Efficacy of Commercially Available Irrigation Solutions on Removal of Staphylococcus aureus and Biofilm from Porous Titanium Implants: An In Vitro Study.

BACKGROUND: Periprosthetic joint infection (PJI) remains a major problem. The bactericidal efficacy of commercial irrigation solutions for the treatment of infection is not well established in the presence of porous titanium (Ti) implants. This study compared the in vitro efficacy of five irrigation solutions on infected three-dimensional (3D)-printed porous Ti discs. METHODS: Titanium discs (2 x 4 mm, 400, 700, and 1,000 µm) were infected with S. aureus (1x106 CFU/ml) and incubated for 3 hours or 3 days to create acute or chronic infection with biofilm. Discs were irrigated with saline, antibiotic, or antiseptic solutions, then repeatedly sonicated. Sonicates were cultured for bacterial quantification. Statistical analyses were performed using one-way analysis of variance (ANOVA), followed by Tukey-Kramer post hoc testing (P < 0.05 significance). Biofilms were visualized by scanning electron microscopy (SEM). RESULTS: Saline irrigation was ineffective in both groups. In acute infections with 400 µm pores, differences were found with saline versus solution #3 (P = 0.015) and #4 (P = 0.015). Solution #4 had the lowest bacterial counts for all pore sizes. For biofilm, irrigation with saline, solutions #1, #2, and #3 inadequately cleared bacteria in all pore sizes. Lower remaining concentrations were observed in #4 with 400µm pores compared to saline (P = 0.06) and #2 (P = 0.039). The SEM showed a reduction of biofilm in samples washed with #4. CONCLUSION: Irrigation of infected porous Ti discs with saline, solutions #1 and #2 failed to reduce the bacterial load. The 400 µm discs consistently had more bacteria despite irrigation, highlighting the difficulty of removing bacteria from small pores. Solutions #3 and #4 reduced bacteria acutely, but only #4 demonstrated efficacy in clearing biofilm compared to saline. These results should be considered when treating PJI in the presence of porous components and the potential presence of biofilm.

Effects of Vancomycin/Tobramycin-Doped Ceramic Composite (Polyvinyl Alcohol Composite-Vancomycin/Tobramycin-Polymeric Dicalcium Phosphate Dihydrate) in a Rat Femur Model Implanted With Contaminated Porous Titanium Cylinders.

BACKGROUND: Periprosthetic joint infection (PJI) remains common and problematic. We hypothesized that using a bioceramic that provided rapid release of the antibiotics (vancomycin [VAN] or VAN and tobramycin [VAN and TOB]) from a polyvinyl-alcohol-composite (PVA) combined with a delayed and sustained antibiotic release from polymeric-dicalcium-phosphate-dihydrate (PDCPD) ceramic would inhibit S. aureus-associated implant infections. METHODS: A total of 50 male Sprague Dawley rats were randomly divided into 5 groups-I: negative control; II: bacteria only; III: bacteria + saline wash; IV: bacteria + PVA-VAN-PDCPD, and V: bacteria + PVA-VAN-TOB-PDCPD. A porous titanium (Ti) implant was press-fit into the rat knee. S. aureus-containing broth was added into the joint space creating a PJI. After 1 week, the joints from groups III to V were washed with saline and the fluid collected for bacterial quantification. This was followed by saline irrigation treatment (groups III to V) and application of the antibiotic-loaded PVA-PDCPD bioceramic (groups IV and V). On day 21, joint fluid was collected, and the implants harvested for bacterial quantification. RESULTS: No bacteria were isolated from the negative control (group I). The positive control (group II) was positive on both days 7 and 21. Bacteria were still present on day 21 in the fluid and implant in group III. Groups (IV and V) showed a decrease in the bacterial burden in the fluid and implant on day 21. There were significant differences in bacteria levels in the collected wash fluid and on the implant at day 21 between the saline wash (group III) and treatment groups (IV and V). CONCLUSIONS: In this animal model of acute periprosthetic infection, treatment with PVA-VAN-PDCPD and PVA-VAN/TOB-PDCPD reduced bacterial load in the infected joint and the infected Ti implant. Application of PVA-VAN-PDCPD and/or PVA-VAN/TOB-PDCPD after saline irrigation could be used as an addition to the treatment of PJI.

Short-term Comparison of Survivorship and Functional Outcomes for Metaphyseal Cones with Short and Long Stems in Revision Total Knee Arthroplasty.

Printed porous titanium metaphyseal cones have become a mainstay for managing bone loss in revision total knee arthroplasty (rTKA). A short or long stem is routinely used when implanting a cone to augment fixation and offload stresses. This retrospective analysis compared the short-term survivorships and functional outcomes for use of a short or long stem with a metaphyseal cone.A total of 179 cases using metaphyseal cones and stems with median follow-up of 1.95 years (interquartile range, 1.00-2.14) were compared based on stem type. There were 55 cases with long stem(s) and 124 cases with short stem(s). Cases with both long and short stems were excluded. Demographics, Kaplan-Meier survivorships, and preoperative and 1-year postoperative patient-reported outcome measures (PROMs; 2011 Knee Society Score [KSS] objective knee score, function, and satisfaction scores; EuroQol five-dimension scale; and Short Form Survey Physical Component Summary and Mental Component Summary scores) were compared using t-tests with a significance level of α = 0.05. There were no significant differences in body mass index (mean ± standard deviation) or sex (men [%]) between the short and long stem cohorts (32.3 ± 5.3, 36.3% and 31.5 ± 5.5, 38.2%, respectively; p > 0.05). Patients who had short stems were younger (65.9 ± 8.8 vs. 69.0 ± 9.4, p = 0.0323).Revision-free survivorship for the femoral or tibial component was 100% for long stems and 98.2% for short stems at 1 and 2 years, respectively (log-rank p = 0.6330). The two revisions in the short group were for infection, thus the survivorship for aseptic loosening was 100% at 2 years for both cohorts. There were no significant differences in preoperative or postoperative PROMs.This study demonstrated that highly porous printed metaphyseal cones provided rTKA with excellent early survivorship and similar PROMs whether a short or long stem was used. Additional studies will be needed to discern longer term differences.

Repair of a rat calvaria defect with injectable strontium (Sr)-doped polyphosphate dicalcium phosphate dehydrate (P-DCPD) ceramic bone grafts.

The trace element strontium (Sr) enhances new bone formation. However, delivering Sr, like other materials, in a sustained manner from a ceramic bone graft substitute (BGS) is difficult. We developed a novel ceramic BGS, polyphosphate dicalcium phosphate dehydrate (P-DCPD), which delivers embedded drugs in a sustained pattern. This study assessed the in vitro and in vivo performance of Sr-doped P-DCPD. In vitro P-DCPD and 10%Sr-P-DCPD were nontoxic and eluents from 10%Sr-P-DCPD significantly enhanced osteoblastic MC3T3 cell differentiation. A sustained, zero-order Sr release was observed from 10%Sr-P-DCPD for up to 70 days. When using this BGS in a rat calvaria defect model, both P-DCPD and 10% Sr-P-DCPD were found to be biocompatible and biodegradable. Histologic data from decalcified and undecalcified tissue showed that 10%Sr-P-DCPD had more extensive new bone formation compared with P-DCPD 12-weeks after surgery and the 10%Sr-P-DCPD had more organized new bone and much less fibrous tissue at the defect margins. The new bone was formed on the surface of the degraded ceramic debris within the bone defect area. P-DCPD represented a promising drug-eluting BGS for repair of critical bone defects.

Effect of Commercially Available Wound Irrigation Solutions on Uninfected Host Tissue in a Murine Model.

Background: Commercially available irrigation solutions are used to reduce bacterial contamination and prevent surgical site infections. However, the effect of these solutions on the healing capacity of tissue has not been well-established. The purpose of this study was to investigate the effects of 5 commercially available irrigation solutions on host tissue in a murine model. Methods: There were 5 treatment groups: bacitracin, Clorpactin, Irrisept, Prontosan, Bactisure, and normal saline control. The irrigation solutions were applied to the wound for 30 seconds or 1 minute, as per the manufacturer's instructions, and then washed with normal saline. Mice were sacrificed at 3 days and 10 days. The tissue was examined histologically for inflammation, edema, granulation tissue formation, and re-epithelialization. Granulation tissue formation and re-epithelialization were surrogates for effective wound healing. Results: All of the irrigation solutions had negative effects on host tissue in the acute phase. The inflammation and edema were improved in the later phase (10 days). Recovery and healing of the open wounds were observed for all groups at 10 days. The antiseptic irrigation solutions had similar cytotoxic effects on host tissue at 3 days and did not have delayed or compromised wound healing at 10 days when compared to normal saline control. Conclusions: Single short-duration use of these commercially available antiseptic irrigation solutions appears to be safe in an uninfected wound. Data from this study will provide surgeons with useful information regarding the safety of using antiseptic wound irrigation solutions intraoperatively for prevention of surgical site infections.

The Differential Effect of COVID on Total Joint Arthroplasty Between Hospital and Ambulatory Surgery Centers/Hospital Outpatient Departments: A Michigan Arthroplasty Registry Collaborative Quality Initiative Analysis.

Background: Coronavirus disease (COVID) created unprecedented challenges, especially for high-volume elective subspecialties like total joint arthroplasty. Limited inpatient capacity and resource conservation led to new outpatient selection criteria and site of service changes. As a Michigan Arthroplasty Registry Quality Collaborative Initiative quality project, demographic changes, complications, and differential effects on inpatient vs outpatient centers pre- and post-COVID were analyzed. Methods: The registry identified all total joint arthroplasty at hospitals and ASCs/HOPDs between 07/2019-12/2019 and 07/2020-12/2020. These intervals represented pre-COVID and post-COVID elective surgery shutdowns. Case volumes, demographics, and 90-day complications were compared. Results: Comparing 2020 to 2019, hospital volumes decreased (-9% total hip arthroplasty [THA], -17% total knee arthroplasty [TKA]), and ambulatory surgery center (ASC)/hospital outpatient department (HOPD) increased (+84% THA, +125% TKA). Entering 2020, ASC/HOPD patients were older (P = .0031, P < .0001: THA, TKA), had more American Society of Anesthesiologists score 3-4 (P = .0105, P = .0021), fewer attended joint class (P < .0001, P < .0001), and more hips were women (P = .023). Hospital patients had higher preoperative pain scores (P = .0117, P < .0001; THA, TKA), less joint education attendance (P < .0001, P < .0001), younger TKAs (P = .0169), and more American Society of Anesthesiologists score 3-4 (0.0009). After propensity matching, there were no significant differences between site of service for 90-day fractures, deep vein thromboses or pulmonary embolisms, infection, or hip dislocations. Hospital THAs had higher readmissions (P = .0003) and TKAs had higher 30-day emergency department visits (P = .005). ASC/HOPD patients were prescribed higher oral morphine equivalents (P < .0001, P < .0001; THA, TKA). Conclusions: COVID's elective surgery shutdown caused a dramatic site of service shift. Traditional preoperative education was negatively impacted, and older and sicker patients became outpatients. But short-term complications were not increased in ASCs/HOPDs. These site of service and associated patient demographic changes may be safely sustained.

Do 'Surgeon Champions' and High-Volume Surgeons Have Lower Rates of Periprosthetic Femur Fracture? Perspective From a State-Wide Quality Improvement Registry.

BACKGROUND: Recently, a state-wide registry identified fracture as a major cause of total hip arthroplasty revision. There were 52.8% of revisions occurring within 6 months (fracture leading cause). Registry sites have a 'surgeon champion' who acts as liaison and advocate. This study evaluated the effect of surgeon volume and role of 'surgeon champion' on fracture rates. METHODS: There were 95,948 cases from 2012 to 2019 queried with peri-implant femoral fractures identified (within 6 months). Funnel plots were generated to compare individual surgeon-specific fracture rates. Surgeons who had a fracture rate below the confidence interval were labeled 'green' (lower than mean), within were 'yellow' (no difference), and above were 'red' (significantly higher). RESULTS: For all surgeons, 19.6% were red, 72.1% yellow, and 8.3% green. There were 17.2% 'surgeon champions' and 6.2% 'nonchampions' that were green (P = .01), while 20.7 and 19.3% were red (P = .82). There was a significant association between volume and performance (P < .01). No surgeons in the lower two quartiles (<84; 84 to 180 cases), while 4 and 29% of higher-volume surgeons (181 to 404; >404 cases) were green. There was no statistical difference in red status by volume (P = .53). CONCLUSION: 'Surgeon champions' and high-volume surgeons were more likely to be high performers but not less likely to be low performers. Active involvement in quality improvement and/or high volume was associated with better outcomes but did not impart complication immunity. 'Green' surgeons should mentor colleagues to help reduce fractures by re-evaluating modifiable factors. Analyzing outcomes to promote quality and decrease complications is paramount.

Early Survivorship of Uncemented Total Knee Arthroplasty Varies by Age and Sex Based on Data From the Michigan Arthroplasty Registry Collaborative Quality Initiative.

BACKGROUND: Outcome data for newer uncemented total knee arthroplasty (TKA) designs has been mixed. Registry studies showed worse survivorship, but clinical trials have not demonstrated differences compared to cemented designs. There has been renewed interest in uncemented TKA with modern designs and improved technology. The utilizations of uncemented knees in Michigan, 2-year outcomes, and the effects of age and sex were evaluated. METHODS: A statewide database from 2017 through 2019 was analyzed for incidence, distribution, and early survivorship of cemented versus uncemented TKAs. There was 2-year minimum follow-up. Kaplan-Meier survival analysis was used to generate time to first revision cumulative percent revision curves. The impacts of age and sex were examined. RESULTS: Use of uncemented TKAs increased from 7.0 to 11.3%. Uncemented TKAs were more commonly men, younger, heavier, American Society of Anesthesiologists score > 2, and opioid users (P < .05). At 2 years, overall cumulative percent revision was higher in uncemented (2.44% [2.00, 2.99]) versus cemented (1.76% [1.64, 1.89]), particularly in women uncemented (2.41 [1.87, 3.12]) versus cemented (1.64 [1.50, 1.80]). Revision rates were greater with uncemented women >70 years (1.2% 1 year, 1.02% 2 years) versus < 70 years (0.56%, 0.53%), notably uncemented were inferior in both groups (P < .05). Men, regardless of age, had similar survivorships with both cemented and uncemented designs. CONCLUSION: The use of an uncemented TKA had an increased risk of early revision compared to cemented. This finding, however, was only apparent in women, especially those >70 years old. Surgeons should consider cement fixation in women >70 years.

A Reduction in Opioid Prescription Size After Total Joint Arthroplasty Can be Safely Performed Without an Increase in Complications.

BACKGROUND: Excessive opioid prescriptions after total joint arthroplasty (TJA) increase risks for adverse opioid-related events, chronic opioid use, and unlawful opioid diversion. Decreasing postoperative prescriptions may improve quality after TJA. Concerns exist that a decrease in opioids prescribed may increase complications, such as readmissions, emergency department (ED) visits, or worsened patient-reported outcomes (PROs). The purpose of this study was to explore whether a reduction in opioids prescribed after TJA resulted in increased complications. METHODS: Data originated from a statewide database prospectively abstracted, including oral morphine equivalents prescribed at discharge, readmissions, ED visits, and PROs. Data were collected from 84,998 TJA occurring 1 year before and after the creation of an opioid-prescribing protocol that had decreased prescriptions by approximately 50%. Trends were monitored using Shewhart control charts. Regression models were used to determine statistically significant changes over time. RESULTS: All groups showed a reduction in opioids prescribed by almost 50% without an increase in emergency room visits or readmissions and without a detrimental effect on PROs. Compared to baseline data before opioid reduction, opioid-naive total knee arthroplasty had significant improvements in all outcomes (P = .03, P = .02, P < .001, P < .001). Opioid-tolerant total knee arthroplasty and total hip arthroplasty had no worsened outcomes and significant improvement in (Knee Injury and Osteoarthritis Outcome score for Joint Replacement P = .03) and (Hip Disability and Osteoarthritis Outcome Score for Joint Replacement P = .03). Opioid-naive total hip arthroplasty had significant improvements in Hip Disability and Osteoarthritis Outcome Score Joint Replacement (P = .003) and Patient Reported Outcomes Measurement Information System (P = .001). CONCLUSIONS: Postoperative opioid prescription recommendations from a statewide registry decreased prescribing by approximately 50% without decreasing PROs or increasing ED visits or readmissions. A reduction in opioids prescribed after TJA can be accomplished safely and without increased complications.

Common Wound Irrigation Solutions Produce Different Responses in Infected vs Sterile Host Tissue: Murine Air Pouch Infection Model.

Background: Despite desirable microbicidal actions of irrigation solutions in surgical site infection treatment, several studies demonstrate potential cytotoxic effects. This study investigated tissue damage caused by irrigation solutions in the presence or absence of infection. Methods: Air pouches were created in 60 mice and evenly divided into 2 groups as infected with Staphylococcus aureus and control. Groups were then subdivided both by type of solution and by timing after irrigation. Solutions included control (0.9% saline), bacitracin (33 IU/ml), 0.2% sodium oxychlorosene, 0.05% chlorhexidine gluconate, and 0.013% benzalkonium chloride. Results: Inflammation decreased in infected pouches compared to the sterile ones for all solutions except bacitracin on day 0 and for all on day 7. On day 0, infected pouches had increased necrosis with bacitracin (P = .006), chlorhexidine gluconate (P = .18), and benzalkonium chloride (P = .07); on day 7, there was decreased necrosis in infected pouches for all solutions (P < .05) except for sodium oxychlorosene (P = .18). Edema decreased in infected pouches on day 0 for all solutions. On day 7, infected pouches had decreased edema with 0.9% saline, bacitracin, and benzalkonium chloride (P < .05) and increased edema with chlorhexidine gluconate (P < .05) and sodium oxychlorosene (P = .069). Bacitracin allowed for more bacteria growth than sodium oxychlorosene (P = .024), chlorhexidine gluconate (P = .025), and benzalkonium chloride (P = .025). Conclusions: The presence of bacteria led to less immediate tissue inflammation and edema, while tissue necrosis varied over time. The current study may guide surgeons on which solution to use and whether to irrigate a possibly sterile wound or joint.

Factors That Influence Time to Operating Room for Geriatric Hip Fractures: A Quality Improvement Initiative.

Background: For geriatric hip fractures, the current American College of Surgeons guideline recommends surgery within 48 hours. We sought to identify which factors delayed a patient's progression to definitive surgery at 2 associated level II trauma centers using chart abstraction. Methods: We reviewed all geriatric patients who underwent a surgical procedure for a hip fracture. Data regarding age, length of stay, procedure, and minutes from emergency department arrival to operating room (OR) were evaluated. Chart abstraction determined if cardiac or medical clearance and an echocardiogram were obtained. For patients that entered the OR over 24 hours, a reason was identified for the delay. Analysis of variance was used to compare continuous data, and chi-squared tests were used for categorical data. Results: Of 477 patients, 288 (60%) presented to the OR in under 24 hours, 114 (24%) between 24 and 36 hours, and 75 (16%) over 36 hours. There was a significant increase in length of stay for patients, over 36 hours. Patients presenting to the OR between 24 and 36 hours were often delayed due to facility reasons such as OR or surgeon availability while patients presenting over 36 hours were delayed due to medical comorbidities. Of all patients in the under-24-hours group, 34.7% had an echocardiogram compared with 56.1% and 69.3%, respectively. Similarly, 17.7% of patients received cardiac clearance in the under-24-hours group, compared with 31.8% and 48%, respectively. Conclusions: The timeliness of presentation of hip fractures to the OR is a multidisciplinary effort and requires cooperation between a variety of services to increase safety and efficiency as well as to control costs.

Attachment and Growth of Fibroblasts and Tenocytes Within a Porous Titanium Scaffold: A Bioreactor Approach.

Background: Direct attachment of tendons to metallic implants is important in orthopedics. Tissue integration depends on scaffold microstructure and composition. This study evaluated the effect of pore size of titanium on the viability and function of fibroblasts and tenocytes in a dynamic bioreactor. Methods: Standardized Ti porous cylinders with 3 pore sizes (400, 700, and 1000 µm) were seeded with fibroblasts or tenocytes (4500 cells/µL) in silicon tubes. Cells were analyzed via alamarBlue (AB) assay in addition to scanning electron microscopy at day 7 (fibroblasts) or day 8 (tenocytes) and day 15. AB functions as a cell health indicator where functional living cells reduce the resazurin dye (blue) in the solution to resorufin (pink), and cell viability can be quantified via spectroscopy. Results: At day 7, fibroblasts cultured on all sizes reduced AB, with significant differences noted between 400 vs 1000 µm (P = .013) and 700 vs 1000 µm (P = .001). At day 15, fibroblasts reduced AB on all sizes with a significant difference noted between 700 vs 1000 µm (P = .004). Fibroblasts on all 3 pore sizes increased AB reduction from day 7 to day 15. Tenocytes reduced AB with significant differences between the 400 vs 700 µm (P = .049) and the 400 vs 1000 µm pore sizes at day 8. In contrast, tenocyte reduction of AB decreased from day 8 to day 15. Scanning electron microscopy performed on fibroblast cylinders showed fibroblasts reached the surface of the cylinders, confirming interconnectivity. Conclusions: While both fibroblasts and tenocytes penetrated the pores, fibroblasts preferred larger size, whereas tenocytes favored smaller size. Results are encouraging since soft-tissue attachment to a metallic scaffold is difficult but clinically desirable. Future studies could be performed in an in vivo animal model.

Osteoblastic differentiation and bactericidal activity are enhanced by erythromycin released from PCL/PLGA-PVA coaxial nanofibers.

Prosthesis with antibiotic-eluting nanofibrous (NF) coating represents coating alternative to prevent periprosthetic joint infection (PJI). In this study, four formulas of erythromycin (EM)-embedded both in core and sheath components of coaxial PCL/PLGA-PVA NF coatings were developed: EM 0 (no EM), EM 100 (100 µg/mL), EM500 (500 µg/mL) and EM1000 (1000 µg/mL). EM doping altered the physicochemical and structural properties of NFs to some extent, including the increase of NF porosity and surface wettability. A sustained EM release from EM-NFs for >4 weeks was observed. Eluents collected from EM-NFs showed strong zone of inhibition (ZOI) to Staphylococcus aureus growth and the sizes of ZOI positively related to the amount of EM released. EM-NFs were nontoxic to rat bone marrow stem cells (rBMSCs). Cell growth was significantly enhanced when comparing rBMSCs cultured on EM-NFs (EM0 and EM 100) to those cultured on NF-free control. Cell differentiation (ALP activity) was notably enhanced by EM100, compared to control and EM0. Eluents from EM-NFs on rBMSCs were also investigated. The presence of 10% EM-NF eluents inhibited the growth of rBMSCs, which was proportional to the amount of EM doped. The ALP activity was notably enhanced by eluents from EM-NFs with the highest activity in EM100 compared to control and EM0. Our data indicate that EM-doped PCL/PLGA-PVA coaxial NF coatings have a great potential to be applied as a new implant coating matrices. Further in vivo testing in animal models is currently planned that should represent the first step in predicting the clinical outcomes of EM-eluting NF coating approach.

Mark Coventry Award: Efficacy of Saline Wash Plus Antibiotics Doped Polyvinyl Alcohol (PVA) Composite (PVA-VAN/TOB-P) in a Mouse Pouch Infection Model.

BACKGROUND: The efficacy of saline irrigation for treatment of periprosthetic infection (PJI) is limited by the presence of contaminated medical devices. This study evaluated treatment efficacy of locally placed polyvinyl alcohol (PVA)/bioceramic composite doped with vancomycin (PVA-VAN-P) or vancomycin and tobramycin (PVA-VAN/TOB-P) after saline irrigation in a mouse pouch infection model. METHODS: Sutures were implanted into air pouches of BALB/cJ mice, then inoculated with Staphylococcus aureus. Mice were randomized into 6 groups (n = 6 each): (1) no bacteria; (2) bacteria without saline wash; (3) saline wash only; (4) saline wash + PVA-P; (5) saline wash + PVA-VAN-P, and (6) saline wash + PVA-VAN/TOB-P. After 7 days, pouches were washed with saline alone or with additional injection of 0.2 mL of the composites. Sacrifice occurred 14 days after the washout. Histology was performed on the pouch tissues and bacteria cultures on the washout fluid. RESULTS: Bacterial culture (optical density) showed that infection persisted after saline irrigation (0.10 ± 0.14) but was effectively eradicated by the addition of PVA-VAN-P (0.05 ± 0.09) and PVA-VAN/TOB-P (0.002 ± 0.003, P < .05). These effects were confirmed by histology. Importantly, no residues of the PVA-P were detected in either the pouch washouts or pouch tissues. CONCLUSION: PJI is common and problematic, and few innovations have changed clinical practice and/or outcome. Our data confirmed that the effect of saline irrigation was very limited in the presence of contaminated sutures. PVA-VAN/TOB-P was biodegradable, biocompatible, and effective in eradicating bacterial retention after saline irrigation. Application of PVA-VAN/TOB-P after saline irrigation could be an option for treatment of PJI and should be evaluated in future PJI animal models.

John N. Insall Award: MARCQI's Pain-Control Optimization Pathway (POP): Impact of Registry Data and Education on Opioid Utilization.

BACKGROUND: In 2019, the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) recommended an evidence-based opioid pain pathway to participating physicians and hospitals for patients undergoing total joint arthroplasty (TJA). The purpose of this study was to determine if the education could influence and have lasting effects on the prescribing patterns for TJA patients. METHODS: Using the MARCQI database, the number of oral morphine equivalents (OMEs) prescribed at discharge were collected from January 2018 through December 2019 for all primary arthroplasty procedures. Periods compared included before and after July 2018 Michigan opioid laws as well as before and after the March 2019 MARCQI recommendations. The data compared total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients, opioid-naive vs opioid-tolerant patients, individual surgeons, and MARCQI sites. RESULTS: The data included 84,998 TJAs: 22,774 opioid-naive THAs, 9124 opioid-tolerant THAs, 40,882 opioid-naive TKAs, and 12,218 opioid-tolerant TKAs. In all the groups and at all time periods there were a significant decrease in prescriptions (P < .001). Individual surgeons and participating sites also demonstrated decreased OMEs on discharge after the recommendations. Between the first and last months of collection, this represented an overall decrease of opioid OMEs for THA by 47.1% for opioid-naive patients and 53.4% for opioid-tolerant patients. For TKA patients, the OME decrease was 48.3% for opioid-naive patients, and 48.4% for opioid-tolerant patients. CONCLUSION: The MARCQI pain control optimization pathway (POP) program has been successful in drastically reducing opioid prescribing with lasting effects, which has substantially limited the overall opioid prescription burden for patients undergoing arthroplasty.

Causes of Early Hip Revision Vary by Age and Gender: Analysis of Data From a Statewide Quality Registry.

BACKGROUND: While total hip arthroplasty (THA) is extremely successful, early failures do occur. The purpose of this study was to determine the cause of revision in specific patient demographic groups at 3 time points to potentially help decrease the revision risk. METHODS: Data for cases performed between 2012 and 2018 from a statewide, quality improvement arthroplasty registry were used. The database included 79,205 THA cases and 1,433 revisions with identified etiology (1,584 in total). All revisions performed at <5 years from the primary THA were reviewed. Six groups, men/women, <65, 65-75, and >75 years, were compared at revision time points <6 months, <1 year, and <5 years. RESULTS: There were obvious and significant differences between subgroups based on demographics and time points (P < .0001). Seven hundred and fifty-six (53%) of all revisions occurred within 6 months. The most common etiologies within 6 months (756 revisions) were fracture (316, 41.8%), dislocation/instability (194, 25.7%), and infection (98, 12.9%). At this early time point, the most common revision cause was fracture for all age/gender-stratified groups, ranging from 27.6% in young men to 60% in older women. Joint instability became the leading cause for revision after 1 year in all groups. CONCLUSION: This quality improvement project demonstrated clinically meaningful differences in the reason for THA revision between gender, age, and time from surgery. Strategies based on these data should be employed by surgeons to minimize the factors that lead to revision.

Tuberculosis Screening via Chest X-Ray is Financially Burdensome in Previously Independently Living Elective Total Knee Arthroplasty Patients.

BACKGROUND: In 1995, to reduce the transmission of Tuberculosis (TB) the Centers for Disease Control and Prevention recommended that all patients discharged from hospitals be required to have chest x-rays (i.e., radiography) performed before admission to long term care facilities (LTCFs). Previously independently living patients (PILPs) who undergo elective total knee replacement (TKA) surgery are a population at higher risk to end up in LTCFs for rehabilitation. By 2017, the incidence of TB was 9,105 cases compared to 22,762 in 1995. However, the recommendations that hospitals be required to perform a chest x-ray in all patients (including PILPs) being transferred to LTCF's have remained in place. The purposes of this study were to: a) determine the incidence of TB-positive chest x-rays in PILPS discharged to LTCFs after undergoing elective TKA surgery, and b) assess the cost (i.e., both financial and possible exposure to unnecessary radiation) of mandated chest x-rays before hospital discharge to LTCF for PILPs. METHODS: Retrospective 2012-2017 patient chart data were collected from the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) to identify all elective TKAs for PILPs performed at two Ascension participating centers. Study data included sex, age, body mass index (BMI), length of stay, comorbidities, and chest x-ray results before discharge. Patients who underwent surgery for fracture, infection, trauma, or malignancy were excluded from the study. Categorical data were analyzed using Fisher's exact test and Student's t-test were used for continuous data. RESULTS: The authors identified 4,041 total elective TKA's, from which 500 PILPs were discharged to a LTCF due to functional, medical and/or social concerns. Chest x-rays were associated with 500 (100%) negative findings for TB. Overall hospital costs for chest x-rays for patient's being discharged to an extended care facility totaled $90,848. CONCLUSIONS: The mandated use of chest x-rays for TB screening of PILPs undergoing elective surgery TKA prior to discharge to LTCFs appear to place an unnecessary financial burden on the healthcare system. The mandatory use of x-rays for assessment of possible TB infection before transfer to LTCFs appears to also expose PILPs unnecessarily to radiation. Although further studies are needed to verify these results, the authors recommend that perhaps instead chest x-rays should be reserved for patients with specific comorbidities (e.g., patients on immunosuppressive therapy, with HIV, etc.) or for those patients residing in LTCFs prior to surgery.

Impacts of compacting methods on the delivery of erythromycin and vancomycin from calcium polyphosphate hydrogel matrices.

Designing hydrogels for controlled drug delivery remains a big challenge. We developed a calcium polyphosphate hydrogel (CPP) as matrix for delivery of vancomycin (VCM) and erythromycin (EM) by unique ionic binding and physical wrapping. In this continuing study, we investigated if gel discs prepared by mechanical compaction (at 3000 psi pressure, C-discs) is superior to that of discs prepared by regular manual compaction (M-discs) for the release of VCM and EM (10 wt.%). Data demonstrated a significant reduction of burst release of VCM and EM in C-discs (1.8% and 5%, respectively) as compared to that from M-discs within 72 hr (55% and 60%, respectively, p < 0.05). In addition, C-discs significantly extended the VCM release (1500 hr) and EM (800 hr) as compared to M-discs (160 and 96 hr, respectively, p < 0.05). The VCM released from C-discs retained its bactericidal activity much longer (1500 hr) than that from M-discs (700 hr, p < 0.05). Raman Spectroscopy indicated an ionic bond of both VCM and EM with fully hydrated polyphosphate chains of CPP hydrogel matrix for both M-discs and C-discs. Micro CT showed that C-discs had much denser microstructures and less number/depth of microcracks as a result of high pressure. We propose that CPP hydrogel represents an excellent tool for the controllable and sustained delivery of VCM and EM. Extensive experiments are currently underway to evaluate the potential impacts of the modification of compaction techniques, other antibiotics, gel concentrations on the drug release, degradation behavior and infection control both in vitro and in vivo.

Irrigation Solutions Negatively Affect the Viability and Function of Human Fibroblasts: An in vitro Study.

Introduction: Multiple irrigation solutions are used in orthopedic surgeries although there are limited studies on their lasting effects on human tissues. The purpose of this work was to investigate the cytotoxic effects of the irrigation solutions Bacitracin, Clorpactin (sodium oxychlorosene), Irrisept (0.05% chlorhexidine gluconate), and Bactisure (ethanol 1%, acetic acid 0.6%, sodium acetate 0.2%, benzalkonium chloride 0.013%, and water) on 3D cultures of human fibroblasts. Methods: Two independent experiments with 6 replicates were performed for the following conditions: Control (saline), bacitracin, Clorpactin, Irrisept, and Bactisure. Human fibroblast cell sheets were exposed to these solutions (1 or 2 min), followed by three washes with warm saline. Cell sheets were then cultured for additional 5- and 7-day posttreatment. Cell viability was measured using the alamarBlue (AB) assay. The more cytotoxic the irrigant, the lower the AB reduction. Results: For 1-min exposure time, significant differences in AB reduction were noted in Clorpactin, Irrisept, and Bactisure groups compared to control at both 5 days (Clorpactin p = 0.0003, Irrisept p = 7.31 × 10-15, Bactisure p = 6.86 × 10-14) and 7 days posttreatment (all groups p < 0.0001). The results were similar in the 2-min exposure groups. Bacitracin-treated fibroblasts displayed no significant difference at all measurement times compared to control. Discussion: Impacts of irrigation solution exposure on cell viability were varied. Irrisept and Bactisure showed the highest cell toxicity even after a brief exposure (1 min), while bacitracin and Clor-pactin exposure showed smaller impacts on cell viability as compared to saline controls. This in vitro study provided insight into the effects of the irrigants on human cells and provides the groundwork essential to move to in vivo studies. Our findings raised the concern that some irrigation solutions may have negative impacts on wound healing and healthy cellular response.

The Effects of Depression and Anxiety on 90-day Readmission Rates After Total Hip and Knee Arthroplasty.

BACKGROUND: Patients undergoing total joint arthroplasty have higher rates of anxiety, depression or anxiety and depression than the general population and higher costs of care, which lead to higher levels of postoperative dissatisfaction and readmission rates. We evaluated the readmission rates of patients undergoing total hip or knee arthroplasty with diagnoses of anxiety, depression, or both. METHODS: Our hospital's prospectively collected data from Michigan's statewide total joint database were reviewed from 2013 to 2018. Rates of anxiety, depression or anxiety and depression were determined based on preoperative anxiolytic or antidepressant medications using National Drug Codes. RESULTS: A total of 4107 cases were included. Of which 4.28% had a readmission within the 90-day global period, and 12% had a history of depression or anxiety or both. For the entire cohort, those on anxiolytic medication were 153% more likely to be readmitted than those not on medication (P = .017). When comparing total hip arthroplasty (THA) or total knee arthroplasty (TKA), patients taking anxiolytic medication and undergoing TKA were 120% more likely to undergo readmission within 90 days (P = .021). Patients on depression medication alone were not at increased risk of readmission in the TKA cohort (P = .991). For THA, neither diagnosis appeared a risk factor for readmission (P = .852). CONCLUSIONS: Patients with depression, anxiety, or both undergoing TKA were at a statistically significant risk of readmission within 90 days compared with patients without these diagnoses. Anxiety and depression were both risk factors for readmission, but anxiety appeared to have a more significant impact. Patients undergoing THA on the other hand did not appear to share this risk profile.