Systemic Inflammation Response Index (SIRI) and Monocyte-to-Lymphocyte Ratio (MLR) Are Predictors of Good Outcomes in Surgical Treatment of Periprosthetic Joint Infections of Lower Limbs: A Single-Center Retrospective Analysis

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication that develops after total joint arthroplasty (TJA), whose incidence is expected to increase over the years. Traditionally, surgical treatment of PJI has been based on algorithms, where early infections are preferably treated with debridement, antibiotics, and implant retention (DAIR) and late infections with two-stage revision surgery. Two-stage revision is considered the "gold standard" for treatment of chronic prosthetic joint infection (PJI) as it enables local delivery of antibiotics, maintenance of limb-length and mobility, and easier reimplantation. Many studies have attempted to identify potential predicting factors for early diagnosis of PJI, but its management remains challenging. In this observational retrospective study, we investigated the potential role of inflammatory blood markers (neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory index (SII), systemic inflammatory response index (SIRI), and aggregate index of systemic inflammation (AISI)) as prognostic factors in two-stage exchange arthroplasty for PJI.

METHODS

A single-center retrospective analysis was conducted, collecting clinical data and laboratory parameters from patients submitted to prosthetic explantation (EP) for chronic PJI. Laboratory parameters (PCR, NLR, MLR, PLR, SIRI, SII, and AISI) were evaluated at the explantation time; at 4, 6, and 8 weeks after surgery; and at reimplantation time. The correlation between laboratory parameters and surgery success was evaluated and defined as infection absence/resolution at the last follow-up.

RESULTS

A total of 57 patients with PJI were evaluated (62% males; average age 70 years, SD 12.14). Fifty-three patients with chronic PJI were included. Nine patients underwent DAIR revision surgery and chronic suppressive therapy; two patients died. Nineteen patients completed the two-stage revision process (prosthetic removal, spacer placement, and subsequent replanting). Among them, none showed signs of reinfection or persistence of infection at the last available follow-up. The other twenty-three patients did not replant due to persistent infection: among them, some (the most) underwent spacer retention; others (fewer in number) were submitted to resection arthroplasty and arthrodesis (Girdlestone technique) or chronic suppressive antibiotic therapy; the remaining were, over time, lost to follow-up. Of the patients who concluded the two-stage revision, the ones with high SIRI values (mean 3.08 SD 1.7 and p-value 0.04) and MLR values (mean 0.4 SD 0.2 and p-value 0.02) at the explantation time were associated with a higher probability of infection resolution. Moreover, higher variation in the SIRI and PCR, also defined, respectively, as delta-SIRI (mean -2.3 SD 1.8 and p-value 0.03) and delta-PCR (mean -46 SD 35.7 and p-value 0.03), were associated with favorable outcomes.

CONCLUSIONS

The results of our study suggest that, in patients with PJI undergoing EP, the SIRI and MLR values and delta-SIRI and delta-PCR values could be predictive of a favorable outcome. The evaluation of these laboratory indices, especially their determination at 4 weeks after removal, could therefore help to determine which patients could be successfully replanted and to identify the best time to replant. More studies analyzing a wider cohort of patients with chronic PJI are needed to validate the promising results of this study.

Periprosthetic shoulder infection management: one-stage should be the way: a systematic review and meta-analysis

BACKGROUND

There is still no consensus among surgeons on whether to perform a 1- or 2-stage surgical revision in infected shoulder arthroplasties. The aim of this systematic review and meta-analysis is to rigorously synthesize published studies evaluating the clinical outcomes, recurrence of infection, and other clinical complications in order to discuss which is the best strategy for treating periprosthetic joint infection after shoulder arthroplasty.

METHODS

Upon research using the PubMed, Scopus, and Web of Science databases, in November 2022, studies that presented 1- or 2-stage surgical revision as a treatment for periprosthetic joint infection after shoulder arthroplasty and assessed the reinfection rate on these patients, as well as other clinical outcomes, with a minimum follow-up of 12 months, were included. Study quality was evaluated using the Methodological Index for Non-Randomized Studies (MINORS) score. Reinfection and complication rates were extracted, and pooled estimates were calculated using the random-effect model.

RESULTS

After careful screening, 44 studies were included, 5 reporting on 1-stage and 30 on 2-stage revisions and 9 assessing both strategies. A total of 185 shoulders were reported in 1-stage revision studies, whereas 526 shoulders were reported in 2-stage revision studies. The overall pooled random-effects reinfection rate was 6.68% (95% confidence interval [CI]: 3.76-10.13), with low heterogeneity (I2 = 28%, P = .03). One-stage revision showed a reinfection rate of 1.14% (95% CI: 0.00-4.88), whereas 2-stage revision analysis revealed a reinfection rate of 8.81% (95% CI: 4.96-13.33). There were significant statistical differences between 1- and 2-stage reinfection rates (P = .04). The overall pooled rate for other clinical complications was 16.76% (95% CI: 9.49-25.15), with high heterogeneity (I2 = 70%, P < .01). One-stage revision had a complication rate of 6.11% (95% CI: 1.58-12.39), whereas the 2-stage revision complication rate was 21.26% (95% CI: 11.51-32.54). This difference was statistically significant (P = .03).

CONCLUSIONS

This is the first systematic review and meta-analysis showing significant statistical differences between 1- and 2-stage surgical revision in infected shoulder arthroplasties. Provided the right conditions exist, 1-stage revision shows better results in infection control, with lower clinical complications and possible better clinical outcomes.

Decreased Patellar Fractures and Subluxation with Patellar Component Replacement at Stage-One Spacer

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication of total knee arthroplasty (TKA) and is often treated with two-stage revision. We retrospectively assessed whether replacing the patellar component with articulating stage-one spacers was associated with improved outcomes compared to spacers without patellar component replacement.

METHODS

A total of 139 patients from a single academic institution were identified who underwent an articulating stage-one revision TKA and had at least 1-year follow-up. Of the 139 patients, 91 underwent patellar component removal without replacement, while 48 had a patellar component replaced at stage-one revision. Patellar fracture and reinfection at any point after stage-one were recorded. Knee range of motion (ROM), patellar thickness, lateral tilt, and lateral displacement were measured at six-weeks post stage-one. Chi-squared, Fisher's exact, and t-tests were utilized for comparisons. There were no significant demographic differences between groups.

RESULTS

Patellar component replacement at stage-one revision was associated with fewer patellar fractures (2.1 versus 12.1%, P = 0.046), less lateral patellar displacement (1.7 versus 16.0 mm, P < 0.01), and improved pre to postoperative knee ROM six weeks after stage-one (+5.9 versus -11.4°, P = 0.03). There was no difference in reinfections after stage-two revision for the replaced or unreplaced patellar groups (15.4 versus 15%, P = 1.000). While the mean time between stage-one and stage-two was not different (5.2 versus 4.5 months, P = 0.50), at one-year follow-up, significantly more patients in the patellar component replacement group were satisfied and refused stage-two revision (45.8% versus 3.3%, P < 0.001).

CONCLUSION

Replacing the patellar component at stage-one revision is associated with a decreased rate of patellar fracture and lateral patellar subluxation, improved ROM, and possible increased patient satisfaction, as reflected by nearly half of these patients electing to keep their spacer. There was no difference in reinfection rates between the cohorts.

Two-stage Partial Component Retention and Interim Cemented Liner for Infected Total Hip Arthroplasty: A Case Report

Introduction

There is interest in partial exchange for infected total hip arthroplasty, as an alternative to complete removal of components in a traditional two-stage revision. Partial exchange avoids the difficulty of removing a well-fixed component and its associated bone loss.

Case Report

We report a case of a 61-year-old male patient with an infected total hip arthroplasty, who underwent a two-stage partial exchange, with retention of the well-fixed femoral stem, and an interim cemented liner. He had excellent function and no infection recurrence at 4 years of follow-up.

Conclusion

Two-stage partial exchange with interim cemented liner could be an effective option for infected total hip arthroplasty.

Clinical and Functional Outcomes of Extended Trochanteric Osteotomy in 2-Stage Revision Total Hip Arthroplasty for Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis

BACKGROUND

Extended trochanteric osteotomy (ETO) has long been used in 2-stage revision surgeries of the hip, for both aseptic and septic indications. The purpose of this systematic review is to summarize the cumulative occurrence rates of the clinical and functional outcomes associated with the use of ETO in 2-stage revision total hip arthroplasty for periprosthetic joint infection.

METHODS

PubMed/MEDLINE and the Cochrane Database of Systematic Reviews databases were searched for articles published from January 1980 to January 2022 using the following keywords: "extended" AND "trochanteric" AND "osteotomy" AND "infection." Cumulative occurrence rates of outcomes and complications were calculated. A fixed-effects model and a 95% CI were applied. A P value of .05 was considered the significance threshold.

RESULTS

Nine studies were in full compliance with the inclusion criteria, with a total population size across all studies of 378. Union and infection eradication rates among studies were 95.1% (95% CI, 92.7-97.1, P = .018) and 94.0% (95% CI, 91.1-96.4, P = .089), respectively. Postoperation complications occurred in 15.34% of patients (95% CI, 10.34-21.22, P = .066). Occurrence rates for stem subsidence, dislocation, and femoral fractures were 6.2% (95% CI, 3.3-9.9, P = .187), 7.6% (95% CI, 4.8-10.9, P = .075), and 9.1% (95% CI, 5.8-13, P = .106), respectively.

CONCLUSION

With high rates of union and infection eradication, and low rates of postoperation complications, this study concludes the use of ETO in performing 2-stage revision total hip arthroplasty for the septic hip to be effective and safe.

Impact and Modification of the New PJI-TNM Classification for Periprosthetic Joint Infections

The comprehensive "PJI-TNM classification" for the description of periprosthetic joint infections (PJI) was introduced in 2020. Its structure is based on the well-known oncological TNM classification to appreciate the complexity, severity, and diversity of PJIs. The main goal of this study is to implement the new PJI-TNM classification into the clinical setting to determine its therapeutic and prognostic value and suggest modifications to further improve the classification for clinical routine use. A retrospective cohort study was conducted at our institution between 2017 and 2020. A total of 80 consecutive patients treated with a two-stage revision for periprosthetic knee joint infection were included. We retrospectively assessed correlations between patients' preoperative PJI-TNM classification and their therapy and outcome and identified several statistically significant correlations for both classifications, the original and our modified version. We have demonstrated that both classifications provide reliable predictions already at the time of diagnosis regarding the invasiveness of surgery (duration of surgery, blood and bone loss during surgery), likelihood of reimplantation, and patient mortality during the first 12 months after diagnosis. Orthopedic surgeons can use the classification system preoperatively as an objective and comprehensive tool for therapeutic decisions and patient information (informed consent). In the future, comparisons between different treatment options for truly similar preoperative baseline situations can be obtained for the first time. Clinicians and researchers should be familiar with the new PJI-TNM classification and start implementing it into their routine practice. Our adjusted and simplified version ("PJI-pTNM") might be a more convenient alternative for the clinical setting.

Diagnostic Value of C-Reactive Protein and Serum White Blood Cell Count during Septic Two-Stage Revision of Total Knee Arthroplasties

AIMS AND METHODS

In septic two-stage revision arthroplasty, the timing of reimplantation is crucial for therapeutic success. Recent studies have shown that singular values of C-reactive protein (CRP) and white blood cell count (WBC count) display weak diagnostic value in indicating whether periprosthetic joint infection (PJI) is controlled or not during two-stage revision surgery of knee arthroplasty. Therefore, in addition to the values of CRP and WBC, the course of CRP and WBC counts were compared between groups with and without later reinfection in 95 patients with two-stage revision (TSR) of infected total knee arthroplasties (TKA). Of these patients, 16 had a reinfection (16.84%).

RESULTS

CRP values decreased significantly after the first stage of TSR in both the reinfection and no-reinfection groups. WBC count values decreased significantly in the no-reinfection group. Decrease in WBC count was not significant in the reinfection group. No significant difference could be found in either the CRP values or the WBC counts at the first stage of TSR, the second stage of TSR, or their difference between stages when comparing groups with and without reinfection. Area under the curve (AUC) values ranging between 0.631 and 0.435 showed poor diagnostic value for the calculated parameters. The courses of CRP over 14 days after the first stage of both groups were similar with near identical AUC.

CONCLUSIONS

CRP and WBC count as well as their course over 14 days postoperatively are not suitable for defining whether a PJI of the knee is under control or not.

Major Shortening of the Patellar Tendon During Septic Two-Stage Knee Arthroplasty Revision Using Static Spacers

BACKGROUND

Two-stage septic revision knee arthroplasty (TKA) often results in inferior functional outcome after reimplantation, which might be due to impairments of the extensor mechanism. The aim of the current study was to elucidate possible alterations in extensor mechanisms during septic two-stage revision of TKA treated with a static spacer.

METHODS

This retrospective study included 87 patients (42 women, 45 men, age 64.5 ± 10.5; range, 29-85 years) undergoing septic two-stage TKA revision using a static spacer. The modified Insall Salvati ratio (mISR) was calculated via calibrated true lateral radiographs by two independent orthopedic surgeons before TKA explantation (G0), 6-8 days after TKA removal (G1), one day before TKA reimplantation (G2) and 6-8 days after TKA reimplantation (G3). Age, sex, body mass index (BMI), index C-reactive protein level, and number of previous surgeries were evaluated to identify the possible correlations.

RESULTS

Overall, mISR significantly decreased within the first 6 days after index surgery from 1.71 ± 0.41 to 1.63 ± 0.41 (G0 versus G1, P < .001) and showed a further decline within the next 6 weeks to 1.54 ± 0.39 (G1 versus G2, P = .002). Conversely, mISR increased after reimplantation of TKA to 1.6 ± 0.43 (G3 versus G2, P = .08), though it did not regain preoperative baseline levels (G0 versus G3, P < .001). The subgroup with mISR decrease ≥10% experienced patellar tendon shortening of 16% between G0 and G1, 19% between G0 and G2 and up to 20% between G0 and G3. There were weak correlations concerning age (r = -0.240, P = .038), preoperative C-reactive protein level (r = 0.239, P = .04) and patellar tendon shortening. Intraclass correlation coefficient (ICC)was 0.88 concerning radiographic measurement.

CONCLUSION

Septic two-stage TKA revision using static spacers leads to irreversible alterations of the extensor mechanism, specifically a major shortening of the patellar tendon, in one out of 3 patients.

LEVEL OF EVIDENCE

II.

Paradoxical Behavior of Plasma d-Dimer From Explantation to Reimplantation in a Two-Stage Revision for Periprosthetic Joint Infection

BACKGROUND

The variation of plasma d-dimer, an inflammatory marker, from pre-explantation to pre-reimplantation in two-stage revision remains unclear. Our objective was to evaluate delta-changes (Δ) in d-dimer, erythrocyte sedimentation rate (ESR), and C-reactive-protein (CRP), to ascertain whether these delta-changes are associated with the outcome of reimplantation. We hypothesized a decrease in d-dimer before reimplantation.

METHODS

A retrospective review was performed on a consecutive series of 95 two-stage revisions indicated for periprosthetic joint infection. Surgeries were performed by 3 surgeons at a single institution (2018-2020). The minimum follow-up was 1 year. The inclusion criteria comprised availability of d-dimer results at pre-explantation and pre-reimplantation. As a result, only 30 reimplantations were included. Success of reimplantation was defined by Musculoskeletal Infection Society outcome reporting tool: Tier 1/Tier 2 vs Tier 3/Tier 4. Nonparametric tests and Mann-Whitney U-tests were conducted to compare Δd-dimer% (pre-explantation value - pre-reimplantation value/pre-explantation value × 100). The bootstrapped receiver operating characteristic curve analyses with 2,000 replicates of 30 cases were conducted.

RESULTS

The median time between explantation and reimplantation was 86 days (interquartile range [IQR] = 77.7-138.5 days). Overall, a paradoxical median percent increase (Δd-Dimer% [INCREMENT] = 12.6%) in d-dimer was found from pre-explantation to pre-reimplantation (IQR = -28.06% to 77.3%). However, there was a percentage decrease in ESR (ΔESR% [DECREMENT] = -40%; IQR = -70.52% to 3.85%) and CRP (ΔCRP% [DECREMENT] = -75%; IQR = -87.43% to -61.34%). The changes in all these markers were not different between Musculoskeletal Infection Society Tier 1/2 and 3/4 outcomes (Δd-Dimer%, P = .146; ΔESR%, P = .946; ΔCRP%, P = .463). With area under curve of 0.676, Δd-dimer% (INCREMENT) appeared to be performing best in diagnosing infection control, which was nonexplanatory.

CONCLUSION

Plasma d-dimer paradoxically increases before reimplantation while other inflammatory markers (ESR/CRP) decrease, emphasizing that surgeons shall adopt caution using d-dimer to make clinical decisions.

Clinical Outcomes After Stage-One Antibiotic Coated Molded Hip Spacer

BACKGROUND

Two-stage exchange remains the gold standard for managing periprosthetic joint infection (PJI). We evaluated the outcomes of patients treated with a specific molded articulating antibiotic hip spacer for PJI at a tertiary referral center.

METHODS

An institutional database was retrospectively queried for patients who underwent implantation of spacer between 2009-2019. Patient demographics and clinical outcomes were collected.

RESULTS

We identified 88 patients at an average age of 60.4 years who received a spacer implant, with an average of 4.2 years follow-up (standard deviation [SD] 2.5 years). A total of 34 patients (38.6%) had a "clean" two-stage course with successful reimplantation and no evidence of infection at 1-year follow-up. The remaining patients (61.4%) required 3.67 (±0.52) additional surgeries. Overall reimplantation rate was 72%. Causative bacterial agents included MSSA (n = 22), MRSA (n = 16), coagulase-negative Staphylococcus (n = 14), and polymicrobial (n = 12). Regarding complications, there were 13 (15%) dislocations, 16 (18%) periprosthetic fractures, 8 (9%) bent/fractured stems, and 16 (18%) patients had clinically significant subsidence. Patients with previous extended trochanteric osteotomy (ETO) experienced higher rates of bent/broken spacer stems (25% vs 3.1%; P = .006) periprosthetic fractures (37.5% vs 10.9%; P = .010), and dislocations (37.5% vs 6.2%; P = .001). The rate of infection clearance was lower in the prior ETO cohort (26.6% vs 54.2%; P = .029).

CONCLUSION

We report outcomes in patients who underwent implantation of a specific molded articulating hip spacer at our institution. Infection eradication was roughly in line with published series of hip PJI treatment. There was a high rate of mechanical complications, especially in those patients who required an ETO.

Synovial White Blood Cell Count and Differential to Predict Successful Infection Management in a Two-Stage Revision

BACKGROUND

An array of synovial white blood cell (WBC) count and polymorphonuclear differential (PMN%) thresholds have been reported using 2013 Musculoskeletal Infection Society (MSIS) definition which has a poor accuracy to confirm infection control before reimplantation. The workgroup of MSIS recently developed a comprehensive definition of successful infection management. Our objectives were to determine optimal thresholds for WBC count and PMN% associated with reimplantation success based on this new MSIS definition and assess if values above these thresholds indicate decreased survival time.

METHODS

A retrospective review was conducted on a consecutive series of 133 two-stage hip/knee arthroplasties performed by 15 surgeons (2014-2020) at 2 institutions. All surgeries had a minimum follow-up of 1 year. The inclusion criteria included reporting of preoperative synovial fluid aspiration results. Thus, 88 were finally included. Surgical success was defined by MSIS outcome reporting tool (Tiers 1-4). Receiver operating characteristic curve analyses were performed to estimate optimal thresholds of WBC count and PMN%. A Kaplan-Meier survival analyses with log-rank test were performed.

RESULTS

With area under the curve of 0.65, synovial PMN% showed superior accuracy than WBC count (area under the curve = 0.52) in determining outcome of reimplantation. The optimal PMN% threshold (62%) demonstrated sensitivity of 57% and specificity of 77%. The calculated WBC count threshold (2,733/μL) showed poor sensitivity (21%) but high specificity (95%). There was a significant difference in failure-free survival (24 months) between the cases with WBC count higher vs lower than 2,733/μL (P = .002). This was also true for PMN% at 5 months postoperatively (P = .009).

CONCLUSION

WBC count (2,733/μL) shows very high specificity to confirm successful reimplantation. Both WBC count and PMN% (62%) thresholds can significantly determine reimplantation survival.

Correlation between body mass index and two-stage revision failure of periprosthetic joint infection following total joint arthroplasty: A systematic review and meta-analysis

Background: Although the correlation between body mass index (BMI) and two-stage revision failure of periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) have been frequently reported, the results remain controversial. Therefore, the correlation between them was systematically evaluated and meta-classified in this study. Methods: Literature on the correlation between BMI and two-stage revision failure of PJI following TJA was retrieved in PubMed, Embase and Cochrane Library due May 2020. Stata 13.0 software and Cochrane Collaboration Review Manager software (RevMan version 5.3) were applied to data synthesis, subgroup analysis, analyses of publication bias, and sensitivity. Results: A total of 15 observational studies included 1267 patients, of which 15 studies were included in systematic review and 11 studies in meta-analysis. Eight studies found a correlation between BMI and two-stage revision failure of PJI following TJA, but seven other studies found no correlation. Meta-analysis found that the risk of two-stage revision failure of PJI following TJA significantly boosted by 3.53 times in patients with BMI ≥ 30 kg/m² (OR = 3.53; 95% CI = 1.63-7.64 for the BMI ≥ 30 kg/m² vs. BMI < 30 kg/m²) and the risk of two-stage revision failure of PJI following TJA significantly increased by 2.92 times in patients with BMI ≥ 40 kg/m² (OR = 2.92; 95%CI = 1.06-8.03 for the BMI ≥ 40 kg/m² vs. BMI < 30 kg/m²). The subgroup analysis showed that significant association was observed among the studies performed in TKA (OR = 3.63; 95% CI = 2.27-5.82), but not among those conducted in THA (OR = 3.06; 95% CI = 0.42-22.19). A significant association remained consistent, as indicated by sensitivity analyses. Because there are too few studies that can be combined in the included studies, Egger's and Begg's tests were not performed. Conclusion: Meta-analysis suggests that the risk of two-stage revision failure of PJI following TJA significantly boosted in obese patients. However, because there may be publication bias of this study, combined overall systematically evaluated and meta-analysis results, we cannot yet conclude that BMI is associated with two-stage revision failure of PJI following TJA.

Hospital Costs for Unsuccessful Two-Stage Revisions for Periprosthetic Joint Infection

BACKGROUND

Although 2-stage exchange arthroplasty is the preferred surgical treatment for periprosthetic joint infection (PJI) in the United States, little is known about the risk of complications between stages, mortality, and the economic burden of unsuccessful 2-stage procedures.

METHODS

The 2015-2019 Medicare 100% inpatient sample was used to identify 2-stage PJI revisions in total hip and knee arthroplasty patients using procedural codes. We used the Fine and Gray sub-distribution adaptation of the conventional Kaplan-Meier method to estimate the probability of completing the second stage of the 2-stage PJI infection treatment, accounting for death as a competing risk. Hospital costs were estimated from the hospital charges using "cost-to-charge" ratios from Centers for Medicare and Medicaid Services.

RESULTS

A total of 5094 total hip arthroplasty and 13,062 total knee arthroplasty patients had an index revision for PJI during the study period. In the first 12 months following the first-stage explantation, the likelihood of completing a second-stage PJI revision was 43.1% (95% confidence interval [CI] 41.7-44.5) for hips and 47.9% (95% CI 47.0-48.8) for knees. Following explantation, 1-year patient survival rates for hip and knee patients were 87.4% (95% CI 85.8-88.9) and 91.4% (95% CI 90.6-92.2), respectively. The median additional cost for hospitalizations between stages was $23,582 and $20,965 per patient for hips and knees, respectively. Hospital volume, Northeast or Midwest region, and younger age were associated with reduced PJI costs (P < .05).

CONCLUSION

Although viewed as the most preferred, the 2-stage revision strategy for PJI had less than a 50% chance of successful completion within the first year, and was associated with high mortality rates and substantial costs for treatment failure.

Case Report of a Diagnosed Septic Hip Joint Treated with a 2-Stage Hip Arthroplasty

Introduction

Identifying and determining appropriate treatment of adult hip septic arthritis (SA) can be quite challenging. Although rare, the annual incidence of this diagnosis is approximately 8 cases per 100,000 patients. The timing of patient symptoms is wide spread. The presentation may be acute, subacute, or even chronic, and moreover, the disease process may be masked by an underlying etiology. Once diagnosed, SA requires rapid and aggressive treatment.

Case Report

A 67-year-old patient presented with left hip pain. Physical examination shifted the differential diagnosis from osteoarthritis to a possible septic joint. Elevated inflammatory markers were revealed. Joint aspiration was obtained, which demonstrated rare Group G streptococcus. Two-stage hip arthroplasty was performed. Intra-operative cultures still reveal no growth of bacteria, and the patient is progressing well.

Conclusion

Adult septic hip arthritis is a rare diagnosis. Hence, a proper history, physical examination, infectious laboratory workup is important. The treatment of the condition is based on the duration of symptoms and the physician's clinical gestalt.

Risk of reinfection after two- or multiple-stage knee revision surgery using superficial vancomycin coating and conventional spacers

This study investigates the effect of superficial vancomycin coating (SVC) in two- or more-stage exchange procedures of prosthetic knee joint infections. We hypothesized that spacer treatment with SVC result in lower reinfection rates than conventional spacers after prosthetic reimplantation. Our secondary aim was to determine the demographic and treatment factors associated with reinfection rates. This retrospective cohort study compromised 96 cases with prosthetic knee infections. Twenty-four cases were treated with a temporary SVC spacer and 72 cases with conventional spacers. Prosthetic reinfection occurred after a median observation period of 1.7 ± 4.0 years in 24 cases (25%). The prevalence of having a reinfection was not significantly different between the two treatment groups (13% [3 cases] in the SVC group vs. 29% [21 cases] in the conventional spacer group [p = .104]). In seven cases (7.3%), two in the SVC group (8.3%) and five (6.9%) in the conventional spacer group (p ≥ .999), histological, respectively microbiological evaluations from the intraoperative specimens revealed persistent infection at the second stage. Nevertheless, in all seven cases no significant higher risk of periprosthetic reinfection was observed during follow-up (p = .750). Our secondary investigation of cofactors revealed that spacers additionally stabilized by nails were significantly associated with a 3.9-fold higher hazard ratio of sustaining a reinfection of revision prosthesis (p = .005).

Emergence of Antibiotic Resistance Across Two-Stage Revision for Periprosthetic Joint Infection

BACKGROUND

The current preferred treatment for chronic hip and knee periprosthetic joint infection (PJI) involves both surgical intervention and antibiotic treatment as part of a two-stage revision. The purpose of this study is to determine how often patients who underwent a two-stage revision for chronic PJI developed a subsequent antibiotic-resistant infection.

METHODS

We retrospectively reviewed the clinical records of 142 patients who underwent a two-stage revision for a chronic culture-positive PJI from January 2014 to May 2019. Demographic data and risk factors for PJI were identified. Resistance was defined in accordance with microbiology laboratory report and minimum inhibitory concentration. Statistical analysis consisted of descriptive statistics and univariate analysis.

RESULTS

Only 10 of the 142 patients (7.04%) demonstrated emergence of resistance to antibiotics across their two-stage revision. At reimplantation, 25 (17.6%) patients had positive cultures. Of these, 16 patients presented with a novel organism and 9 patients had positive culture for the same organism as the initial infection. During the entire course of the two-stage revision, including spacer exchanges and irrigation and debridement procedures, 15 (10.56%) patients demonstrated persistent infections, whereas 25 (17.6%) patients presented with novel infections. 26 (18.3%) patients had reinfection of the same joint within one year.

CONCLUSION

In the given cohort, there does not appear to be a major emergence of antibiotic resistant organisms in patients undergoing two-stage exchange arthroplasty and antibiotic treatment.

Two-Stage Revision Total Hip Arthroplasty Without Spacer Placement: A Viable Option to Manage Infection in Patients With Severe Bone Loss or Abductor Deficiency

BACKGROUND

High rates of spacer-related complications in two-stage exchange total hip arthroplasty (THA) have been reported. Patients with advanced bone defects and abductor deficiency may benefit from a nonspacer two-stage revision. This study reports on the clinical course of a contemporary two-stage exchange for periprosthetic hip infection without spacer insertion.

METHODS

We reviewed 141 infected THAs with extensive bone loss or abductor damage who underwent two-stage exchange without spacer placement. The mean duration from resection arthroplasty to reimplantation was 9 weeks (2-29). Clinical outcomes included interim revision, reinfection, and aseptic revision rates. Restoration of leg-length and offset was assessed radiographically. Modified Harris hip scores were calculated. Mean follow-up was 5 years (3-7). Treatment success was defined using the modified Delphi consensus criteria.

RESULTS

Thirty-four patients (24%) had treatment failure, including 13 reinfections, 16 interim redebridements for persistent infection, 2 antibiotic suppressive therapies, and 3 prosthetic joint infection-related deaths. Aseptic rerevision after reimplantation was necessary in 14 patients (10%). Dislocation accounted for most aseptic complications, with 20 dislocations occurring in 15 patients (11%). Leg-length and offset were restored to preoperative measures. Mean modified Harris hip scores significantly improved from 35 points to 67 points.

CONCLUSION

A nonspacer two-stage exchange is a viable option for managing chronically infected THA with severe bone loss or abductor deficiency, showing comparable rates of interim revision and recurrence of infection. Cementless reimplantation demonstrates good midterm survivorship with comparable functional outcomes and leg-length restoration. However, dislocation continues to be a major concern.

Two-Stage Total Knee Arthroplasty Revision With Extended Antibiotic Spacer Use

Despite the many benefits of total knee arthroplasty (TKA) in the treatment of degenerative arthritis, infection of the total knee prosthesis presents a dangerous post-operative complication affecting 0.5-1.9% of all cases. Infection after the first three post-operative weeks is treated with either one or two-stage revision operations involving the removal of all prosthetic components. Two-stage revision operations are more commonly used and involve the removal of prosthetic components followed by the implantation of a cement mold infused with antibiotics (antibiotic spacer) as well as systemic antibiotic treatment for four to six weeks before prosthetic reimplantation. This case report details a TKA revision in a patient with osteoarthritis of the knee. The patient presented with an elevated erythrocyte sedimentation rate, C-reactive protein, and white blood cell count nearly two years after the primary operation and was found to have an infected total knee prosthetic. A two-stage revision was planned but due to scheduling disruption by the coronavirus disease 2019 pandemic, the second stage of the operation was delayed until 12 months after the stage one operation. The patient ambulated without pain on an antibiotic spacer for 12 months, providing information about the long-term use of spacers. This case also offers a look at a potential benefit to one-stage operations, which have been shown in the literature to have similar outcomes as two-stage operations. The patient had a medical history of psoriasis and immunosuppressive treatment with methotrexate, two risk factors for prosthetic joint infection, and may have benefited from prophylactic antibiotic therapy extending beyond the perioperative period. The goal of this case report is to detail the prolonged use of an antibiotic spacer, examine the risks and benefits of one and two-stage total knee revisions, and discuss prophylactic antibiotic use in high-risk patients following TKA.

Facing multidrug-resistant pathogens in periprosthetic joint infections with self-administered outpatient parenteral antimicrobial therapy-A prospective cohort study

A key factor in the successful management of periprosthetic joint infection (PJI) besides the surgical regime is a consistent antimicrobial therapy. Recently, oral versus intravenous (IV) antibiotics for bone and joint infection trial demonstrated the noninferiority of oral antimicrobial therapy compared to IV, implying that an early transition to oral administration is reasonable. It is likely that the international consensus meeting of musculoskeletal Infections and the European Bone and Joint Infection Society will consider these findings. However, rising levels of antimicrobial resistance are challenging and recommendations for dealing with multidrug-resistant (MDR) pathogens resistant to oral antibiotics are lacking. This study focuses on establishing guidance towards their management in PJI. From December 2015 to June 2019, patients with MDR pathogens were included in a single-center prospective cohort study and treated with self-administered outpatient parenteral antimicrobial therapy (S-OPAT) based on a two-stage revision strategy. Demographics, pathogens, antimicrobial agents, and outcomes were recorded. A total of 1738 outpatient days in 26 patients were analyzed. The incidence of pathogens resistant to oral antibiotics in PJI was 4%, most frequently encountered were staphylococcus epidermidis. The Kaplan-Meier-estimated infection-free survival after 3 years was 90% (95% confidence interval, 84.6%-95.5%). We recorded adverse events in 6 of 54 (11%) S-OPAT episodes (3.45/1000 S-OPAT days). (i) S-OPAT in two-stage revision arthroplasty to counter increasing numbers of MDR pathogens resistant to oral agents can achieve a high infection eradication rate and (ii) should therefore be taken into account at the next society's consensus treatment updates.

Single-stage versus two-stage revision for shoulder periprosthetic joint infection: a systematic review and meta-analysis

BACKGROUND

Shoulder periprosthetic joint infection (PJI) is a significant complication after arthroplasty with high morbidity. An evidence-based algorithm for the treatment of shoulder PJI is lacking in current practice. The purpose of this systematic review and meta-analysis was to understand and compare the role of single- and 2-stage shoulder arthroplasty revision for PJI.

METHODS

A comprehensive literature review was performed to identify all studies related to shoulder arthroplasty for PJI in PubMed, Scopus, and EMBASE. Inclusion criteria for this systematic review were studies that reported on single- or 2-stage revision, with infection eradication and a minimum follow-up of 12 months and a minimum of 5 patients for analysis. A random-effects meta-analysis was performed, and heterogeneity was assessed with Cochrane Q and I2.

RESULTS

A total of 13 studies reporting on single-stage revision and 30 studies reporting on 2-stage revision were included in final analysis. The majority of positive cultures from single-stage revision for PJI resulted in Cutibacterium acnes with 113 of 232 (48.7%) reported cases compared with 190 of 566 (33.7%) reported cases for 2-stage revision. However, there was a lower percentage of methicillin-resistant Staphylococcus aureus positive cultures, with 2.5% for single-stage compared with 9.7% for 2-stage revision. The overall pooled random-effect reinfection incidence was 0.05 (95% confidence interval: 0.02-0.08), with moderate heterogeneity (I² = 34%, P = .02). The reinfection rate was 6.3% for single-stage and 10.1% for 2-stage revision, but this was not significant (Q = 0.9 and P = .40).

CONCLUSION

Based on a systematic review with meta-analysis, single-stage revision for shoulder PJI is an effective treatment. Indeed, our analysis showed single-stage to be more effective than 2-stage, but this is likely confounded by a treatment bias given the higher propensity of virulent and drug-resistant bacteria treated with 2-stage in the published literature. This implies that shoulder surgeons treating PJI can be reassured of a low recurrence rate (6.3%) when using single-stage treatment for C acnes or other sensitive, low-virulence organisms.

Hip Spacers with a Metal-on-Cement Articulation Did Not Show Significant Surface Alterations of the Metal Femoral Head in Two-Stage Revision for Periprosthetic Joint Infection

Two-stage revision is considered the gold standard treatment for chronic periprosthetic joint infection (PJI). During the interim period, between explantation of the infected hip endoprosthesis and revision arthroplasty, individually formed articulating hip spacers made of polymethylmethacrylate (PMMA) bone cement can be used to provide better soft tissue preservation, local antibiotic release, and improved postoperative mobilization. If effective prevention from luxation is achieved, hip function and hence overall patient satisfaction is improved. Zirconium oxide particles inside conventional PMMA bone cement, however, are known to enhance third-body wear, which may cause alterations of the metal head in the articulating spacer and hence become a serious risk for the patient. Therefore, the aim of our study was to analyze whether the articular surface of cobalt-chrome (CoCr) femoral heads is significantly altered in the setting of a metal-on-cement articulation during the interim period of two-stage revision for PJI. We analyzed a consecutive series of 23 spacer cases and compared them with femoral heads from two series of conventional hip arthroplasty revisions with metal-on-polyethylene articulations and different time intervals in situ. To investigate metallic wear, the femoral heads were thoroughly examined, and their surface roughness was measured and analyzed. We found no significant differences between the two conventional hip arthroplasty groups, despite their very different times in situ. Furthermore, the individually different times in situ within the spacer group had no significant impact on surface roughness, either. Compared with the spacer group, the surface roughness of the metal femoral heads from both conventional hip arthroplasty groups were even higher. Within the spacer group, roughness parameters did not show significant differences regarding the five predefined locations on the metal head. We conclude that metal-on-cement articulations do not cause enhanced surface alterations of the metal femoral head and hence do not limit the application in articulating hip spacers in the setting of two-stage revision for PJI.

The Results of Two-stage Revision for Methicillin-resistant Periprosthetic Joint Infection (PJI) of the Hip

Introduction:

Periprosthetic joint infection (PJI) of the hip due to methicillin-resistant bacteria is difficult to treat and remain a challenge for arthroplasty surgeon.

Material and Methods:

Retrospective review was done to the patients who received two-stage revisions with an antibiotic loaded cement-spacer for PJI of the hip between January 2010 to May 2015. We found 65 patients (65 hips) with positive culture findings. Eight patients were lost to follow-up and excluded from the study. Among the rest of the 57 patients, methicillin-resistant infection (MR Group) was found in 28 cases. We also evaluate the 29 other cases that caused by the other pathogen as control group. We compared all of the relevant medical records and the treatment outcomes between the two groups.

Results:

The mean of follow-up period was 33.7 months in the methicillin-resistant group and 28.4 months in the control group (p = 0.27). The causal pathogens in the methicillin-resistant group were: Methicillin-resistant Staphylococcus aureus (MRSA) in 10 cases, Methicillin-resistant Staphylococcus epidermidis (MRSE) in 16 cases and Methicillin-resistant coagulase-negative Staphylococcus (MRCNS) in two cases. The reimplantation rate was 92.8% and 89.6% in the methicillin-resistant and control group, respectively (p= 0.66). The rates of recurrent infection after reimplantation were 23.1% (6/26) in the methicillin-resistant group and 7.6% (2/26) in the control group (p= 0.12). The overall infection control rate was 71.4% (20/28) and 89.6% (26/29) in the methicillin-resistant and control group, respectively (p = 0.08). Both groups showed comparable baseline data on mean age, BMI, gender distribution, preoperative ESR/CRP/WBC and comorbidities.

Conclusions:

Two-stage revision procedure resulted in low infection control rate and high infection recurrency rate for the treatment of methicillin-resistant periprosthetic joint infection (PJI) of the hip. Development of the treatment strategy is needed to improve the outcome of methicillin-resistant periprosthetic joint infection (PJI) of the hip.

Single vs 2-Stage Revision for the Treatment of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) is one of the most devastating complications following total joint arthroplasty, accounting for a projected 10,000 revision surgeries per year by 2030. Chronic PJI is complicated by the presence of bacterial biofilm, requiring removal of components, thorough debridement, and administration of antibiotics for effective eradication. Chronic PJI is currently managed with single-stage or 2-stage revision surgery. To date, there are no randomized, prospective studies available evaluating eradication rates and functional outcomes between the 2 techniques. In this review, both treatment options are described with the most current literature to guide effective surgical decision-making that is cost-effective while decreasing patient morbidity.

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.

Complications of Resection Arthroplasty in Two-Stage Revision for the Treatment of Periprosthetic Hip Joint Infection

Little data is available regarding complications associated with resection arthroplasty in the treatment of hip periprosthetic joint infection (PJI). We assessed complications during and after two-stage revision using resection arthroplasty. In this retrospective study, 93 patients undergoing resection arthroplasty for hip PJI were included. Patients were assigned to a prosthesis-free interval of ≤10 weeks (group 1; 49 patients) or >10 weeks (group 2; 44 patients). The complication rates between groups were compared using the chi-squared test. The revision-free and infection-free survival was estimated using a Kaplan-Meier survival analysis. Seventy-one patients (76%) experienced at least one local complication (overall 146 complications). Common complications were blood loss during reimplantation (n = 25) or during explantation (n = 23), persistent infection (n = 16), leg length discrepancy (n = 13) and reinfection (n = 9). Patients in group 1 experienced less complications after reimplantation (p = 0.012). With increasing severity of acetabular bone defects, higher incidence of complications (p = 0.008), periprosthetic bone fractures (p = 0.05) and blood loss (p = 0.039) was observed. The infection-free survival rate at 24 months was 93.9% in group 1 and 85.9% in group 2. The indication for resection arthroplasty needs to be evaluated carefully, considering the high rate of complications and reduced mobility, particularly if longer prosthesis-free intervals are used.

[Research progress of two-stage revision for periprosthetic joint infection after hip and knee arthroplasties]

Objective

To summarize the research progress of two-stage revision for periprosthetic joint infection (PJI) after hip and knee arthroplasties.

Methods

The related literature on two-stage revision for PJI was summarized, and the new progress in the choice of spacers, systemic antibiotic therapy, and risk factors were analyzed.

Results

Two-stage revision is a common way to treat infection after hip and knee arthroplasties. The types of spacers used in the one-stage operation are diverse and each has its own advantages and disadvantages. Non-articular spacers are mainly used for the patients with poor soft tissue conditions around the joints and severe bone defects. But the joint mobility is not good after the placement of the spacer. Articular spacers can restore the affected joint movement after operation, which is beneficial to the joint mobility after two-stage operation. The use of antibiotics is an indispensable part of the treatment process, and the effectiveness of short-term antibiotic treatment is similar to long-term treatment. Identifying the relevant risk factors that influence the prognosis of the two-stage revision can help preoperative management and reduce the recurrence rate of infection.

Conclusion

There are still controversies about the choice of spacers and systemic antibiotic therapy during the two-stage revision and treatment of PJI. The factors affecting the prognosis of the two-stage revision need to be explored and the further high-quality research is needed.

Impact of Hip Antibiotic Spacer Dislocation on Final Implant Position and Outcomes

BACKGROUND

Dislocation of dynamic antibiotic hip spacers during the treatment of periprosthetic joint infection is a well-described complication. Unfortunately, the repercussions of such events after reimplantation of the definitive prosthesis remain largely unknown. As such, we devised a study comparing the perioperative and postoperative outcomes of patients having undergone reimplantation with and without spacer dislocation.

METHODS

A search of our institutional database was performed. Two retrospective cohorts were created: dislocated and nondislocated hip spacers. The radiographic and clinical outcomes for each cohort were collected.

RESULTS

The two retrospective cohorts contained 24 patients for the dislocated group and 66 for the nondislocated group. Continuous variables noted to be significantly different between the dislocated and nondislocated groups were as follows: clinical leg-length discrepancy (1.35 cm vs 0.41 cm, P = .027), acetabular center of rotation (1.34 cm vs 0.60 cm, P = .011), total packed red blood cell transfusions (4.05 vs 2.37, P = .019), operative time (177.4 min vs 147.3 min, P = .002), and hospital length of stay (7.79 days vs 5.89 days, P = .018). Categorical variables noted to be significantly different were requirement for complex acetabular reconstruction (58.3% vs 13.7%, P < .001), requirement of constrained liners (62.5% vs 37.3%, P = .040), and dislocation after second stage (20.8% vs 6.1%, P = .039).

CONCLUSION

Dislocation of dynamic hip spacers leads to inferior clinical results and perioperative outcomes after reimplantation of the definitive prosthesis. Additionally, complex acetabular reconstruction is often required. As such, every effort should be made to prevent hip spacer dislocation.

Management of Chronically Infected Total Knee Arthroplasty With Severe Bone Loss Using Static Spacers With Intramedullary Rods

BACKGROUND

Two-stage revision with static antibiotic spacers is the preferred treatment for chronically infected total knee arthroplasty (TKA) associated with severe bone loss. Intramedullary rods to reinforce static spacers have been described. On those, however, bacterial colonization may occur and hamper infection control. This study reports the microbiological findings on the spacer rods and the treatment outcome among these patients.

METHODS

We reviewed 97 infected TKA with extensive bone loss treated with antibiotic-loaded cement spacers reinforced with intramedullary rods. Mean interim period with the spacer in situ was 9 weeks (range: 6-24 weeks). Intraoperative cultures and sonicated spacer rods were analyzed. Mean follow-up after TKA reimplantation was 41 months (range: 27-56 months). Treatment success was defined using the modified Delphi consensus criteria.

RESULTS

Twenty-two patients (23%) had treatment failure, including 3 reinfections caused by the same organism, 9 reinfections caused by a different organism, 9 patients required interim spacer exchange, and 1 patient died in the early postoperative course. Sonication cultures of the spacer rods were positive in 2 cases (2%), and none of them failed. Host and limb status was significantly worse in patients who sustained reinfection. At the latest follow-up, all patients had a TKA in place, and 2 patients received chronic antibiotic suppression.

CONCLUSION

Two-stage revision with the use of intramedullary rods is a safe and efficient treatment for chronically infected TKA with severe bone loss. Most reinfections grew different organisms compared with initial infection. Compromised hosts and extremities may be subjected to chronic antibiotic suppression.

The Use of Extended Trochanteric Osteotomy in 2-Stage Reconstruction of the Hip for Infection

BACKGROUND

The effect of extended trochanteric osteotomy (ETO) with immediate cerclage wire fixation on the scene of chronic periprosthetic joint infection on infection eradication and the osteotomy healing remains unclear.

METHODS

One hundred seventeen patients who underwent two-stage revision total hip arthroplasty for chronic periprosthetic joint infection were enrolled in the study. The minimum follow-up was 2 years. Of these, 48 patients had underwent ETO and immediate cerclage wire fixation during the first-stage surgery, while 69 did not undergo ETO or any other osteotomy. In addition, 18 patients had underwent ETO in the second-stage reimplantation surgery. Repeated debridement, curative rate of infection, and complications were compared between the 2 groups. Meanwhile, osteotomy healing between the first and second osteotomy were also compared.

RESULTS

The repeated debridement rate and curative rate of infection were 2.1% and 95.8% in the ETO group, compared with 13.0% and 82.6% in the non-ETO group; there were significant difference between the 2 groups in these parameters (P = .037 and .030, respectively). Meanwhile, osteotomy healing rate was 93.8% in first-stage surgery with infection scene and 100% in second-stage surgery without infection; no significant difference was detected in osteotomy healing rate and time to healing (P = .278 and .803, respectively). The rate of complication was similar in both groups.

CONCLUSIONS

ETO combined with immediate cerclage wire fixation does not appear to reduce the rate of infection eradication. There was no harmful effect on complication rate and osteotomy healing.

Utility of Serological Markers for Detecting Persistent Infection in Two-Stage Revision Arthroplasty in Patients With Inflammatory Arthritis

BACKGROUND

Serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are commonly used for the diagnosis of persistence of infection after the first stage of 2-stage revision arthroplasty for periprosthetic joint infection (PJI). As both ESR and CRP are markers of systemic inflammation, the utility of these tests to monitor infection clearance in patients with inflammatory arthritis is unclear.

METHODS

From 2001 to 2016, 44 two-stage revision total hip or knee arthroplasties in patients with an inflammatory arthritis diagnosed by a rheumatologist were identified. Persistence of infection at the time of planned second stage was defined as satisfying the Musculoskeletal Infection Society criteria for PJI (14 infected, 30 noninfected). ESR and CRP values were compared between the stages using nonparametric tests. Receiver operating characteristic analysis was performed to obtain the diagnostic parameters.

RESULTS

ESR and CRP decreased between the stages in the noninfected group (ESR: mean decrease = 31.6 mm/h [19.2-44.0], P < .001; CRP: mean decrease = 5.2 mg/dL [2.1-8.2], P < .001), but remained elevated in the infected group (ESR: mean decrease = 7.7 [-23.1 to 36.6], P = .572; CRP: mean decrease = 1.5 [-2.2 to 5.1], P = .258). Optimal thresholds for persistent infection were 29.5 mm/h and 2.8 mg/dL, respectively, for ESR and CRP. The sensitivity and specificity at the optimal thresholds were 64% and 77% for ESR, and 64% and 90% for CRP.

CONCLUSION

ESR and CRP responded to the treatment of PJI in patients with inflammatory arthritis and had reasonably high specificities with moderate sensitivities. ESR and CRP appear to be useful tools in diagnosing persistent infection even in patients with inflammatory arthritis.

Characterization of Outcomes of 2-Stage Exchange Arthroplasty in the Treatment of Prosthetic Joint Infections

BACKGROUND

Two-stage revision is the preferred treatment for prosthetic hip and knee infections in the United States. Recent studies have questioned the true success rate of this treatment. The purpose of this study is to investigate outcomes of prosthetic hip and knee infections undergoing resection arthroplasty and spacer insertion at a single institution.

METHODS

We identified 103 patients who underwent prosthesis resection and spacer placement for infection over a 10-year period. Twenty-three cases were excluded based on preset exclusion criteria leaving 80 cases (56 knees, 24 hips). A retrospective review was performed to examine the outcomes of these patients.

RESULTS

Following spacer placement but before reimplantation, 9 (11.25%) of the 80 joints underwent repeat debridement and spacer exchange for persistent infection. Twenty-four (30.00%) patients had a serious complication during their treatment course. Fourteen (17.50%) patients never underwent reimplantation. Of these, 10 continued with spacer retention, 2 had resection arthroplasty, and 1 each had an amputation and an arthrodesis. Of the 66 patients with successful reimplantation, 48 (72.70%) remained infection free at most recent follow-up.

CONCLUSIONS

Two-stage revision does not result in the high rates of cure reported previously, when taking into account the substantial number of patients who never undergo the subsequent reimplantation surgery. Of those who underwent reimplantation in our study, many required additional spacer exchange or had complications. Surgeons and patients should consider these outcomes when discussing the treatment of prosthetic hip and knee infections.

Selected Heat-Sensitive Antibiotics Are Not Inactivated During Polymethylmethacrylate Curing and Can Be Used in Cement Spacers for Periprosthetic Joint Infection

BACKGROUND

Antibiotic use in polymethylmethacrylate (PMMA) spacers has historically been limited to those which are "heat-stable" and thus retain their antimicrobial properties after exposure to the high temperatures which occur during PMMA curing.

METHODS

This study examines the requirement of "heat stability" by measuring temperatures of Palacos and Simplex PMMA as they cure inside commercial silicone molds of the distal femur and proximal tibia. Temperature probes attached to thermocouples were placed at various depths inside the molds and temperatures were recorded for 20 minutes after PMMA introduced and a temperature curve for each PMMA product was determined. A "heat-stable" antibiotic, vancomycin, and a "heat-sensitive" antibiotic, ceftazidime, were placed in a programmable thermocycler and exposed to the same profile of PMMA curing temperatures. Antimicrobial activity against Staphylococcus aureus was compared for heat-treated antibiotics vs room temperature controls.

RESULTS

Peak PMMA temperatures were significantly higher in tibial (115.2°C) vs femoral (85.1°C; P < .001) spacers. In the hottest spacers, temperatures exceeded 100°C for 3 minutes. Simplex PMMA produced significantly higher temperatures (P < .05) compared with Palacos. Vancomycin bioactivity did not change against S aureus with heat exposure. Ceftazidime bioactivity did not change when exposed to femoral temperature profiles and was reduced only 2-fold with tibial profiles.

CONCLUSION

The curing temperatures of PMMA in knee spacers are not high enough or maintained long enough to significantly affect the antimicrobial efficacy of ceftazidime, a known "heat-sensitive" antibiotic. Future studies should investigate if more "heat-sensitive" antibiotics could be used clinically in PMMA spacers.

Factors Associated with Choice and Success of One- Versus Two-Stage Revision Arthroplasty for Infected Hip and Knee Prostheses

BACKGROUND

Prosthetic joint infections (PJI) of hip and knee arthroplasties are becoming increasingly common with an aging population and an increasing demand for these procedures. Despite attempts at standardization, medical and surgical approaches vary widely among practitioners.

QUESTIONS/PURPOSES

We first sought to determine if there were specific factors associated with choice of one- versus two-stage revision. Then we investigated whether the type of revision approach influenced clinical treatment success. Finally, among two-stage revisions, we assessed if an antibiotic holiday prior to the second procedure affected clinical treatment success.

METHODS

We retrospectively reviewed patients who had revision surgery for infection of a hip or knee arthroplasty between January 1, 2000, and December 31, 2013, at the Sunnybrook Health Sciences Centre and the Holland Orthopedic and Arthritic Centre. PJI cases were identified using the Ontario Joint Replacement Registry. Infection was defined by gross intraoperative evidence of infection, positive intraoperative culture(s), and/or sinus tract prior to operation. The primary outcome was treatment failure at 1 year after revision surgery based on requirement for further surgery, ongoing infection, and/or continuous suppressive antibiotics.

RESULTS

Of 110 eligible patients identified, 35 patients had a one-stage and 75 patients had a two-stage revision. Choice of a one-stage approach was most influenced by particular surgeon preference and was more likely for hip revision versus knee revision (OR 3.39 (95%CI 1.85-6.23). There was no statistical difference in clinical treatment success rate between one-stage (33/35; 94.2% success) and two-stage revision (63/75; 84%; p = 0.13). Enterococcus spp. (21 versus 3%; p = 0.027) and Peptostreptococcus spp. (14 versus 1%; p = 0.042) were more common among clinical treatment failures than successes, with a trend towards the same for Staphylococcus aureus (29 versus 9%; p = 0.06). Additionally, treatment success was not influenced by whether the patient had an antibiotic holiday with a two-stage revision.

CONCLUSION

Our findings confirm the uncertainty of surgical strategy for treatment of PJI in hip and knee arthroplasty. Superiority of one- versus two-stage revision and the value of antibiotic-free periods prior to definitive revision remain unclear. Large prospective studies or randomized controlled trials are needed to inform best practice for treatment of these complex clinical problems.

A Strategic Protocol to Improve the Process and Outcomes of Two-stage Revision Total Hip Arthroplasty

Two-stage revision total hip arthroplasty (THA) is the most commonly used treatment approach for deep prosthetic infection. However, in this approach the interval between the first and second stage tends to be prolonged. We devised a strategic protocol for improving the infection eradication rate and shortening the interval between the stages in two-stage revision THA. This study analyzed a series of 14 patients (14 hips) from 2008 to 2012, who were treated using an antibiotic-loaded acrylic cement (ALAC) spacer at the first stage and re-implantation at the second stage. The ALAC included vancomycin and amikacin for most of the cases. Patients with MRSA infection were additionally administered intravenous vancomycin in combination with either oral rifampicin or trimethoprim-sulfamethoxazole. The average interval between the stages was 54.2 days overall, and 58.7 days for cases with MRSA infection. Our infection eradication rate was 100%, with no reported recurrence of infection. The presence of MRSA tended to be associated with a longer interval between the two stages. Our protocol for two-stage revision THA was associated with a high eradication rate of infection and a shortened interval between the stages.

Two-stage revision for infected shoulder arthroplasty

BACKGROUND

Periprosthetic shoulder infections (PSIs) are challenging to treat and often result in significant patient morbidity. Without a standardized treatment protocol, PSIs are often managed similarly to periprosthetic hip and knee infections. Because 2-stage revision is the gold standard for treating periprosthetic hip and knee infections, we performed a case series and literature review to determine its effectiveness in PSIs.

METHODS

We identified 19 patients (14 men) from our institution who were treated with a 2-stage revision after presenting with a PSI. Mean patient age was 63 ± 9 years, and average body mass index was 30.8 ± 5.8. The average time from the index arthroplasty to treatment was 40 months, 8 of 13 positive cultures were Propionibacterium acnes, and 9 of 19 patients had multiple shoulder operations before presenting with infection. Minimum follow-up for all patients was 2 years.

RESULTS

After a mean follow-up of 63 months (range, 25-184 months), 15 of 19 patients in our study were successfully treated for PSI. Average postoperative American Shoulder and Elbow Surgeons (ASES) Shoulder Assessment score was 69 (range, 32-98) and average postoperative forward elevation was significantly increased from 58° to 119° (P < .001). The incidence of recurrent infection was 26%. The rate of noninfection complications was 16%, for a total complication rate of 42%.

CONCLUSION

In patients with PSIs, especially those with intractable, chronic infections, a 2-stage revision represents a viable treatment option for eradicating infection and restoring function. However, it is important to recognize the risk of recurrent infection and postoperative complications in this challenging patient population.

Periprosthetic Infection Recurrence After 2-Stage Exchange Arthroplasty: Failure or Fate?

BACKGROUND

Two-stage exchange arthroplasty remains the preferred method for treating a chronic periprosthetic joint infection (PJI) in North America. However, infection recurrence may occur. Previously, recurrent infections have been classified as persistent (same isolated pathogen) or new (different pathogen identified). We sought to determine (1) recurrence rates among patients with chronic hip and knee PJI, treated with 2-stage exchange arthroplasty; (2) risk factors for infection recurrence; and (3) risk factors for developing persistent vs new infection.

METHODS

We retrospectively reviewed clinical characteristics of patients with chronic hip and knee PJI, treated with 2-stage revision between January 1998 and March 2014. Minimum follow-up was 24 months. Two multivariate logistic regression models were constructed to determine independent predictors for infection recurrence and persistence.

RESULTS

In total, 548 patients were identified (283 men, 265 women). Forty-eight had a recurrent infection (8.76%). Men had 54.8% lower odds of PJI recurrence than women (odds ratio [OR] = 0.452; 95% confidence interval [CI], 0.235-0.869). Patients with heart disease had 109% higher odds of infection recurrence than patients without heart disease (OR = 2.09; 95% CI, 1.097-3.081). The risk of infection recurrence was 119% higher in patients with psychiatric disorders than in patients without psychiatric disorders (OR = 2.19; 95% CI, 1.011-4.761). Patients with recurrent knee PJI had 84.6% lower odds of persistent infection (OR = 0.154; 95% CI, 0.034-0.696) compared to hip PJI. Patients with heart disease had 5-fold increased odds for persistent PJI (OR = 5.068; 95% CI, 1.38-22.56).

CONCLUSION

Female gender, heart disease, and psychiatric disorders increase the risk of hip and knee PJI recurrence. Patients with PJI of the hip and with heart disease are at higher risk of infection persistence.

Usefulness of Prosthesis Made of Antibiotic-Loaded Acrylic Cement as an Alternative Implant in Older Patients With Medical Problems and Periprosthetic Hip Infections: A 2- to 10-Year Follow-Up Study

BACKGROUND

The purpose of this study was to compare the clinical outcomes after 2-stage revision with those following single-stage revision in patients who developed periprosthetic joint infection after primary hip arthroplasty.

METHODS

Between January 2004 and January 2013, we retrospectively reviewed patients who developed periprosthetic joint infection after primary hip arthroplasty and who underwent surgery for placement of a prosthesis made of antibiotic-loaded acrylic cement (PROSTALAC). Patients were divided into 2 groups based on the stages of revision. Group A was made up of patients who had undergone 2-stage revision using PROSTALAC as an interim prosthesis. Group B was made up of patients who had been compelled to undergo single-stage revision using PROSTALAC as an alternative implant because of older age and/or medical problems. Clinical outcomes were evaluated using a visual analog scale to score pain by calculating the Harris Hip Score and by determining the patient's walking ability.

RESULTS

There were 20 patients in group A and 19 patients in group B. The mean follow-up period after final surgery was 68.8 months (range, 24-114 months). The infection resolution rate after initial PROSTALAC placement was 92.3%, and the final resolution rate was 94.9%. The visual analog scale and Harris Hip Score of group A were significantly better than those of group B. However, no significant difference in walking ability was found between the 2 groups.

CONCLUSION

Although the clinical outcomes in patients with PROSTALAC implants were not as good as those who underwent 2-stage revision, PROSTALAC can be a useful alternative implant in selected patients who are debilitated because of older age and/or who have critical medical problems.

Articulating spacers compared to fixed spacers for the treatment of infected knee arthroplasty: A follow-up of 37 cases

BACKGROUND

The standard treatment of a periprosthetic infection after TKA involves a two-stage reimplantation with the intermittent implantation of spacers. Different designs of spacers have been described; currently articulating spacers and fixed spacers are used. The aim of the present study is to compare the advantages/disadvantages of the different spacers.

PATIENTS AND METHODS

In this retrospective study we analyzed 37 cases after revision surgery of infected TKA. All patients that received spacers as part of the two-stage reimplantation were included. Exclusion criteria were massive bone loss prior to revision, because the implantation of a mobile spacer would not have been possible.

RESULTS

The average ROM was 98.0 (± 14.9) degrees in the articulating spacer group (group 1) and 79.3 (± 22.5) in the group that received the fixed spacers (group 2) before revision surgery started. At a late follow up the average ROM for group 1 was 102.0 (± 8.4) and 79.0 (± 26) for group 2.

CONCLUSION

The use of articulating spacers in the two-stage revision for infected total knee arthroplasty is a safe alternative to fixed spacers, that equally preserves ligament balancing and has equal infection eradication rates. A long term improvement of the range of motion following reimplantation of the new joint was, however, not observed.

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

Antibiotic spacer designs have proven effective at eradicating infection during a two-stage revision arthroplasty. Temporary reuse of the steam-sterilized femoral component and a new all poly tibia component has been described as an effective articulating antibiotic spacer, but sterility concerns persist. Six explanted cobalt chrome femurs from patients with grossly infected TKA's and six stock femurs inoculated with different bacterial species were confirmed to be bacteria-free after autoclaving under a standard gravity-displacement cycle. The effect of steam sterilization on cobalt chrome fragments contaminated with MRSA biofilm was analyzed microscopically to quantify remaining biofilm. The autoclave significantly reduced the biofilm burden on the cobalt chrome fragments. This study confirmed sterility of the femur after a standard gravity-displacement cycle (132°C, 27 PSIG, 10 minutes).

Two-Stage Cementless Revision Total Hip Arthroplasty for Infected Primary Hip Arthroplasties

The main purpose of the present study was to analyze the clinical features, the most common infective agents, and the results of two-stage total hip revision using a teicoplanin-impregnated spacer. Between January 2005 and July 2011, 41 patients were included. At the clinical status analysis, physical examination was performed, Harris hip score was noted, isolated microorganisms were recorded, and the radiographic evaluation was performed. The mean Harris hip score was improved from 38.9 ± 9.6 points to 81.8 ± 5.8 points (P<0.05). Infection was eradicated in 39 hips. Radiographic evidence of stability was noted in 37 acetabular revision components, and all femoral stems. Two-stage revision of the infected primary hip arthroplasty is a time-consuming but a reliable procedure with high rates of success.

Transfer of patient care during two-stage exchange for periprosthetic joint infection leads to inferior outcomes

The two-stage exchange algorithm is the gold standard for managing chronic periprosthetic joint infection (PJI); this study evaluated the impact of having the stages performed at different institutions. Patients with a chronically infected total joint arthroplasty (hip or knee) with initial resection at an outside hospital and subsequent care at our institution (transferred group) were identified then matched with a similar cohort that received both stages at our institution (continuous group). Eighteen patients (transferred group) were compared to 36 matched controls. There were significantly lower rates of successful reimplantation and retention, longer duration of treatment and more procedures in the transferred group compared to the continuous group. Patients transferred during their care for chronic PJI underwent more surgeries, longer treatment times, and less favorable outcomes.

The impact of patellar resurfacing in two-stage revision of the infected total knee arthroplasty

Evidence for optimal management of the patellofemoral joint in revision surgery for the infected TKA is limited. We reviewed 69 infected TKAs undergoing two-stage revision. Fifty four patellae were resurfaced, 11 had patelloplasty performed, two were augmented with trabecular metal, one had impaction grafting, and one knee underwent patellectomy. Average follow-up was 4.5 years. The patients that received patellar resurfacing at re-implantation experienced statistically significant improvements in KSS pain score, functional KSS, and patellar score (P < 0.03). One further patient treated with impaction grafting improved significantly in terms of pain and function. Patients treated with patelloplasty, trabecular metal augmentation, or patellectomy did not have significant improvements in clinical or functional outcome. Patient age, use of dynamic vs. static spacer, use of extensor mechanism release, and differences in Charlson index did not seem to statistically affect outcome. We recommend that every effort should be made to minimize patellar bone loss in first stage resection, as inability to resurface the patella at time of reimplantation may adversely affect patient outcome.

Two-stage revision for prosthetic joint infection: outcome and role of reimplantation microbiology in 107 cases

Two-stage revision is widely used for the treatment of prosthetic joint infections. However, the duration of antibiotic treatment between stages and role of reimplantation microbiology are controversial. The purpose of this study was to evaluate the outcome and influence of the reimplantation microbiology of two-staged revisions with 6 weeks of antibiotic treatment. We retrospectively reviewed 107 patients treated with two-stage revision between 2001 and 2009. The overall treatment success rate was 94.4%. The reimplantation cultures were positive in 5/97 (5.2%) cases, and only one of them failed. Therefore, we achieved excellent results with a 6-week course of antibiotics between stages in two-stage revision. Positive reimplantation cultures do not seem to be associated with worse outcomes.

The fate of unplanned retention of prosthetic articulating spacers for infected total hip and total knee arthroplasty

Eighteen patients with periprosthetic joint infection (11 hips and 7 knees) treated by prosthetic articulating spacers retained their spacers and were followed up at an average of 43.8 months(range, 13-78 months). Fifteen patients maintained well-functioning spacers for an average of 42.7 months, of which 4 patients died with the spacers in situ at an average of 48.7 months. The mean Harris Hip Score and Knee Society knee and function scores of survivors were 92, 92, 88, respectively. Spacers were revised in 3 patients because of recurrent infection (n = 1) at 24 months and mechanical loosening (n = 2) at 74 and 50 months. Findings of this study suggest that a proportion of patients with unplanned retention of prosthetic spacers appear to function well up to 6 years without necessarily requiring further surgical intervention.

Comparison of one-stage revision with antibiotic cement versus two-stage revision results for infected total hip arthroplasty

Eighty three patients of infected total hip arthroplasty (THA) treated by implant removal and staged revision were retrospectively analyzed. Clinical characteristics and treatment outcomes were compared between three groups: 17 one-stage revisions (one-stage group), 44 two-stage revisions with second stage reimplantation (two-stage reimplanted group), and 22 planned two-stage but no reimplantation (two-stage non-reimplanted group). The rate of infection control was 82% (14/17) in the one-stage group, 75% (33/44) in the two-stage reimplanted group, and 68% (15/22) in the two-stage non-reimplanted group (P=0.60). The mean of latest Harris hip score was 77, 60, and 58 (P=0.14), and the UCLA activity score was 4.0, 4.2, and 3.6 (P=0.74) for each group, respectively. Results of this study suggest that one-stage revision arthroplasty can be a treatment option in selected cases of infected THA with a satisfactory infection control rate and functional outcomes comparable to those of two-stage revision.

Revision in cemented and cementless infected hip arthroplasty

Infection is a frequent cause of failure after joint replacement surgery. The infection rate after total hip arthroplasty (THA) has been reduced to 1-2% in the last years. However, it still represents a challenging problem for the orthopedic surgeon.

Difficulty of therapeutic approach, and poor functional outcomes together with length of treatment and overall cost are the main burden of this issue. Even the diagnosis of an infected hip could be challenging although it is the first step of an accurate treatment. At the end, many cases require removing the implants. Afterwards, the treatment strategy varies according to authors with three different procedures: no re-implantation, immediate placement of new implants or a two-stage surgery re-implantation.

Based on the most recently systematic review there is no suggestion that one- or two-stage revision methods have different re-infection outcomes.

The two-stage implant-exchange protocol remains the gold standard. It is considered as the most efficacious clinical approach for the treatment of periprosthetic infection, especially in patients with sinus tracts, swelling, extended abscess formation in depth and infection of Methicillin Resistant Staphylococcus Aureus (MRSA), and other multidrug-resistant bacteria as reported in recent consensus documents.