Risk Factors for Repeat Debridement, Spacer Retention, Amputation, Arthrodesis, and Mortality After Removal of an Infected Total Knee Arthroplasty With Spacer Placement

Prosthetic spacers in two-stage revision for knee periprosthetic joint infection achieve better function and similar infection control

Aims

To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI).

Methods

A retrospective cohort study of 50 chronic kPJI patients treated with two types of articulating spacers between January 2014 and March 2022 was conducted. The clinical outcomes and functional status of the different articulating spacers were compared. Overall, 17 patients were treated with prosthetic spacers (prosthetic group (PG)), and 33 patients were treated with cement spacers (cement group (CG)). The CG had a longer mean follow-up period (46.67 months (SD 26.61)) than the PG (24.82 months (SD 16.46); p = 0.001).

Results

Infection was eradicated in 45 patients overall (90%). The PG had a better knee range of motion (ROM) and Knee Society Score (KSS) after the first-stage revision (p = 0.004; p = 0.002), while both groups had similar ROMs and KSSs at the last follow-up (p = 0.136; p = 0.895). The KSS in the CG was significantly better at the last follow-up (p = 0.013), while a larger percentage (10 in 17, 58.82%) of patients in the PG chose to retain the spacer (p = 0.008).

Conclusion

Prosthetic spacers and cement spacers are both effective at treating chronic kPJI because they encourage infection control, and the former improved knee function status between stages. For some patients, prosthetic spacers may not require reimplantation.

Outcomes of Antibiotic-Impregnated Calcium Sulfate, Reamer-Irrigator-Aspirator, and Locked Intramedullary Static Spacer in the Treatment of Periprosthetic Joint Infection in the Multiply Revised and Infected Knee: A Single-Center Case Series

Background

Periprosthetic joint infection after total knee arthroplasty is commonly treated via 2-stage revision utilizing either articulating or static antibiotic cement spacers. While recent literature exhibits a slight functional advantage in favor of articulating spacers, those patients with a history of recurrent infection/multiple revision procedures are frequently excluded from these studies. The purpose of this study was to report infection eradication rates and efficacy of utilizing antibiotic-loaded locked intramedullary nail for infection for the multiply revised, infected total knee arthroplasty.

Methods

A retrospective review was performed of all consecutive patients receiving static spacers between 2017 and 2020 at an academic medical center. Surgical techniques for all patients included irrigation and debridement using a reamer-irrigator-aspirator, injection of antibiotic-loaded calcium sulfate into the intramedullary canal, and nail placement. Antibiotic-loaded cement is then used to create a spacer block in the joint space. A Cox proportional hazard regression was run to identify risk factors for reinfection.

Results

Forty-two knees in 39 patients were identified meeting inclusion criteria. Overall, there was an 68.8% infection eradication rate at an average of 46.9 months following spacer placement. The only risk factors identified on cox regression were increasing number of previous spacers, a surrogate for previous infections (hazards ratio = 14.818, P value = .021), and increasing operative time during spacer placement (hazards ratio = 1.014, P value = .039).

Conclusions

Use of static spacers, in conjunction with reamer-irrigator-aspirator and antibiotic-loaded calcium sulfate, can be effective in treating chronic, complex periprosthetic joint infections in the setting of bone loss and or soft-tissue compromise and produced similar results to more simple infection scenarios.

Recurrent Periprosthetic Joint Infections: Diagnosis, Management, and Outcomes

Periprosthetic joint infection (PJI) remains one of the most common complications after total joint arthroplasty. It is challenging to manage, associated with significant morbidity and mortality, and is a financial burden on the health care system. Failure of 2-stage management for chronic PJI is not uncommon. Repeat infections are oftentimes polymicrobial, multiple drug-resistant microorganisms, or new organisms. Optimizing the success of index 2-stage revision is the greatest prevention against failure of any subsequent management options and requires a robust team-based approach.

Inferior Outcomes for Patients Transferred Between Surgical Stages for Knee Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infection (PJI) in total knee arthroplasty may result in 2-stage revision surgery. There are limited data describing outcomes when the first stage is completed at an outside hospital and the patient is referred to a tertiary center. We hypothesized that patients have greater success when both surgeries occur at a single center.

METHODS

There were 25 knee PJI patients who presented with an antibiotic spacer and had a minimum 2-year follow-up who were retrospectively identified at a single tertiary referral center from 2014 to 2021. A cohort matched for age, sex, body mass index, Elixhauser comorbidity measure, spacer type, infectious organism, and year of surgery was established with patients who had both stages completed at the investigating institution. Modified Delphi success criteria of no subsequent surgery or reinfection with any species were compared.

RESULTS

The transferred group demonstrated a treatment success of 40% compared to 84% in the continuous group (P < .01). The transferred group was more likely to have an additional procedure between stages (44 versus 8%, P < .01), with a higher number of surgeries after primary total knee arthroplasty (4.8 versus 3.0, P < .01), between stages (1.4 versus 0.2, P < .01), and after second stage (0.8 versus 0.2, P = .03). The transferred group had longer durations between stages (20.1 versus 7.0 weeks, P < .01).

CONCLUSION

Patients who have PJIs transferred between stages demonstrated higher treatment failure. Surgeons should consider transfer early with a goal of continuous management by a single institution.

Debridement, antimicrobials, and implant retention in the treatment of late acute and early acute Staphylococcus aureus prosthetic joint infections

BACKGROUND

Staphylococcus aureus is the most common microbe in prosthetic joint infections (PJIs). Debridement, antimicrobials, and implant retention (DAIR) are often-recommended treatment modality for acute PJIs, even though it has had relatively poor outcomes in some studies. In this study, we wanted to examine treatment results with a multidisciplinary team in a specialised centre and obtain further information for treatment decisions in acute Staphylococcus aureus PJIs.

METHODS

All consecutive haematogenous late acute and postoperative early acute hip and knee Staphylococcus aureus PJIs treated with DAIR during 2011-2016 were included in this retrospective study. DAIR within three weeks from symptom onset and the exchange of modular parts were required.

RESULTS

Eighty-five acute Staphylococcus aureus PJIs were treated with DAIR in 83 patients: 28 late acute and 57 early acute PJIs. The late acute PJI patients were older and had malignancies more often than the early acute PJI patients. Bacteraemia was present in 50.6% of Staphylococcus aureus PJI patients, more often in late acute (73.1%) than in early acute (40.4%) patients (p = .006). The implant was retained in 80.0%: 89.3% of the late acute and 75.4% of the early acute PJIs. In 17 joints, DAIR failed and the joint had to be removed. Fourteen of these joints were successfully replaced. One infection-related death occurred. The one-year all-cause mortality rate was 3.6%. Suppressive antimicrobial treatment was given to 22 (26.5%) patients.

CONCLUSIONS

Reasonably good treatment results for acute Staphylococcus aureus PJIs are achievable by DAIR in a specialised centre with a strict treatment protocol and a multidisciplinary team. If the DAIR fails, a two-stage exchange is usually still possible, with good results.

Does Treatment at a Specialized Prosthetic Joint Infection Center Improve the Rate of Reimplantation

INTRODUCTION

Two-Stage exchange arthroplasty is currently the preferred treatment method for periprosthetic joint infection (PJI). The effectiveness of this strategy in returning patients to premorbid function has recently been challenged. In a review of 18, 535 PJI knee patients, 38% did not undergo reimplantation (17). In another review of 18,156 hip and knee PJI patients, 43% did not undergo reimplantation (16). These disturbing statistics led us to ask whether treatment at a specialized prosthetic joint infection center could improve the rate of reimplantation compared to the previously noted studies from large national administrative databases.

METHODS

A retrospective review of our registry was performed to identify 390 patients who underwent a two-stage exchange after total knee arthroplasty (TKA) and total hip arthroplasty (THA) who had a confirmed chronic bacterial PJI, defined by Musculoskeletal Infection Society (MSIS) criteria, from January 2010 through December 2019. Variables included number of joints resected, number replanted, and the number not replanted.

RESULTS

Of the 390 patients undergoing 2-stage treatment, 386 of 390 (99%) were reimplanted and 4of 390 (1%) were not replanted due to medical issues.

CONCLUSION

We have shown that 2-stage treatment at a PJI Center significantly improves the rate of reimplantation. A specialized Prosthetic Joint Infection Center with experienced revision surgeons doing high volume infection procedures, complemented by infectious disease and medical consultants familiar with the special needs of PJI patients may be advantageous. A national network of such centers may have the ability to improve outcomes, standardize treatment protocols, and allow for collaborative research.

How do pre-operative intra-articular injections impact periprosthetic joint infection risk following primary total hip arthroplasty? A systematic review and meta-analysis

INTRODUCTION

Although intra-articular injections (IAIs) serve as the first-line non-surgical management for severe osteoarthritis (OA), recent analyses have suggested they are associated with an increased infection risk following primary total hip arthroplasty (THA). Therefore, our systematic review and meta-analysis explored the relationship between IAIs and periprosthetic joint infection (PJI) following THA reported in the current literature.

METHODS

Five online databases were queried for analyses published from January 1st, 2000-May 1st, 2021 reporting on PJI rates between patients undergoing primary THA who did and did not preoperatively receive an IAI. The overall pooled effect of injection status on PJI incidence was determined using Mantel-Haenszel (M-H) models. This was similarly conducted for segregated preoperative intervals: 0-3 months, > 3-6 months, > 6 + months.

RESULTS

A total of 11 articles were included in our analysis reporting on 278,782 THAs (IAI: n = 41,138; no IAI: n = 237,644). Patients receiving pre-operative injections had a significantly higher risk of PJI (OR: 1.31, 95% CI 1.07-1.62; p = 0.009). However, this finding was not robust. IAI receipt within 3-months of THA was associated with significantly higher PJI rates (OR: 1.68, 95% CI 1.48-1.90; p < 0.001). However, no significant difference was demonstrated in the > 3-6 month (OR: 1.19, 95% CI 0.94-1.52; p = 0.16) and > 6 + month sub-analyses (OR: 1.20, 95% CI 0.96-1.50; p = 0.11). The results of all sub-analyses remained were robust.

DISCUSSION

Our findings suggest that patients requiring THA should wait at least 3-months following IAI to reduce post-operative infection risk. This information can help inform patients considering OA management options, as well as adult reconstruction surgeons during preoperative optimization.

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

BACKGROUND

Two-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.

METHODS

This 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.

RESULTS

Fifty-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).

CONCLUSION

Men 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.

Increased short- and long-term mortality amongst patients with early periprosthetic knee joint infection

BACKGROUND

Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a severe complication in terms of disability, morbidity, and cost. We performed a study to investigate whether early PJI (within 90 days of primary TKA) is associated with increased mortality. Secondary aims were to compare mortality rates over time and between surgical treatment methods.

METHODS

Patients with suspected PJI were identified by linkage of the Swedish Knee Arthroplasty Register (SKAR) and the Swedish Prescribed Drug Register (SPDR) in 2007-2008 and 2012-2013. Medical records of patients receiving more than 4 weeks of continuous antibiotic therapy were subsequently reviewed to verify the PJI diagnosis. Information on mortality was obtained through the SKAR which is updated daily from the tax agency and patients with PJI were compared to patients without PJI.

RESULTS

Four hundred sixty-six patients were diagnosed with PJI within 90 days and compared to 40,362 patients without PJI. Mortality rates were significantly higher for PJI patients in both short- and long term: 2.6% vs. 0.8% at 1 year, 4.9% vs. 1.9% at 2 years, 15.7% vs. 7.1% at 5 years, and 38% vs. 21.4% at 10 years. The difference in mortality rate remained after adjusting for sex, age, diagnosis, and time period for surgery with Hazard Ratio 1.8 (95% CI:1.6-2.1). Mortality rates did not differ between time periods, and we found no correlation to surgical treatment.

CONCLUSION

Patients with early PJI after primary TKA have an increased mortality rate compared to TKA patients without PJI. Improvements in surgical treatment strategy has not resulted in better survival. Long term difference in mortality rates indicates that PJI is not the sole reason for mortality suggesting a general frailty in PJI patients.

Effects of Knee Debridement with Flurbiprofen on Knee Function, Inflammatory Levels, and Bone Metabolism Activity in Patients with Knee Osteoarthritis

Objective

The objective of this study is to explore the effects of knee debridement with flurbiprofen on the knee function, inflammatory levels, and bone metabolism activity in patients with knee osteoarthritis.

Methods

110 patients with knee osteoarthritis who underwent arthroscopic debridement in our hospital from 2020.01 to 2022.01 were selected for retrospective analysis. Based on whether or not flurbiprofen was used in combination during the perioperative phase, the patients were divided into the control group (only arthroscopic debridement of the knee) and the research group (flurbiprofen with arthroscopic debridement of the knee), with 55 cases in each group. The indexes such as knee function, inflammatory levels, and bone metabolism activity of the two groups were analyzed.

Results

According to hospital for special surgery (HSS) evaluation for knee function, most patients in the control group were assessed as “moderate,” while patients in the research group were mainly focused on “excellent” and “good,” and their excellent and good rates were remarkably higher than those in the control group (P < 0.05). There were no significant variations in bone metabolism indices such as osteoprotegerin levels (OPG), insulin-like growth factor-1 (IGF-1), β-isomerized C-terminal telopeptide (β-CTX), and receptor activator of nuclear factor-κB ligand (RANKL) before treatment between both groups (P > 0.05), with higher OPG, IGF-1 levels, and remarkably lower β-CTX, RANKL levels in the research group than those in the control group after treatment (P < 0.05). There were no remarkable differences in pain between both groups before treatment (P > 0.05), while at 24 h and 48 h after surgery, the VAS scores in the research group were remarkably lower than those in the control group (P < 0.05). In terms of inflammatory factors, the levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) in the research group were remarkably lower than those in the control group after treatment (P < 0.05).

Conclusion

Arthroscopy coupled with flurbiprofen provides a good analgesic effect in the therapeutic treatment of patients with knee osteoarthritis, which contributes to the recovery of knee function with definite results. Its mechanism may be associated with the control of inflammatory response and the regulation of bone metabolism disorder.

Failure analysis of articulating polymethyl methacrylate spacers in two-stage revision total hip arthroplasty

Aims

Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors.

Methods

We retrospectively included 125 patients with chronic hip PJI who underwent a staged THA revision performed between January 2013 and December 2019. All spacer complications were systematically collected, and risk factors were analyzed. Statistical evaluations were performed using the Student's t-test, Mann-Whitney U test, and Fisher's exact test.

Results

Our staged exchange practice shows poor results, which means a 42% mechanical spacer failure rate, and a 20% recurrent infection rate over the two years average follow-up period. Moreover, we found a high rate of spacer dislocation (23%) and a low rate of spacer fracture (8%) compared to the previous literature. Our findings stress that the majority of spacer complications and failures is reflecting a population with high comorbid burden, highlighted by the American Society of Anesthesiology grade, Charlson Comorbidity Index, and Lee score associations, as well as the cardiac, pulmonary, kidney, or hepatic chronic conditions.

Conclusion

Our experience of a two-stage hip exchange revision noted important complication rates associated with high failure rates of polymethylmethacrylate spacers. These findings must be interpreted in the light of the patient’s comorbidity profiles, as the elective population for staged exchange has an increasing comorbid burden leading to poor results. In order to provide better results for this specific population, our conclusion suggests that comparative strategy studies are required to improve our therapeutic indication.

Cite this article: Bone Jt Open 2022;3(6):485–494.

Poor Outcome of Above-Knee Amputation after Septic Failure of Revision Total Knee Arthroplasty

Persistent periprosthetic infection following total knee arthroplasty is one of the most dreaded complications of orthopaedic surgery. Treatment strategies include arthrodesis of the knee joint, stable fistula, long-lasting antibiotic therapy, or above-knee amputation. The advantage of amputation in comparison to other treatment options is the possible cure of infection, because the source of infection is removed and no foreign material left in situ. The aim of the study is to examine whether a septic amputation of the femur in case of persistent periprosthetic infection at the knee joint leads to the healing of the patient. Moreover, the physical and mental state should be evaluated. All patients with above-knee amputation because of periprosthetic joint infection after primary total knee arthroplasty between 2016 and 2018 were included in this retrospective study. A questionnaire with the clinical scores visual analog scale, modified Lysholm, Western Ontario and McMaster Universities Osteoarthritis Index and 36-Item Short Form Survey has been designed. In addition, all characteristics and perioperative data were documented. Eleven patients were included in the study. One patient died after above-knee amputation; all other patients live with a marked impairment of quality of life but with absence of the infection of the leg. Two out of ten are able to walk regularly with an exoprosthesis with forearm crutches, 50% are in a wheelchair, while 30% are bedridden. Patients with above-knee amputation after persistent periprosthetic infections were free of infection and without signs of inflammation. However, this is associated with worse mobility and high mortality rate.

In-hospital Mortality after Septic Revision TKA: Analysis of the New York and Florida State Inpatient Databases

The aims of this study were to investigate (1) in-hospital mortality rates following septic revision total knee arthroplasty (rTKA); (2) compare septic rTKA mortality rates between differing knee revision volume (KRV) hospitals; and (3) identify independent risk factors associated with in-hospital mortality after septic rTKA (up to 2-year follow-up). The Healthcare Cost and Utilization Project State Inpatient Databases of New York and Florida were used to identify septic rTKA, and control groups of aseptic rTKA and primary TKA between 2007 and 2012 via International Classification of Diseases, Ninth Revision codes. Mortality was compared between septic rTKA and aseptic rTKA/primary TKA control groups. Hospital KRV was stratified, and independent risk factors of in-hospital mortality were identified and analyzed using unadjusted and adjusted logistic regression analyses. In this study, 3,531 septic rTKA patients were identified; 105 (3%) patients suffered in-hospital mortality, compared with the control aseptic rTKA (n = 178; 1.7%; p < 0.0001) and primary TKA groups (n = 930; 0.6%; p < 0.0001). Being an octogenarian (adjusted odds ratio [AOR]: 2.361; 95% confidence interval [CI]: 1.514-3.683; p < 0.0002) and having a medium- or high-Elixhauser comorbidity score was associated with in-hospital mortality (AOR: 2.073; 95% CI: 1.334-3.223; p = 0.0012, and AOR: 4.127; 95% CI: 2.268-7.512, p < 0.0001). There were no significant in-hospital mortality rate differences in high- versus medium- versus low-KRV hospitals (1.9 vs. 3.6 vs. 2.9%, respectively, p = 0.0558). Age >81 years and higher comorbidity burden were found to contribute to increased risk of 2-year postoperative mortality after septic rTKA. This association could not be established for hospital KRV.

Primary and Revision Total Knee Arthroplasty in Patients With Pulmonary Hypertension: High Perioperative Mortality and Complications

BACKGROUND

Although perioperative medical management during total knee arthroplasty (TKA) has improved, there is limited literature characterizing outcomes of patients with pulmonary hypertension (HTN). This study examined mortality, medical complications, implant survivorship, and clinical outcomes in this medically complex cohort.

METHODS

We identified 887 patients with pulmonary HTN who underwent 881 primary TKAs and 228 revision TKAs from 2000 to 2016 at a tertiary care center. Patients were followed up at regular intervals until death, revision surgery, or last clinical follow-up. Perioperative medical complications were individually reviewed. The risk of death was examined by calculating standardized mortality ratios and Cox proportional hazards regression models. Cumulative incidence analysis was used for reporting mortality, revision, and reoperation with death as a competing risk.

RESULTS

The 90-day mortality was 0.7% and 4.8% for primary and revision TKAs, respectively. The risk of death was 2-fold higher compared to primary (hazard ratio 2.54, 95% confidence interval [CI] 2.12-3.05) and revision (hazard ratio 2.16, 95% CI 1.78-2.62) TKA patients without pulmonary HTN. Rate of medical complications within 90 days from surgery was 6.5% and 14% in primary and revision TKAs. The 10-year cumulative incidence of any revision was 5% and 16% in primaries and revisions, respectively.

CONCLUSION

Patients with pulmonary HTN undergoing primary and revision TKAs had excess risk of death and experience a high rate of medical complications within 90 days of surgery. Counseling of risks, medical optimization, and referral to tertiary centers should be considered.

LEVEL OF EVIDENCE

Level IV.

Current Insights in the Evaluation and Treatment of Infected Total Knee Arthroplasty

Total knee arthroplasty is a widely successful procedure, but a small percentage of patients have a postoperative course complicated by periprosthetic joint infection (PJI). PJI is a difficult problem to diagnose and to treat, and the management of PJI differs, depending on the acuity of the infection. This paper discusses the established and newer technologies developed for the diagnosis of PJI as well as different treatment considerations and surgical solutions currently available.

Modular knee arthrodesis secures limb, mobility, improves quality of life, and leads to high infection control in periprosthetic knee infection, when revision knee arthroplasty is not an option

INTRODUCTION

This study compared the outcome of knee arthrodesis versus hinged total knee arthroplasty (TKA) in patients suffering from periprosthetic joint infection (PJI).

METHODS

104 patients with PJI were treated using a two-stage exchange of failed TKA. In case of non reconstructable bone loss or loss of extension mechanism, a modular intramedullary arthrodesis nail was used for reimplantation [Knee Arthrodesis Module (KAM); n = 52]. The control group was retrospectively matched treated using a hinged revision TKA [Rotating Hinge Knee (RHK); n = 52]. PJI remission rates, functional outcome (WOMAC; KSS) and quality of life (SF-12), as well as comorbidities and pain were evaluated.

RESULTS

Mean age was 72.5 years. Charlson Comorbidity Index was higher in the KAM group (3.3 vs. 2.8). PJI remission rate was 89.4% (88.5% vs. 90.4%, respectively). In case of reinfection, implant retention was mostly possible in the RHK group (7.7%), whereas amputations were mostly performed in the KAM group (9.6%). Significant pain reduction (VAS 7.9-2.8) was achieved in both groups. Walking distance was significantly reduced in the KAM groups versus the RHK group (504 vs. 1064 m). WOMAC and KSS function scores were significantly reduced in the KAM group (25 vs. 40 and 35 vs. 64). Only moderate reduction in quality of life in the KAM group was observed (SF-12 physical: 34 vs. 40; SF-12 mental: 51 vs. 56) respectively.

CONCLUSIONS

Arthrodesis using a modular intramedullary nail is an alternative for limb salvage, pain reduction, and preservation of quality of life and everyday mobility, when revision TKA is not an option. This study presents the largest number of case, comparing the outcome after performing an arthrodesis versus hinged TKA after septic failed TKA.

Systematic review of risk prediction studies in bone and joint infection: are modifiable prognostic factors useful in predicting recurrence?

Background: Classification systems for orthopaedic infection include patient health status, but there is no consensus about which comorbidities affect prognosis. Modifiable factors including substance use, glycaemic control, malnutrition and obesity may predict post-operative recovery from infection. Aim: This systematic review aimed (1) to critically appraise clinical prediction models for individual prognosis following surgical treatment for orthopaedic infection where an implant is not retained; (2) to understand the usefulness of modifiable prognostic factors for predicting treatment success. Methods: EMBASE and MEDLINE databases were searched for clinical prediction and prognostic studies in adults with orthopaedic infections. Infection recurrence or re-infection after at least 6 months was the primary outcome. The estimated odds ratios for the primary outcome in participants with modifiable prognostic factors were extracted and the direction of the effect reported. Results: Thirty-five retrospective prognostic cohort studies of 92 693 patients were included, of which two reported clinical prediction models. No studies were at low risk of bias, and no externally validated prediction models were identified. Most focused on prosthetic joint infection. A positive association was reported between body mass index and infection recurrence in 19 of 22 studies, similarly in 8 of 14 studies reporting smoking history and 3 of 4 studies reporting alcohol intake. Glycaemic control and malnutrition were rarely considered. Conclusion: Modifiable aspects of patient health appear to predict outcomes after surgery for orthopaedic infection. There is a need to understand which factors may have a causal effect. Development and validation of clinical prediction models that include participant health status will facilitate treatment decisions for orthopaedic infections.

Inflation-Adjusted Medicare Reimbursement for Revision Hip Arthroplasty: Study Showing Significant Decrease from 2002 to 2019

BACKGROUND

Investigations into reimbursement trends for primary and revision arthroplasty procedures have demonstrated a steady decline over the past several years. Revision total hip arthroplasty (rTHA) due to infection (rTHA-I) has been associated with higher resource utilization and complexity, but long-term inflation-adjusted data have yet to be compared between rTHA-I and rTHA due to aseptic complications (rTHA-A). The present study was performed to analyze temporal reimbursement trends regarding rTHA-I procedures compared with those for rTHA-A procedures.

METHODS

The Centers for Medicare & Medicaid Services (CMS) Physician Fee Schedule Look-Up Tool was used to extract Medicare reimbursements associated with 1-stage and 2-stage rTHA-I as well as 1-stage rTHA-A procedures from 2002 to 2019. Current Procedural Terminology (CPT) codes for rTHA were grouped according to the American Academy of Orthopaedic Surgeons coding reference guide. Monetary values were adjusted for inflation using the consumer price index (U.S. Bureau of Labor Statistics; reported as 2019 U.S. dollars) and used to calculate the cumulative and average annual percent changes in reimbursement.

RESULTS

Following inflation adjustment, the physician fee reimbursement for rTHA-A decreased by a mean [and standard deviation] of 27.26% ± 3.57% (from $2,209.11 in 2002 to $1,603.20 in 2019) for femoral component revision, 27.41% ± 3.57% (from $2,130.55 to $1,542.91) for acetabular component revision, and 27.50% ± 2.56% (from $2,775.53 to $2,007.61) for both-component revision. Similarly, for a 2-stage rTHA-I, the mean reimbursement declined by 18.74% ± 3.87% (from $2,063.36 in 2002 to $1,673.36 in 2019) and 24.45% ± 3.69% (from $2,328.79 to $1,755.45) for the explantation and reimplantation stages, respectively. The total decline in physician fee reimbursement for rTHA-I ($1,020.64 ± $233.72) was significantly greater than that for rTHA-A ($580.72 ± $107.22; p < 0.00001).

CONCLUSIONS

Our study demonstrated a consistent devaluation of both rTHA-I and rTHA-A procedures from 2002 to 2019, with a larger deficit seen for rTHA-I. A continuation of this trend could create substantial disincentives for physicians to perform such procedures and limit access to care at the population level.

LEVEL OF EVIDENCE

Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

Is the Proportion of Patients with "Successful" Outcomes After Two-stage Revision for Prosthetic Joint Infection Different When Applying the Musculoskeletal Infection Society Outcome Reporting Tool Compared with the Delphi-based Consensus Criteria?

BACKGROUND

There are a variety of criteria for defining successful treatment after two-stage exchange arthroplasty for prosthetic joint infection (PJI). To accurately assess current practices and improve techniques, it is important to first establish reliable, clinically relevant, reproducible criteria for defining persistent infection and "successful" outcomes.

QUESTION/PURPOSE

Is the proportion of patients considered to have successful management of PJI after two-stage resection arthroplasty smaller using 2019 Musculoskeletal Infection Society Outcome Reporting Tool (MSIS ORT) criteria than when using a Delphi-based criterion?

METHODS

Patients were retrospectively identified by Current Procedural Technology codes for resection arthroplasty with placement of an antibiotic spacer for infected THA or TKA between April 1, 2011 and January 1, 2018 at a tertiary academic institution. The initial review identified 180 procedures during this time period. Nine patients had documented transition of care outside the system, 16 did not meet the MSIS criteria for chronic PJI, and 34 patients were excluded for lack of documented 2-year follow-up. The mean follow-up duration of the final cohort of 121 procedures in 120 patients was approximately 3.7 ± 1.7 years. Forty percent (49 of 121) of the procedures were performed on the hip and 60% (72 of 121) were performed on the knee. The mean time from primary THA or TKA to explantation was 4.6 years. The mean age of the patients at the time of explantation was 66 years. The mean time from spacer placement to replantation was 119 days. The final 121 patient records were reviewed by a single reviewer and outcomes were subsequently assigned to "successful" and "unsuccessful" outcomes based on the MSIS ORT and Delphi-based consensus criterion, two previously published and validated multidimensional definition schemes. Chi-squared and t-test analyses were performed to identify differences between "successful" and "unsuccessful" outcomes with respect to patient baseline characteristics using each outcome-reporting criterion.

RESULTS

Overall, the MSIS ORT classified a smaller proportion of patients as having a "successful" treatment outcome after two-stage exchange arthroplasty for PJI than the Delphi-based consensus method did (MSIS: 55% [63 of 114], Delphi: 70% [71 of 102]; relative risk 0.79 [0.65-0.98]; p = 0.03). However, there were no differences when stratified by hips (MSIS: 55% [26 of 47], Delphi: 74% [29 of 39]; relative risk 0.74 [0.54-1.02]; p = 0.07) and knees (MSIS: 55% [37 of 67], Delphi: 67% [42 of 63]; relative risk 0.83 [0.63-1.09]; p = 0.19). Notably, the disease of 16% of the patients (19 of 121) was not classifiable per the Delphi method because these patients never underwent reimplantation.

CONCLUSION

The present study demonstrated that the MSIS criteria detect fewer instances of "successful" infection management after two-stage resection arthroplasty for PJI than the Delphi method in this cohort. Based on these findings, researchers and surgeons should aim for standardized reporting after intervention for PJI to allow for a better comparison of outcomes across different studies and ultimately allow for improved techniques and approaches to the treatment of PJI.

LEVEL OF EVIDENCE

Level III, diagnostic study.

A comparison of short term complication rate between 44 two- and 385 one-stage septic exchange arthroplasties in chronic periprosthetic joint infections

BACKGROUND

Periprosthetic joint infection is a serious disease with severe consequences for the patient's life. It is not known whether one-stage or two-stage replacement arthroplasty is superior. So far, there have been no studies on short-term complications between both surgical procedures. Therefore, we performed a retrospective study aiming to determine: 1) Does two-stage septic exchange arthroplasty have a higher short-term complication rate than one-stage? 2) Is there a difference in length of hospital stay and the in-hospital mortality rate between two- and one-stage septic exchange arthroplasty?

HYPOTHESIS

Two-stage septic exchange arthroplasty has a higher short-term complication rate than one-stage.

PATIENTS AND METHODS

Retrospectively 429 patients who underwent a one- or two stage revision arthroplasty (288 hips and 141 knees) due to chronic PJI between January 2015 and December 2016 were recruited (one-stage: n=385, two-stage: n=44). Differences in postoperative complications, surgical therapy, ASA, Charlson Comorbidity Index (CCI), length of hospital, need for plastic surgery, pathogen, in-hospital morbidity and in-hospital mortality were compared using multiple logistic and Poisson regression. Regarding comorbidities, age, gender and BMI the groups were comparable.

RESULTS

It was 3.5 times more likely to suffer from a medical complication if a two stage septic exchange was performed (OR 3.465, (95% CI: 2.573-4.358) [p<0.01]). In medical complications the two-stage group showed significantly more events (two-stage: 9 of 44=20.5%; one-stage: 30 of 385=7.8% [p=0.013]). The one-stage group showed more (not significant) nerve palsies after hip septic exchange. There was no difference in mortality between the groups (two-stage: 1/44=2.3%; one-stage: 3/385=0.8% [p=0.882]), the overall mortality was 0.93%. The duration of hospital stay was 23.9±19 days for the one-stage and 42.2±17.7 days for the two-stage group (p<0.001).

CONCLUSION

We found that it is more likely to develop a medical complication after two-stage septic revision arthroplasty. There was no difference in overall surgical complications between the two surgical approaches. We did not find a significant difference in short term mortality between the two techniques, although the mortality rate was slightly higher in the two-stage group.

LEVEL OF EVIDENCE

III, retrospective case control study.

Complications in the treatment of prosthetic joint infection

AIMS

Two-stage exchange arthroplasty is the most common definitive treatment for prosthetic joint infection (PJI) in the USA. Complications that occur during treatment are often not considered. The purpose of this study was to analyze complications in patients undergoing two-stage exchange for infected total knee arthroplasty (TKA) and determine when they occur.

METHODS

We analyzed all patients that underwent two-stage exchange arthroplasty for treatment of PJI of the knee from January 2010 to December 2018 at a single institution. We categorized complications as medical versus surgical. The intervals for complications were divided into: interstage; early post-reimplantation (three months); and late post-reimplantation (three months to minimum one year). Minimum follow-up was one year. In total, 134 patients underwent a first stage of a two-stage exchange. There were 69 males and 65 females with an mean age at first stage surgery of 67 years (37 to 89). Success was based on the new Musculoskeletal Infection Society (MSIS) definition of success reporting.

RESULTS

Overall, 70 (52%) patients experienced a complication during the planned two-stage treatment, 36 patients (27%) experienced a medical complication and 47 (41%) patients experienced a surgical complication. There was an 18% mortality rate (24/134) at a mean of 3.7 years (0.09 to 8.3). During the inter-stage period, 28% (37/134) of patients experienced a total of 50 complications at a median of 47 days (interquartile range (IQR) 18 to 139). Of these 50 complications, 22 were medical and 28 required surgery. During this inter-stage period, four patients died (3%) and an additional five patients (4%) failed to progress to the second stage. While 93% of patients (125/134) were reimplanted, only 56% (77/134) of the patients were successfully treated without antibiotic suppression (36%, 28/77) or with antibiotic suppression (19%, 15/77) at one year.

CONCLUSION

Reported rates of success of two stage exchanges for PJI have not traditionally considered complications in the definition of success. In our series, significant numbers of patients experienced complications, more often after reimplantation, highlighting the morbidity of this method of treatment. Cite this article: Bone Joint J 2020;102-B(6 Supple A):145-150.

Is Treatment of Periprosthetic Joint Infection Improving Over Time?

BACKGROUND

It is unknown whether the outcomes of treatment for periprosthetic joint infection (PJI) are improving with time. This study evaluated trends in PJI treatment outcomes in the hip and knee following 2-stage exchange arthroplasty and irrigation and debridement (I&D) over the last 17 years.

METHODS

We reviewed 550 two-stage exchange arthroplasties and 194 I&Ds between 2000 and 2016 at our institution. Treatment success was defined according to the Delphi consensus criteria and Kaplan-Meier survivorship curves were generated. A multivariate Cox proportional hazards regression model was generated to determine time trends in the outcome of PJI treatment with the year of surgery included as both a continuous covariate (per 1-year increase) and a categorical covariate (2000-2010 or 2011-2016).

RESULTS

The survivorship of I&D, 2-stage revision, and the total combined cohort were comparable between 2000-2010 and 2011-2016 groups. Multivariate Cox regression analysis showed that the year of surgery was not associated with treatment failure following an I&D or 2-stage exchange arthroplasty, and neither did it increase the risk of non-reimplantation. When year of surgery was considered as a categorical variable, there remained no significant difference in treatment failure following an I&D or 2-stage exchange arthroplasty between the 2000-2010 cohort and 2011-2016 cohort.

CONCLUSION

Despite the increasing clinical focus, research advances, and growing literature relating to PJI, we were unable to detect any substantial improvement in the treatment success rates of PJI at our institution over the 17 years examined in this study. Novel treatments and techniques are certainly needed as current and prior strategies remain far from optimal.

Longitudinal Model of Periprosthetic Joint Infection in the Rat

The majority of periprosthetic joint infections occur shortly after primary joint replacement (<3 months) and require the removal of all implant components for the treatment period (~4 months). A clinically relevant animal model of periprosthetic infection should, therefore, establish an infection with implant components in place. Here, we describe a joint replacement model in the rat with ultrahigh molecular weight polyethylene (UHMWPE) and titanium components inoculated at the time of surgery by methicillin-sensitive Staphylococcus aureus (S. aureus), which is one of the main causative microorganisms of periprosthetic joint infections. We monitored the animals for 4 weeks by measuring gait, weight-bearing symmetry, von Frey testing, and micro-CT as our primary endpoint analyses. We also assessed the infection ex vivo using colony counts on the implant surfaces and histology of the surrounding tissues. The results confirmed the presence of a local infection for 4 weeks with osteolysis, loosening of the implants, and clinical infection indicators such as redness, swelling, and increased temperature. The utility of specific gait analysis parameters, especially temporal symmetry, hindlimb duty factor imbalance, and phase dispersion was identified in this model for assessing the longitudinal progression of the infection, and these metrics correlated with weight-bearing asymmetry. We propose to use this model to study the efficacy of using different local delivery regimens of antimicrobials on addressing periprosthetic joint infections. Statement of clinical significance: We have established a preclinical joint surgery model, in which postoperative recovery can be monitored over a multi-week course by assessing gait, weight-bearing, and allodynia. This model can be used to study the efficacy of different combinations of implant materials and medication regimens. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1101-1112, 2020.

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

BACKGROUND

Glucose 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.

METHODS

We 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.

RESULTS

Glucose 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.

CONCLUSION

Higher 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.

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

BACKGROUND

Two-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.

METHODS

Our 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.

RESULTS

Of 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.

CONCLUSION

Almost 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.

Higher failure rate of two-stage revision for infected knee arthroplasties in significantly compromised (host-C) patients

PURPOSE

To evaluate clinical outcomes of two-stage revision arthroplasty for managing infected knee arthroplasties in significantly compromised patients (host-C).

METHODS

This was a prospective consecutive series of two-stage revisions of infected total knee arthroplasties in host-C-type patients with a minimum 2-year follow-up using objective and patient-reported outcome measures. Thirteen consecutive patients were included and prospectively followed with a median 5-year follow-up (range 2-10). Median age was 68 years (range 59-73) at time of initial presentation. All patients were type-C host using McPherson classification system. All patients had primary arthroplasties in situ with confirmed chronic infections; the infecting pathogens were Staphylococcus aureus in 5/13 patients, coagulase-negative Staphylococci in 5/13, and the remaining three patients had mixed growth. All patients underwent two-stage revision protocol.

RESULTS

At the final follow-up, 9/13 patients were infection free achieving satisfactory outcomes. Two patients had recurrent infections with different organisms and treated with suppressive antibiotics and salvage knee arthrodesis, respectively. Furthermore, two patients had chronic pain and poor functional outcomes with deficient extensor mechanism and significant bone loss; later underwent salvage knee arthrodesis. The preoperative knee society score (median 35.5; range 22-51; n = 10) showed a statistically significant improvement at the final follow-up (median 79.5; range 49-87; n = 10) p < 0.05. Patients reported outcome scores at the final follow-up were WOMAC-knee (median 59.1; range 47.7-94.7; n = 13) and Oxford knee score (median 26; range 11 to 43; n = 13).

CONCLUSION

This study highlights the challenge of treating infected knee arthroplasties in physiologically compromised patients with 9/13 (69%) having satisfactory clinical outcomes.

LEVEL OF EVIDENCE

Case series, level IV.

Transfemoral amputation following total knee arthroplasty

Aims

The aim of this study was to characterize the factors leading to transfemoral amputation after total knee arthroplasty (TKA), as well as the rates of mortality and functional independence after this procedure in these patients.

Patients and Methods

This was a multicentre retrospective review with a prospective telephone survey for the assessment of function. All patients with a TKA who subsequently required transfemoral amputation between January 2001 and December 2015 were included. Demographic information, medical comorbidities, and postoperative mortality data were collected. A 19-item survey was used for the assessment of function in surviving patients.

Results

A total of 111 patients were included. Their mean age was 61.0 years (42.0 to 88.0) at the time of TKA, with a subsequent mean of 3.7 operations (0 to 15) over a mean period of 6.1 years (0.05 to 30.1) before amputation. The indication for amputation was chronic infection in 97 patients (87.4%). The rate of five-year survival was 51.7%, and advanced age (p = 0.001) and renal failure (p = 0.045) were associated with an increased risk of mortality. Of the 62 surviving patients, 34 completed the survey; 32 (94.1%) owned a prosthesis but only 19 (55.9%) used it; 19 (55.9%) primarily used a wheelchair for mobility; 27 (79.5%) had phantom pain; and 16 (47.1%) required chronic pain medication. Only 18 patients (52.9%) were satisfied with the quality of life.

Conclusion

Patients with complications after TKA, in whom transfemoral amputation is considered, should be made aware of the high rate of mortality and the poor functional outcome in the survivors. Alternative forms of treatment including arthrodesis of the knee should be investigated.

Mortality During Total Knee Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infections (PJIs) are fraught with multiple complications including poor patient-reported outcomes, disability, reinfection, disarticulation, and even death. We sought to perform a systematic review asking the question: (1) What is the mortality rate of a PJI of the knee undergoing 2-stage revision for infection? (2) Has this rate improved over time? (3) How does this compare to a normal cohort of individuals?

METHODS

We performed a database search in MEDLINE/EMBASE, PubMed, and all relevant reference studies using the following keywords: "periprosthetic joint infection," "mortality rates," "total knee arthroplasty," and "outcomes after two stage revision." Two hundred forty-two relevant studies and citations were identified, and 14 studies were extracted and included in the review.

RESULTS

A total of 20,719 patients underwent 2-stage revision for total knee PJI. Average age was 66 years. Mean mortality percentage reported was 14.4% (1.7%-34.0%) with average follow-up 3.8 years (0.25-9 years). One-year mortality rate was 4.33% (3.14%-5.51%) after total knee PJI with an increase of 3.13% per year mortality thereafter (r = 0.76 [0.49, 0.90], P < .001). Five-year mortality was 21.64%. When comparing the national age-adjusted mortality (Actuarial Life Table) and the reported 1-year mortality risk in this meta-analysis, the risk of death after total knee PJI is significantly increased, with an odds ratio of 3.05 (95% confidence interval, 2.69-3.44; P < .001).

CONCLUSION

The mortality rate after 2-stage total knee revision for infection is very high. When counseling a patient regarding complications of this disease, death should be discussed.

Red Cell Distribution Width: An Unacknowledged Predictor of Mortality and Adverse Outcomes Following Revision Arthroplasty

BACKGROUND

Revision total joint arthroplasties (TJAs) have been empirically associated with significant postoperative morbidity and mortality. Red blood cell distribution width (RDW), a frequently measured hematological parameter, has been shown to predict mortality in hip fracture patients. However, its utility in risk-stratifying patients before revision TJA remains unknown. The aim of this study was to investigate the possible relationship between preoperative RDW levels and outcome of revision arthroplasty in terms of mortality, adverse outcomes, and length of hospital stay.

METHODS

A single-institution retrospective study was conducted on 4633 patients who underwent revision TJA (3289 hips and 1344 knees) between 2000 and September 2016. Of those, 656 (14.1%) surgeries were performed due to periprosthetic joint infection, and 3977 (85.9%) were aseptic revisions. The association between preoperative RDW and various outcomes, including 1-year mortality, in-hospital medical complications, length of hospital stay, and 90-day all-cause readmission, was examined.

RESULTS

The average age of patients in the cohort was 65.4 ± 12.9 years. The average Charlson comorbidity index was 0.6 (standard deviation = 1.0), with 691 patients (14.9%) having 2 or more comorbidities. Mean preoperative RDW level was 14.4% (standard deviation = 1.8). After adjusting for covariates, higher RDW levels were statistically significantly associated with mortality (adjusted odds ratio [OR], 1.25; 95% confidence interval [CI], 1.13-1.39; P < .001), any in-hospital medical complications (adjusted OR, 1.12; 95% CI, 1.07-1.18; P < .001), and readmission (adjusted OR, 1.07; 95% CI, 1.02-1.13; P < .001).

CONCLUSION

Higher levels of preoperative RDW appeared to be associated with less optimal outcomes after revision TJA. Adult reconstruction orthopedic surgeons should be aware of this predictive factor and exercise caution with TJA revision patients with high values of preoperative RDW. RDW could be included in the routine perioperative workup and used to counsel patients on their postoperative risk.