater than 3.6 g of total antibiotic may reduce overall and infectious failure for infected primary arthroplasties. Furthermore, using at least 2.0 g of vancomycin could independently decrease the risk of infectious failure.

Articulating spacers: what are available and how to utilize them?

Periprosthetic joint infection (PJI) is the most devastating complication following total joint arthroplasty (TJA) and is posing a global healthcare challenge as the demand for TJA mounts. Two-stage exchange arthroplasty with the placement of antibiotic-loaded spacers has been shown to be efficacious against chronic PJI. This study aimed to review the key concepts, types, and outcome evaluations of articulating spacers in the two-stage exchange for PJI. Previous studies indicated that articulating spacers have been widely used due to better functional improvement and a comparable infection control rate relative to static spacers. Several types of articulating spacers are reportedly available, including hand-made spacers, spacers fashioned from molds, commercially preformed spacers, spacers with additional metal or polyethylene elements, new or autoclaved prosthesis, custom-made articulating spacers, and 3D printing-assisted spacers. However, limited evidence suggested no significant difference in clinical outcomes among the different subtypes of articulating spacers. Surgeons should be familiar with different treatment strategies when using various spacers to know which is the most appropriate.

Periprosthetic Knee Infection - Part 2: Treatment

Several treatment modalities are proposed for periprosthetic infections, with variable success rates. However, efficacy is related to the appropriate selection of cases for each type of treatment.

Debridement with implant retention is indicated in acute infections with fixed implant, and its success depends on the type of infection, comorbidities of the host, and virulence of the etiological agent.

One- or two-stage revision is required in cases in which biofilm is forming, or of implant loosening. The choice between performing the review in one or two stages depends on factors such as etiological agent identification, pathogen virulence, local and systemic host factors.

Rescue procedures such as arthrodesis, amputation, resection arthroplasty or even antibiotic suppression are reserved for cases in which the infection has not been eradicated.

Complications and Outcomes Associated With a Novel, Prefabricated, Articulating Spacer for Two-Stage Periprosthetic Joint Infection Treatment

BACKGROUND

Various prefabricated articulating spacer options have been described for 2-stage treatment of chronic periprosthetic joint infection, but their results are poorly generalizable between designs due to differing antibiotic and material properties. This study reports outcomes for a novel, prefabricated, commercially available cement-on-cement articulating spacer.

METHODS

A retrospective review of prospectively collected data for patients undergoing treatment with a prefabricated articulating cement spacer was performed. Outcomes were categorized as spacer complications, reimplantation rates, function, reinfection, and mortality.

RESULTS

Seventy-six knees and 28 hips were analyzed. Spacer survival free of fracture, instability, or other implant-related complication until reimplantation was 100%. There were no bony or spacer fractures during the interstage or reimplantation. Reimplantation occurred in 84.6% of resected joints. Following spacer implantation, all but 1 patient was allowed to bear weight. The proportion of patients requiring an assistive device decreased from 67% prior to resection to 31% following reimplantation. Knee flexion improved from an average of 88.1° before resection to 111.9° following reimplantation. Eighty-seven percent of cases were infection free at mean follow-up of 16.6 ± 10.4 months.

CONCLUSION

Study results demonstrate that this novel, prefabricated, articulating antibiotic spacer is safe, allows for good interstage function, and results in reasonable infection eradication rates at early term follow-up.

LEVEL OF EVIDENCE

Therapeutic Level III.

Poor outcomes of revision total knee arthroplasty in patients with septic loosening compared to patients with aseptic loosening

Background

The purpose of this study was to compare the functional outcomes, activity levels, mortalities, implant survival rates, and complications in revision total knee arthroplasty (TKA) of patients with septic loosening with those in patients with aseptic loosening over a minimum 10-year follow-up period.

Methods

A cohort of 78 patients (36 septic loosening and 42 aseptic loosening) was selected between January 2008 and December 2009. The functional outcomes, activity levels, mortalities, implant survival rates, and complications of revision TKA in patients with septic and aseptic loosening were compared.

Results

The mean Knee Society knee scores in the septic and aseptic groups improved from 36.7 and 37.4 preoperatively to 65.3 and 76.8 points at the final follow-up, respectively (p < 0.05). Outdoor ambulatory patients at the final follow-up included 20 of 29 (69.0%) patients in the septic group and 35 of 39 (89.7%) patients in the aseptic group (p < 0.05). The cumulative mortality rates in the septic and aseptic groups were 19.4% (7/36) and 7.1% (3/42) (p = 0.102) at final follow-up, respectively. Kaplan–Meier survivorship analysis with re-revision of either component as an endpoint in the septic and aseptic groups estimated 86.5% and 95.5% chance of survival for 10 years, respectively.

Conclusions

Revision TKA in patients with septic loosening had worse functional outcomes and higher mortality over a minimum 10-year follow-up period compared with that in patients with aseptic loosening.

Level of evidence

IV.

Clinical outcomes of two-stage revision total knee arthroplasty in infected cases with antibiotic-loaded cement spacers produced using a handmade silicone mold

Purpose

This study assessed the clinical outcomes of periprosthetic joint infection patients who underwent two-stage revision total knee arthroplasty with antibiotic-loaded cement spacers fabricated using a handmade silicone mold.

Materials and methods

This study included seven patients (average age 77 years, average follow-up time 54 months) who underwent surgery at our hospital between 2009 and 2013. Clinical outcomes including knee scores, function scores, knee range of motion, and walking ability at the final observation, period from the primary total knee arthroplasty to implant removal, period from implant removal to revision total knee arthroplasty, and follow-up period after revision total knee arthroplasty were investigated.

Results

At the final follow-up, the average knee range of motion was 99°, with no significant differences at each stage; average knee and function scores were 84 and 77, respectively. With cement spacers, five patients were able to walk with a t-cane. No recurrence of infection was observed.

Conclusions

The clinical outcomes of the current case series demonstrated good knee function with preserved walking ability, without any recurrence of periprosthetic joint infection. This study suggests that using a handmade silicone mold could be an effective option for periprosthetic joint infection after a total knee arthroplasty.

Comparing the Efficacy of Articulating Spacer Constructs for Knee Periprosthetic Joint Infection Eradication: All-Cement vs Real-Component Spacers

BACKGROUND

The most common treatment for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a 2-stage revision. Few studies have compared different articulating spacer constructs. This study compares the outcomes of real-component and all-cement articulating spacers for TKA PJI treatment.

METHODS

This retrospective observational study examined the arthroplasty database at 3 academic hospitals for articulating spacers placed for TKA PJIs between April 2011 and August 2020. Patients were categorized as receiving a real-component or an all-cement articulating spacer. Data on demographics, surgical information, and outcomes were collected.

RESULTS

One-hundred sixty-four spacers were identified: 72 all-cement and 92 real-component spacers. Patients who received real-component spacers were older (67 ± 10 vs 63 ± 12 years; P = .04) and more likely to be former smokers (50.0% vs 28.6%; P = .02). Real-component spacers had greater range of motion (ROM) after Stage 1 (84° ± 28° vs 58° ± 28°; P < .01) and shorter hospital stays after Stage 1 (5.8 ± 4.3 vs 8.4 ± 6.8 days; P < .01). There was no difference in time to reimplantation, change in ROM from pre-Stage 1 to most recent follow-up, or reinfection. Real-component spacers had shorter hospital stays (3.3 ± 1.7 vs 5.4 ± 4.9 days; P < .01) and operative times during Stage 2 (162.2 ± 47.5 vs 188.0 ± 66.0 minutes; P = .01).

CONCLUSION

Real-component spacers had improved ROM after Stage 1 and lower blood loss, shorter operative time, and shorter hospital stays after Stage 2 compared to all-cement articulating spacers. The 2 spacer constructs had the same ultimate change in ROM and no difference in reinfection rates, indicating that both articulating spacer types may be safe and effective options for 2-stage revision TKA.

LEVEL OF EVIDENCE

III, retrospective observational analysis.

Difficult to treat: are there organism-dependent differences and overall risk factors in success rates for two-stage knee revision?

OBJECTIVES

Failure after two-stage procedure for periprosthetic joint infection (PJI) is a rare, but devastating complication. Some authors assume a correlation of underlying organisms and recurrence rate. Methicillin-resistant Staphylococci (MRS) and other organisms (quinolone-resistant Gram-negative bacteria, rifampicin-resistant Staphylococcus, Enterococcus, and Candida) are meant to be "difficult to treat" (DTT) with an inferior outcome for two-stage revision. In addition to the type of bacteria, some more risk factors seem to be present. The aim of this study was (1) to detect a difference of reinfection rates between reinfection-causing groups of bacteria ["difficult to treat" (DTT), "easy to treat" (ETT) and methicillin-resistant staphylococci (MRS)] after a two-stage procedure, and (2) find overall risk factors for reinfection in a standardized long (spacer insertion for at least 6 weeks) two-stage procedure for periprosthetic knee infection.

METHODS

One hundred and thirty-seven two-stage revisions for periprosthetic knee infection were performed at one tertiary referral center. Finally, 96 patients could be included for analyses. Possible risk factors (comorbidities, prior surgery, etc.) and the types of organisms were documented. Quinolone-resistant Gram-negative bacteria, rifampicin-resistant Staphylococcus, Enterococcus, and Candida were classified as "difficult to treat" (DTT). Methicillin-resistant Staphylococci were summarized as "MRS", all other organism are summarized as "easy to treat" (ETT). Statistical analyses included univariate analysis (t test, Fisher's exact test, Chi square test) and logistic regression analysis.

RESULTS

There were no statistical significant differences in recurrent infection rates between organism groups (DTT vs. ETT, p = 0.674; DTT vs. MRS, p = 0.705; ETT vs. MRS, p = 0.537). Risk factors seem to be "need of revision after first stage" (p = 0.019, OR 5.62) or completed second stage (p = 0.000, OR 29.07), numbers of surgeries (p = 0.028) and alcohol abuse (p = 0.019, OR 5.62).

CONCLUSIONS

Revision needed during or after a two-stage exchange, numbers of surgeries and alcohol abuse are risk factors for recurrence, a different recurrence rates between organism-groups cannot be shown. The absence of significant differences in recurrence rates points to the importance of the individuality of each periprosthetic infection case: a reduction of necessary surgeries (with a thorough debridement, appropriate antibiotic addition to spacers) and the control of comorbidities (alcohol abuse) appear to be essential components of a two-stage exchange.