Cervical spine degenerative disease is an independent risk factor for increased revision rate following total knee arthroplasty.

INTRODUCTION: The relationship between cervical degenerative pathology and total knee arthroplasty (TKA) revision rates is not well understood. The aim of the study was to determine whether cervical spine degenerative diseases have a role in complications following TKA within 2 years. METHODS: Data were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2007-2017. Patients who had a primary TKA were identified using Current Procedural Terminology (CPT) code 27,447, and patients with degenerative cervical disease were identified using CPT and International Classification of Diseases (ICD) codes. Data on patients' demographics, comorbidities and postoperative complications were recorded and analyzed with univariate and multivariate analysis with significance set at p < 0.05. A Kaplan-Meier analysis was conducted to estimate the 1- and 2-year rates of survival free from revision. RESULTS: A total of 81,873 patients were included in this study. Following multivariate analysis, cervical spine degenerative disease patients were at increased risk of all-cause revision surgery following 1 year (OR: 1.342 95% CI: 1.149-1.569; p < 0.001) and 2 year (OR: 1.338; 95% CI: 1.184-1.512; p < 0.001). At 2 years, patients with cervical spine degenerative disease had a survival rate of 97.7%, while the survival rate was 99.2% among the non-cervical degenerative cohort. CONCLUSIONS: Based on these results, patients with cervical spine degenerative pathology should be counseled that their spinal pathology may impair outcomes following TKA.

Prior Knee Arthroscopy Is Associated With Increased Risk of Revision After Total Knee Arthroplasty.

BACKGROUND: Knee arthroscopy (KA) is frequently performed to provide improved joint function and pain relief. However, outcomes following total knee arthroplasty (TKA) after prior KA are not fully understood. The purpose of this study is to determine the relationship between prior KA within 2 years of TKA on revision rates after TKA. METHODS: Data were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2006 to 2017. Subjects were identified using Current Procedural Terminology and International Classification of Diseases procedure codes to identify primary TKA. Patients were stratified into 2 groups based upon a history of prior KA. Univariate and multivariate analyses were conducted to determine association between KA and outcomes at 2-year postoperative period. RESULTS: In total, 138,019 patients were included in this study, with 3357 (2.4%) patients receiving a KA before TKA and 134,662 (97.6%) patients who did not. The most common reason for KA was osteoarthritis (40.0%), followed by medial tear of the meniscus (26.0%) and chondromalacia (21%.0). After adjustment, prior KA was associated with increased revision rate (odds ratio [OR], 1.392; P = .003), postoperative stiffness (OR, 1.251; P = .012), periprosthetic joint infection (OR, 1.326; P < .001), and aseptic loosening (OR, 1.401; P = .048). CONCLUSION: Prior KA is significantly associated with increased 2-year TKA revision rate. The most common etiology for arthroscopy was osteoarthritis. The results of the study, showing that arthroscopy before TKA substantially increases the rates of revision, PJI, aseptic loosening, and stiffness, lend further credence to the idea that patients may be better served by nonsurgical management of their degenerative pathology until they become candidates for TKA. Subjecting this population to arthroscopy appears to offer limited benefit at the cost of poorer outcomes when they require arthroplasty in the future. LEVEL OF EVIDENCE: Level III therapeutic study.

Hospital Discharge Within a Day After Total Hip Arthroplasty Does Not Compromise 1-Year Outcomes Compared With Rapid Discharge: An Analysis of an Insurance Claims Database.

BACKGROUND: As health care costs continue to rise, same-day and rapid discharge have become popular options for total hip arthroplasty (THA). However, it remains unclear if there is a difference between within-a-day discharge and early discharge for 1-year clinical outcomes. METHODS: Data were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2007 to 2017, identifying patients receiving a primary THA. Patients were then stratified into three groups: (1) discharge within a day (length of stay [LOS] <24 hours), (2) rapid discharge (LOS: 1-2 days), and (3) traditional discharge (LOS: 3-4 days). The outcomes assessed were all-cause revision surgery, periprosthetic joint infection, prosthetic loosening, prosthetic dislocation, and periprosthetic fracture at 1 year postoperatively. RESULTS: In total, 40,038 patients met inclusion criteria. Among those, 754 (1.88%) patients were discharged within a day, 13,670 (34.14%) patients were in the rapid discharge cohort, and 25,614 (63.97%) patients were in the traditional discharge cohort. After multivariate analysis, no significant differences were observed between the within-a-day discharge group and either the rapid discharge or the traditional discharge group. Rapid discharge patients were at decreased risk of periprosthetic joint infection (odds ratios: 0.747, 95% confidence interval: 0.623-0.896) and readmission (odds ratios: 0.778; 95% confidence interval: 0.735-0.824, P < .001) compared with traditional discharge patients. CONCLUSIONS: No significant differences were observed in the one-year outcomes of primary THA between within-a-day discharge patients, rapid discharge, and traditional discharge. For those that qualify after careful selection, outpatient THA might be a feasible alternative to the traditional inpatient THA.

Inflammatory Arthritis Is a Risk Factor for Multiple Complications After Total Hip Arthroplasty: A Population-Based Comparative Study of 68,348 Patients.

BACKGROUND: Patients with inflammatory arthritis (IA) are likely at higher risk of postoperative complications following total hip arthroplasty (THA), from the underlying disease, the degree of articular deformity, and immunosuppressive medications. The purpose of this study was to perform a comparative study of the risk of complications after THA between IA and osteoarthritis. METHODS: A national private insurance database was used to select patients undergoing unilateral primary THA. Patients were categorized to the inflammatory cohort if they had a diagnosis of IA and treatment with an IA-specific medication within the year before surgery. Patients with no diagnosis of IA were considered osteoarthritis. Risk of Centers for Medicare and Medicaid Services-reportable complications and 90-day readmission was compared between cohorts using multivariate logistic regression controlling for age, gender, length of stay, comorbidities, and corticosteroid use. RESULTS: A total of 68,348 patients were included; 2.12% met criteria for IA. Patients with IA were found to have higher risk of transfusion (odds ratio [OR], 1.29; P < .01), mechanical complications (OR, 1.35; P = .01), infection (OR, 1.96; P < .01), and 90-day readmission (OR, 1.35; P < .01). There were no differences in risk of venous thromboembolism or medical complications. CONCLUSION: Patients with IA have significantly higher risk of transfusion, mechanical complications, infection, and readmission following THA. Efforts should be made to optimize their health and medications before THA to minimize their complication risk. Additionally, hospitals should receive commensurate resources to maintain access to THA for patients with IA who are prone to higher resource utilization. LEVEL OF EVIDENCE: III.

Diagnosing Prosthetic Joint Infections in Patients With Inflammatory Arthritis: A Systematic Literature Review.

BACKGROUND: Patients with inflammatory arthritis (IA) are at increased risk of prosthetic joint infections (PJI), yet differentiating between septic and aseptic failure is a challenge. The aim of our systematic review is to evaluate synovial biomarkers and their efficacy at diagnosing PJI in patients with IA. METHODS: A comprehensive literature search was performed in the following databases from inception to January 2018: Ovid MEDLINE, Ovid EMBASE, and the Cochrane Library. Searches across the databases retrieved 367 results. Two of 5 reviewers independently screened a total of 298 citations. Discrepancies were resolved by a third reviewer. Twenty articles fit our criteria, but due to methodological differences findings could not be pooled for meta-analysis. For 5 studies, raw data were provided, pooled, and used to derive optimal diagnostic cut points. RESULTS: Our final analysis included 1861 non-IA patients, including 426 patients with PJI, and 90 IA patients of whom 26 had PJI. There was a significant difference among the 4 groups for serum C-reactive protein (CRP), erythrocyte sedimentation rate, and synovial CRP, polymorphonuclear neutrophil percent, white blood cells, interleukin (IL)-6, IL-8, and IL-1b. Polymorphonuclear neutrophil percent had the highest sensitivity (95.2%) and specificity (85.0%) to detect infections with an optimum threshold of 78%. CONCLUSION: While levels of synovial white blood cells, IL-6, IL-8, and serum CRP appear higher in patients with IA, there is overlap with those who are not infected. Further studies are needed to explore diagnostic tests that will better detect PJI in patients with IA.

Rates and Risk Factors of Conversion Hip Arthroplasty After Closed Reduction Percutaneous Hip Pinning for Femoral Neck Fractures-A Population Analysis.

BACKGROUND: Closed reduction with percutaneous pinning (CRPP) for nondisplaced or valgus impacted femoral neck fractures is a relatively low-risk operation that can produce excellent union rates in some patients; however, failure can occur in selected patients requiring conversion to arthroplasty. The primary aim of this study was to perform a population-level analysis to determine the rate and timeframe of conversion from CRPP to total hip arthroplasty (THA) or hemiarthroplasty. METHODS: The PearlDiver database was queried from 2007-2015 for all patients who underwent CRPP for a femoral neck fracture. Survival analysis was used to evaluate the rate of conversion of CRPP to hemiarthroplasty or THA. Risk factors for conversion arthroplasty were identified using a multivariable cox proportional hazards model that included patient demographics and comorbidities. RESULTS: There were 5122 patients in the Humana database and 4840 patients in the Medicare database that were included in analysis. At 5 years after CRPP, the conversion rate was 10.0% in the Medicare patients and 10.8% in the Humana patients. Risk factors for undergoing conversion from CRPP to arthroplasty in the Medicare cohort included preexisting diagnoses of pulmonary and/or circulatory comorbidities, peripheral vascular disease, hypertension, hypothyroidism, and metastatic cancer. In the Humana cohort, the only risk factors were male gender and acute blood loss anemia. CONCLUSION: Although CRPP remains a successful operation in elderly patients and patients with certain comorbidities, failure of CRPP for the treatment of a femoral neck fracture is high at approximately 10%-11%, which is much higher than reported failure rates for THA in the same population. Patients with femoral neck fractures being considered for CRPP should be counseled about the possibility of further surgery.

Short-term Complications After Revision Hip Arthroplasty for Prosthetic Joint Infection Are Increased Relative to Noninfectious Revisions.

BACKGROUND: Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is associated with significant morbidity and cost. The purpose of this study was to determine how rates of perioperative complications, operative duration, and postoperative length of stay (LOS) in patients undergoing revision THA for PJI compare to primary THA and to revision THA for non-PJI. METHODS: We used the National Surgical Quality Improvement Program registry from 2005 to 2015 to identify all patients who underwent primary and revision THA. Patients were placed into cohorts based on the surgical procedure and by indication, including (1) primary THA, (2) revision THA for PJI, and (3) revision THA for non-PJI. Differences in 30-day postoperative medical complications, hospital readmissions, operative duration, and LOS were compared using bivariate and multivariate analyses. RESULTS: One lakh fourteen thousand five hundred five THA patients were identified, with 102,460 (89.5%) patients undergoing a primary THA and 12,045 (10.5%) undergoing a revision procedure. Of the 12,045 revision procedures, 10,777 (89.5%) were for non-PJI indications and 1268 (10.5%) were for PJI. Relative to primary THA, patients undergoing revision THA for PJI had an increased rate of total complications (odds ratio [OR] 3.96), sepsis (OR 13.15), deep surgical site infections (SSIs, OR 8.58), superficial SSI (OR 2.14, P = .002), nonhome discharge (OR 1.85), readmissions (OR 2.46), LOS (+3.0 days), and operative duration (+61 minutes). Compared with non-PJI revisions, PJI revisions had an increased rate of total complications (OR 2.42), sepsis (OR 5.51), deep SSI (OR 2.12), nonhome discharge (OR 1.47), and LOS (+1.8 days). CONCLUSION: Revision THA for PJI is associated with increased postoperative complications, nonhome discharge, and LOS relative to non-PJI revision THA. Separate care pathways and reimbursement bundles should be considered for patients with PJI. LEVEL OF EVIDENCE: III.

Adult Reconstruction Hip and Knee Fellowship Program Content and Accessibility.

BACKGROUND: The objective of the study was to assess the accessibility and content of accredited adult reconstruction hip and knee fellowship program websites. METHODS: Using the online database of the American Association of Hip and Knee Surgeons (AAHKS), we compiled a list of accredited adult hip and knee/tumor reconstruction fellowship programs. A full list of adult reconstruction hip and knee fellowship programs was gathered from the AAHKS website. The program website links they provided were evaluated. A Google search was conducted to identify program websites and analyzed for accessibility and content in 3 domains: program overview, applying/recruitment, and education. RESULTS: At the time the study was conducted, there were 78 accredited adult reconstruction hip and knee fellowship programs identified through the AAHKS program directory. Three of the 78 programs identified had a functional link on the AAHKS fellowship program directory; however, Google search identified 60 websites. Eighteen programs did not have a website and were not evaluated for content. Data analysis of content in the domains of program details, application process/recruitment, and education revealed that most websites included a program description and director name with contact information. However, they were not as comprehensive in the application process/recruitment and education domains. CONCLUSIONS: AAHKS provides a reasonable method of identifying programs. Yet, most programs can readily be identified using a Google search (76.9%). Although most fellowship program websites contained program details, there is still paucity of information for fellowship candidates.

Spontaneous intraneural hematoma of the sural nerve.

Symptomatic intraneural hemorrhage occurs rarely. It presents with pain and/or weakness in the distribution following the anatomic innervation pattern of the involved nerve. When a purely sensory nerve is affected, the symptoms can be subtle. We present a previously healthy 36-year-old female who developed an atraumatic, spontaneous intraneural hematoma of her sural nerve. Sural dysfunction was elicited from the patient's history and physical examination. The diagnosis was confirmed with magnetic resonance imaging, and surgical decompression provided successful resolution of her preoperative symptoms. To our knowledge, this entity has not been reported previously. Our case highlights the importance of having a high index of suspicion for nerve injury or compression in patients whose complaints follow a typical peripheral nerve distribution. Prior studies have shown that the formation of intraneural hematoma and associated compression of nerve fibers result in axonal degeneration, and surgical decompression decreases axonal degeneration and aids functional recovery.

Anticoagulant Usage After Anterior Cruciate Ligament Reconstruction Is Associated With Increased Rate of Manipulation Under Anesthesia.

BACKGROUND: Arthrofibrosis after anterior cruciate ligament reconstruction (ACLR) is a notable but uncommon complication of ACLR. To improve range of motion after ACLR, aggressive physical therapy, arthroscopic/open lysis of adhesions, and revision surgery are currently used. Manipulation under anesthesia (MUA) is also a reasonable choice for an appropriate subset of patients with inadequate range of motion after ACLR. Recently, the correlation between anticoagulant usage and arthrofibrosis after total knee arthroplasty has become an area of interest. The purpose of this study was to determine whether anticoagulant use has a similar effect on the incidence of MUA after ACLR. METHODS: The Mariner data set of the PearlDiver database was used to conduct this retrospective cohort study. Patients with an isolated ACLR were identified by using Current Procedural Terminology codes. Patients were then stratified by MUA within 2 years of ACLR, and the use of postoperative anticoagulation was identified. In addition, patient demographics, medical comorbidities, and timing of ACLR were recorded. Univariate and multivariable analyses were used to model independent risk factors for MUA. RESULTS: We identified 216,147 patients who underwent isolated ACLR. Of these patients, 3,494 (1.62%) underwent MUA within 2 years. Patients who were on anticoagulants after ACLR were more likely to require an MUA (odds ratio [OR]: 2.181; P < 0.001), specifically low-molecular-weight heparin (OR: 2.651; P < 0.001), warfarin (OR: 1.529; P < 0.001), and direct factor Xa inhibitors (OR: 1.957; P < 0.001). DISCUSSION: In conclusion, arthrofibrosis after ACLR is associated with the use of preoperative or postoperative thromboprophylaxis. Healthcare providers should be aware of increased stiffness among these patients and treat them aggressively.

Decreased Implant Survival is Associated With Younger Patients Undergoing Total Knee Arthroplasty.

Background: Younger patients are undergoing total knee arthroplasty (TKA) at increasing rates and may face multiple revisions during their lifetimes due to mechanical complications or infections. Questions/Purposes: We sought to compare the early complication rates and revision-free implant-survival rates across age groups of patients undergoing TKA, with particular focus on implant survival in younger patients. Methods: We conducted a retrospective analysis of data taken from a national insurance database on patients who underwent primary TKA from 2007 to 2015. Kaplan-Meier curve survival analysis and log rank test were performed to evaluate revision rates in 7 age groups (younger than 40, 40-49, 50-59, 60-69, 70-79, 80-89, and 90 or more years of age). Complication rates were compared to rates in the age 60 to 79 years age groups using multiple logistic regression, controlling for baseline demographics and comorbidities. Results: There were 114,698 patients included in the analysis. Patients in the younger than 40 years, 40 to 49 years, and 50 to 59 years age groups had increased rates of early mechanical complications; 90-day readmission rates were significantly higher in those age groups as well. Revision-free implant survival at 5 years was significantly worse in patients younger than 60 years of age, particularly those less than 40 years, who had a 77% revision-free implant-survival rate at 5 years. Conclusions: Younger patients had a higher risk of early revision after TKA, as well as an increased rate of mechanical complications and readmissions at 90 days. These outcomes suggest more study is needed to better understand these discrepancies and to better guide preoperative counseling for young patients considering TKA.

Trends in Utilization of Total and Unicompartmental Knee Arthroplasty in the United States.

Total knee replacement (TKR) and unicompartmental knee replacement (UKR) are successful procedures for patients with knee arthritis. While strict criteria were proposed early on for UKR, some surgeons have expanded these indications to include younger and heavier patients. The purpose of this study is to analyze trends in usage of TKR and UKR in the United States. This retrospective study analyzed an insurance administrative dataset. Patients who underwent primary TKR and UKR were identified via current procedural terminology codes. Information on incidence, obesity, use of computer navigation, and surgical setting were collected. We analyzed 7,194 UKRs and 128,849 TKRs performed from 2007 to 2016. Prevalence of obesity in both groups increased over the study period. Utilization of computer navigation increased for UKR but declined for TKR. The rate of outpatient procedures significantly increased for UKR but remained constant for TKR. Both TKR and UKR are being performed at increasing rates and on heavier patients. The use of computer navigation and outpatient surgical setting is increasing for UKR but not for TKR. Knowledge of these trends is important for surgeons and policy-makers to help inform surgical indications and resource allocation.

Association of Lumbar Degenerative Disease and Revision Rate following Total Knee Arthroplasty.

Recently, a variety of studies have analyzed the potential correlation between lumbar degenerative disease (LDD) and inferior clinical outcomes after total hip arthroplasty. However, there has been limited data concerning the role of LDD as a risk factor for failure after total knee arthroplasty (TKA). The aim of our study was to determine: (1) what is the association of LDDs with TKA failure (all-cause revision) within 2 years of index arthroplasty and (2) if patients with LDD and lumbar fusion are at increased risk of TKA revision within 2 years compared with LDD patients without fusion. Data were collected from the Humana insurance database using the PearlDiver database from 2007 to 2017. To assess aim 1, patients were stratified into two groups based on a prior history of LDD (International Classification of Diseases [ICD]-9 or -10 diagnostic codes). To analyze aim 2, patients within the LDD cohort were stratified based on the presence of lumbar fusion (lumbar fusion Current Procedural Terminology code). All-cause revision rate was 3.4% among LDD patients versus 2.4% of patients with non-LDD (p < 0.001) at 2 years. Following multivariate analysis, LDD patients were at increased risk of all-cause revision surgery at 2 years (odds ratio [OR]: 1.361; 95% confidence interval [CI]: 1.238-1.498; p < 0.001) as well as aseptic loosening (OR: 1.533; 95% CI: 1.328-1.768; p < 0.001), periprosthetic joint infection (OR: 1.245; 95% CI: 1.129-1.373; p < 0.001), and periprosthetic fracture (OR: 1.521; 95% CI: 1.229-1.884; p < 0.001). Among LDD patients, patients who have a lumbar fusion had an all-cause revision rate of 5.0%, compared with 3.2% among LDD with no lumbar fusion patients at 2 years (p = 0.021). Following multivariate analysis, lumbar fusion patients were at increased risk of all-cause revision surgery (OR: 1.402; 95% CI: 1.362-1.445; p = 0.028), aseptic loosening (OR: 1.432; 95% CI: 1.376-1.489; p = 0.042), and periprosthetic fracture (OR: 1.302; 95% CI: 1.218-1.392; p = 0.037). Based on these findings, TKA candidates with preoperative LDD should be counseled that TKA outcome may be impaired by the coexistence of lumbar spine degenerative disease. This is Level III therapeutic study.

Hip arthroscopy for hip osteoarthritis is associated with increased risk for revision after total hip arthroplasty.

BACKGROUND: It has not been determined yet whether hip arthroscopy (HA) leads to adverse outcomes after total hip arthroplasty (THA). The purpose of this study was to (1) determine 2-year conversion rate of HA done for osteoarthritis (OA) to THA and (2) explore the relationship between HA performed in patients with hip osteoarthritis and the risk of revision THA within 2 years of index arthroplasty. METHODS: Data was collected from the Medicare Standardized Analytic Files insurance database using the PearlDiver Patient Records Database from 2005-2016. Patients were stratified into 2 groups based upon a history of hip arthroscopy prior to THA. RESULTS: The 2-year conversion to THA rate for hip arthroscopy in patients with OA was 68.4% (95% CI, 66.2-70.6%). Multivariate analysis demonstrated that OA patients who underwent HA prior to THA were at an increased risk of revision surgery (OR 3.72; 95% CI, 3.15-4.57; p = 0.012), periprosthetic joint infection (OR 1.86; 95% CI, 1.26-2.77, p = 0.010) and aseptic loosening (OR 2.81; 95% CI, 1.66-4.76; p < 0.001) within 2 years of THA. CONCLUSIONS: Analysis of a large insurance database found the conversion rate from HA performed in Medicare OA patients to THA within 2 years is unacceptably high. Hip arthroscopy prior to THA also significantly increased the risk of THA revision within 2 years after index THA. These results suggest that arthroscopic hip surgery should not be performed in patients with a diagnosis of OA as conversion rates are high and revision rates post THA are significantly increased.

Hospital Discharge Within a Day After Total Knee Arthroplasty Does Not Affect 1-Year Complications Compared With Rapid Discharge.

INTRODUCTION: In patients undergoing total knee arthroplasty (TKA), it is unclear whether a difference in complication rates exists between patients discharged the day of surgery compared with subsequent postoperative days. METHODS: Data were collected from the PearlDiver Patient Records Database from 2007 to 2017. Subjects were identified using International Classification of Diseases codes. Eligible patients were stratified into the following three groups: (1) same day discharge (<24 hours postoperatively), (2) rapid discharge (1 to 2 days), and (3) traditional discharge (3 to 4 days) based on the length of stay. RESULTS: In total, 84,864 patients were identified as having undergone primary TKA. The incidence of same day discharge, rapid discharge, and traditional discharge was 2.36% (2,004/84,864), 28.56% (24,235/84,864), and 69.08% (58,625/84,864), respectively. After adjustment, no notable differences were observed in the overall complication and revision rates between the same day discharge group and either the rapid discharge or the traditional discharge group. On multivariate analysis, patients in the rapid discharge cohort were less likely to require manipulation under anesthesia or develop periprosthetic joint infection when compared with the traditional discharge group at 1 year postoperatively. CONCLUSIONS: For those who qualify after careful selection, same day and rapid discharge TKA may be a feasible alternative to the traditional inpatient TKA. LEVEL OF EVIDENCE: A level 3 retrospective, prognostic study.

Comparison of pharmacologic prophylaxis in prevention of venous thromboembolism following total knee arthroplasty.

BACKGROUND: Anticoagulants are used following total knee arthroplasty (TKA) to prevent venous thromboembolism (VTE). These drugs reduce VTE risk but may lead to bleeding-related complications. Recently, surgeons have advocated using antiplatelet agents including aspirin (ASA). However, there is no consensus regarding which medication has the optimal risk/benefit profile. The purpose of this study was to compare rates of VTE using different anticoagulants in anticoagulation-naïve patients being discharged home after TKA. METHODS: A national private insurance database was used to identify patients undergoing unilateral TKA. Patients with a prior history of VTE were excluded. Anticoagulants included ASA, low molecular weight heparin (LMWH), warfarin, factor Xa inhibitors (XaI), and fondaparinux. Postoperative complications, including VTE, blood transfusion, myocardial infarction, and hematoma, were identified using ICD-9 diagnosis codes. Risk of each complication was compared between groups using multivariate logistic regression controlling for demographics, length of stay, and comorbidities. RESULTS: Of 30,813 patients, 1.82% were diagnosed with VTE. Using ASA as a baseline, there was significantly decreased risk of VTE with LMWH (OR 0.47), XaI (OR 0.50), and fondaparinux (OR 0.32). There was significantly higher risk of transfusion with LMWH (OR 1.56) and fondaparinux (OR 1.84), but no difference in hematoma between medications. CONCLUSIONS: This study shows that there is a decreased risk of VTE with LMWH, XaI, and fondaparinux compared to ASA. However, these medications also had higher rates of bleeding-associated complications. The choice of pharmacologic prophylaxis should be made based on a balance of the risk/benefit profile of each medication. LEVEL OF EVIDENCE: III.

Comparison of Infection Risk with Corticosteroid or Hyaluronic Acid Injection Prior to Total Knee Arthroplasty.

BACKGROUND: Recent studies have shown that intra-articular injections ≤3 months before total knee arthroplasty increase the risk of periprosthetic joint infection. We are aware of no previous study that has differentiated the risk of periprosthetic joint infection on the basis of the type of medication injected. In addition, we are aware of no prior study that has evaluated whether hyaluronic acid injections increase the risk of infection after total knee arthroplasty. In this study, we utilized pharmaceutical data to compare patients who received preoperative corticosteroid or hyaluronic acid injections and to determine whether a specific injection type increased the risk of periprosthetic joint infection. METHODS: Patients undergoing unilateral primary total knee arthroplasty were selected from a nationwide private insurer database. Ipsilateral preoperative injections were identified and were grouped by medication codes for corticosteroid or hyaluronic acid. Patients who had received both types of injections ≤1 year before total knee arthroplasty were excluded. The outcome of interest was periprosthetic joint infection that occurred ≤6 months following the total knee arthroplasty. The risk of periprosthetic joint infection was compared between groups (no injection, corticosteroid, hyaluronic acid) and between patients who received single or multiple injections. Statistical comparisons were performed using logistic regression controlling for age, sex, and comorbidities. RESULTS: A total of 58,337 patients underwent total knee arthroplasty during the study period; 3,249 patients (5.6%) received hyaluronic acid and 16,656 patients (28.6%) received corticosteroid ≤1 year before total knee arthroplasty. The overall infection rate was 2.74% in the no-injection group. Multivariable logistic regression showed independent periprosthetic joint infection risk for both corticosteroid (odds ratio [OR], 1.21; p = 0.014) and hyaluronic acid (OR, 1.55; p = 0.029) given ≤3 months before total knee arthroplasty. There was no increased risk with injections >3 months prior to total knee arthroplasty. Direct comparison of corticosteroid and hyaluronic acid showed no significant difference (p > 0.05) between medications or between single and multiple injections. CONCLUSIONS: Preoperative corticosteroid or hyaluronic acid injection ≤3 months before total knee arthroplasty increased the risk of periprosthetic joint infection. There was no difference in infection risk between medications or between multiple and single injections. On the basis of these data, we recommend avoiding both injection types in the 3 months prior to total knee arthroplasty. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Cost Comparison of Femoral Distraction Osteogenesis With External Lengthening Over a Nail Versus Internal Magnetic Lengthening Nail.

INTRODUCTION: Femoral lengthening is performed by distraction osteogenesis via lengthening over a nail (LON) or by using a magnetic lengthening nail (MLN). MLN avoids the complications of external fixation while providing accurate and easily controlled lengthening. However, the increased cost of implants has led many to question whether MLN is cost-effective compared with LON. METHODS: A retrospective review was performed comparing consecutive femoral lengthenings using either LON (n = 19) or MLN (n = 39). The number of surgical procedures, time to union, and amount of lengthening were compared. Cost analysis was performed using both hospital and surgeon payments. Costs were adjusted for inflation using the Consumer Price Index. RESULTS: No difference was observed in the length of femoral distraction. Patients treated with MLN underwent fewer surgeries (3.1 versus 2.1; P < 0.001) and had a shorter time to union (136.7 versus 100.2 days; P = 0.001). Total costs were similar ($50,255 versus $44,449; P = 0.482), although surgeon fees were lower for MLN ($4,324 versus $2,769; P < 0.001). DISCUSSION: Although implants are more expensive for MLN than LON, this appears to be offset by fewer procedures. Overall, the two procedures had similar total costs, but MLN was associated with a decreased number of procedures and shorter time to union. LEVEL OF EVIDENCE: III.

Incidence and safety profile of outpatient unicompartmental knee arthroplasty.

BACKGROUND: Outpatient surgery is an increasingly attractive option for patients undergoing procedures with established, acceptable risk profiles. Benefits of outpatient surgery include cost savings, enhanced patient experience and improved resource allocation at busy hospitals. The purpose of this study was to compare 90-day complication and readmission rates for patients undergoing unicompartmental knee arthroplasty (UKA) in the outpatient as opposed to the inpatient setting. METHODS: Patients who underwent UKA (CPT code 27446) between 2007 and 2016 were retrospectively selected from a national private insurance database. Patients were defined as ambulatory if their coded location of procedure was in an ambulatory surgery center or as an in-hospital outpatient. Postoperative complications were identified using the Reportable Center for Medicare Services (CMS) Complication Measures. Risks of complications were compared between the inpatient and outpatient cohorts using multivariate logistic regression controlling for age, gender, and comorbidities. RESULTS: 2600 patients undergoing ambulatory UKA and 5084 patients undergoing inpatient UKA were identified. The percentage of UKA procedures performed on an outpatient basis significantly increased over the course of the study (14.5% to 58.1%, p < 0.001). After adjusting for age, gender, and comorbidities, ambulatory surgery was found to be associated with a decreased risk of postoperative transfusion (OR 0.28; p < 0.001) and pneumonia (OR 0.23; p = 0.008) and there was a trend towards decreased 90-day readmission risk (OR = 0.83; p = 0.062). CONCLUSION: Ambulatory discharge following UKA is increasing in popularity, does not increase risk for perioperative complications or readmission, and may even portend a safer post-operative course.