New Evaluation and Management Code Level Selection Trends in Hip and Knee Osteoarthritis Patients.

BACKGROUND: On January 1, 2021, the American Medical Association implemented changes regarding the outpatient Evaluation and Management (E/M) criteria dictating Current Procedural Terminology code level selection to help diminish administrative burden and emphasize medical decision-making as the primary determinant in E/M level of service (EML). The goal of this study was to describe EML coding trends in outpatient visits for hip and knee osteoarthritis after the 2021 Centers for Medicare and Medicaid Services changes to the E/M system. METHODS: All outpatient visits for primary hip and knee osteoarthritis within the divisions of Joint Replacement, Operative Sports Medicine, and Nonoperative Sports Medicine at a single orthopaedic practice were retrospectively analyzed during 2 separate 10-month timeframes in 2019 and 2021. The primary endpoint was the visit EML (1 through 5) based on Current Procedural Terminology E/M codes. RESULTS: In 2019, 7.8% of all visits were billed as level 2, 85.8% of all visits were billed as level 3, and 6.3% of all visits were billed as level 4. In 2021, 2.8% of visits were billed as level 2, 54% of visits were billed as level 3, and 41.3% of visits were billed as level 4. Level 1 and Level 5 visits did not exceed 2% in either year. Across all 3 divisions, level 2 and 3 visits decreased significantly (P < .05), while level 4 visits increased significantly (P < .05). CONCLUSION: Since the E/M coding criteria overhaul in 2021, there has been a significant trend towards higher level of service code selection across multiple divisions in our orthopaedic practice.

Risk Factors and Effect of Acute Kidney Injury on Outcomes Following Total Hip and Knee Arthroplasty.

BACKGROUND: Development of acute kidney injury (AKI) following primary total joint arthroplasty (TJA) is a potentially avoidable complication associated with negative outcomes including discharge to facilities and mortality. Few studies have identified modifiable risk factors or strategies that the surgeon may use to reduce this risk. METHODS: We identified all patients undergoing primary TJA at a single hospital from 2005 to 2017, and collected patient demographics, comorbidities, short-term outcomes, as well as perioperative laboratory results. We defined AKI as an increase in creatinine levels by 50% or 0.3 points. We compared demographics, comorbidities, and outcomes between patients who developed AKI and those who did not. Multivariate regressions identified the independent effect of AKI on outcomes. A stochastic gradient boosting model was constructed to predict AKI. RESULTS: In total, 814 (3.9%) of 20,800 patients developed AKI. AKI independently increased length of stay by 0.26 days (95% confidence interval [CI] 0.14-0.38, P < .001), in-hospital complication risk (odds ratio = 1.73, 95% CI 1.45-2.07, P < .001), and discharge to facility risk (odds ratio = 1.26, 95% CI 1.05-1.53, P = .012). Forty-one predictive variables were included in the predictive model, with important potentially modifiable variables including body mass index, perioperative hemoglobin levels, surgery duration, and operative fluids administered. The final predictive model demonstrated excellent performance with a c-statistic of 0.967. CONCLUSION: Our results confirm that AKI has adverse effects on outcome metrics including length of stay, discharge, and complications. Although many risk factors are nonmodifiable, maintaining adequate renal perfusion through optimizing preoperative hemoglobin, sufficient fluid resuscitation, and reducing blood loss, such as through the use of tranexamic acid, may aid in mitigating this risk.

What is the Geographic Distribution of Women Orthopaedic Surgeons Throughout the United States?

BACKGROUND: Orthopaedic surgery has a shortage of women surgeons. An even geographic distribution of women orthopaedic surgeons may provide more uniform care to patients. However, little is known about the geographical distribution of women orthopaedic surgeons. QUESTIONS/PURPOSES: (1) Is there substantial geographic variation in the distribution of orthopaedic surgeons who are women? (2) How does the geographic distribution of women orthopaedic surgeons compare with that of other physicians? (3) What are the variables associated with increased region-based proportions of orthopaedic surgeons who are women? METHODS: To obtain a national snapshot of orthopaedic providers, two Medicare databases were used (Medicare Provider Utilization and Payment Data and Medicare's current and archived Physician Compare Data). These databases were used to identify physicians with self-reported specialties of "Orthopedic Surgeon," "Hand Surgeon," or "Sports Medicine" with at least 11 Medicare claims in 1 year for a single procedure type between 2012 and 2014. These databases are the only databases known to specifically report surgeon gender on a national scale and include physician demographics and education. The Dartmouth Atlas's hospital referral regions and United States Census Bureau divisions were used to group physicians by geographic region. The Gini coefficient, a measure of statistical dispersion, was used to quantify the regional distribution of orthopaedic surgeons. This was compared with the dispersion of non-orthopaedic physicians within the same Medicare databases. Surgeon and regional characteristics were correlated with the proportion of women orthopaedic surgeons in the region. RESULTS: There is substantial geographic variation in the distribution of orthopaedic surgeons who are women, ranging from 0% to 15%. There was a greater prevalence of women orthopaedic surgeons in New England (7.3%, 107 of 1469 surgeons) and the Pacific region (6.5%, 208 of 3196 surgeons) than in the South Atlantic (4.5%, 210 of 4618 surgeons) and East South Central regions (3.5%, 50 of 1442 surgeons). This represents a greater level of variation (Gini coefficient = 0.37) compared with other specialties (0.30 and 0.37) and compared with men orthopaedic surgeons (0.16). Variables independently associated with an increased prevalence of women orthopaedic surgeons based on hospital referral region were an increased proportion of currently practicing women physicians who graduated from medical schools in that region (beta = 0.03; p = 0.01), increased proportion of Medicaid-eligible patients (beta = 0.12; p = 0.002), increased proportion of regional population is black (beta = -0.06; p = 0.03), and increased regional supply of women physicians (beta = 0.26; p < 0.0001). CONCLUSIONS: Despite the recent increase in women orthopaedic surgeons nationally, gains have not been equally distributed throughout the United States. CLINICAL RELEVANCE: In other medical fields, gender diversity has been proven to be beneficial for patients. If this holds true in the field of orthopaedic surgery, we should be mindful of the geographic distribution of women orthopaedic surgeons as the percentage of these surgeons increases.

Self-Directed Home Exercises vs Outpatient Physical Therapy After Total Knee Arthroplasty: Value and Outcomes Following a Protocol Change.

BACKGROUND: The need for outpatient physical therapy (OPPT) has been questioned following primary total knee arthroplasty (TKA). Recent studies have suggested that similar outcomes may be possible with self-directed home exercise programs (HEP) compared to OPPT, which can be costly to both the patient and healthcare system. The aim of the present study is to compare the safety, efficacy, and health economics of formal OPPT with self-directed home exercises after TKA following a protocol change. METHODS: A single-surgeon, retrospective study of 520 consecutive patients undergoing primary unilateral TKA from 2016 to 2018 was performed. All 251 TKAs performed in 2016 were routinely prescribed OPPT, while all 269 TKAs in 2017 completed a self-directed HEP alone for 2 weeks. At their 2-week visit, OPPT was prescribed if patients had less than 90° range of motion or per patient request. Financial data of postdischarge costs were collected for all patients. Multivariate logistic regression evaluated for variables associated with failure of the HEP program. RESULTS: Overall, 65.8% (177/269) of patients in the HEP group did not require OPPT. There was no significant difference in percentage of patients whose range of motion was less than 90° at 2-week follow-up between OPPT and HEP (14% vs 11.9%, P = .467). Between OPPT and HEP, there were no differences in manipulation under anesthesia (3.2% vs 3%, P = .883). On average, patients who received OPPT incurred an increase in average cost of $1340.87 and $1893.42 for Medicare and private insurer patients, respectively. We did not identify any significant risk factors for failing HEP. CONCLUSION: Comparable outcomes were demonstrated between patients receiving HEP compared to OPPT with a substantial cost saving. While a portion of patients still require formal OPPT, the majority do not. Surgeons should consider an initial trial of HEP with close follow-up in order to limit unnecessary costs associated with OPPT.

Perioperative Telephone Encounters Should Be Included in the Relative Value Scale Update Committee Review of Time Spent on Total Hip and Knee Arthroplasty.

BACKGROUND: Providing care for patients undergoing hip and knee arthroplasty requires substantial effort beyond the actual replacement surgery to ensure a safe, clinical, and economically effective outcome. Recently, the Centers for Medicare and Medicaid Services has stated that the procedural codes for total hip (THA) and total knee arthroplasty (TKA) are potentially misvalued and has asked for a review by the Relative Value Scale Update Committee (RUC). The purpose of this study is to quantify one of the additional work efforts associated with telephone encounters during the perioperative episode of care. METHODS: We retrospectively reviewed all 47,841 telephone calls from patients to our office from 2015 to 2017 in a consecutive series of 3309 patients who underwent TKA and 3651 patients who underwent THA. We recorded reasons for communication, amount of communication, and the caller identity for both 30 days preoperatively and 90 days postoperatively. We then used the RUC Building Block Method to calculate the preservice and postservice work included in a review of the time and intensity of the codes for THA and TKA. RESULTS: The average number of preoperative patient calls per patient was 2.31 for TKA and 2.44 for THA, and the average number of postoperative calls was 5.01 for TKA and 4.00 for THA. The most common reasons for patient calls were perioperative care instructions, medications, medical clearance, paperwork/insurance, and complications. Using the RUC-approved work relative value units (wRVUs) assigned to each telephone encounter, an additional 1.83 wRVUs for perioperative telephone encounters for TKA and 1.61 for THA should be assigned. CONCLUSIONS: Providing patients with appropriate support during the arthroplasty episode of care requires substantial telephonic support, which should be acknowledged. As the RUC considers reviewing the time and intensity spent on perioperative care for patients undergoing THA and TKA, they should consider appropriately documenting the amount of work required for telephone communication.

Survivorship and Outcomes in Patients With Multiple Sclerosis Undergoing Total Joint Arthroplasty.

BACKGROUND: Patients with multiple sclerosis (MS) frequently require total joint arthroplasty (TJA). The outcomes of TJA in patients with MS, who are frequently on immunomodulatory medications and physically deconditioned, remain largely unknown. The aim of this study is to elucidate the survivorship and reasons for failure in this patient population. METHODS: A single-institution retrospective review of 108 TJAs (46 knees and 62 hips) was performed from 2000 to 2016. An electronic chart query based on MS medications and International Classification of Diseases, Ninth Revision codes was used to identify this population followed by a manual review to confirm the diagnosis. Outcomes were then assessed using revision for any reason as the primary end point. Functional outcomes were assessed using Short Form 12 scores. Survivorship curves were generated using the Kaplan-Meier method. RESULTS: At an average follow-up of 6.2 years, 19.4% (21/108) of patients required a revision surgery. Instability (5.6%, P = .0278) and periprosthetic joint infection (4.6%, P = .0757) were among the most common reasons for revision. The overall survivorship of TJA at years 2, 5, and 7, respectively, was 96.5% (95% confidence interval [CI], 92.6-100), 86.3% (95% CI, 77.7-94.5), and 75.3% (95% CI, 63.5-87.0). Functional score improvement was less in MS cohort than patients without MS. CONCLUSION: Patients with MS are at increased risk of complications, particularly instability and periprosthetic joint infection. Despite this increased risk of complications, patients with MS can demonstrate improved functional outcomes, but not as much as patients without MS. Patients with MS should be counseled appropriately before undergoing TJA.

Who Goes to Inpatient Rehabilitation or Skilled Nursing Facilities Unexpectedly Following Total Knee Arthroplasty?

BACKGROUND: Inpatient rehabilitation facilities (IRFs) and skilled nursing facilities (SNFs) represent a significant portion of post-operative expenses of bundled payments for total knee arthroplasty (TKA). Although many surgeons no longer routinely send patients to IRFs or SNFs, some patients are unable to be discharged directly home. This study identified patient factors for discharge to post-acute care facilities with an institutional protocol of discharging TKA patients home. METHODS: A retrospective review of patients undergoing primary unilateral TKA at a single institution from 2012 to 2017 was performed. All surgeons discharged patients home as a routine protocol. An electronic query followed by manual review identified discharge disposition, demographic factors, co-morbidities, and other patient factors. In total, 2281 patients were identified, with 9.6% discharged to SNFs or IRFs and 90.4% discharged home. Univariate and multivariate analyses were conducted to create 2 predictive models for patient discharge: pre-operative visit and hospital course. RESULTS: Among 43 variables studied, 6 were found to be significant pre-operative risk factors for a discharge disposition other than home. In descending order, age 75 or greater, female, non-Caucasian race, Medicare status, history of depression, and Charlson Comorbidity Index were predictors for patients going to IRFs. In addition, any in-hospital complications led to a higher likelihood of being discharged to IRFs and SNFs. Both models had excellent predictive assessments with area under curve values of 0.79 and 0.80 for pre-operative visit and hospital course. CONCLUSION: This study identifies pre-operative and in-hospital factors that predispose patients to non-routine discharges, which allow surgeons to better predict patient post-operative disposition.

Total Joint Arthroplasty in Patients With Parkinson's Disease: Survivorship, Outcomes, and Reasons for Failure.

BACKGROUND: Gait instability and muscle rigidity are known characteristics of Parkinson's disease (PD), putting PD patients at risk for complications following total joint arthroplasty (TJA). The outcomes of Parkinson's patients undergoing TJA are largely unknown. This study evaluated the outcomes of TJA in this population. METHODS: A single institution retrospective cohort of 123 TJAs (52 hips, 71 knees) from 2000 to 2016 was reviewed. An electronic chart query was performed using International Classification of Diseases, Ninth revision codes to identify this population. A manual chart review was performed to confirm the diagnosis of PD, survivorship, and reason for failure. A control cohort was matched 2:1 based on age, body mass index, joint, and comorbidities. Outcomes were assessed using revision for any reason as the primary endpoint. Functional outcomes were assessed using Short-Form 12 scores. RESULTS: At an average follow-up of 5.3 years, 23.6% of patients required revision surgery. The most common reasons for revision for total knee arthroplasty (TKA) were periprosthetic infection and for total hip arthroplasty (THA) were periprosthetic fracture and dislocation. Overall survivorship of TJA at years 2, 5, and 10 respectively were 94.9%, 87.9%, and 72.3%. The survivorship of TKA was 95.2%, 89.8%, and 66.2%. THA implant survivorship was 94.3%, 85.3%, and 78.7%. Functional score improvement was less in PD cohort than the control. CONCLUSION: Patients with PD are at increased risk for complications, particularly periprosthetic infection following TKA and periprosthetic fracture and dislocation following THA. Despite this increased risk of complications, patients with PD can demonstrate improved functional outcomes but not as high as patients without PD. Patients with PD should be counseled appropriately prior to undergoing TJA.

Periarticular Injection of Liposomal Bupivacaine Offers No Benefit Over Standard Bupivacaine in Total Knee Arthroplasty: A Prospective, Randomized, Controlled Trial.

BACKGROUND: Periarticular injection of liposomal bupivacaine has been adopted as part of multimodal pain management after total knee arthroplasty (TKA). METHODS: In this prospective, randomized clinical trial, we enrolled 162 patients undergoing primary TKA in a single institution between January 2014 and May 2015. Eighty-seven patients were randomized to liposomal bupivacaine (experimental group), and 75 patients were randomized to free bupivacaine (control group). All patients received spinal anesthesia and otherwise identical surgical approaches, pain management, and rehabilitation protocols. Outcomes evaluated include the patient-reported visual analog pain scores, narcotic consumption, and narcotic-related side effects (Brief Pain Inventory) within 96 hours after surgery as well as functional outcomes using the Knee Society Score and the Short-Form 12 measured preoperatively and at 4-6 weeks after surgery. RESULTS: There were no statistically significant differences between the groups in terms of postoperative daily pain scores, narcotic consumption (by-day and overall), or narcotic-related side effects. There were no statistically significant differences between the groups in terms of surgical (P = .76) and medical complications or length of hospital stay (P = .35). There were no statistically significant differences in satisfaction between the groups (P = .56) or between the groups in postoperative Knee Society Score (P = .53) and the Short-Form 12 at 4-6 weeks (P = .82, P = .66). CONCLUSION: As part of multimodal pain management protocol, periarticular injection of liposomal bupivacaine compared with bupivacaine HCl did not result in any clinically or statistically significant improvement of the measured outcomes following TKA.

Can We Reduce the Utilization of Home-Visiting Nurse Services After Primary Total Joint Arthroplasty?

BACKGROUND: Home-visiting nurse services (HVNSs) after total joint arthroplasty (TJA) are touted as advantageous compared with inpatient rehabilitation. No study has established the utility of HVNSs compared with discharge home without services. METHODS: A retrospective single-surgeon consecutive series of 509 primary TJA patients compared discharge disposition, length of stay, complications, and patient satisfaction between 2 cohorts. The cohorts were defined by the elimination of routine HVNSs. RESULTS: Surprisingly, without routine HVNSs, more patients were discharged home (95% vs 88.3% with routine HVNSs) and mean length of stay significantly decreased. Complication rate was similar (2.9% vs 3.9% with routine HVNSs). Patient satisfaction remained favorable. We estimated that eliminating HVNSs avoids excess costs of $1177 per hip and $1647 per knee arthroplasty. CONCLUSIONS: With dramatically diminished HVNS utilization after primary TJA, there was an associated decrease in length of stay and no increase in complication rate suggesting no compromise of patient care with significant cost savings.

Direct Cost and Complications Associated With Total Joint Arthroplasty in Patients With Preoperative Anxiety and Depression.

INTRODUCTION: The outcome of total joint arthroplasty (TJA) may be affected by numerous factors including the mental health status of patients and the presence of psychological disorders Therefore, the present study was designed and conducted to determine the impact of concomitant psychiatric disorders on the hospitalization charges and complications in patients with preoperative depression or anxiety undergoing TJA. MATERIALS AND METHODS: International Classification of Diseases, Ninth Revision, codes were used to identify perioperative complications in patients with and without concomitant diagnosis of depression or anxiety who underwent TJA at our institution during 2009. Hospitalization charges and complications were compared for patients with and without depression or anxiety undergoing TJA. RESULTS: Respectively, 12.7% and 6.4% of knee and the hip arthroplasty patients had concomitant depression or anxiety. In the knee but not the hip group, the charge was $3420 higher in patients with depression/anxiety (P < .001). Anxiety and depression and higher American Society of Anesthesiologists score were independent predictors of complications. DISCUSSION: Depression or anxiety was a predictor of increased complications after TJA. Therefore, patients with depression or anxiety undergoing TJA need to be counselled appropriately, and all efforts need to be invested to minimize complications and the added cost in these patients.

Staphylococcal persistence due to biofilm formation in synovial fluid containing prophylactic cefazolin.

Antibiotic prophylaxis is standard for patients undergoing surgical procedures, yet despite the wide use of antibiotics, breakthrough infections still occur. In the setting of total joint arthroplasty, such infections can be devastating. Recent findings have shown that synovial fluid causes marked staphylococcal aggregation, which can confer antibiotic insensitivity. We therefore asked in this study whether clinical samples of synovial fluid that contain preoperative prophylactic antibiotics can successfully eradicate a bacterial challenge by pertinent bacterial species. This study demonstrates that preoperative prophylaxis with cefazolin results in high antibiotic levels. Furthermore, we show that even with antibiotic concentrations that far exceed the expected bactericidal levels, Staphylococcus aureus bacteria added to the synovial fluid samples are not eradicated and are able to colonize model implant surfaces, i.e., titanium pins. Based on these studies, we suggest that current prophylactic antibiotic choices, despite high penetration into the synovial fluid, may need to be reexamined.

Administration of Aspirin as a Prophylaxis Agent Against Venous Thromboembolism Results in Lower Incidence of Periprosthetic Joint Infection.

The efficacy and safety of aspirin (ASA) for prevention of venous thromboembolism (VTE) following total joint arthroplasty (TJA) have been demonstrated. Our hypothesis was that postoperative ASA compared to warfarin lowers the incidence of periprosthetic joint infection (PJI). Between January 2006 and December 2012, 1456 patients received ASA and 1700 patients received warfarin following primary TJA as standard VTE prophylaxis. Logistic regression was utilized to identify independent risk factors of PJI. Incidence of PJI was significantly lower at 0.4% in patients receiving ASA vs. 1.5% in patients receiving warfarin (P<0.001). Warfarin and elevated BMI were independent risk factors for PJI following TJA (P<0.05). Our research suggests that the use of ASA compared to warfarin for VTE prophylaxis reduces the risk of PJI following TJA.

Intraoperative Proximal Femoral Fracture in Primary Cementless Total Hip Arthroplasty.

Intraoperative proximal femoral fracture is a complication of primary cementless total hip arthroplasty (THA) at rates of 2.95-27.8%. A retrospective review of 2423 consecutive primary cementless THA cases identified 102 hips (96 patients) with fracture. Multivariate analysis compared fracture incidences between implants, Accolade (Stryker Orthopaedics) and Tri-Lock (DePuy Orthopaedics, Inc.), and evaluated potential risk factors using a randomized control group of 1150 cases without fracture. The fracture incidence was 4.4% (102/2423), 3.7% (36/1019) using Accolade and 4.9% using Tri-Lock (66/1404) (P=0.18). Female gender (OR=1.96; 95% CI 1.19-3.23; P=0.008) and smaller stem size (OR=1.64; 95% CI 1.04-2.63; P=0.03) predicted increased odds of fracture. No revisions of the femoral component were required in the fracture cohort.

Direct Costs of Aspirin versus Warfarin for Venous Thromboembolism Prophylaxis after Total Knee or Hip Arthroplasty.

Interest in aspirin as an alternative strategy for venous thromboembolism prophylaxis after arthroplasty has grown, as studies have suggested improved clinical efficacy and lower complication rates with aspirin compared to warfarin. The goal of this study was to compare the direct costs of an episode of arthroplasty care, when using aspirin instead of warfarin. The charts of patients who either received aspirin or warfarin after arthroplasty from January 2008 to March 2010 were retrospectively reviewed. Charges were recorded for their index admission, and for subsequent admissions related to either VTE or complications of prophylaxis. Multivariate analysis revealed that aspirin was an independent predictor of decreased cost of index hospitalization, and total episode of care charges, achieved largely through a shorter length of hospitalization.

Patellar clunk syndrome after total knee arthroplasty; risk factors and functional outcomes of arthroscopic treatment.

This study reports the incidence, risk factors, and functional outcomes of the largest reported series of patients treated arthroscopically for patella clunk syndrome (PCS). All patients treated arthroscopically for PCS were identified. Patients were matched with controls by sex and date of surgery. Follow-up was conducted using SF-12 and WOMAC questionnaires. Operative notes and preoperative and postoperative radiographs were reviewed. Seventy-five knees in 68 patients were treated arthroscopically for PCS. Average follow-up was 4.2 years. Functional scores demonstrated no statistical difference. PCS patients had a significantly more valgus preoperative alignment, greater change in posterior femoral offset and smaller patellar component size. PCS is a relatively common complication following TKA. Arthroscopy yields functional results comparable to controls. Radiographic and technical factors are associated with PCS.

In Vivo Intra-Articular Antibiotic Concentrations at 24 Hours After TKA Fall Below the Minimum Inhibitory Concentration for Most Bacteria: A Randomized Study of Commercially Available Bone Cement.

BACKGROUND: The use of antibiotic-loaded bone cement (ALBC) to help reduce the risk of infection after primary total knee arthroplasty (TKA) is controversial. There is a paucity of in vivo data on the elution characteristics of ALBC. We aimed to determine whether the antibiotic concentrations of 2 commercially available ALBCs met the minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) for common infecting organisms. METHODS: Forty-five patients undergoing TKA were randomized to receive 1 of the following: bone cement without antibiotic (the negative control; n = 5), a commercially available formulation containing 1 g of tobramycin (n = 20), or a commercially available formulation containing 0.5 g of gentamicin (n = 20). Intra-articular drains were placed, and fluid was collected at 4 and 24 hours postoperatively. An automated immunoassay measuring antibiotic concentration was performed, and the results were compared against published MIC and MBEC thresholds. RESULTS: The ALBC treatment groups were predominantly of White (65%) or Black (32.5%) race and were 57.5% female and 42.4% male. The mean age (and standard deviation) was 72.6 ± 7.2 years in the gentamicin group and 67.6 ± 7.4 years in the tobramycin group. The mean antibiotic concentration in the tobramycin group was 55.1 ± 37.7 µg/mL at 4 hours and 19.5 ± 13.0 µg/mL at 24 hours, and the mean concentration in the gentamicin group was 38.4 ± 25.4 µg/mL at 4 hours and 17.7 ± 15.4 µg/mL at 24 hours. Time and antibiotic concentration had a negative linear correlation coefficient (r = -0.501). Most of the reference MIC levels were reached at 4 hours. However, at 24 hours, a considerable percentage of patients had concentrations below the MIC for many common pathogens, including Staphylococcus epidermidis (gentamicin: 65% to 100% of patients; tobramycin: 50% to 85%), methicillin-sensitive Staphylococcus aureus (gentamicin: 5% to 90%; tobramycin: 5% to 50%), methicillin-resistant S. aureus (gentamicin: 5% to 65%; tobramycin: 50%), Streptococcus species (gentamicin: 10% to 100%), and Cutibacterium acnes (gentamicin: 10% to 65%; tobramycin: 100%). The aforementioned ranges reflect variation in the MIC among different strains of each organism. Gentamicin concentrations reached MBEC threshold values at 4 hours only for the least virulent strains of S. aureus and Escherichia coli. Tobramycin concentrations did not reach the MBEC threshold for any of the bacteria at either time point. CONCLUSIONS: The elution of antibiotics from commercially available ALBC decreased rapidly following TKA, and only at 4 hours postoperatively did the mean antibiotic concentrations exceed the MIC for most of the pathogens. Use of commercially available ALBC may not provide substantial antimicrobial coverage following TKA. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Has the rate of in-hospital infections after total joint arthroplasty decreased?

BACKGROUND: Although infections are a major cause of morbidity and mortality after total joint arthroplasty (TJA), little is known about nationwide epidemiology and trends of infections after TJA. QUESTIONS/PURPOSES: We therefore determined (1) trends of postoperative pneumonia, urinary tract infection (UTI), surgical site infection (SSI), sepsis, and severe sepsis after TJA; (2) risk factors of these infections; (3) effect of these infections on length of stay (LOS) and hospital charges; and (4) the infection-related mortality rate and its predictors. METHODS: The International Classification of Diseases, 9th Revision codes were used to identify patients who underwent TJA and were diagnosed with aforementioned infections during hospitalization in the Nationwide Inpatient Sample database from 2002 to 2010. Multivariate analysis was performed to identify risk factors of these infections. RESULTS: Rates of pneumonia, UTI, SSI, sepsis, and severe sepsis were 0.74%, 3.26%, 0.31%, 0.25%, and 0.15%, respectively. Number of comorbidities and type of TJA were independent predictors of infection. Mortality decreased during the study period (odds ratio, 0.87; 95% confidence interval, 0.86-0.89). The median LOS was 3 days without complications but increased in the presence of SSI (median, 7 days), sepsis (median, 12 days), and severe sepsis (median, 15 days). Occurrence of pneumonia, sepsis, and severe sepsis increased risk of mortality 5.2, 8.5, and 66.2 times, respectively. CONCLUSIONS: Rates of UTI, pneumonia, and SSI but not sepsis and severe sepsis are apparently decreasing. The likelihood of infection is increasing with number of comorbidities and revision surgeries. Rate of sepsis-related mortality is also decreasing. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.