Complication rates following reverse and anatomic shoulder replacement in treatment of glenohumeral arthritis: a 10-year Medicare review study.

BACKGROUND: We sought to compare the complication rates after anatomic total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (RSA) for primary glenohumeral arthritis in a Medicare population. METHODS: Patients who underwent a shoulder arthroplasty were identified from the 5% subset of Medicare parts A/B between 2009 and 2019. Patients with less than 1-year follow-up were excluded. A total of 8846 patients with a diagnosis of glenohumeral arthritis were then subdivided into those who received aTSA (5935 patients) and RSA (2911 patients). A multivariate Cox regression analysis was then performed comparing complication rates at 3 months, 6 months, 1 year, 2 years, and 5 years. RESULTS: Statistically significant increased rates of instability (hazard ratio [HR] = 1.46), fracture of the scapula (HR = 7.76), infections (HR = 1.45), early revision (HR = 1.79), and all complications (HR = 1.32) were seen in the RSA group. There was no significant difference in revision rate at 5 years between the 2 groups. There was no difference in patient characteristics or comorbid conditions (smoking status, diabetes, Charlson score, etc.) or hospital characteristics (location, teaching status, public vs. private, etc.) between the 2 groups. CONCLUSION: An increased rate of early complications was observed with the use of RSA compared with aTSA for the treatment of primary glenohumeral arthritis, including instability, scapula fracture, infection, and all cause complication. No difference in revision rate between RSA and aTSA at 5 years was observed.

Incidence of Instability Following Primary Total Hip Arthroplasty Continues to Decline in the Medicare Population.

BACKGROUND: Instability has been the primary cause of failure following primary total hip arthroplasty (THA) leading to revision hip surgery. The purpose of this study was to determine if instability rates have further declined following advances in primary THA, including dual mobility articulations, direct anterior approaches, advanced technologies, and improved knowledge of the hip-spine relationships. METHODS: Using the 5% Medicare Part B claims data from 1999 to 2019, we identified 81,573 patients who underwent primary THA for osteoarthritis. Patients who experienced instability at 3 months, 6 months, 1 year, and 2 years were identified. Multivariate cox regression analyses evaluated the effect of patient and procedure characteristics on the risk of instability. RESULTS: Instability at 1 year following primary THA declined from approximately 4% in 2000 to 2.3% in 2010 and 1.6% in 2018. The leading cause of revision surgery was infection (18.6%), followed by periprosthetic fracture (14%), mechanical loosening (11.5%), and instability (9.4%). High-risk groups for instability continue to include increased age, higher Charlson index, obesity, lumbar spine pathology, and neurocognitive disorders. CONCLUSION: Instability is no longer the leading etiology of failure following primary THA with a decline of approximately 40% over the past decade. Infection, periprosthetic fracture, mechanical loosening, and then instability are now the leading causes of failure. Multiple factors may play a role in the decline of instability, including increased use of dual mobility articulations, direct anterior approaches, improved knowledge of the hip-spine relationships, and use of advanced technologies.

Manipulation Following Primary Total Knee Arthroplasty is Associated With Increased Rates of Infection and Revision.

BACKGROUND: Stiffness following total knee arthroplasty (TKA) is a disabling complication and manipulation under anesthesia (MUA) is often performed as an early intervention. Few studies have focused on the revision risk, infection risk, demographics, and clinical outcomes in Medicare patients undergoing MUA following primary TKA. METHODS: We reviewed 142,440 patients who had primary TKA from a national database and identified 3,652 patients (2.6%) who underwent MUA. Patient demographics and comorbid conditions were evaluated to identify risk factors. Incidence of revision and periprosthetic joint infection (PJI) at 1-, 2-, and 5-year time points in a cohort of MUA patients was compared to patients who did not undergo MUA. Multivariate Cox regressions were used for statistical analyses. RESULTS: The incidence of MUA was higher in Black versus White individuals (4.1 versus 2.5%, P < .001). Revision risk was significantly greater in the MUA group at 1-, 2-, and 5-year time points with a hazard ratio (HR) of, 3.81, 3.90, and 3.22 respectively, P < .001. One- and 2-year revision risk was significantly greater when MUA occurred at 6 to 12 months post-TKA when compared to <3 months, P < .05. Risk of PJI was significantly greater in the MUA group with a HR of 2.2, 2.2, and 2.1 at 1, 2, and 5 years, respectively P < .001. CONCLUSION: The incidence of MUA was 2.6%. There was an increased incidence of revision surgery and PJI in patients undergoing MUA. Patients at increased risk for stiffness following TKA should be closely monitored and treated with early intervention to minimize risk of poor outcomes.

Cost Analysis of Medicare Patients with Varying Complexities Who Underwent Total Knee Arthroplasty.

The effort to reduce overall healthcare costs may affect more complex patients, as their pre- and postoperative care can be substantially involved. Therefore, the purpose of this study was to use a large nationwide insurance database to compare (1) costs, (2) reimbursements, and (3) net losses of 90-day episodes of care (EOC) for total knee arthroplasty (TKA) patients according to Elixhauser's Comorbidity Index (ECI) scores. All TKAs performed between 2005 and 2014 in the Medicare Standard Analytic Files were extracted from the database and stratified based on ECI scores, ranging from 1 to 5. ECI 1 patients served as the control cohort, while ECI 2, 3, 4, and 5 patients were considered study cohorts. Each study cohort and control cohort were matched based on age and sex, resulting in a total of 715,398 patients included for analysis. Total EOC costs, reimbursements, and total net losses (defined as total EOC costs minus total EOC reimbursements) were compared between the cohorts. Overall, total EOC costs increased with ECI. For example, compared with the matched ECI 1 cohorts, the total EOC costs for ECI 5 patients ($56,589.19 vs. $51,747.54) were significantly greater (p < 0.01). Although reimbursements increased with increasing ECI, so did net losses. The net losses for ECI 5 patients were greater than that for ECI 1 patients ($42,309.39 vs. $40,007.82). The bundled payments for care improvement (BPCI) and comprehensive care for joint replacement (CJR) are alternative payment models that might de-incentivize treatment of more complex patients. Our study found that despite increasing reimbursements, overall costs, and therefore net losses, were greater for more complex patients with higher ECI scores.

Corrosion Concerns? Trends in Metal-on-Polyethylene Total Hip Arthroplasty Revision Rates and Comparisons Against Ceramic-on-Polyethylene up to 10 Years of Follow-Up.

BACKGROUND: We compared the revision risk between metal-on-polyethylene (MOP) and ceramic-on-polyethylene (COP) total hip arthroplasty patients and evaluated temporal changes in short-term revision risks for MOP patients. METHODS: Primary MOP (n = 9480) and COP (n = 3620) total hip arthroplasties were evaluated from the Medicare data set (October 2005 to December 2015) for revision risk, with up to 10 years of follow-up using multivariate analysis. Temporal change in the short-term revision risk for MOP was evaluated (log-rank and Wilcoxon tests). RESULTS: Revision incidence was 3.8% for COP and 4.3% for MOP. MOP short-term revision risk did not change over time (P ≥ .844 at 1 year and .627 at 2 years). Dislocation was the most common reason for revision (MOP: 23.5%; COP: 24.8%). Overall adjusted revision risks were not different between MOP and COP up to 10 years of follow-up (P ≥ .181). CONCLUSIONS: Concerns with corrosion for metal heads do not appear to result in significantly elevated revision risk for MOP at up to 10 years. Corrosion does not appear as a primary reason for revision compared to other mechanisms.

Does Timing of Primary Total Hip Arthroplasty Prior to or After Lumbar Spine Fusion Have an Effect on Dislocation and Revision Rates?

BACKGROUND: Patients undergoing primary total hip arthroplasty (THA) following lumbar spine fusion have an increased incidence of dislocation compared to those without prior lumbar fusion. The purpose of this study is to determine if timing of THA prior to or after lumbar fusion would have an effect on dislocation and revision incidence in patients with both hip and lumbar spine pathology. METHODS: One hundred percent Medicare inpatient claims data from 2005 to 2015 were used to compare dislocation and revision risks in patients with primary THA with pre-existing lumbar spine fusion vs THA with subsequent lumbar spine fusion within 1, 2, and 5 years after the index THA. A total of 42,300 patients met inclusion criteria, 28,668 patients of which underwent THA with pre-existing lumbar spinal fusion (LSF) and 13,632 patients who had prior THA and subsequent LSF. Patients who had THA first followed by LSF were further stratified based on the interval between index THA and subsequent LSF (1, 2, and 5 years), making 4 total groups for comparison. Multivariate cox regression analysis was performed adjusting for age, socioeconomic status, race, census region, gender, Charlson score, pre-existing conditions, discharge status, length of stay, and hospital characteristics. RESULTS: Patients with prior LSF undergoing THA had a 106% increased risk of dislocation compared to those with LSF done 5 years after THA (P < .001). Risk of revision THA was greater in the pre-existing LSF group by 43%, 41%, and 49% at 1, 2, and 5 years post THA compared to the groups with THA done first with subsequent LSF. Dislocation was the most common etiology for revision THA in all groups, but significantly higher in the prior LSF group (26.6%). CONCLUSION: Results of this study demonstrate that sequence of surgical intervention for concomitant lumbar and hip pathology requiring LSF and THA respectively significantly impacts the fate of the THA performed. Patients with prior LSF undergoing THA are at significantly higher risk of dislocation and subsequent revision compared to those with THA first followed by delayed LSF. LEVEL OF EVIDENCE: 3.

Complications After Revision Total Hip Arthroplasty in the Medicare Population.

BACKGROUND: The purpose of this study was to identify the incidence and types of complications after revision total hip arthroplasty (THA) within the first year, and determine the relative risk factors for these complications and of re-revision. METHODS: The sample size of 5% Medicare claims data from 1998-2011 was studied. Primary THA patients who underwent subsequent revision were identified using ICD-9-CM codes. Outcomes and complications after revision THA were assessed. Multivariate Cox regression was used to evaluate the effect of patient demographic characteristics on the adjusted complication risk for revision THA patients. RESULTS: Of the 64,260 primary THA patients identified between 1998 and 2011, 3555 patients (5.71%) underwent revision THA. Etiology of primary hip failure included mechanical complications such as loosening and wear (40.7%), dislocation (14.0%), and infection (11.3%). Complications after revision THA included infection and redo revision, 17.3% and 15.8% followed by venous thromboembolic disease (VTE) at 11.1%, dislocation at 5.43%, PE at 3.24%, and death at 2.11%. The rate of "new" infections after an aseptic revision was 8.13%. Patients in the 85+-year-old age group had a 100% greater adjusted risk of VTE (P < .001) and 406% higher adjusted risk of death (P < .001) than those in the 65-69 years-old age group. Patients with higher Charlson scores had higher adjusted risks of VTE (P < .001), infection (P < .001), death (P = .002), and re-revision THA (P = .011). CONCLUSION: Advanced age is a clear risk factor for VTE and mortality, but not for dislocation, infection, or re-revision. Higher Charlson index was found to be a risk factor for every complication after revision except dislocation. Greater attention is required to address the high rate of infection and re-do revision after revision THA (17.3% and 15.8%).

High Risk of Readmission in Octogenarians Undergoing Primary Hip Arthroplasty.

BACKGROUND: As life expectancy increases, more elderly patients with end-stage hip arthritis are electing to undergo primary THA. Octogenarians undergoing THA have more comorbidities than younger patients, but this is not reflected in risk adjustment models for bundled care programs. The burden of care associated with THA in octogenarians has not been well characterized, and doing so may help these value-based programs make adjustments so that this vulnerable patient population does not risk losing access under accountable care models. QUESTIONS/PURPOSES: The purpose of this study was to describe care use, comorbidities, and complications among octogenarians undergoing primary THA. METHODS: Five percent of the Medicare national administrative claims data was queried to identify patients diagnosed with hip osteoarthritis between January 1, 1998, and December 31, 2013. Patients who underwent primary THA were identified and followed longitudinally during the study period using their unique, encrypted Medicare beneficiary identifiers. We compared risk factors and complications between the octogenarian group versus those aged 65 to 69 years. Multivariate Cox regression was used to evaluate the effect of patient/hospital factors on risk of revision, periprosthetic joint infection, dislocation, venous thromboembolism (VTE), and mortality. Patient factors in the model included age, sex, race, region, socioeconomic status, and health status based on Charlson comorbidity score 12 months before replacement surgery. RESULTS: There were 11,960 THAs in the octogenarians in 1998, which increased to 21,620 in 2013, an 81% increase during this study period. Octogenarians were more likely to have a Charlson score of 3 or higher than those patients aged 65 to 69 years (30% versus 17%, odds ratio [OR] 2.07 [1.98-2.20]; p < 0.001), and they were more likely to have coronary artery disease or congestive heart failure (47% versus 29%, OR 2.16 [2.06-2.26]; p < 0.001). The octogenarian group had a greater risk of dislocation (+12%, p = 0.01), VTE (+14%, p < 0.001), and mortality (+150%, p < 0.001) compared with the younger age cohort. A total of 21% of the octogenarians were readmitted after surgery compared with 12% for patients in the younger group (OR=1.64, 95% confidence interval 1.54-1.75; p < 0.001). CONCLUSIONS: Because octogenarians are at increased risk of dislocation, VTE, medical complications, and mortality after THA, value-based care models that penalize hospitals for readmissions and complications may inadvertently result in loss of access to care for this group of patients as a result of the financial makeup of these bundled care models. Value-based care models were developed to improve care and decrease healthcare costs but may have unintended consequences in the octogenarian with higher complication and readmission risks. Financial losses may lead to institutions from withdrawing from the Bundled Payments for Care Improvement program. To try to prevent this from happening to this vulnerable patient population, bundled care programs should evolve and be modified to allow for risk stratification in the overall payment formula to account for increased age and comorbid conditions to ensure continued successful participation in the program among all the stakeholders. LEVEL OF EVIDENCE: Level III, therapeutic study.

Economic evaluation of different suture closure methods: barbed versus traditional interrupted sutures.

Healthcare systems are receiving increasing pressures from payers, such as the Centers for Medicare and Medicaid (CMS), to reduce the costs associated with procedures, and with the implementation of the Affordable Care Act, high costs are addressed through pay-for-performance programs. Thus, multiple areas of total knee arthroplasty (TKA) surgery are under scrutiny, including surgical times, material costs, and the costs of associated complications and readmissions. Suture type has been determined to be a factor that may influence closure times, as well as direct material costs. Therefore, the purpose of this review was to compare: (I) the cost of using barbed vs. conventional interrupted sutures; (II) the additional cost of differences in complications, if any; (III) to extrapolate cost savings on a hospital and national level; and (IV) to discuss the role of these findings on hospital savings and the effect on bundled payments. It was found that the main factors affecting differences in overall costs between barbed and standard interrupted suture were material cost and closure time. Many studies have demonstrated greater cost savings with the barbed suture due to shorter operative times, despite the higher material costs. The majority of studies also demonstrated similar complication rates between the suture types, and thus these are unlikely to affect the cost difference. However, to the best of our knowledge, there are no TKA studies in the literature evaluating the effect of suture type and associated complications on lengths of stay and readmission rates. Thus, it is unclear how these cost savings will translate to reimbursements rates and the role that they might play in bundled payments. Several studies in other specialties demonstrate decreased infection rates with the use of barbed sutures, which, if found to be true for TKA can be extrapolated to 3 million dollars of savings in revision TKA costs. Further studies on this topic are needed to define these relationships.

Complication Risk After Treatment of Intertrochanteric Hip Fractures in the Medicare Population.

The study evaluated the incidence of and complications associated with the use of an intramedullary nail vs open reduction and internal fixation (ORIF) with a sliding compression hip screw and plate in treating intertrochanteric fractures. The authors hypothesized that the biomechanically stronger and less invasive intramedullary nail would have superior results and fewer complications compared with ORIF. Patients followed for up to 1 year postoperatively were identified from the 5% nationwide sample of Medicare administrative claims data (1998-2007) using the corresponding International Classification of Diseases, 9th revision, Clinical Modification, codes 820.21 and 820.31. There were 9157 patients treated with intramedullary nails and 27,687 treated with compression screw and plate fixation. Intertrochanteric hip fractures treated with an intramedullary nail during this period increased from 3.3% to 63.1% compared with ORIF. Patients treated with an intramedullary nail had a higher adjusted risk of pulmonary embolism at 90 days (P=.003) and a higher risk of mortality at 1 year (P<.001) compared with those treated with ORIF. Patients who underwent intramedullary nailing during 2006 to 2007 had a lower adjusted risk of conversion to total hip replacement at 1 year (P=.037) compared with those who had ORIF. Over the decade of the study, intramedullary nail usage increased 59.8% compared with ORIF. Increased use of intramedullary nails compared with ORIF has not shown improved outcomes or decreased complications in patients with intertrochanteric hip fractures. The increased use of intramedullary nails for intertrochanteric hip fractures appears to be multifactorial, including the less invasive nature of the surgery and increased experience with the closed surgical technique.

Readmission and Complications for Catheter and Injection Femoral Nerve Block Administration After Total Knee Arthroplasty in the Medicare Population.

There is general agreement that femoral nerve blocks (FNB) provide adequate immediate postoperative analgesia after total knee arthroplasty (TKA), although the effect of this technique on hospital readmission and other complications has not been quantified in a large sample. The Medicare 5% sample was used to identify TKA patients who were grouped according to postoperative FNB administration: FNB via injection; FNB via pain pump; and no FNB. Multivariate Cox regressions were used to evaluate risk factors for the postoperative outcomes. Both FNB groups were associated with a lower risk of readmission (30, 90 and 365 days, P<0.001). Future clinical studies may help elucidate whether the lower hospital readmissions may be associated with more effective pain control with the use of FNB.

Patient Selection in Short Stay Total Hip Arthroplasty for Medicare Patients.

There is a trend towards shortening inpatient hospital stays following total hip arthroplasty (THA) in an effort to reduce healthcare costs and potentially decrease complications. The purpose of this study was to identify patients who are at risk for readmission, complications, and mortality after short stay THA. The Medicare sample (1997-2011) was used to identify THA patients with 1-2-day (Group A, n=2949) or 3-day (Group B, n=8707) stays. Complication risks were similar between groups, though there was a reduced risk for hospitalization for Group A (adjusted hazard ratio=0.90, P=0.029). These findings suggest that age and comorbidities, particularly diabetes and cardiovascular conditions, have the greatest effect on readmission and event risk after short stay THA.

Dislocation rates following primary total hip arthroplasty have plateaued in the Medicare population.

The purpose of this study was to determine if the use of larger femoral head diameters, in combination with recent practice including enhanced soft tissue choices and various operative exposure choices has led to any further decline in dislocation rates. 51,901 patients undergoing primary THA were identified from 5% Medicare Part B (physician/carrier) claims between January 1, 1997 and December 31, 2011. Dislocation rate at 6 months following THA was 2.84% over the study period (1997-2011). From 2005 to 2011, dislocation rates following primary THA have plateaued in the United States at approximately 2%. This suggests that the full benefits using large femoral head sizes are now realized. For further improvement in dislocation rates, a greater emphasis will be required on patient selection, surgical technique and component alignment.

Complications, mortality, and costs for outpatient and short-stay total knee arthroplasty patients in comparison to standard-stay patients.

The purpose of the present study is to determine the differences in cost, complications, and mortality between knee arthroplasty (TKA) patients who stay the standard 3-4 nights in a hospital compared to patients who undergo an outpatient procedure, a shortened stay or an extended stay. TKA patients were identified in the Medicare 5% sample (1997-2009) and separated into the following groups: outpatient, 1-2 days, 3-4 days, or 5+ days inpatient. At two years, costs associated with the outpatient and the 1-2 day stay groups were $8527 and $1967 lower than the 3-4 day stay group, respectively. Out to 2 years, the outpatient and 1-2 day stay groups reported less pain and stiffness, respectively, though the 1-2 day group also had a higher risk for revision.

Operative treatment of acetabular fractures in the Medicare population.

The purpose of this study was to determine the incidence of and evaluate the risk for complications and mortality following open treatment of acetabular fractures in the Medicare population. Patients treated with open reduction and internal fixation (ORIF) for acetabular fractures were identified using current procedural terminology codes in a 5% national sample of Medicare records. Complications within 90 days and within 1 year were evaluated based on the presence of ICD-9-CM diagnosis codes and Current Procedural Terminology reoperation codes. A total of 1286 fractures were treated closed and 359 were treated with ORIF. Multivariate Cox regression was performed to compare complication rates and risk factors. The incidence of acetabular fractures in the Medicare population has increased by 29% since 1998. Complications in the ORIF group included cardiac complications, deep venous thrombosis, infection, pulmonary embolism, refixation, and conversion to total hip arthroplasty. Risk factors for complications with ORIF included advanced age and comorbidities. Mortality in the ORIF group was 14.4% at 1 year. The incidence of reoperation with conversion to total hip arthroplasty or revision fixation following ORIF is 10% and 15%, respectively. Further investigation is required to improve outcomes and decrease complications in this group of patients, especially cardiac, deep vein thrombosis, and infection.

Closed midshaft femur fractures: are they only for trauma centers?

Trauma centers are limited resources, particularly in rural areas, and availability of emergency care in some parts of the United States may be inadequate. The declining number of orthopedic surgeons willing to care for injured patients has limited access to fracture repair in some communities. We studied the management of closed midshaft femur fractures in both trauma centers (TCs) and nontrauma centers (NTCs) to evaluate outcome for this common orthopedic injury and determine if these issues have affected fracture care in Kentucky. All patients 16-years-old and older who suffered femur fractures in Kentucky from 2004 and 2005 were identified. There were 334 TC patients and 341 NTC patients with closed, midshaft femur fractures. The mean age of TC patients (33 ± 17 years) was significantly lower than that of NTC patients (59 ± 25 years). TC patients were more likely men (71% vs 44%), had more associated injuries (2.4 ± 2.1 vs 0.5 ± 1.2), and had longer lengths of stay (8.3 ± 9.8 vs 6.4 ± 7.1 days) (TCs vs NTCs, all P < 0.005). Although both groups ultimately underwent internal fixation (97% vs 99%, TCs vs NTCs), TC patients were more likely (2.7% vs 0.3%) to receive external fixation than the NTC patients (P < 0.05). There was no significant difference in the percentage of patients that received only a closed reduction. There was no significant difference in hospital mortality (0.3% vs 0.9%, TCs vs NTCs, P = 0.62). Although differences in patient populations exist between TCs and NTCs, both TCs and NTCs manage substantial numbers of patients with closed, midshaft femur fractures with low mortality in this state database.

Early- and late-term dislocation risk after primary hip arthroplasty in the Medicare population.

From 1998 to 2007 Medicare 5% national sample dataset, 39 271 primary total hip arthroplasty (THA) patients were identified. Dislocations within 2 years (early) and after 2 years (late) of primary THA were identified. Cox regression was used to evaluate patient, hospital, and procedure characteristics for risk of dislocation, and 1540 (3.92%) and 451 (1.15%) patients were diagnosed with early and late dislocations, respectively. Dislocation rate at 6 months' follow-up decreased steadily between 1998 and 2007 from 4.21% to 2.14%. Early and late dislocation risks were lower by 35% (P < .001) and 43% (P = .01), respectively, for patients operated during 2004 and 2007 compared with 1998 and 2003. Higher Charlson index scores (i.e., more comorbid conditions) and surgeon volume were significant risk factors (P < or = .04). Decrease in dislocation risks after primary THA seems to coincide with increasing use of larger diameter femoral heads. An awareness of risk factors for dislocation can help surgeons identify high-risk patients so as to prescribe appropriate intervention strategies.

Cost of antibiotic beads is justified: a study of open fracture wounds and chronic osteomyelitis.

BACKGROUND: The purpose of this study was to track the cost of antibiotic-impregnated bead chains and the outcome of treatment over a 30-month period occurring before USP Chapter 797 went into effect. Our overall objective was to determine whether the costs of antibiotic beads were justified by reduced rates of active infections associated with open fracture wounds or chronic osteomyelitis. METHODS: We retrospectively reviewed 125 patients with open fracture wounds (Group 1) and 16 patients with chronic osteomyelitis (Group 2) treated over a 2.5-year period. We reviewed the medical records and performed cost calculations for the beads. The minimum time from treatment to the latest follow-up evaluation was six weeks (average, 30.7 weeks; range, 6-134 weeks) for Group 1 and six months (average, 61.8 weeks; range, 24-156 weeks) for Group 2. RESULTS: The overall infection rates were 3.2% (96.8% free of active infection) for Group 1 and 25.0% (75.0% free of active infection) for Group 2. The average cost of antibiotic bead treatment per patient was $419.36 for Group 1 and $484.54 for Group 2. CONCLUSIONS: The costs of antibiotic beads to prevent active infection of open fracture wounds or to treat active infection associated with chronic osteomyelitis are justified based on the cost structure prior to the impact of new federal regulations (USP Chapter 797 regulations). We anticipate that the cost of antibiotic beads will increase dramatically with these new regulations.