Risk of Periprosthetic Joint Infection in Patients With Ipsilateral Infected Arthroplasties.

Background: The risk of periprosthetic joint infection (PJI) subsequently developing at a second site after an initial PJI has been documented to be approximately 18%-20%. To the best of our knowledge, only a single study has evaluated the incidence in ipsilateral joints and if the risk of infection would be different. While this was the only other study to evaluate this specific subfield, we set to re-evaluate and confirm the incidence of developing a second PJI in the setting of an ipsilateral prosthesis and possible associated risk factors. Methods: We retrospectively reviewed all patients treated surgically for lower-extremity PJI at our institution by 5 surgeons from 2015 to 2021. Patients with multiple arthroplasties on the ipsilateral extremity were included. Time between initial and subsequent infection, risk factors for infection, bacterial source, and bacteremia were identified. Results: Of 392 patients treated for PJI, 179 (45.6%) had multiple prosthetic joints. Forty-seven of those 179 patients had ipsilateral extremity prosthesis, which made up our study population. Three patients (6.4%) developed a separate infection at an ipsilateral TJA. In total, 10 patients (21.3%) developed a separate PJI. Patients on immunosuppressants had a higher likelihood of developing second PJI on the ipsilateral extremity (P = .02). Conclusions: Our study identified the risk of developing an ipsilateral PJI to not be any greater than that in patients with contralateral TJAs. It appears that sharing an extremity with an infected TJA does not pose substantially increased risk of subsequent infection of the un-involved prosthesis. Furthermore, immunosuppressant use may increase the risk of a separate ipsilateral PJI.

Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Knee Arthroplasty.

BACKGROUND: Frailty can predict adverse outcomes after various orthopaedic procedures, but is not well-studied in revision total knee arthroplasty (rTKA). We investigated the correlation between the Hospital Frailty Risk Score (HFRS) and post-rTKA outcomes. METHODS: Using the Nationwide Readmissions Database, we identified rTKA patients discharged from January 2017 to November 2019 for the most common diagnoses (mechanical loosening, infection, and instability). Using HFRS, we compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients with multivariate and binomial regressions. The 30-day complication and reoperation rates were compared using univariate analyses. We identified 25,177 mechanical loosening patients, 12,712 infection patients, and 9,458 instability patients. RESULTS: Frail patients had higher rates of 30-day readmission (7.8 versus 3.7% for loosening, 13.5 versus 8.1% for infection, 8.7 versus 3.9% for instability; P < .01), longer length of stay (4.1 versus 2.4 days for loosening, 8.1 versus 4.4 days for infection, 4.9 versus 2.4 days for instability; P < .01), and greater cost ($32,082 versus $27,582 for loosening, $32,898 versus $28,115 for infection, $29,790 versus $24,164 for instability; P < .01). Frail loosening patients had higher 30-day complication (6.8 versus 2.9%, P < .01) and reoperation rates (1.8 versus 1.2%, P = .01). Frail infection patients had higher 30-day complication rates (14.0 versus 8.3%, P < .01). Frail instability patients had higher 30-day complication (8.0 versus 3.5%, P < .01) and reoperation rates (3.2 versus 1.6%, P < .01). CONCLUSIONS: The HFRS may identify patients at risk for adverse events and increased costs after rTKA. Further research is needed to determine causation and mitigate complications and costs.

Patient Frailty is Correlated With Increased Adverse Events and Costs After Revision Total Hip Arthroplasty.

BACKGROUND: Frailty has been associated with poor outcomes and higher costs after primary total hip arthroplasty. However, frailty has not been studied in relation to outcomes after revision total hip arthroplasty (rTHA). This study examined the relationship between the Hospital Frailty Risk Score (HFRS), postoperative outcomes, and cost profiles following rTHA. METHODS: In this retrospective cohort study, we identified patients who underwent rTHA from January 2017 to November 2019 in the Nationwide Readmission Database. The 3 most frequently reported diagnosis codes for rTHA were then selected: dislocation; mechanical loosening; and infection. We calculated the HFRS for each patient to determine frailty status. We compared 30-day readmission rate, length of stay, and hospitalization cost between frail and nonfrail patients, using multivariate logistic and negative binomial regressions to adjust for covariates. We identified 36,243 total patients who underwent rTHA. Overall, 15,448 patients had a revision for dislocation, 11,062 for mechanical loosening, and 9,733 for infection. RESULTS: Compared to nonfrail patients, frail patients had higher rates of 30-day readmission, longer length of stay, and higher hospitalization cost. Frail patients had significantly higher rates of 30-day complication and 30-day reoperation. CONCLUSIONS: Frailty, measured using HFRS, is associated with increased postoperative complications and costs after rTHA. The HFRS has the ability to efficiently identify frail patients at-risk for perioperative complications enabling care teams to better focus optimization interventions on this patient cohort.

The Microbiome of Osteoarthritic Hip and Knee Joints: A Prospective Multicenter Investigation.

BACKGROUND: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients. METHODS: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed. RESULTS: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages. CONCLUSIONS: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Frailty is Associated With Increased Complication, Readmission, and Hospitalization Costs Following Primary Total Knee Arthroplasty.

BACKGROUND: Frailty has been associated with poor postoperative outcomes in various medical conditions and surgical procedures. However, the relationship between frailty and outcomes after primary total knee arthroplasty (TKA) has not been well-described. This study investigated the association of the Hospital Frailty Risk Score (HFRS) with postoperative events and hospitalization costs after primary TKA. METHODS: Using a nationwide readmissions database, we identified 884,479 patients discharged after primary TKA for osteoarthritis between January 2017 and November 2019. HFRS was calculated for each patient to determine frailty status. We used multivariate logistic regressions to evaluate the association of frailty with 30-readmission rate and negative binomial regressions to evaluate lengths of hospital stay and hospitalization costs. The 30-day reoperation and complication rates were compared using chi-square tests. RESULTS: Frailty was associated with increased odds of 30-day readmissions (odds ratio [OR]: 1.89, 95% confidence interval [CI]: 1.82-1.96), longer lengths of stay (OR: 1.43, 95% CI: 1.43-1.44), and higher hospitalization costs (OR: 1.16, 95% CI: 1.16-1.17). Frail patients also had significantly higher rates of 30-day reoperations (0.6 versus 0.4%), surgical complications (0.6 versus 0.4%), medical complications (3.4 versus 1.3%), and other complications (0.9 versus 0.5%) (P < .01). CONCLUSIONS: Frailty, as measured using HFRS, was associated with increased adverse events and health care burdens in patients undergoing TKA. The HFRS could be used to swiftly identify high-risk patients undergoing TKA and to potentially help optimize patients prior to elective TKA. TYPE OF STUDY: Level III retrospective cohort study.

Clinical Outcomes of Total Knee Arthroplasty With Concomitant Total Ankle Arthroplasty Versus Ankle Arthrodesis.

Prior studies have demonstrated a high incidence of ankle osteoarthritis (OA) in patients undergoing total knee arthroplasty (TKA) as well as inferior outcomes in the setting of ankle OA or hindfoot malalignment. Little is known about the effect of the 2 most common surgical treatments for ankle OA, ankle arthrodesis and total ankle arthroplasty (TAA) on TKA. This hypothesis is that the preservation of ankle motion afforded by total ankle arthroplasty may reduce pathologic stresses across the knee joint. This study compares outcomes of patients who underwent both TKA and TAA versus those that underwent TKA and ankle arthrodesis. We retrospectively reviewed a cohort of patients who had undergone TKA and either TAA or ankle arthrodesis at this institution, examining knee injury and OA outcome scores, foot and ankle ability measure scores, revision surgery, knee range of motion, and pain. There were 69 eligible subjects, 13 who had undergone total knee arthroplasty and total ankle arthroplasty and 56 who had undergone TKA and ankle arthrodesis. No significant differences were observed in KOOS Jr scores, FAAM scores, incidence of revision, knee range of motion, or pain at final follow up (p > .05). Mean follow-up time was 46 months after both surgeries were completed. Equivalent outcomes were observed between the 2 groups. The presence of a TKA should not alter the indications for treatment of ankle OA with TAA versus arthrodesis. Further studies are needed as these relatively rare concomitant procedures are likely to become more common in the future.

Conversion total hip arthroplasty following extracapsular hip fracture fixation with a cephalomedullary device: a comprehensive review.

With the annual incidence of hip fractures and hip fracture fixation rising, the need for conversion total hip arthroplasty has also risen. About half of the 280,000 hip fractures that occur annually in the United States are extracapsular. Commonly extracapsular hip fractures are treated with either cephalomedullary nails (CMNs) or sliding hip screws (SHS). More recently, there has been a shift toward increased CMN use due to increased training with this fixation method as well as perioperative and biomechanical benefits. Given this shift, orthopedic surgeons need to understand the factors that lead to CMN failure. Failed CMN treatment leaves both patients and surgeons with few management options including revision fixation with or without osteotomy, conversion total hip arthroplasty, and conversion hemiarthroplasty. Surgeons must consider the patient and injury characteristics before deciding the best treatment plan. Conversion total hip arthroplasty is indicated in younger patients without femoral head and/or acetabular articular injury, degenerative joint disease, or avascular necrosis. Conversion total arthroplasty is a technically demanding and resource-intensive surgery associated with lower success rates and outcomes than primary total hip arthroplasty. Orthopedic surgeons should have thorough understanding of preoperative workup needed prior to surgery, implant selection associated with best outcomes, most common surgical approaches used, intraoperative considerations, and complications associated with conversion total hip arthroplasty. A comprehensive understanding of these concepts gives patients the best chance of having a successful outcome.

An Enhanced Understanding of Culture-Negative Periprosthetic Joint Infection with Next-Generation Sequencing: A Multicenter Study.

BACKGROUND: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI. METHODS: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis. RESULTS: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections. CONCLUSIONS: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial. LEVEL OF EVIDENCE: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Digital Radiography During Total Hip Arthroplasty: Early Results With a Combined Anteversion Technique.

Ideal component positioning is critical to outcomes in total hip arthroplasty. We describe our early results using digital radiographs with a combined ante-version technique. We report the incidence of component adjustments made based on digital radiographs and show how this technology can be used during patient positioning to achieve appropriate starting pelvic alignment. We reviewed 176 cases of primary total hip arthroplasty performed by a single arthroplasty surgeon using a posterior approach. Mean follow-up was 1 year (range, 3 months to 2.7 years). Digital radiographs (Surgeon's Checklist Hip; Radlink) and a combined anteversion technique were used for component positioning. For a subset of 100 patients, we recorded the incidence of pelvic mal-positioning found on digital radiographs obtained during initial positioning of the patient. For this same subset we also detail the component changes made as a result of intraoperative radiographs during trialing. Among 176 cases we have had 2 (1.1%) postoperative dislocations. Both underwent closed reduction with no further dislocation. We have had no revisions and 1 intraoperative calcar fracture. For our 100-case subset, digital radiographs during patient positioning identified pelvic malpositioning greater than 5° (coronal or axial plane) among 17% of cases. During trialing, we made component adjustments 71% of the time because of findings on intraoperative imaging. Digital radiography can be a valuable tool for component positioning during total hip arthroplasty. We experienced favorable early outcomes and show the utility of digital radiographs for proper pelvic positioning and making intraoperative adjustments to achieve optimal component placement. [Orthopedics. 2022;45(4):221-226.].

Complete Eradication of Biofilm From Orthopedic Materials.

BACKGROUND: Interest exists in finding alternatives to current management strategies in periprosthetic joint infections, which typically include a 2-stage revision with placement of an antibiotic spacer and delayed placement of a new implant. We studied the efficacy of autoclaving, ultrasonication, and mechanical scrubbing for sterilization and biofilm eradication on infected cobalt-chrome discs. METHODS: Strains of Staphylococcus aureus MRSA252 or Staphylococcus epidermidis RP62A were grown on the discs. For each strain, discs were divided into 5 groups (5 discs each) and exposed to several sterilization and biofilm eradication treatments: (1) autoclave, (2) autoclave + sonication, (3) autoclave + saline scrub, (4) autoclave + 4% chlorhexidine (CHC) scrub, and (5) autoclave + sonication + CHC scrub. Sterilization and biofilm eradication were quantified with crystal violet assays and scanning electron microscopy. RESULTS: Relative to nontreated controls, autoclaving alone reduced biofilm load by 33.9% and 54.7% for MRSA252 and RP62A strains, respectively. Biofilm removal was maximized with the combined treatment of autoclaving and CHC scrub for MRSA252 (100%) and RP62A (99.5%). The addition of sonication between autoclaving and CHC scrubbing resulted in no statistically significant improvement in biofilm removal. High-resolution scanning electron microscopy revealed no cells or biofilm for this combined treatment. CONCLUSION: Using 2 commonly encountered bacterial strains in periprosthetic joint infection, infected cobalt-chrome discs were sterilized and eradicated of residual biofilm with a combination of autoclaving and CHC scrubbing.

Soft Tissue Releases in Total Knee Arthroplasty for Valgus Deformities.

BACKGROUND: Primary total knee arthroplasty (TKA) for valgus knee deformities can be challenging. Soft tissue releases are often necessary to achieve a well-balanced knee. We reviewed the frequency of soft tissue releases including lateral retinacular release (LRR) as it pertains to preoperative limb alignment. Postoperatively, we evaluated limb alignment, knee range of motion, and complications. METHODS: From 2010 to 2016, 214 primary TKAs with valgus deformity were performed by a single surgeon. One hundred eighty-one patients had an average follow-up of 24 months. For these patients, clinical data including preoperative and postoperative range of motion, complications, and revision rates were collected. Soft tissue releases, preoperative and postoperative limb axis deviation, and level of prosthetic constraint were recorded in all patients regardless of length of follow-up. RESULTS: There were 33 knees (15%) that required 1 release, 69 knees (32%) required 2 releases, 81 knees (38%) required 3 releases, and 31 knees (14%) that required 4 or more releases. The average preoperative mechanical axis was 9.4°, and the average postoperative mechanical axis was 0.13°. There were 85 knees (40%) that required an LRR. Increased severity of preoperative deformity correlated with the need for more soft tissue release, but did not correlate with the need for LRR. No knees were revised for instability. No patella complications resulted from LRR. CONCLUSION: Selective soft tissue release for primary valgus TKA was effective without increasing prosthetic constraint. Severe deformities required more soft tissue releases. LRR can be frequently used with minimal complications.

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

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

Articulating spacers for the treatment of infected total knee arthroplasty: effect of antibiotic combinations and concentrations.

Performing 2-stage procedures using articulating antibiotic cement spacers to eradicate infection while providing pain relief and maintaining function has become common among many surgeons. Despite the efficacy of antibiotic cement spacers in the treatment of infected total knee arthroplasty, questions remain regarding the dosing of the antibiotic cement. The authors assessed their experience with different antibiotic regimens and concentrations for the eradication of infection. Sixty-nine infected total knee arthroplasties with an average follow up of 31 months (range, 6-70 months) treated with articulating antibiotic spacers were retrospectively reviewed. Treatment groups were divided according to spacer antibiotic agents used and the amount of antibiotics added to the cement. Low-dose spacers were defined as those incorporating less than 4 g of antibiotic per 40-g bag of cement, and high-dose spacers were defined as those incorporating 4 g or more of antibiotic per 40-g bag of cement. High- vs low-dose spacers using a single or multiple antibiotic agents were compared. The overall rate of infection eradication was 88%. Dose dependency was not detected for spacers that incorporated single or multiple antibiotic agents, and multiple-agent spacers produced comparable success rates despite more frequent use in patients with impaired immune function. Further study of optimal combinations and concentrations of antibiotic agents incorporated into these spacers is needed to help minimize treatment failures while maximizing treatment efficacy.