Commercial Synovial Antigen Testing is Inferior to Traditional Culture for the Diagnosis of Periprosthetic Joint Infection in Patients Undergoing Revision Total Knee Arthroplasty.

BACKGROUND: Despite its limitations, a culture remains the "gold standard" for pathogen identification in patients who have periprosthetic joint infection (PJI). Recently, a synovial fluid antigen test has been introduced by a commercial entity. The purpose of this multicenter study was to determine the accuracy of the antigen test in the diagnosis of PJI. METHODS: This retrospective study identified 613 patients undergoing revision total knee arthroplasty who had undergone preoperative synovial fluid analysis. A PJI was defined using the 2018 International Consensus Meeting (ICM) criteria. Patients who had an extended period (> 180 days) from aspiration to revision procedure (n = 62), those presenting within 90 days of their index arthroplasty procedure (n = 17), and patients who had an inconclusive ICM score (n = 8) were excluded. Using receiver operator characteristic curve analyses, we examined the utility of the microbial identification (MID) antigen test and any positive culture (either preoperative or intraoperative) in the diagnosis of PJI. RESULTS: A total of 526 patients were included. Of these, 125 (23.8%) were ICM positive and 401 (76.2%) were ICM negative. Culture demonstrated an area under the curve (AUC) of 0.864, sensitivity of 75.2%, and specificity of 97.5%. On the other hand, the MID test exhibited an AUC of 0.802, sensitivity of 61.6%, and specificity of 98.8%. The AUC of culture was significantly higher than that of the MID test (P = .037). The MID test was positive in 41.9% of culture-negative PJI cases. We also observed a high rate of discordance (29.7%) when both culture and the MID test were positive in the ICM-positive group. CONCLUSIONS: Synovial fluid antigen testing does not provide additional clinical benefit when compared to traditional cultures for the diagnosis of PJI. The antigen test had low sensitivity in the diagnosis of PJI and a relatively high rate of discordance with culture. LEVEL OF EVIDENCE: Level III.

Total Hip Arthroplasty in Patients Who Have Respiratory Disease Who use Supplemental Home Oxygen.

BACKGROUND: The purpose of this study is to investigate the association between supplemental home oxygen prior to surgery and both medical and surgical complications after primary elective total hip arthroplasty (THA) in patients who have respiratory disease (RD). METHODS: The Mariner database was used to identify patients who have RD who received primary elective THA from 2010 to 2020. The THA patient cohorts consisted of 20,872 patients who had RD prescribed home oxygen and 69,520 patients who had RD without home oxygen. For patients who had a diagnosis of RD and were prescribed supplemental home oxygen (O2) and those who were not, the rates of postoperative medical and surgical complications, hospital readmissions, and emergency room visits were determined. Reimbursements and lengths of stay were also determined. Logistic regression analyses were utilized to compare both cohorts to matched cohorts without RD, as well as to each other directly. RESULTS: In comparison to the matched control group, the RD with home oxygen group had a significantly higher rate of pneumonia (odds ratio [OR] 4.27, P < .0001), pulmonary embolism (OR 1.81, P < .0001), periprosthetic joint infection (OR 1.21, P < .0001), and periprosthetic fracture (OR 1.81, P = .001). The RD with home oxygen cohort also had a significantly higher incidence of pneumonia (OR 2.16, P < .0001), periprosthetic joint infection (OR 1.38, P < .0001), and periprosthetic fracture (OR 1.24, P = .009) compared to RD patients who did not have home oxygen. CONCLUSION: Supplemental home oxygen use prior to surgery is associated with a significantly higher risk of postoperative medical and surgical complications after elective THA.

Osteopetrosis is Associated With an Increased Risk for Intraoperative Periprosthetic Fracture in Total Hip Arthroplasty but not in Total Knee Arthroplasty.

BACKGROUND: Osteopetrosis is a rare, inherited disorder in which bone remodels to become pathologically dense. There has been a paucity of data evaluating medical and surgical complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA) in this patient population. The objective of this study was to evaluate osteopetrosis as a potential risk factor for medical and surgical complications following THA and TKA. METHODS: Patients who had a diagnosis of osteopetrosis and underwent THA or TKA from 2010 to 2020 were identified in a national database. A total of 534 THA and 972 TKA patients who had osteopetrosis were identified and compared with matched cohorts of 2,670 and 4,860 patients, respectively. The rates of postoperative medical and surgical complications, hospital readmissions, and emergency room visits were calculated. In addition, reimbursements and lengths of stay were determined. Osteopetrosis patients were then compared to a 5:1 matched cohort without osteopetrosis using logistic regression analyses to control for additional confounding factors. RESULTS: The osteopetrosis THA group had a substantially higher incidence of intraoperative periprosthetic fracture compared to the matched cohort (1.12% versus 0.19%, Odds Ratio 5.88, P = .005). Patients who had a history of osteopetrosis were not found to be at a significantly increased risk for other investigated medical or surgical complications compared to matched controls following THA or TKA. CONCLUSION: Patients who had a history of osteopetrosis undergoing elective primary THA are associated with a significantly increased risk for intraoperative periprosthetic fracture. Patients with a history of osteopetrosis undergoing elective primary TKA were not found to be at an increased risk for any of the investigated complications.

Increased Dislocation Rates After Total Hip Arthroplasty in Patients With Prior Isolated Sacroiliac Joint Arthrodesis.

BACKGROUND: While stiffness of the lumbosacral spine is a known predictor of instability following total hip arthroplasty (THA), little is known about the medical- and surgical-related outcomes following THA in patients who have prior isolated sacroiliac (SI) joint arthrodesis. METHODS: 197 patients who had a history of isolated SI joint arthrodesis who subsequently underwent elective primary THA for a diagnosis of osteoarthritis (THA-SI) from 2015 to 2021 were identified in a national administrative database. Using propensity score matching and logistic regression analyses, this cohort was compared to two groups of patients: patients who did not have any history of lumbar or SI arthrodesis and patients undergoing primary THA who had a history of lumbar arthrodesis without extension into the SI joint (THA-LF). RESULTS: The THA-SI group had a significantly higher incidence of dislocation (odds ratio 2.06, 95% confidence interval 1.04-4.04, P = .037) with no increased incidence of medical complications or other surgical complications when compared to patients without a history of SI or lumbar arthrodesis. There were no significant differences in any complications in THA-SI patients when compared to THA-LF patients. CONCLUSION: Patients who had prior isolated SI joint arthrodesis undergoing primary THA demonstrated a two-fold increased incidence of dislocation when compared to those who did not have prior SI arthrodesis, although the risk of complications in this population was similar to that observed in patients who had prior isolated lumbar spine arthrodesis.

Use of Supplemental Home Oxygen is Associated With Early Postoperative Complications Following Total Knee Arthroplasty.

BACKGROUND: The objective of this study is to evaluate preoperative supplemental home oxygen use as a potential risk factor for both medical and surgical complications following primary elective total knee arthroplasty (TKA) in patients who have respiratory disease (RD). METHODS: Patients with a diagnosis of RD who underwent elective TKA from 2010 to 2020 were identified using a national database. The rates of postoperative medical and surgical complications, hospital readmissions, and emergency room visits were calculated for RD patients who used supplemental home oxygen and those who did not. Additionally, reimbursements and lengths of stay were determined. Both cohorts were then compared to matched cohorts who did not have RD using logistic regression analyses. RESULTS: A total of 41,418 patients who underwent TKA with RD on home oxygen and 138,635 patients who had RD without home oxygen use were compared with matched cohorts. The RD cohort with home oxygen use had a significantly higher incidence of periprosthetic joint infection (5.78% versus 2.69%, odds ratio [OR] 1.42, P < .0001), pneumonia (3.95% versus 0.69%, OR 4.44, P < .0001), venous thromboembolism (3.17% versus 2.10%, OR 1.12, P = .007), and periprosthetic fracture (0.82% versus 0.34%, OR 1.72, P < .0001) compared to the matched control cohort. Additionally, the RD with home oxygen cohort had a significantly higher incidence of periprosthetic joint infection (5.78% versus 3.77%, OR 1.15, P < .0001), pneumonia (3.95% versus 1.63%, OR 1.99, P < .0001), and several other medical complications compared to RD patients without home oxygen use. CONCLUSION: Preoperative supplemental home oxygen use is associated with significantly increased risk of postoperative surgical and medical complications following elective TKA. This finding can help guide risk assessment and the informed consent process prior to surgery.

The 2021 Association Research Circulation Osseous Classification for Early-Stage Osteonecrosis of the Femoral Head to Computed Tomography-Based Study.

BACKGROUND: The Association Research Circulation Osseous developed a novel classification for early-stage (precollapse) osteonecrosis of the femoral head (ONFH). We hypothesized that the novel classification is more reliable and valid when compared to previous 3 classifications: Steinberg, modified Kerboul, and Japanese Investigation Committee classifications. METHODS: In the novel classification, necrotic lesions were classified into 3 types: type 1 is a small lesion, where the lateral necrotic margin is medial to the femoral head apex; type 2 is a medium-sized lesion, with the lateral necrotic margin being between the femoral head apex and the lateral acetabular edge; and type 3 is a large lesion, which extends outside the lateral acetabular edge. In a derivation cohort of 40 early-stage osteonecrotic hips based on computed tomography imaging, reliabilities were evaluated using kappa coefficients, and validities to predict future femoral head collapse by chi-squared tests and receiver operating characteristic curve analyses. The predictability for future collapse was also evaluated in a validation cohort of 104 early-stage ONFH. RESULTS: In the derivation cohort, interobserver reliability (k = 0.545) and intraobserver agreement (63%-100%) of the novel method were higher than the other 3 classifications. The novel classification system was best able to predict future collapse (P < .05) and had the best discrimination between non-progressors and progressors in both the derivation cohort (area under the curve = 0.692 [0.522-0.863], P < .05) and the validation cohort (area under the curve = 0.742 [0.644-0.841], P = 2.46 × 10-5). CONCLUSION: This novel classification is a highly reliable and valid method of those examined. Association Research Circulation Osseous recommends using this method as a unified classification for early-stage ONFH. LEVEL OF EVIDENCE: Level III, diagnostic study.

Are Patients More Susceptible to Viral Illness Immediately Following Hip and Knee Arthroplasty? An Analysis of Influenza Diagnoses Using Multiple Administrative Databases.

BACKGROUND: Elective surgery elicits a systemic immune response and may result in transient immunosuppression in certain patients. It is currently unknown whether patients are at increased risk for viral infection and associated illness in the immediate postoperative period following total joint arthroplasty (TJA). METHODS: Four large administrative datasets (Medicare 5% and 100% standard analytic files, Humana claims, and Mariner Database) were analyzed to identify patients who underwent total knee arthroplasty (TKA) and total hip arthroplasty (THA) from 2005 to 2017. The influenza vaccination status of each patient was defined using the presence or absence of a code for vaccination. The incidence of an influenza diagnosis was recorded in both vaccinated and unvaccinated patients during peak influenza season following the date of surgery and compared to a cohort of vaccinated patients who did not undergo surgery. RESULTS: The incidence of postoperative influenza diagnoses in TKA and THA patients was similar to that of vaccinated patients who did not undergo TJA at all time points. The results were largely consistent across all datasets. CONCLUSION: Large administrative databases fail to show an increased incidence of influenza in patients who have recently undergone TJA. While the lack of signal in the data is reassuring, these findings are limited by the nature of large administrative datasets and the accuracy of coding for influenza. Further studies will be necessary to fully understand an individual patient's postoperative risk for contracting a viral illness. LEVEL OF EVIDENCE: Level III.

Prior Nonarthroplasty Surgery Increases Risk of Complication in Primary Total Knee Arthroplasty.

BACKGROUND: Prior ipsilateral knee surgery may increase the risk for complications after total knee arthroplasty (TKA). It remains unclear if the extent of previous surgery affects those risks disparately. The purpose of this study is to evaluate prior nonarthroplasty bony procedure (BP) and soft tissue only procedure (STP) as a potential risk factor for complications after TKA and determine the association with charges or reimbursement of the primary TKA. METHODS: Patients who underwent primary TKA with previous knee surgery were identified using a national Medicare database and matched 1:5 to controls without prior knee surgery. Rates of postoperative medical and surgical complications were calculated in addition to hospital-associated charges and reimbursements. Logistic regression analysis was used to control for confounding factors. RESULTS: Patients who underwent BP (n = 835) had increased risk of readmission (58.6% vs 45.3%, odds ratio (OR) 1.72, 95% confidence interval (CI) 1.59-1.85, P < .001) and emergency room visits (14.5% vs 10.4%, OR 1.44, 95% CI 1.29-1.61, P = .001). Patients who underwent STP (n = 6766) had increased risk of readmission (58.1% vs 45.2%, OR 1.69, 95% CI 1.64-1.73, P < .001), emergency room visits (12.6% vs 0.7%, OR 1.33, 1.28-1.39, P < .001), revision (1.8% vs 1.4%, OR 1.33, 95% CI 1.21-1.47, P = .006), cerebrovascular accident (2.3% vs 1.7%, OR 1.33, 95% CI 1.22-1.46, P = .002), and venous thromboembolism (3.8% vs 3.2%, OR 1.21, 95% CI 1.13-1.29, P = .009). Prior surgery was associated with increased charges and reimbursements. CONCLUSION: Prior ipsilateral knee surgery is associated with significantly increased risks of postoperative complications after primary TKA. Interestingly, previous STP but not BP increased the risk of short-term revision and venous thromboembolism.

Iron Deficiency Anemia is Associated with Increased Early Postoperative Surgical and Medical Complications Following Total Hip Arthroplasty.

BACKGROUND: Iron deficiency anemia (IDA) is a medical comorbidity commonly diagnosed in those undergoing primary total hip arthroplasty (THA). The authors sought to evaluate IDA as a risk factor for early postoperative complications following discharge and describe the hospital resource utilization of this patient population. METHODS: Patients with a diagnosis of IDA who underwent THA from 2005 to 2014 were identified in a national insurance database. The rates of postoperative medical complications and surgery-related complications, as well as hospital readmission, emergency department visits, and death were calculated. Additionally, 90-day and day of surgery cost and length of stay were calculated. IDA patients were then compared to a 4:1 matched control population without IDA using a logistic regression analysis to control for confounding factors. RESULTS: In total, 98,681 patients with a preoperative diagnosis of IDA who underwent THA were identified and compared to 386,724 controls. IDA was associated with increased risk of 30-day emergency department visits (odds ratio [OR] 1.35, P < .001) and 30-day readmission (OR 1.49, P < .001). IDA was also associated with an increased 90-day medical complication rate (cerebrovascular accident OR 1.11, P = .003; urinary tract infection OR 1.14, P < .001; acute renal failure OR 1.24, P < .001; transfusion OR 1.40, P < .001), as well as 1-year periprosthetic joint infection (OR 1.27, P < .001), revision (OR 1.22, P < .001), dislocation (OR 1.25, P < .001), and fracture (OR 1.43, P < .001). Patients with IDA accrued higher hospital charges ($27,658.27 vs $16,709.18, P < .001) and lower hospital reimbursement ($5509.90 vs $3605.59, P < .001). CONCLUSION: Patients with preoperative IDA undergoing THA are at greater risk of experiencing early postoperative complications and have greater utilization of hospital resources.

Trends in Hospital and Surgeon Charges and Reimbursements for Revision Total Knee Arthroplasty.

BACKGROUND: The relationship between surgeon and hospital charges and reimbursements for revision total knee arthroplasty (TKA) has not been well examined. The objective of this study is to report trends and variations in hospital charges and payments compared to surgeons for stage 1 (S1) vs stage 2 (S2) septic revision TKA and aseptic revision (AR) TKA. METHODS: The 5% Medicare sample was used to capture hospital and surgeon data for revision TKA from 2005 to 2014. The charge multiplier (CM) and ratio of hospital to surgeon charges, and the payment multiplier (PM) and ratio of hospital to surgeon payments were calculated. Year-to-year variation and regional trends in-patient demographics, Charlson Comorbidity Index, length of stay (LOS), CM, and PM were evaluated. RESULTS: In total, 4570 AR, 1323 S1, and 863 S2 TKA patients were included. CM increased for all cohorts: 8.1-13.8 for AR (P < .001), 21.0-22.5 (P = .07) for S1, and 11.8-22.0 (P < .001) for S2. PM followed a similar trend, increasing 8.1-13.8 (P < .001) for AR, 19.8-27.3 (P = .005) for S1, and 14.7-30.7 (P < .001) for S2. Surgeon reimbursement decreased for all cohorts. LOS decreased for AR (3.8-2.8 days), S1 (12.8-6.9 days), and S2 (4.5-3.9 days). Charlson Comorbidity Index remained stable for AR patients but increased significantly for S1 and S2 cohorts. CONCLUSION: Hospital charges and payments relative to the surgeons have significantly increased for revision TKA in the setting of stable or increasing patient complexity and decreasing LOS.

Reimbursements for Revision Total Hip Arthroplasty Have Increased for Hospitals but Not for Surgeons.

BACKGROUND: With increases in total hip arthroplasty procedures the need for revision total hip arthroplasty (rTHA) has increased as well. This study aims to analyze the trends in hospital charges and payments relative to corresponding surgeon charges and payments in a Medicare population for rTHA for aseptic revisions, stage 1 and stage 2 revisions. METHODS: The 5% Medicare sample database was used to capture hospital and surgeon charges and payments related to 4449 patients undergoing aseptic revision, 517 for stage 1 revision, and 300 for stage 2 revision in between the years 2004 and 2014. Two values were calculated: (1) the ratio of hospital to surgeon charges (CM) and (2) the ratio of hospital to surgeon payments (PM). Year-to-year variation and trends in patient demographics, Charlson Comorbidity Index (CCI), length of stay (LOS), CM, and PM were evaluated. RESULTS: The mean CCI for aseptic revisions and stage 1 revisions did not significantly change (P < .088 and P < .063). The CCI slightly increased for stage 2 revisions (P < .04). The mean LOS decreased significantly over time in all 3 procedure types. The CM increased by 39% (P < .02) in aseptic revisions, 109% in stage 1 revisions (P < .001) but did not significantly change in stage 2 revisions (P < .877). PM for aseptic revisions increased around 103% (P < .001), 107% for stage 1 revisions (P < .001), and 9.7% for stage 2 revisions (P < .176). CONCLUSION: Hospital charges and payments relative to surgeon charges and payments have increased substantially for THA aseptic revisions, stage 1 revisions, and stage 2 revisions despite stable patient complexity and decreasing LOS.

Risk of Prosthetic Joint Infection Increases Following Early Aseptic Revision Surgery of Total Hip and Knee Arthroplasty.

BACKGROUND: It is important to identify risk factors for periprosthetic joint infection (PJI) following total joint arthroplasty in order to mitigate the substantial social and economic burden. The objective of this study is to evaluate early aseptic revision surgery as a potential risk factor for PJI following total hip (THA) and total knee arthroplasty (TKA). METHODS: Patients who underwent primary THA or TKA with early aseptic revision were identified in 2 national insurance databases. Control groups of patients who did not undergo revision were identified and matched 10:1 to study patients. Rates of PJI at 1 and 2 years postoperatively following revision surgery were calculated and compared to controls using a logistic regression analysis. RESULTS: In total, 328 Medicare and 222 Humana patients undergoing aseptic revision THA within 1 year of index THA were found to have significantly increased risk of PJI at 1 year (5.49% vs 0.91%, odds ratio [OR] 5.61, P < .001 for Medicare; 7.21% vs 0.68%, OR 11.34, P < .001 for Humana) and 2 years (5.79% vs 1.10%, OR 4.79, P < .001 for Medicare; 8.11% vs 1.04%, OR 9.05, P < .001 for Humana). Similarly for TKA, 190 Medicare and 226 Humana patients who underwent aseptic revision TKA within 1 year were found to have significantly higher rates of PJI at 1 year (6.48% vs 1.16%, OR 7.69, P < .001 for Medicare; 6.19% vs 1.28%, OR 4.89, P < .001 for Humana) and 2 years (8.42% vs 1.58%, OR 6.57, P < .001 for Medicare; 7.08% vs 1.50%, OR 4.50, P < .001 for Humana). CONCLUSION: Early aseptic revision surgery following THA and TKA is associated with significantly increased risks of subsequent PJI within 2 years.

Surgeon Reimbursement Unchanged as Hospital Charges and Reimbursements Increase for Total Joint Arthroplasty.

BACKGROUND: Despite increasing demands on physicians and hospitals to increase value and reduce unnecessary costs, reimbursement for healthcare services has been under downward pressure for several years. This study aimed to analyze the trend in hospital charges and payments relative to corresponding surgeon charges and payments in a Medicare population for total hip (THA) and knee arthroplasty (TKA). METHODS: The 5% Medicare sample database was used to capture hospital and surgeon charges and payments related to 56,228 patients who underwent primary THA and 117,698 patients who underwent primary TKA between 2005 and 2014. Two values were calculated: (1) the charge multiplier (CM), the ratio of hospital to surgeon charges and (2) the payment multiplier (PM), the ratio of hospital to surgeon payments. Year-to-year variation and regional trends in patient demographics, Charlson Comorbidity Index, length of stay (LOS), CM, and PM were evaluated. RESULTS: Hospital charges were significantly higher than surgeon charges and increased substantially for both THA (CM increased from 8.7 to 11.5, P < .0001) and TKA (CM increased from 7.9 to 11.4, P < .0001). PM followed a similar trend, increasing for both THA and TKA (P < .0001). LOS decreased significantly for both THA and TKA (P < .0001), while Charlson Comorbidity Index remained stable. Both CM (r2 = 0.84 THA, 0.90 TKA) and PM (r2 = 0.75 THA, 0.84 TKA) were strongly negatively associated with LOS. CONCLUSION: Hospital charges and payments relative to surgeon charges and payments have increased substantially for THA and TKA despite stable patient complexity and decreasing LOS.

Risk of Periprosthetic Infection Following Intra-Articular Corticosteroid Injections After Total Knee Arthroplasty.

BACKGROUND: Recent literature has advocated for the effectiveness of postoperative steroid injections following total knee arthroplasty (TKA) for improving pain and range of motion when other correctible causes of these symptoms have been eliminated. The safety of such injections has not been thoroughly evaluated. The aim of this study was to determine the risk of acute infection following intra-articular corticosteroid injection into a preexisting TKA. METHODS: The Humana dataset was used to identify patients who underwent TKA from 2007 to 2017. Patients with ipsilateral knee corticosteroid injections in the postoperative period were then identified and compared to a 2:1 matched control cohort. A diagnosis of infection within 6 months and 1 year following the injection and an ipsilateral procedure for infection at any time postoperatively were then assessed and compared to controls using a multivariate binomial logistic regression analysis. RESULTS: Of the 166,946 TKA performed during the study period, 5628 patients had a postoperative corticosteroid injection (3.4%). Patients with injections had a significantly higher rate of periprosthetic infection compared to noninjection matched controls at all studied time points. CONCLUSION: In a large national database, about 3% of patients who undergo TKA have a postoperative steroid injection into their postoperative knee. While there is some existing literature demonstrating improvement in pain and stiffness symptoms after TKA with postoperative injections, the present study demonstrates a significant correlation between postoperative intra-articular corticosteroid injections in patients with preexisting TKA and periprosthetic joint infection compared to matched controls who did not receive an injection.

Urinary Self-Catheterization is Not Associated with Increased Risk of Major Complications Following Total Hip and Knee Arthroplasty.

BACKGROUND: The objective of this study is to evaluate urinary self-catheterization as a potential risk factor for postoperative complications following total hip (THA) and knee (TKA) arthroplasty procedures. METHODS: Self-catheterization patients who underwent total joint arthroplasty from 2005 to 2014 were identified in a national insurance database. Rates of death, hospital readmission, emergency room visit, infection, revision, and dislocation for THA or arthrofibrosis for TKA were calculated, as well as cost and length of stay. Self-catheterizing patients were then compared to a 4:1 matched control cohort using a logistic regression analysis to control for confounding factors. RESULTS: Sixty-nine patients underwent THA, and 128 patients who underwent TKA and who actively self-catheterized at the time of surgery were identified. Self-catheterization was not associated with infection, emergency room visits, readmissions, revision surgery, arthrofibrosis, or cost compared to the 4:1 matched control cohort. However, self-catheterization was associated with significantly longer length of stay (difference for THA = 1.91 days, confidence interval = 0.97-2.86, P < .001; difference for TKA = 0.61, odds ratio = 0.16-1.06, P = .01). CONCLUSION: Self-catheterization does not appear to be associated with increased risk of major complications following total joint arthroplasty with the numbers available in this study. Reassurance can be given regarding concerns for infection and other complications following surgery in this patient population.

Hospital and Surgeon Reimbursement Trends for Femoral Neck Fractures Treated With Hip Hemiarthroplasty and Total Hip Arthroplasty.

BACKGROUND: The economic impact of hip fractures on the health care system continues to rise with continued pressure to reduce unnecessary costs while maintaining quality patient care. This study aimed to analyze the trend in hospital charges and payments relative to surgeon charges and payments in a Medicare population for hip hemiarthroplasty and total hip arthroplasty (THA) for femoral neck fracture. METHODS: The 5% Medicare sample database was used to capture hospital and surgeon charges and payments related to 32,340 patients who underwent hemiarthroplasty and 4323 patients who underwent THA for femoral neck fractures between 2005 and 2014. Two values were calculated: (1) charge multiplier (CM, ratio of hospital to surgeon charges), and (2) payment multiplier (PM, ratio of hospital to surgeon payments). Year-to-year variation and regional trends in patient demographics, Charlson Comorbidity Index (CCI), length of stay (LOS), 90-day and 1-year mortality, CM, and PM were evaluated. RESULTS: Hospital charges were significantly higher than surgeon charges and increased substantially for hemiarthroplasty (CM of 13.6 to 19.3, P < .0001) and THA (CM of 9.8 to 14.9, P = .0006). PM followed a similar trend for both hemiarthroplasty (14.9 to 20.2; P = .001) and THA (11.9 to 17.4; P < .0001). LOS decreased significantly for hemiarthroplasty (3.78 to 3.37d; P < .0001) despite increasing CCI (6.36 to 8.39; P = .018), whereas both LOS (3.71 to 3.79 days; P = .421) and CCI (5.34 to 7.08; P = .055) remained unchanged for THA. CONCLUSION: Hospital charges and payments relative to surgeon charges and payments have increased substantially for hemiarthroplasty and THA performed for femoral neck fractures.

Hypogonadism Is Associated With Increased Risks of Postoperative Complications Following Total Hip Arthroplasty.

BACKGROUND: Despite being a relatively common problem among aging men, hypogonadism has not been previously studied as a potential risk factor for postoperative complications following total hip arthroplasty (THA). METHODS: In total, 3903 male patients with a diagnosis of hypogonadism who underwent primary THA from 2006 to 2012 were identified using a national insurance database and compared to 20:1 matched male controls using a logistic regression analysis. RESULTS: Hypogonadism was associated with an increased risk of major medical complications (odds ratio [OR] 1.24, P = .022), urinary tract infection (OR 1.43, P < .001), wound complications (OR 1.33, P = .011), deep vein thrombosis (OR 1.64, P < .001), emergency room visit (OR 1.24, P < .001), readmission (OR 1.14, P = .015), periprosthetic joint infection (OR 1.37 and 1.43, P < .05), dislocation (OR 1.51 and 1.48, P < .001), and revision (OR 1.54 and 1.56, P < .001) following THA. A preoperative diagnosis of hypogonadism was associated with increased total reimbursement and charges by $390 (P < .001) and $4514 (P < .001), respectively. CONCLUSION: The diagnosis of hypogonadism is associated with an elevated risk of postoperative complications and increased cost of care following primary THA. Data from this study should influence the discussion between the patient and the provider prior to undergoing joint replacement and serve as the basis for further research.

Patients With Multiple Sclerosis are at Increased Risk for Postoperative Complications Following Total Hip and Knee Arthroplasty.

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system. Patients with MS are living longer due to improved medical therapy and thus the demand for arthroplasty in this population will increase. The objective of this study is to evaluate MS as a potential risk factor for postoperative complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: Patients with a diagnosis of MS who underwent THA or TKA from 2005 to 2014 were identified in a national insurance database. Rates of death, hospital readmission, emergency room visits, infection, revision, and dislocation (for THA) or stiffness (for TKA) were calculated, in addition to cost and length of stay. MS patients were then compared to a matched control population. RESULTS: In total, 3360 patients who underwent THA and 6436 patients who underwent TKA with a history of MS were identified and compared with 10:1 matched control cohorts without MS. The MS group for both TKA and THA had significantly higher incidences of hospital readmission (THA odds ratio [OR] 2.05, P < .001; TKA OR 1.99, P < .001), emergency room visits (THA OR 1.41, P < .001; TKA OR 1.66, P < .001), and infection (THA OR 1.35, P = .001; TKA OR 1.32, P < .001). MS patients who underwent THA had significantly higher rates of revision (OR 1.35, P = .001) and dislocation (OR 1.52, P < .001). Diagnosis of MS was also associated with significantly higher costs and hospital length of stay for patients undergoing both TKA and THA. CONCLUSION: A diagnosis of MS is associated with increased risk of postoperative complications and higher costs following both THA and TKA.

Normal Pressure Hydrocephalus Is Associated With Increased Risks of Postoperative Complications Following Total Knee and Total Hip Arthroplasty.

BACKGROUND: Normal pressure hydrocephalus (NPH) has not been studied as a potential risk factor for postoperative complications after primary total knee (TKA) and total hip arthroplasty (THA). METHODS: Nearly 2000 patients with a diagnosis of NPH who underwent TKA or THA from 2005 to 2014 were identified in a national insurance database and compared to 10:1 matched controls using a logistic regression analysis. RESULTS: NPH was associated with an increased risk of hospital readmission, emergency room visit, and infection following TKA (odds ratio 1.48-2.70, all P < .01). NPH was associated with an increased risk of hospital readmission, emergency room visit, and dislocation following THA (odds ratio 2.40-2.50, all P < .01). NPH was also associated with significantly higher costs and hospital length of stay following both procedures. CONCLUSION: The diagnosis of NPH is associated with an elevated risk of postoperative complications and increased resource utilization following TKA and THA.

Rates of Registry Research Have Increased in Podium and Poster Presentations at the American Association of Hip and Knee Surgeons.

Background: As state, regional, and national registries have rapidly expanded, the goal of this study is to assess the frequency of registry abstracts accepted for both podium and poster presentations at the American Association of Hip and Knee Surgeons between 2012 and 2022. Methods: Final programs and poster e-collections were examined over the past 11 years. Two reviewers evaluated each abstract to determine if they utilized large datasets and the location of each registry. Studies were excluded if they used institutional registries. Reviewers also identified the most frequently utilized registries to determine how their use has fluctuated over this time frame. Results: A total of 3354 abstracts were reviewed and included. Of those, 577 abstracts utilized data obtained from orthopaedic registries (17.2%): 450 of which were poster presentations (16.5% of total poster acceptances), and 127 were podium presentations (20.5% of accepted podiums). The National Surgical Quality Improvement Program (NSQIP) was the most frequent dataset utilized, with 118 (20.5%) abstracts. Of note, NSQIP's use peaked between 2018 and 2020 and has since slowly trended downward. On the other hand, use of both American Joint Replacement Registry (AJRR) and PearlDiver registry have drastically increased since 2019, with only 6 abstracts chosen in 2019 and 28 abstracts in 2022 (10 AJRR [3 podiums] and 18 PearlDiver [6 podiums]). The proportion of registry data has increased, with the registry abstracts peaking in 2022 as 24% of posters and 37% of podium utilized data from large registry data sets (P < .001). Conclusions: There has been a significant increase in the number of studies utilizing registry data for both podium and poster presentations at the American Association of Hip and Knee Surgeons annual meeting. While NSQIP was the most utilized, its use has steadily declined while AJRR and PearlDiver use have increased over the past 3 years. Individuals should understand the strengths and weaknesses of each registry before making conclusions on study results. Level of Evidence: Level IV.