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.     

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.     

Two-Stage Revision Total Hip Arthroplasty With a Specific Articulating Antibiotic Spacer Design: Reliable Periprosthetic Joint Infection Eradication and Functional Improvement

Background

Two-stage revision utilizing spacers loaded with high-dose antibiotic cement prior to reimplantation remains the gold standard for treatment of periprosthetic joint infections (PJI) in total hip arthroplasty (THA) in North America, but there is a paucity of data on mid-term outcomes. We sought to analyze the survivorship free of infection, clinical outcomes, and complications of a specific articulating spacer utilized during 2-stage revision.

Survival and Outcomes of 1.5-Stage vs 2-Stage Exchange Total Knee Arthroplasty Following Prosthetic Joint Infection

BackgroundTraditional management of prosthetic joint infection following total knee arthroplasty (TKA) consists of a 2-stage approach. However, 1.5-stage exchange has seen preliminary success, whereby metal femoral and all-polyethylene tibia components are placed without intention for subsequent second stage. We sought to examine all patients who underwent a 1.5-stage exchange TKA at a single institution compared to historical 2-stage controls. We assessed the following: (1) infection-free survivorship and risk factors for reinfection; (2) 1-year surgical/medical outcomes; (3) patient-reported outcomes (ie, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS JR]); and (4) radiographic outcomes.MethodsWe reviewed all patients undergoing a 1.5-stage (between 2015 and 2019) and 2-stage exchange TKA (between 2011 and 2016) at a single institution. A total of 162 knees were included (1.5-stage: 114; 2-stage: 48) with mean clinical follow-up of 2.6 years. KOOS JR scores and radiographic outcomes were evaluated at last clinical follow-up.ResultsThe 1.5-stage exchange TKA resulted in a 10.1% difference in infection-free survival (85.1% vs 75.0%, P = .158), compared to 2-stage exchange. Prior prosthetic joint infection was found to be an independent risk factor for reinfection (P = .030). Overall, postoperative complications were lower among 1.5-stage exchanges (8.8% vs 31.3%, P < .001). KOOS JR scores improved more from baseline among 1.5-staged (Δ24.7 vs Δ16.6, P < .001). Radiographic review did not demonstrate any progressive radiolucent lines, subsidences, or failures in either group.ConclusionA 1.5-stage exchange TKA is an effective alternative to the traditional 2-stage protocols with noninferior infection eradication and absence of radiographic complications at over 2 years of mean follow-up.     

Partial 2-Stage Exchange for Infected Total Hip Arthroplasty: An Updated Report

BackgroundManagement of an infected total hip arthroplasty (THA) is challenging. The eradication of infection as well as complications of component removal must all be considered. This study is an update on previous reports of treating periprosthetic infection of the hip with a partial 2-stage exchange with retention of the femoral component.MethodsA retrospective review of our practice’s arthroplasty registry from 2000 to 2018 revealed 41 hips with 2-year minimum follow-up that were treated with a 2-stage partial exchange for an infected THA. All first-stage procedures allowed an articulating construct with 1 of 3 variations: cemented constrained liner (13 hips), StageOne Hip Cement Spacer Mold (14 hips), or an antibiotic polymethylmethacrylate head molded from a bulb syringe (14 hips). Of 41 cases, 34 were culture positive, with 3 cases having methicillin-resistant Staphylococcus.ResultsMean follow-up was 5.5 years (range, 1.5-18.5 years). The second-stage reimplantation was accomplished in 39 of the 41 hips (95%) at a mean interval of 9.2 weeks (range, 5-9 weeks). Two patients underwent repeat radical debridement with removal of all components before reimplantation for persistent clinical evidence of infection. Thirty-three of the 41 hips (81%) were infection free at most recent follow-up. The mean postoperative Harris hip score at most recent evaluation was 63.6 (range, 24-100).ConclusionEradication of periprosthetic joint infections, while minimizing patient morbidity, continues to be a challenge. Partial 2-stage exchange may be considered in cases where removal of a well-fixed femoral component may result in significant bony destruction.     

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.     

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.     

High Rate of Positive Cultures in Patients Referred With Antibiotic Spacers as Part of 2-Stage Exchange

Background

Two-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains the gold standard treatment in North America. Occasionally, patients with knee PJI are referred for definitive management after resection and antibiotic spacer placement. Currently, little literature exists to suggest how these patients should be managed. The purpose of this study is to report the clinical outcomes of these patients.

A Permanent Articulating Spacer Versus Two-Stage Exchange for Chronic Periprosthetic Joint Infection: A Propensity Score-Matched Study

BackgroundAlthough 2-stage revision has been proposed as gold standard for periprosthetic joint infection treatment, limited evidence exists for the role of articulating spacers as definitive management. The purpose of this study was to compare clinical outcomes and costs associated with articulating spacers (1.5-stage) and a matched 2-stage cohort.MethodsA retrospective review was performed for patients who had chronic periprosthetic joint infections after total knee arthroplasty defined by Musculoskeletal Infection Society criteria and were matched via propensity score matching using cumulative Musculoskeletal Infection Society scores and a comorbidity index. Patients who maintained an articulating spacer (cemented cobalt-chrome femoral component and all-poly tibia) were included in the 1.5-stage cohort. Patients who underwent a 2-stage reimplantation procedure were included in the 2-stage cohort. Outcomes included visual analog scale pain scores, 90-day emergency department visits, 90-day readmission, unplanned reoperation, reinfection, as well as cost at 1 and 2-year intervals. A total of 116 patients were included for analyses.ResultsThe 90-day pain scores were lower in the 1.5-stage cohort compared to the 2-stage cohort (2.9 versus 4.6, P = .0001). There were no significant differences between readmission and reoperation rates. Infection clearance was equivalent at 79.3% for both groups. Two-stage exchange demonstrated an increased cost difference of $26,346 compared to 1.5-stage through 2 years (P = .0001). Regression analyses found 2 culture-positive results with the same organism decreased the risk for reinfection [odds ratio: 0.2, 95% confidence interval 0.04-0.8, P = .03].ConclusionFor high-risk candidates, articulating spacers can preserve knee function, reduce morbidity from second-stage surgery, and lower the costs with similar rates of infection clearance as 2-stage exchange.Level of EvidenceLevel III, therapeutic study.     

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.     

Vancomycin-Gentamicin Prefabricated Spacers in 2-Stage Revision Arthroplasty for Chronic Hip and Knee Periprosthetic Joint Infection: Insights Into Reimplantation Microbiology and Outcomes

BackgroundSecond-stage positive cultures in 2-stage revision arthroplasty are a matter of concern, as their influence in outcomes is not clearly defined. We sought to study reimplantation microbiology when using vancomycin-gentamicin prefabricated cement spacers in hip and knee periprosthetic joint infection. The associations of second-stage positive cultures with treatment failures and patient-associated factors were analyzed.MethodsWe conducted a retrospective cohort study, examining patients managed with 2-stage revision arthroplasty due to knee or hip chronic periprosthetic joint infection between 2010 and 2017. Prefabricated vancomycin-gentamicin cement spacers were used during the spacer stage. Intraoperative microbiological culture results after the first and second stages were evaluated. The primary end point was infection eradication or relapse.ResultsA total of 108 cases were included (61 hips and 47 knees). And 22.2% of patients had ≥1 second-stage positive culture, while 9.3% had ≥2 positive samples. Overall success, at an average follow-up of 46.4 months, was 77.8%. Treatment failure was higher among cases with positive cultures (15.5% vs 45.8%, P < .01) regardless of the number of positive samples. Diabetes was identified as a risk factor for second-stage positive cultures (P = .03); use of cement loaded with extra antibiotics for spacer fixation showed a protective effect (P < .01).ConclusionSecond-stage positive cultures were related to a higher failure rate when using vancomycin-gentamicin cement spacers. Diabetes increased the likelihood of second-stage positive cultures. The use of extra-antibiotic-loaded cement for spacer fixation during the first stage showed a protective effect.     

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 Following Total Hip or Knee Arthroplasty Is Associated With High Attrition Rate and Mortality

BackgroundWe sought to determine the ultimate fate of patients undergoing resection arthroplasty as a first stage in the process of 2-stage exchange and evaluate risk factors for modes of failure.MethodsA retrospective case study was performed including all patients with minimum 2-year follow-up who underwent first-stage resection of a hip or knee periprosthetic joint infection from 2008 to 2015. Patient demographics, laboratory, and health status variables were collected. The primary outcome analyzed was defined as failure to achieve an infection-free 2-stage revision. Univariate pairwise comparison followed by multivariate regression analysis was used to determine risk factors for failure outcomes.ResultsEighty-nine patients underwent resection arthroplasty in a planned 2-stage exchange protocol (27 hips, 62 knees). Mean age was 64 years (range, 43-84), 56.2% were males, and mean follow-up was 56.3 months. Also, 68.5% (61/89) of patients underwent second-stage revision. Of the 61 patients who complete a 2-stage protocol, 14.8% (9/61) of patients failed with diagnosis of repeat or recurrent infection. Mortality rate was 23.6%. Multivariate analysis identified risk factors for failure to achieve an infection-free 2-stage revision as polymicrobial infection (P < .004; adjusted odds ratio [AOR], 7.8; 95% confidence interval [CI], 2.1-29.0), McPherson extremity grade 3 (P < .024; AOR, 4.1; 95% CI, 1.2-14.3), and history of prior resection (P < .013; AOR, 4.7; 95% CI, 1.4-16.4).ConclusionPatients undergoing resection arthroplasty for periprosthetic joint infection are at high risk of death (24%) and failure to complete the 2-stage protocol (32%). Those who complete the 2-stage protocol have a 15% rate of reinfection at 4.5-year follow-up.     

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

BackgroundAlthough 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.MethodsThe 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.ResultsA 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).ConclusionAlthough 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.     

Patients With Failed Prior Two-Stage Exchange Have Poor Outcomes After Further Surgical Intervention

Background

Failure of 2-stage exchange arthroplasty for the management of periprosthetic joint infection (PJI) poses a major clinical challenge. There is a paucity of information regarding the outcomes of further surgical intervention in these patients. Thus, we aim to report the clinical outcomes of subsequent surgery for a failed prior 2-stage exchange arthroplasty.

Risk Factors for Treatment Failure in Patients Who Have Knee Periprosthetic Joint Infection Treated With Two-Stage Exchange Arthroplasty as Well as Their Fate

BackgroundTwo-stage exchange arthroplasty is considered the gold standard treatment for chronic periprosthetic joint infection (PJI). However, there is a scarcity of research investigating the major risk factors for infection recurrence and the prognosis after infection recurrence.MethodsThis study included 203 patients who underwent 2-stage exchange arthroplasty between June 22, 2010 and January 24, 2017. The need of reoperation for infection-related or PJI-related mortality was considered treatment failure. Participant age, gender, body mass index, comorbidities, culture results, length of hospital stay, cause of treatment failure, operative procedure, and fate were analyzed.ResultsFifty-three patients experienced treatment failure (26.1%). Mean follow-up was 63 months (range, 26-103). Based on the multivariate analyses, risk factors for treatment failure included men and positive intraoperative culture during reimplantation. Recurrent infection was most commonly caused by Staphylococcus aureus (32.1%, 17/53), and new microorganisms caused recurrent infection in 34 of 53 (64.2%) patients. In 44 patients who had treatment failure, debridement, antibiotic therapy, irrigation, and retention of prosthesis (DAIR) performed within 6 months of reimplantation and at <3 weeks from symptom onset resulted in a significantly higher success rate than the use of other DAIR protocols (P = .031).ConclusionMen and positive intraoperative culture are major risk factors for 2-stage exchange arthroplasty failure in patients who have knee PJI. Recurrent infection in these patients is usually caused by new microorganisms. DAIR within 6 months of reimplantation and at <3 weeks from symptom onset results in good outcomes in these patients.     

Greater Knee Soft Tissue Thickness Predisposes Patients to Subsequent Periprosthetic Joint Infection After Total Knee Arthroplasty

BackgroundAlthough obesity is a risk factor for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA), the role of soft tissue thickness (STT) at the surgical site has not been well studied. This study examined if increased STT in the medial and anterior aspects of the knee are independent risk factors for PJI.MethodsA retrospective study was conducted on 206 patients who underwent 2-stage exchange arthroplasty for PJI from 2000 to 2015. They were matched 1:3 to a control group of primary, noninfected TKA patients with minimum 2 years infection-free survival by age, gender, age-adjusted Charlson Comorbidity Index, date of surgery, and body mass index (BMI). Two blinded orthopedic surgeons measured the medial STT from the medial aspect of the knee at the level of the joint line on an anteroposterior radiograph, and anterior STT 8 cm above the joint line on a lateral radiograph from the skin to the quadriceps tendon.ResultsIncreased STT was significantly associated with a higher risk for PJI. The mean anterior STT was 29.74 ± 13.76 mm in the PJI group and 24.88 ± 9.76 mm in the control group. The mean medial STT was 42.42 ± 14.66 mm for PJI and 37.27 ± 12.51 mm for control. Both STT measurements were significantly higher in PJI cases with BMI <30 kg/m² vs control patients with BMI <30 kg/m².ConclusionAnterior and medial knee STT was an independent risk factor for PJI after primary TKA and represents a simple radiographic method to assess postoperative infection risk. Excess adipose tissue around the surgical site can predispose patients to PJI after TKA regardless of BMI.     

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.     

Defining Treatment Success After 2-Stage Exchange Arthroplasty for Periprosthetic Joint Infection

Background

Two-stage exchange arthroplasty remains the preferred surgical treatment method for patients with chronic periprosthetic joint infection (PJI). The success of this procedure is not known exactly as various definitions of success have been used. This study aimed at analyzing the difference in outcome following 2-stage exchange arthroplasty using different definitions for success.

Cumulative Intraarticular Injections Are Not a Risk Factor for Periprosthetic Joint Infection Following total Knee Arthroplasty

BackgroundWhile injections within 90 days prior to total knee arthroplasty (TKA) are associated with an increased risk of periprosthetic joint infection (PJI), there is a paucity of literature regarding the impact of cumulative injections on PJI risk. This study was conducted to assess the association between cumulative corticosteroid and hyaluronic acid (HA) injections and PJI risk following TKA.MethodsThis retrospective study using an injection database included patients undergoing TKA with a minimum 1-year follow-up from 2015 to 2020. Patients with injections within 90 days prior to surgery were excluded. The sum of corticosteroid and HA injections within five years prior to TKA was recorded. The primary outcome was PJI within 90 days following TKA. Area under the curve (AUC) values were calculated for a cumulative number of injections.Results648 knees with no injections and 672 knees with injections prior to TKA were included, among whom 243 received corticosteroids, 151 received HA, and 278 received both. No significant differences in early PJI rates existed between patients who received injections (0.60%) or not (0.93%) (P = .541). No significant differences existed in early PJI rates between patients injected with corticosteroids (0.82%), HA (0.66%), or both (0.36%) (P = .832). No cutoff number of injections was predictive for PJI.DiscussionA cumulative amount of steroid or HA injections, if given more than 90 days prior to TKA, does not appear to increase the risk of PJI within 90 days postoperatively. Multiple intraarticular corticosteroid injections and HA injections may be safely administered before TKA, without increased risk for early PJI.