Confirming Sterility of an Autoclaved Infected Femoral Component for Use in an Articulated Antibiotic Knee Spacer: A Pilot Study

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.

A Mid-term Follow-up Study on the Reimplantation of Autoclaved Femoral and Tibial Components as Spacers for Treating Infected Total Knee Arthroplasty

Objective

Infection after total knee arthroplasty (TKA) is a rare but devastating complication. Different types of spaces have been used in two‐stage revision. The study aimed to evaluate the effect of autoclaved femoral and tibial components as spacers for treating periprosthetic infections after TKA.

Methods

A retrospective study was performed for 13 patients (five males, eight females) with a mean age of 69 ± 6 (range, 57–80) years and suffering from periprosthetic infection after TKA. They were treated with unconventional two‐stage revision from May 2008 to June 2017. In the first‐stage surgery, the autoclaved femoral and tibial components were reimplanted with a new liner as a spacer after a thorough debridement. After 4–6 months, the second‐stage surgery was performed according to the patients' requirements. The knee society score (KSS) and knee range of motion (ROM) were assessed before and after surgery. The reinfection rate was calculated.

Results

The mean duration of follow‐up was 5.7 ± 2.1 (range, 3.1–8.8) years. Culture‐positive infections comprised 69% of the cohort. All patients were able to walk 24 h after the first stage surgery, and the knee ROM could reach 90° in 1 week. Two patients (15.4%) experienced an infection recurrence. One patient was reinfected 1 year after the first stage surgery. Another patient developed reinfection 3 years after surgery but did not choose re‐revision and died of pneumonia. Only one patient underwent the second stage revision. The remaining 10 patients refused to receive a new prosthesis. At the time of the final follow‐up, six patients had slight pain in the knee while walking, and one patient required crutches to walk. There were no signs of prosthesis dislocation, rupture, deep vein thrombosis, pulmonary embolism, or delayed wound healing. No radiolucent lines or osteolysis were found. The mean KSS improved from 51 ± 10 (range, 35–63) points preoperatively to 79 ± 5 (range, 60–85) points at the final follow‐up. The average ROM before and after the first stage surgery were 62° ± 29° (range, 10°–100°) and 104° ± 9° (range, 90°–120°) (t = 4.659, P < 0.01) respectively. The infection control rate was 84.6%.

Conclusion

Reimplantation of the autoclaved original femoral and tibial components as an articulating spacer during the first stage surgery is a valuable addition for treating an infected TKA.

The autoclaving and re-implantation of an infected prosthesis as a spacer during resection knee arthroplasty: a systematic review

BACKGROUND

Hofmann et al., in 1995, first described an articulating spacer made by cleaning and autoclaving the original femoral component, which is then re-implanted with a new tibial polyethylene. This systematic review aims to assess the state of existing evidence on the intraoperative autoclaving and re-use of an infected prosthesis, as a spacer, during a two-stage revision following Periprosthetic Joint Infections (PJI).

METHODS

A systematic review was conducted with methods described in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. OVID-MEDLINE®, EMBASE, Cochrane Library, SCOPUS, Web of Science, Google Scholar and PubMed were searched from 1995 to April 2020 to identify relevant studies.

RESULTS

Fourteen studies were included in this systematic review: two prospective case series; six retrospective comparative studies and six retrospective case series. The reviewed studies included 567 patients (571 knees): 394 patients treated with autoclaved components and 173 with a spacer made of new components. The cumulative re-infection rate in patients treated with re-used autoclaved components was 13.7% (54 re-infections in 394 patients), whereas in control patients the re-infection rate was 13.3% (23 re-infections in 173 patients). The final Range of Movement in patients treated using the autoclaved components as a spacer, compared with patients receiving static spacers, was significantly higher in three out of four comparative studies.

CONCLUSION

There is a moderate level of evidence that the intraoperative autoclaving and re-use of an infected prosthesis as a spacer, during a knee resection arthroplasty, is an effective procedure in the management of knee PJI.

Temporary new implant spacers increase post-reimplantation total knee prosthesis survival after periprosthetic joint infection

PURPOSE

Two-stage exchange arthroplasty is considered the gold standard for treatment of periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). Antibiotic cement spacers can include cement-based spacers (CBS), new components (NEW), and autoclaved components (ACL). The factors that most influence post-reimplantation prosthesis (PRP) survival were determined.

METHODS

A retrospective database review of patients undergoing two-stage exchange arthroplasty from 2008 to 2014 was performed. There were 85 patients, 25 patients and 30 patients in CBS, NEW and ACL groups, respectively. Patient, disease and surgical characteristics were collected and analyzed. Post-reimplantation prosthesis (PRP) survival was modeled using the Kaplan-Meier method. Cox proportional hazard modeling was then performed to identify risk factors associated with implant failure.

RESULTS

Overall PRP survival was 82% in 140 unilateral TKAs. PRP survival between groups was 81%, 96% and 73% within the minimum 2-year follow-up period, respectively. There was a difference in median interval-to-reimplantation between groups (CBS, 72.0 days; NEW, 111.0 days; ACL, 84.0 days, p = 0.003). Adjusting for time-to-reimplantation, NEW spacers demonstrated greater PRP survival compared with ACL spacers (p = 0.044), and a trend towards greater survival compared with CBS spacers (p = 0.086). Excluding early failures (< 90 days), NEW spacers still demonstrated greater survival than ACL spacers (p = 0.046). Lower volume (≤ 10 within this series) surgeons tended to use more CBS spacers, while higher volume surgeons were comfortable with ACL spacers.

CONCLUSIONS

There was greater PRP survival with NEW spacers. NEW spacers also demonstrated an increased inter-stage interval, likely because of increased comfort and motion. There were spacer choice differences between low- and high-volume surgeons.

LEVEL OF EVIDENCE

III.

Flash Sterilization and Component Reimplantation Is a Viable Option for Articulating Antibiotic Spacers in Periprosthetic Knee Infections

The articulating antibiotic spacer is a treatment utilized for two-stage revision of an infected total knee arthroplasty. The original femoral component is retained and reused in one described variation of this technique. The purpose of this study is to determine the safety and efficacy of flash sterilization of the femoral component for reimplantation in an articulating antibiotic spacer for the treatment of chronic periprosthetic joint infection. A total of 10 patients were identified prospectively with a culture positive infected total knee arthroplasty. The patients underwent explantation, debridement, and placement of an articulating antibiotic spacer consisting of the explanted and sterilized femoral component and a new polyethylene tibial insert. The explanted tibial components were cleaned and flash-sterilized with the femoral components, but the components were then aseptically packaged and sent to our microbiology laboratory for sonication and culture of the sonicate for 14 days. Ten of 10 cleaned tibial components were negative for bacterial growth of the infecting organism after final testing and analysis. At 18-month follow-up, 9 of 10 of patients remained clear of infection. Among the 10 patients, 7 were pleased with their articulating spacer construct and had no intention of electively pursuing reimplantation. Also, 3 of 10 of patients were successfully reimplanted at a mean of 6.5 months after explantation. Autoclave sterilization and reimplantation of components may be a safe and potentially resource-sparing method of articulating spacer placement in two-stage treatment of PJI. Patient follow-up demonstrated clinical eradication of infection in 90% of cases with good patient tolerance of the antibiotic spacer.

Antibiotic Cement Spacers for Infected Total Knee Arthroplasties

Periprosthetic infection remains a frequent complication after total knee arthroplasty. The most common treatment is a two-stage procedure involving removal of all implants and cement, thorough débridement, insertion of some type of antibiotic spacer, and a course of antibiotic therapy of varying lengths. After some interval, and presumed eradication of the infection, new arthroplasty components are implanted in the second procedure. These knee spacers may be static or mobile spacers, with the latter presumably providing improved function for the patient and greater ease of surgical reimplantation. Numerous types of antibiotic cement spacers are available, including premolded cement components, surgical molds for intraoperative spacer fabrication, and the use of new metal and polyethylene knee components; all these are implanted with surgeon-prepared high-dose antibiotic cement. As there are advantages and disadvantages of both static and the various mobile spacers, surgeons should be familiar with several techniques. There is inconclusive data on the superiority of any antibiotic spacer. Both mechanical complications and postoperative renal failure may be associated with high-dose antibiotic cement spacers.

A retrospective comparative study of infection control rate and clinical outcome between open debridement using antibiotic-impregnated cement beads and a two-stage revision in acute periprosthetic knee joint infection

The aim of this study was to determine whether the infection control rate of a modified debridement, antibiotics, and implant retention (DAIR) protocol (DAIR with antibiotic-impregnated cement beads) is comparable to that of 2-stage revision for acute periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). We also aimed to determine whether this modified DAIR technique produced better clinical results than those obtained using 2-stage revision in terms of functional outcome, range of motion (ROM), and patient satisfaction at 2 years after surgery.This retrospective comparative study included patients who underwent modified DAIR (7 patients, 9 knees) or 2-stage revision (8 patients, 9 knees) for acute PJI of the knee joint. Infection control rate, functional outcome measured using Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, ROM and patient satisfaction were compared between the two groups.There was no difference in infection control rates between the modified DAIR and 2-stage revision groups (78% vs 78%, respectively). In contrast, surgical outcome in the modified DAIR group was tended to be better than 2-stage revision group, but it did not reach statistical significance. Median maximal range of flexion was 103° in the modified DAIR group and it was 90° in the 2-stage group (P = .191). In addition, the median WOMAC function score was 24 in the modified DAIR group and it was 30 in the 2-stage group (P = .076). Median patient satisfaction measured using visual analogue scale was 8 in the modified DAIR group and 5 in the 2-stage group (P = .069).The infection control rates of the modified DAIR protocol and 2-stage revision protocol were similar for the treatment of acute PJI of the knee joint. However, the modified DAIR protocol could not provide substantially increased functional outcomes and patient satisfaction compared to 2-stage revision. Therefore, the modified DAIR technique should be considered to be of limited use in patients with high surgical morbidity.

Early to midterm results of "low-friction" articulating antibiotic spacers for septic total knee arthroplasty

BACKGROUND

Infection of total knee arthroplasty is a complex problem often resulting in multiple surgeries for the patient. We examined the early to midterm results of a retained cemented "low-friction" metal-on-polyethylene articulating antibiotic spacer in total knee arthroplasty.

METHODS

We retrospectively reviewed patients with a total knee cemented articulating antibiotic spacer performed for joint sepsis. Patients were allowed full weight bearing and normal activities after eradication of the infection at 6 weeks postop. Two months later, patients were given the option of conversion to a revision implant vs retention of the spacer. We examined infection cure rate, mechanical failure, Knee Society Scores, range of motion, and patient factors associated with spacer retention.

RESULTS

Fifty-five knees were studied with average follow-up of 1.8 years (0.2-8.4). Among patients choosing spacer retention (40%), the average follow-up time of the spacer was 3.3 years (0.6-8.4). Five patients (9.1%) required a repeat spacer for recurrent infection.

CONCLUSIONS

Usage of articulating cement antibiotic spacers with a metal-on-polyethylene bearing couple provides excellent infection eradication, while also resulting in good functional outcomes. Early evidence suggests that use of the implant can be extended beyond typical timeframes and, in certain patient populations, may be suitable for a single-stage procedure.

Safety of Temporary Use of Recycled Autoclaved Femoral Components in Infected Total Knee Arthroplasty: Confirming Sterility Using a Sonication Method

Background

The purpose of this study was to evaluate the usefulness of sonication technique for microbiological diagnosis and the sterility of the recycled autoclaved femoral components from infected total knee arthroplasty (TKA) using a sonication method.

Methods

Nineteen femoral implants explanted from patients with infected TKA were sterilized with a standard autoclave method. Standard culture of the fluid before and after sonication of the sterilized implants was performed to detect pathogenic microorganisms. Additional experiments were performed to evaluate the sterility of the recycled implant by inducing artificial biofilm formation. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated into 10 implants and sterilization in a standard autoclave was performed, and then the fluid was cultured before and after sonication.

Results

Two of the 19 sterilized implants were positive for growth of bacteria after sonication, whereas no growth was detected in the cultured fluid from the sterilized implants before sonication. The bacteria were Staphylococcus species in all two cases. In one of 10 implants inoculated with MRSA, the culture was positive for growth of bacteria both before and after sonication. However, Staphylococcus epidermidis was cultured from both occasions and thus this implant was thought to be contaminated.

Conclusions

We found sonication for identification of pathogens could be helpful, but this finding should be interpreted carefully because of the possibility of contamination. Sterilization of an infected femoral implant with an autoclave method could be a good method for using the temporary articulating antibiotic spacer in two-stage revision arthroplasty.

Outcomes of Articulating Spacers With Autoclaved Femoral Components in Total Knee Arthroplasty Infection

BACKGROUND

In 2-stage revision of total knee arthroplasty (TKA) infection, articulating antibiotic spacers show similar eradication rates and superior range of motion compared with static spacers. This study evaluated infection control and other outcomes in articulating spacers with an autoclaved index femoral component.

METHODS

We reviewed 59 patients who underwent 2-stage treatment of TKA infection using articulating antibiotic spacers with an autoclaved femoral component with at least 2-year follow-up (mean: 5.0 years) from spacer placement. Reinfection was defined as any subsequent infection; recurrence was defined as reinfection with the same organism, need for chronic antibiotics, or conversion directly to amputation/arthrodesis.

RESULTS

Nine patients (15%) experienced a recurrence and 22 patients (37%) experienced a reinfection. Incidence of diabetes mellitus was significantly higher in patients who became reinfected. Other comorbidities, revision history, prior spacer, or presence of virulent organisms did not predict infection recurrence. Forty-seven spacers underwent reimplantation, 6 (13%) of these went on to above-knee amputation, 6 (13%) received another 2-stage procedure, and 3 (6%) underwent subsequent irrigation and debridement. Three patients (5%) proceeded directly from spacer to above-knee amputation (2) or arthrodesis (1). Nine spacers (15%) in 7 patients were retained indefinitely (mean: 3.4 years), with overall good motion and function.

CONCLUSION

Accounting for methodology, articulating spacers with autoclaved femoral components provide similar infection control to previous reports. Most patients with reinfection grew different organisms compared with initial infection, suggesting that some subsequent infections may be host related. Some patients retained spacers definitively with overall good patient satisfaction.

Flash autoclave settings may influence eradication but not presence of well-established biofilms on orthopaedic implant material

Flash autoclaving is one of the most frequently utilized methods of sterilizing devices, implants or other materials. For a number of decades, it has been common practice for surgeons to remove implantable devices, flash autoclave and then reimplant them in a patient. Data have not yet indicated the potential for biofilms to survive or remain on the surface of orthopaedic-relevant materials following flash autoclave. In this study, monomicrobial and polymicrobial biofilms were grown on the surface of clinically relevant titanium materials and exposed to flash autoclave settings that included varying times and temperatures. Data indicated that when the sterilization and control temperatures of an autoclave were the same, biofilms were able to survive flash autoclaving that was performed for a short duration. Higher temperature and increased duration rendered biofilms non-viable, but none of the autoclave settings had the ability to remove or disperse the presence of biofilms from the titanium surfaces. These findings may be beneficial for facilities, clinics, or hospitals to consider if biofilms are suspected to be present on materials or devices, in particular implants that have had associated infection and are considered for re-implantation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1543-1550, 2018.

Complete Eradication of Biofilm From Orthopedic Materials

BACKGROUND

Interest exists in finding alternatives to current management strategies in periprosthetic joint infections, which typically include a 2-stage revision with placement of an antibiotic spacer and delayed placement of a new implant. We studied the efficacy of autoclaving, ultrasonication, and mechanical scrubbing for sterilization and biofilm eradication on infected cobalt-chrome discs.

METHODS

Strains of Staphylococcus aureus MRSA252 or Staphylococcus epidermidis RP62A were grown on the discs. For each strain, discs were divided into 5 groups (5 discs each) and exposed to several sterilization and biofilm eradication treatments: (1) autoclave, (2) autoclave + sonication, (3) autoclave + saline scrub, (4) autoclave + 4% chlorhexidine (CHC) scrub, and (5) autoclave + sonication + CHC scrub. Sterilization and biofilm eradication were quantified with crystal violet assays and scanning electron microscopy.

RESULTS

Relative to nontreated controls, autoclaving alone reduced biofilm load by 33.9% and 54.7% for MRSA252 and RP62A strains, respectively. Biofilm removal was maximized with the combined treatment of autoclaving and CHC scrub for MRSA252 (100%) and RP62A (99.5%). The addition of sonication between autoclaving and CHC scrubbing resulted in no statistically significant improvement in biofilm removal. High-resolution scanning electron microscopy revealed no cells or biofilm for this combined treatment.

CONCLUSION

Using 2 commonly encountered bacterial strains in periprosthetic joint infection, infected cobalt-chrome discs were sterilized and eradicated of residual biofilm with a combination of autoclaving and CHC scrubbing.