Single-Stage Revision of the Infected Total Knee Arthroplasty Is Associated With Improved Functional Outcomes: A Propensity Score–Matched Cohort Study

BackgroundSingle-stage revision is an alternative to the standard 2-stage revision, potentially minimizing morbidities and improving functional outcomes. This study aimed at comparing single-stage and 2-stage revision total knee arthroplasty (TKA) for chronic periprosthetic joint infection (PJI) with regard to patient-reported outcome measures (PROMs) and complication rates.Methods:A total of 185 consecutive revision TKA patients for chronic PJI with complete preoperative and postoperative PROMs were investigated. A total of 44 patients with single-stage revision TKA were matched to 88 patients following 2-stage revision TKA using propensity score matching, yielding a total of 132 propensity score–matched patients for analysis. Patient demographics and clinical information including reinfection and readmission rates were evaluated.Results:There was no significant difference in preoperative PROMs between propensity score–matched single-stage and 2-stage revision TKA cohorts. Postoperatively, significantly higher PROMs for single-stage revision TKA were observed for Knee disability and Osteoarthritis Outcome Score physical function (62.2 vs 51.9, P < .01), physical function short form 10A (42.8 vs 38.1, P < .01), PROMIS SF Physical (44.8 vs 41.0, P = .01), and PROMIS SF Mental (50.5 vs 47.1, P = .02). There was no difference between propensity score–matched single-stage and 2-stage revision TKA cohorts for clinical outcomes including reinfection rates (25.0% vs 27.2%, P = .78) and 90-day readmission rates (22.7% vs 25.0%, P = .77).ConclusionThis study illustrated that single-stage revision TKA for chronic PJI may be associated with superior patient-reported outcomes compared to 2-stage revision for the infected TKA using a variety of PROMs. Improved PROMs were not accompanied by differences in complication rates between both cohorts, suggesting that single-stage revision TKA may provide an effective alternative to 2-stage revision in patients with chronic TKA PJI.     

Increased Postoperative Glucose Variability Is Associated With Adverse Outcome Following Two-Stage Exchange Arthroplasty for Periprosthetic Joint Infection

BackgroundGlucose variability in the postoperative period has been associated with increased rates of periprosthetic joint infection (PJI) following primary arthroplasty. It is unknown how postoperative glucose control affects outcome of surgical treatment of PJI patients. We hypothesized that postoperative glucose variability adversely affects the outcome of 2-stage exchange arthroplasty.MethodsWe retrospectively reviewed records of 665 patients with PJI of the knee and hip who underwent 2-stage exchange arthroplasty from 2000 to 2017. Of them, 341 PJIs with a minimum follow-up of 1 year, and either a minimum of 2 glucose values per day or greater than 3 overall during the reimplantation were included. Glucose variability was assessed by calculating the coefficient of variation. Adverse outcomes included treatment failure according to the Delphi consensuses criteria, reinfection, reoperation, and mortality. A subgroup analysis was performed based on patients with or without diabetes.ResultsGlucose variability following reimplantation was associated with higher treatment failure, reinfection, and reoperation. Adjusted analysis indicated that for every standard deviation (15%) increase in the coefficient of variation, the risks of treatment failure, reinfection, and reoperation increased by 27%, 31%, and 26%. Although stratifying patients with (n = 81) or without diabetes (n = 260), these associations remained robust in nondiabetic patients, but not in diabetic patients.ConclusionHigher glucose variability is associated with increased risks of treatment failure, reinfection, and reoperation after 2-stage exchange arthroplasty in PJI patients. Compared to diabetic patients, nondiabetic patients have a higher association between glucose variability and poor outcomes. Reducing adverse outcomes may be achieved with close monitoring and strict postoperative glucose control.     

Primary Total Knee Arthroplasty Implants as Functional Prosthetic Spacers for Definitive Management of Periprosthetic Joint Infection: A Multicenter Study

BackgroundThere are limited data on the utility of a standard primary total knee arthroplasty (TKA) femoral component with an all polyethylene tibia as a functional prosthetic spacer in place of a conventional all cement spacer for the management of periprosthetic joint infection (PJI). The aim of this multicenter study was to retrospectively review (1) ultimate treatment success; (2) reimplantation rates; (3) reoperation rates; and (4) change in knee range of motion in patients managed with functional prosthetic spacers following TKA PJI.MethodsA retrospective review was performed for patients at 2 tertiary care centers who underwent a functional prosthetic spacer implantation as part of a functional single-stage (n = 57) or all cement spacer conventional two-stage (n = 137) revision arthroplasty protocol over a 5-year period. Outcomes including reinfection, reimplantation, and reoperation rates, success rate as defined by the Delphi criteria, and final range of motion were compared between the 2 cohorts at a minimum of 2-year follow-up.ResultsThere was no significant difference in reinfection (14.0 vs 24.1%), reoperation (19.3 vs 27.7%), or success rates (78.9 vs 70.8%; P > .05 for all) between the one-stage and two-stage revision TKA cohorts. Mean final total arc of motion was also similar between the 2 groups (105.8 vs 101.8 degrees, respectively).ConclusionFunctional prosthetic spacers offer the advantage of a single procedure with decreased overall hospitalization and improved cost-effectiveness with analogous success rates (78.9%) compared with two-stage exchange (70.8%) at mid-term follow-up. Although long-term data are required to determine its longevity and efficacy, the outcomes in this study are encouraging.Level of Evidence3.     

Outcomes and Risk Factors Associated With 2-Stage Reimplantation Requiring an Interim Spacer Exchange for Periprosthetic Joint Infection

BackgroundPatients undergoing a 2-stage revision for periprosthetic joint infection (PJI) often require a repeat spacer in the interim due to persistent infection. This study aims to report outcomes for patients with repeat spacer exchange and to identify risk factors associated with interim spacer exchange in 2-stage revision arthroplasty.MethodsA total of 256 consecutive 2-stage revisions for chronic infection of total hip arthroplasty and total knee arthroplasty with reimplantation and minimum 2-year follow-up were investigated. An interim spacer exchange was performed in 49 patients (exchange cohort), and these patients were propensity score matched to 196 patients (nonexchange cohort). Multivariate analysis was performed to analyze risk factors for failure of interim spacer exchange.ResultsPatients in the propensity score–matched exchange cohort demonstrated a significantly increased reinfection risk compared to patients without interim spacer exchange (24% vs 15%, P = .03). Patients in the propensity score–matched exchange cohort showed significantly lower postoperative scores for 3 patient-reported outcome measures (PROMs): hip disability and osteoarthritis outcome score physical function (46.0 vs 54.9, P = .01); knee disability and osteoarthritis outcome score physical function (43.1 vs 51.7, P < .01); and patient-reported outcomes measurement information system physical function short form (41.6 vs 47.0, P = .03). Multivariate analysis demonstrated Charles Comorbidity Index (odds ratio, 1.56; P = .01) and the presence of Enterococcus species (odds ratio, 1.43; P = .03) as independent risk factors associated with 2-stage reimplantation requiring an interim spacer exchange for periprosthetic joint infection.ConclusionThis study demonstrates that patients with spacer exchange had a significantly higher risk of reinfection at 2 years of follow-up. Additionally, patients with spacer exchange demonstrated lower postoperative PROM scores and diminished improvement in multiple PROM scores after reimplantation, indicating that an interim spacer exchange in 2-stage revision is associated with worse patient outcomes.     

1.5-Stage Exchange Arthroplasty for Total Knee Arthroplasty Periprosthetic Joint Infections

BackgroundPeriprosthetic joint infection (PJI) in total knee arthroplasty (TKA) is a challenging problem. The purpose of this study was to outline a novel technique to treat TKA PJI. We define 1.5-stage exchange arthroplasty as placing an articulating spacer with the intent to last for a prolonged time.MethodsA retrospective review was performed from 2007 to 2019 to evaluate patients treated with 1.5-stage exchange arthroplasty for TKA PJI. Inclusion criteria included: articulating knee spacer(s) remaining in situ for 12 months and the patient deferring a second-stage reimplantation because the patient had acceptable function with the spacer (28 knees) or not being a surgical candidate (three knees). Thirty-one knees were included with a mean age of 63 years, mean BMI 34.4 kg/m², 12 were female, with a mean clinical follow-up of 2.7 years. Cobalt-chrome femoral and polyethylene tibial components were used. We evaluated progression to second-stage reimplantation, reinfection, and radiographic outcomes.ResultsAt a mean follow-up of 2.7 years, 25 initial spacers were in situ (81%). Five knees retained their spacer(s) for some time (mean 1.5 years) and then underwent a second-stage reimplantation; one of the five had progressive radiolucent lines but no evidence of component migration. Three knees (10%) had PJI reoccurrence. Four had progressive radiolucent lines, but there was no evidence of component migration in any knees.Conclusions1.5-stage exchange arthroplasty may be a reasonable method to treat TKA PJI. At a mean follow-up of 2.7 years, there was an acceptable rate of infection recurrence and implant durability.     

Utility of Synovial White Blood Cell Count and Differential Before Reimplantation Surgery

BackgroundDetermining optimal timing of reimplantation during 2-stage exchange for periprosthetic joint infection (PJI) remains elusive. Joint aspiration for synovial white blood cell (WBC) count and neutrophil percentage (PMN%) before reimplantation is widely performed; yet, the implications are rarely understood. Therefore, this study investigates (1) the diagnostic yield of synovial WBC count and differential analysis and (2) the calculated thresholds for persistent infection.MethodsInstitutional PJI databases identified 129 patients undergoing 2-stage exchange arthroplasty who had joint aspiration before reimplantation between February 2005 and May 2014. Persistent infection was defined as a positive aspirate culture, positive intraoperative cultures, or persistent symptoms of PJI—including subsequent PJI-related surgery. Receiver-operating characteristic curve was used to calculate thresholds maximizing sensitivity and specificity.ResultsThirty-three cases (33 of 129; 25.6%) were classified with persistent PJI. Compared with infection-free patients, these patients had significantly elevated PMN% (62.2% vs 48.9%; P = .03) and WBC count (1804 vs 954 cells/μL; P = .04). The receiver-operating characteristic curve provided thresholds of 62% and 640 cells/μL for synovial PMN% and WBC count, respectively. These thresholds provided sensitivity of 63% and 54.5% and specificity of 62% and 60.0%, respectively. The risk of persistent PJI for patients with PMN% >90% was 46.7% (7 of 15).ConclusionSynovial fluid analysis before reimplantation has unclear utility. Although statistically significant elevations in synovial WBC count and PMN% are observed for patients with persistent PJI, this did not translate into useful thresholds with clinical importance. However, with little other guidance regarding the timing of reimplantation, severely elevated WBC count and differential analysis may be of use.     

Randomized Trial of Static and Articulating Spacers for Treatment of the Infected Total Hip Arthroplasty

BackgroundThe purpose of this randomized clinical trial is to compare perioperative and postoperative variables between static and articulating spacers for the treatment of chronic periprosthetic joint infection (PJI) complicating total hip arthroplasty (THA).MethodsFifty-two patients undergoing resection arthroplasty as part of a 2-stage exchange for PJI at 3 centers were randomized to either a static (n = 23) or articulating spacer (n = 29). The primary endpoint was operative time of the second-stage reimplantation and power analysis determined that 22 patients per cohort were necessary to detect a 20-minute difference. Seven patients were lost to follow-up, 4 were never reimplanted, and one died before discharge after reimplantation. Forty patients were followed for a mean 3.2 years (range 2.0-7.1).ResultsThere were no differences in operative time at second-stage reimplantation (143 minutes static vs 145 minutes articulating, P = .499). Length of hospital stay was longer in the static cohort after stage 1 (8.6 vs 5.4 days, P = .006) and stage 2 (6.3 vs 3.6 days, P < .001). Although it did not reach statistical significance with the numbers available for study, nearly twice as many patients in the static cohort were discharged to an extended care facility after stage 1 (65% vs 30%, P = .056).ConclusionThis randomized trial demonstrated that the outcomes of static and articulating spacers are similar in the treatment of THA PJI undergoing 2-stage exchange arthroplasty. The significantly longer length of hospital stay associated with the use of static spacers may have important economic implications for the health care system.     

Morbid Obesity Is a Risk Factor for Infection Recurrence Following Debridement,Antibiotics, and Implant Retention for Periprosthetic Joint Infection

BackgroundAlthough morbid obesity is an established risk factor for periprosthetic joint infection following total hip arthroplasty and total knee arthroplasty, little is known regarding the infection control rate of this cohort following debridement, antibiotics, and implant retention (DAIR). The purpose of this study is to investigate the infection control rate following DAIR in a morbidly obese patient cohort compared to a nonobese patient cohort and discern the relationship between time from diagnosis to treatment and risk of DAIR failure.MethodsResults of all DAIR procedures were retrospectively reviewed across 4 institutions. Those with a body mass index of at least 40 kg/m² were matched 2:1 on the basis of patient age, sex, date of surgery, and presence of staphylococcal species in culture to a cohort of patients with body mass index of <30 kg/m². Demographic variables were collected for each patient. Kaplan-Meier survivorship curves were constructed and multivariable Cox regression was performed for analysis.ResultsThe morbidly obese group experienced a higher treatment failure rate (57.9%) compared to the nonobese group (36.8%; P = .035). Morbid obesity and major depressive disorder/generalized anxiety disorder diagnosis significantly increased the risk of failure, with hazard ratios of 1.82 and 2.09, respectively. Morbidly obese patients who received DAIR within 48 hours of symptom presentation did not face an increased risk of reinfection compared to nonobese patients.ConclusionOur findings suggest morbidly obese patients face an increased risk of DAIR failure; however, this risk can be mitigated if DAIR is received within 48 hours of symptom onset.     

Short Course of Oral Antibiotic Treatment After Two-Stage Exchange Arthroplasty Appears to Decrease Early Reinfection

BackgroundRecent evidence has suggested a benefit to extended postoperative prophylactic oral antibiotics after two-stage exchange arthroplasty for treatment of periprosthetic joint infections. We sought to determine reinfection rates with and without a short course of oral antibiotics after two-stage exchange procedures.MethodsA retrospective review identified patients undergoing two-stage exchange arthroplasty for periprosthetic joint infection of the hip or knee. Patients were excluded if they failed a prior two-stage exchange, had positive cultures at reimplantation, prolonged intravenous antibiotics postoperatively, and/or life-long suppression. This resulted in 444 reimplantations (210 hips and 234 knees). Patients were divided into three cohorts based on the duration of oral antibiotics after reimplantation: no antibiotics (102), ≤2 weeks (266), or >2 weeks (76). The primary endpoint was reinfection within 1 year of reimplantation.ResultsWithin 1 year of reimplantation, there were 34 reinfections. In the no-antibiotic, ≤ 2-week, and >2-week cohorts the reinfection rates were 14.1, 7.0, and 6.4%, respectively. Multivariate Cox regression showed a reduced reinfection rate in the ≤2-week cohort relative to no antibiotics (hazard ratio [HR]: 0.38, P = .01). While the smaller cohort with >2 weeks of antibiotics did not significantly reduce the reinfection rate (HR: 0.41, P = .12), when combined with the ≤2-week cohort, use of oral antibiotics had an overall reduction of the reinfection rate (HR: 0.39, P = .01).ConclusionsThese data support the hypothesis that a short course of oral antibiotics after reimplantation decreases the 1-year reinfection rate. Future randomized studies should seek to examine the efficacy of different durations of oral antibiotics to reduce reinfection.Level of EvidencePrognostic Level IV.     

TKA is More Durable Than UKA for Morbidly Obese Patients: A Two-Year Minimum Follow-Up Study

BackgroundUnicompartmental knee arthroplasty (UKA) indications have expanded during the past two decades to include some morbidly obese patients (body mass index (BMI) > 40 kg/m²). Few published studies have compared UKA and total knee arthroplasty (TKA) in this unique patient subgroup with conflicting observations.MethodsWe retrospectively compared 89 mobile bearing UKA (71 patients) and 201 TKA (175 patients) performed at a single institution with a minimum 2-year follow-up (mean 3.4 years). Demographic characteristics were similar for both patient cohorts. A detailed medical record review was performed to assess the frequency of component revision, revision indications, minor secondary procedures (components retained), and infections.ResultsUKA was more frequently associated with clinical failure (29.2% vs 2.5%, P < .001) and component revision (15.7% vs 2.5%, P < .001), TKA was more frequently associated with extensor mechanism complications or knee manipulation (5.5% vs 0.0%, P = .02), and there was no difference in the infection rate (3.0% vs 2.2%, P = 1.0).ConclusionEarly complications were lower following UKA but were outweighed by higher component revision rates for arthritis progression and implant failure. The study findings suggest that TKA provides a more predictable mid-term outcome for morbidly obese patients considering knee arthroplasty surgery.     

Time to Reimplantation: Waiting Longer Confers No Added Benefit

Background

While the preferred surgical treatment for chronic periprosthetic joint infection (PJI) in North America is a 2-stage exchange arthroplasty, the optimal time between first-stage and reimplantation surgery remains unknown. This study was conceived to examine the association between time to reimplantation and treatment failure.

Does Time to Reimplantation After Explant for Prosthetic Joint Infection Influence the Likelihood of Successful Outcomes at 2 Years?

BackgroundConsensus recommendations are lacking regarding appropriate timing of reimplantation following 2-stage resection arthroplasty for prosthetic joint infections (PJIs). We investigated whether the time from resection arthroplasty to reimplantation was associated with treatment outcome at 2 years.MethodsRetrospective cohort review was conducted for 101 patients undergoing resection arthroplasty with an antibiotic spacer for PJI at a single tertiary academic referral institution. Time from explantation and spacer placement to reimplantation was categorized into 3 groups: <12, 12-18, and >18 weeks. Baseline patient and treatment course characteristics across these groups were obtained. Multivariate binary logistic regression was used to characterize association between treatment failure and time to reimplantation, controlling for American Society of Anesthesiologists (ASA) score and prior revision surgery.ResultsTime to reimplantation (TTR) >18 weeks demonstrated statistically significant increased odds of treatment failure, after controlling for ASA score and prior revision surgery (odds ratio 7.00, confidence interval 2.14-25.42, P = .002). After excluding patients requiring second spacer or Girdlestone prior to replant, this increased odds of failure remained (odds ratio 4.12, confidence interval 1.18-15.37, P = .029). TTR groups were similar with respect to demographics, except for ASA (2.96 for time to reimplantation >18 weeks vs 2.55 for time to reimplantation <12 weeks; P = .011). Patients with TTR >18 weeks were more likely to have an unplanned readmission during the spacer period (48%, 19%, and 6% for time to reimplantation >18, 12-18, and 0-12 weeks, respectively; P < .002).ConclusionAlthough decision regarding TTR is largely patient specific, surgeons should be aware that TTR >18 weeks may be associated with higher rates of treatment failure at 2 years.     

Irrigation,Débridement,and Implant Retention for Recurrence of Periprosthetic Joint Infection Following Two-Stage Revision Total Knee Arthroplasty: A Matched Cohort Study

BackgroundWe investigated clinical/functional outcomes and implant survivorship in patients who underwent 2-stage revision total knee arthroplasty (TKA) after periprosthetic joint infection (PJI), experienced acute PJI recurrence, and underwent irrigation, débridement, and polyethylene exchange (IDPE) with retention of stable implant.MethodsTwenty-four patients (24 knees) were identified who underwent 2-stage revision TKA for PJI, experienced acute PJI recurrence, and then underwent IDPE between 2005 and 2016 (minimum 2-year follow-up). After IDPE, intravenous antibiotics (6 weeks) and oral suppression therapy (minimum 6 months) were administered. Data were compared with 1:2 matched control group that underwent 2-stage revision TKA for chronic PJI and did not receive IDPE.ResultsAverage IDPE group follow-up was 3.8 years (range, 2.4-7.2). Reinfection rate after IDPE was 29% (n = 7): 3 of 7 underwent second IDPE (2 of 3 had no infection recurrence) and 5 (one was patient who had recurrent infection after second IDPE) underwent another 2-stage revision TKA. Control group reinfection rate was 27% (n = 13) (P = .85). For IDPE group, mean time to reinfection after 2-stage revision TKA was 4.6 months (range, 1-8 months) (patients presented with acute symptoms less than 3 weeks duration). At latest follow-up, mean Knee Society Score was 70 (range, 35-85) in IDPE group and 75 (range, 30-85) in control group (P = .53).ConclusionIDPE for acute reinfection following 2-stage revision TKA with well-fixed implants had a 71% success rate. These patients had comparable functional outcome as patients with no IDPE after 2-stage revision TKA. IDPE followed by long-term suppression antibiotic therapy should be considered in patients with acute infection and stable components.     

Do Positive Cultures at Second Stage Re-Implantation Increase the Risk for Reinfection in Two-Stage Exchange for Periprosthetic Joint Infection?

BackgroundIntraoperative cultures are important in the diagnosis and targeted treatment of periprosthetic joint infection (PJI). Positive cultures at reimplantation during a two-stage exchange are discussed as a risk factor for reinfection. The aim of this study is the investigation of the incidence and risk factors for positive cultures during reimplantation.MethodsWe retrospectively identified 204 patients (111 knees, 93 hips) who were treated between 2012 and 2016 for PJI using a two-stage exchange protocol at a median follow-up of 42 months. PJI was diagnosed using the criteria of the musculoskeletal infection society (MSIS) of 2011. All cultural findings from first and second stage surgery were recorded. The primary endpoint was revision for infection. Risk factors for positive cultures and reinfection were analyzed.ResultsDuring reimplantation 25% (51/204) of patients had at least one positive culture, in 19.1% (39/204) only a single culture. Patients with culture-negative infections had a higher risk for positive cultures at reimplantation (HR 2.946 (95% CI 1.247-6.961), P = .014) and patients with infected total hip arthroplasty (THA) (HR 3.547 (95% CI 1.7-7.4), P = .001). Patients with positive cultures during reimplantation had a higher risk for reinfection (HR 2.27 (95% CI 1.181-4.363), P = .014) as well as patients with a single positive culture (HR 2.421 (95% CI 1.139-5.143), P = .021).ConclusionAs positive cultures are common and increase reinfection risk irrespective of their numbers, longer antibiotic therapy following reimplantation can be an option. Single positive cultures in reimplantation surgery should not be considered contamination.     

Surgical Treatment of Chronic Periprosthetic Joint Infection: Fate of Spacer Exchanges

BackgroundPatients with periprosthetic joint infection (PJI) undergoing 2-stage exchange arthroplasty may undergo an interim spacer exchange for a variety of reasons including mechanical failure of spacer or persistence of infection. The objective of this study is to understand the risk factors and outcomes of patients who undergo spacer exchange during the course of a planned 2-stage exchange arthroplasty.MethodsOur institutional database was used to identify 533 patients who underwent a 2-stage exchange arthroplasty for PJI, including 90 patients with a spacer exchange, from 2000 to 2017. A retrospective review was performed to extract relevant clinical information. Treatment outcomes included (1) progression to reimplantation and (2) treatment success as defined by a Delphi-based criterion. Both univariate and multivariate Cox regression models were performed to investigate whether spacer exchange was associated with failure. Additionally, a propensity score analysis was performed based on a 1:2 match.ResultsA spacer exchange was required in 16.9%. Patients who underwent spacer exchanges had a higher body mass index (P < .001), rheumatoid arthritis (P = .018), and were more likely to have PJI caused by resistant (0.048) and polymicrobial organisms (P = .007). Patients undergoing a spacer exchange demonstrated lower survivorship and an increased risk of failure in the multivariate and propensity score matched analysis compared to patients who did not require a spacer exchange.DiscussionDespite an additional load of local antibiotics and repeat debridement, patients who underwent a spacer exchange demonstrated poor outcomes, including failure to undergo reimplantation and twice the failure rate. The findings of this study may need to be borne in mind when managing patients who require spacer exchange.     

Treatment Outcomes and Attrition in Gram-Negative Periprosthetic Joint Infection

BackgroundWhile the prevailing belief is that periprosthetic joint infection (PJI) caused by Gram-negative (GN) organisms confers a poorer prognosis than Gram-positive (GP) cases, the current literature is sparse and inconsistent. The purpose of this study is to compare the treatment outcomes for GN PJI vs GP PJI and Gram-mixed (GM) PJI.MethodsA retrospective review of 1189 PJI cases between 2007 and 2017 was performed using our institutional PJI database. Treatment failure defined by international consensus criteria was compared between PJI caused by GN organisms (n = 45), GP organisms (n = 663), and GM (n = 28) cases. Multivariate regression was used to predict time to failure.ResultsGM status, but not GN, had significantly higher rates of treatment failure compared to GP PJI (67.9% vs 33.2% failure; hazards ratio [HR] = 2.243, P = .004) in the multivariate analysis. In a subanalysis of only the 2-stage exchange procedures, both GN and GM cases were significantly less likely to reach reimplantation than GP cases (HR = .344, P < .0001; HR = .404, P = .013).ConclusionAlthough there was no observed difference in the overall international consensus failure rates between GN (31.1% failure) and GP (33.2%) PJI cases, there was significant attrition in the 2-stage exchange GN cohort, and these patients were significantly less likely to reach reimplantation. Our findings corroborate the prevailing notion that GN PJI is associated with poorer overall outcomes vs GP PJI. These data add to the current body of literature, which may currently underestimate the overall failure rates of GN PJI treated via 2-stage exchange and fail to identify pre-reimplantation morbidity.     

Characterizing Femoral and Acetabular Bone Loss in Two-Stage Revision Total Hip Arthroplasty for Infection

BackgroundThe process of infection and multiple procedure-related factors in 2-stage exchange arthroplasty may lead to severe bone loss that can complicate subsequent reimplantation. The primary purpose of this study is to quantitatively characterize the extent of bone loss on the femoral and acetabular side prior to reimplantation during 2-stage revision hip arthroplasty for infection.MethodsThis retrospective case series includes 47 patients with planned 2-stage exchange arthroplasty for treatment of infected total hip replacement. Demographic, clinical, and surgical information, and complications during the 2-stage process were collected on all patients. The radiographs of all patients were reviewed prior to first-stage explantation and post-reimplantation or latest follow-up to characterize bone loss using the Paprosky classification systems.ResultsOf the 47 patients with planned 2-stage exchange, 10 patients (21%) were not reimplanted. Following explant and spacer placement, 32 patients (68%) experienced progressive femoral bone loss, and 20 (43%) experienced progressive acetabular bone loss. Patients who experienced progression of both femoral and acetabular bone (14, 30%) had a longer time between resection and reimplantation (164 ± 128 vs 88 ± 26 days, P = .03). A reimplantation time of greater than 90 days was associated with an increased risk of combined bone loss progression (15% vs 53%, P = .01). For patients who underwent reimplantation (79%), increased bone loss led to high rates of diaphyseal femoral fixation (97%) and revision acetabular components (38%).ConclusionIncreased time to reimplantation in 2-stage exchange arthroplasty for prosthetic hip infections is associated with a high rate of acetabular and femoral bone loss, and increased complexity of reimplantation.     

Two-Stage Exchange Arthroplasty for Periprosthetic Joint Infection: The Rate and Reason for the Attrition After the First Stage

BackgroundTwo-stage exchange arthroplasty remains a popular surgical treatment for patients with chronic periprosthetic joint infection (PJI). Patients who do not receive reimplantation were largely overlooked in the current literature. We aimed at investigating the clinical outcomes of these patients.MethodsOur institutional PJI database was retrospectively reviewed to identify 616 patients (237 hips, 379 knees) who were treated with an intended 2-stage exchange. Of them, 111 (18%) did not receive reimplantation within a minimum follow-up of 1 year. Chart review and targeted interviews were performed to elucidate the cause of attrition. Patients were considered to have failed treatment in the absence of reimplantation if they remained medically unfit for reimplantation, underwent a salvage procedure, or died during the study period.ResultsOf the 111 patients without reimplantation, 29 (26.1%) did well with their retained spacer and were unwilling to proceed with reimplantation, 23 (20.7%) underwent salvage procedures, and the remaining 59 (53.2%) were considered medically unfit for reimplantation, with 34 of them dying within 1 year of initial spacer insertion. The overall success rate for 2-stage exchange cohort at 2 years was 65.7% when treatment failure without reimplantation was taken into account. Several factors associated with increased risk of treatment failure without reimplantation were identified using a multivariate regression model.ConclusionAlmost 1 in 5 patients may never receive the intended reimplantation. Among many reasons for attrition, mortality appears to be a relatively common event. The current definition of treatment success does not take into account the attrition group and thus inflates the relative success of 2-stage exchange arthroplasty.     

Ninety-Day Costs,Reoperations, and Readmissions for Primary Total Hip Arthroplasty Patients of Varying Body Mass Index Levels

Background

The purpose of this study is to compare 90-day costs and outcomes for primary total hip arthroplasty patients between a nonobese (body mass index, 18.5-24.9) vs overweight (25-29.9), obese (30-34.9), severely obese (35-39.9), morbidly obese (40-44.9), and super obese (45+) cohorts.

Do Extended Oral Postoperative Antibiotics Prevent Early Periprosthetic Joint Infection in Morbidly Obese Patients Undergoing Primary Total Joint Arthroplasty?

BackgroundExtended oral antibiotic prophylaxis after primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) in patients with body mass index (BMI) ≥40 kg/m² may reduce the rate of early periprosthetic joint infection (PJI); however, existing data are limited. The purpose of this study was to examine rates of wound complications and PJI in patients with BMI ≥40 kg/m² treated with and without extended oral antibiotic prophylaxis after surgery.MethodsWe retrospectively identified all primary THA and TKA performed since 2015 in patients with a BMI ≥40 kg/m² at a single institution. Extended oral antibiotic prophylaxis for 7-14 days after surgery was prescribed at the discretion of each surgeon. Wound complications and PJI were examined at 90 days postoperatively.ResultsIn total, 650 cases (205 THA and 445 TKA) were analyzed. Mean age was 58 years and 62% were women. Mean BMI was 44 kg/m². Extended oral antibiotic prophylaxis was prescribed in 177 cases (27%). At 90 days, there was no difference between prophylaxis and nonprophylaxis groups in rate of wound complications (11% vs 8%; P = .41) or PJI (1.7% vs 0.6%; P = .35). The univariate analysis demonstrated increased operative time (odds ratio (OR) 1.01; 95% confidence interval (95% CI) 1.01-1.02) and diabetes mellitus (OR 1.88; 95% CI 1.03-3.46) to be associated with increased risk of 90-day wound complications. No patient factors were associated with increased risk of PJI at 90 days postoperatively.ConclusionExtended oral antibiotic prophylaxis after primary THA and TKA did not reduce rates of wound complications or early PJI in a morbidly obese patient population.