Total Hip Arthroplasty Outcomes before or after Renal Transplant: A Retrospective Large Cohort Analysis.

Background: While it is known that patients with end-stage renal disease (ESRD) are at an increased risk of complications following total hip arthroplasty (THA), there is a gap in the literature in comparing patients with ESRD to patients who undergo renal transplant (RT) before or after THA. This study is to address this gap by analyzing outcomes of THA in ESRD patients, RT patients, and RT candidates. Methods: Using the PearlDiver Mariner database, ESRD patients, RT patients, and RT candidates undergoing primary THA were identified and compared. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. Ninety-day emergency department (ED) visits and inpatient readmission were also documented. Results: A total of 7,868 patients were included: 5,092 had ESRD, 2,520 had RT before THA, and 256 were candidates for RT. Compared to patients with ESRD, RT patients demonstrated lower rates of medical complications such as pneumonia (3.61% vs. 5.99%, p = 0.039) and transfusion (4.60% vs. 7.66%, p < 0.001). Additionally, RT patients displayed decreased rates of surgical complications, including wound complications (2.70% vs. 4.22%, p = 0.001), periprosthetic joint infection (PJI) at 1 year (2.30% vs. 4.81%, p < 0.001) and 2 years (2.58% vs. 5.42%, p < 0.001), and aseptic loosening at 2 years (0.79% vs. 1.43%, p = 0.006). Similarly, when compared to RT candidates, RT patients demonstrated a lower incidence of postoperative complications, including 1-year PJI (2.30% vs. 5.08%, p = 0.013), 2-year PJI (2.58% vs. 5.08%, p = 0.028), 1-year aseptic loosening (0.56% vs. 2.73%, p < 0.001), and 2-year aseptic loosening (0.79% vs. 2.73%, p = 0.005). RT patients also had lower rates of ED visits and hospital readmissions. Conclusions: Compared to ESRD patients and RT candidates, patients with RT have a significantly lower likelihood of medical complications, PJI, aseptic hardware loosening, ED visits, and hospital readmission. Patients with ESRD on the RT waiting list should delay THA until after RT surgery. For those not eligible for RT, it is vital to take extra precautions to reduce the risk of complications.

Synthesis and anti-inflammatory activities of two new N-acetyl glucosamine derivatives.

N-acetyl glucosamine (NAG) is a natural amino sugar found in various human tissues with previously described anti-inflammatory effects. Various chemical modifications of NAG have been made to promote its biomedical applications. In this study, we synthesized two bi-deoxygenated NAG, BNAG1 and BNAG2 and investigated their anti-inflammatory properties, using an in vivo and in vitro inflammation mouse model induced by lipopolysaccharide (LPS). Among the parent molecule NAG, BNAG1 and BNAG2, BNAG1 showed the highest inhibition against serum levels of IL-6 and TNF α and the leukocyte migration to lungs and peritoneal cavity in LPS challenged mice, as well as IL-6 and TNF α production in LPS-stimulated primary peritoneal macrophages. BNAG2 displayed an anti-inflammatory effect which was comparable to NAG. These findings implied potential application of these novel NAG derivatives, especially BNAG1, in treatment of certain inflammation-related diseases.

Knockout of formyl peptide receptor 1 reduces osteogenesis and bone healing.

AIMS: Formyl peptide receptor 1 (FPR1), from a G-protein coupled receptor family, was previously well-characterized in immune cells. But the function of FPR1 in osteogenesis and fracture healing was rarely reported. This study, using the FPR1 knockout (KO) mouse, is one of the first studies that try to investigate FPR1 function to osteogenic differentiation of bone marrow-derived stem cells (BMSCs) in vitro and bone fracture healing in vivo. MATERIALS AND METHODS: Primary BMSCs were isolated from both FPR1 KO and wild type (WT) mice. Cloned mouse BMSCs (D1 cells) were used to examine role of FoxO1 in FPR1 regulation of osteogenesis. A closed, transverse fracture at the femoral midshaft was created to compare bone healing between KO and WT mice. Biomechanical and structural properties of femur were compared between healthy WT and KO mice. KEY FINDINGS: FPR1 expression increased significantly during osteogenesis of both primary and cloned BMSCs. Compared to BMSCs from FPR1 KO mice, WT BMSCs displayed considerably higher levels of osteogenic markers as well as mineralization. Osteogenesis by D1 cells was inhibited by either an FPR1 antagonist cFLFLF or a specific inhibitor of FoxO1, AS1842856. In addition, the femur from WT mice had better biomechanical properties than FPR1 KO mice. Furthermore, bone healing in WT mice was remarkably improved compared to FPR1 KO mice analyzed by X-ray and micro-CT. SIGNIFICANCE: These findings indicated that FPR1 played a vital role in osteogenic differentiation and regenerative capacity of fractured bone, probably through the activation of FoxO1 related signaling pathways.

Increased Rate of Complications Following Total Knee Arthroplasty in Patients Who Have Polymyositis.

BACKGROUND: Polymyositis (PM) is a systemic connective tissue disorder that can lead to early onset degenerative joint disease and a need for total knee arthroplasty (TKA). Outcomes of TKA in patients who have PM are not well documented in the literature. The purpose of this study was to evaluate PM as a risk factor for complications after TKA. METHODS: Using a national private payer insurance database from 2010 to 2022, PM patients undergoing primary TKA were compared to 10:1 matched controls based on age, sex, and comorbidities. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. 90-day emergency department visits and inpatient readmissions were also documented. A total of 25,039 patients undergoing primary TKA were queried, of which 2,290 had PM. RESULTS: Compared to the matched controls, patients who had PM demonstrated higher rates of medical and surgical complications, including pulmonary embolism (1.0% versus 0.5%, P = .001), cerebrovascular accident (1.3% versus 0.7%, P = .002), wound complications (3.4% versus 2.1%, P < .001), and periprosthetic joint infection at 1 year (1.7% versus 1.3%, P = .042) and 2 years (2.6% versus 1.9%, P = .006). Patients who had PM displayed elevated 90-day emergency department (14.9% versus 13.3%, P = .032) and hospital readmission rate (7.1% versus 4.8%, P < .001). CONCLUSIONS: Patients who have PM are at higher risks of postoperative medical and surgical complications, including pulmonary embolism, cerebrovascular accident, wound complication, and periprosthetic joint infection. Given these results, it is helpful for orthopedic surgeons and patients to consider these risks when considering TKA for patients who have PM.

Increased Rate of Complications Following Total Knee Arthroplasty in Patients Who Have Marfan Syndrome.

BACKGROUND: Outcomes of Marfan syndrome (MFS) patients after total knee arthroplasty (TKA) are poorly documented in the literature. The purpose of this study was to evaluate MFS as a potential risk factor for complications after TKA. METHODS: Using a national private payer insurance database from 2010 to 2022, MFS patients undergoing primary TKA were identified and compared to 10:1 matched controls based on age, sex, obesity, diabetes mellitus, and a comorbidity index. A total of 4,092 patients undergoing primary TKA were analyzed, of which 372 had MFS. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. 90-day emergency department-visits and inpatient readmissions were also documented. RESULTS: Compared to the matched controls, patients who have MFS displayed elevated rates of surgical complications, including prosthetic instability (1-year, odds ratio (OR) 3.88, 95% confidence interval (CI) [1.58 to 8.66]; 2-year, OR 4.39, 95% CI [2.16 to 8.44]), and revision surgery (2 year, OR 1.79, 95% CI [1.05 to 2.91]). Additionally, patients who have MFS demonstrated significant higher rates of medical complications, including aortic dissection (2.15 versus 0%) and transfusion (OR 2.63, 95% CI [1.31 to 4.90]). CONCLUSIONS: Patients who have MFS are at higher risks of postoperative complications after TKA, encompassing both medical and surgical complications. Specifically, patients who have MFS have a significantly higher likelihood of experiencing prosthetic instability and requiring revision surgery. Given these results, it is crucial for orthopedic surgeons and patients alike to consider these risks when determining a course of TKA for patients who have MFS.

Effect of Patient Age on Total Hip Arthroplasty Outcomes in Patients Who Have Osteonecrosis of the Femoral Head Compared to Patients Who Have Hip Osteoarthritis.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) affects both young and old patients. However, outcomes following total hip arthroplasty (THA) for these patients may vary with age. This study aimed to examine the effect of age on THA outcomes for non-traumatic ONFH patients, an area currently lacking research. METHODS: Patients who had non-traumatic ONFH undergoing THA with at least 2 years of follow-up were identified using a database and divided into four groups by age. Then, 4 matched control groups of patients who had hip osteoarthritis (OA) were created. Multivariate logistic regression analyses were used to evaluate the rates of medical and surgical complications. Additionally, cohorts with a minimum 5-year follow-up were filtered to obtain further data on surgical outcomes. The study analyzed 85,462 non-traumatic ONFH and 80,120 hip OA patients undergoing THA. RESULTS: Multiple medical complications in ONFH patients increased with age. Periprosthetic fracture within 2 years increased with age, while 90-day wound complications, 2-year periprosthetic joint infections, dislocations, and revisions decreased. The trends for complications continued at the 5-year follow-up. Compared to OA patients, those who had ONFH had higher risks of most complications, but this discrepancy decreased with age. CONCLUSIONS: In ONFH patients undergoing THA, medical complications generally rise with age, while most surgical complications, including revisions, decrease. It is notable that ONFH patients experienced more complications than those who had OA, but this difference diminished with age.

Risks Following Total Knee Arthroplasty in Patients Who Have Antiphospholipid Syndrome.

BACKGROUND: Antiphospholipid syndrome (APS) is recognized as a thrombophilic autoimmune condition characterized by a tendency to develop venous thromboembolism. Total knee arthroplasty (TKA) is a prevalent procedure in patients who have advanced knee arthritis. Notably, TKA is unequivocally considered a thrombotic risk factor. However, outcomes of APS patients after TKA are still poorly documented in literature. The purpose of this study was to evaluate APS as a potential risk factor for complications after TKA. METHODS: Using the PearlDiver Mariner database from 2010 to 2022, APS patients undergoing primary TKA were identified and compared to 10:1 matched control based on age, sex, and relevant comorbidities. A total of 7,478 patients undergoing primary TKA were analyzed, of which 683 had APS. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications including revision up to 2 years. Ninety-day emergency department visit and inpatient readmission were also documented. RESULTS: Within 90 days after TKA, patients who have APS exhibited higher rates of cerebrovascular accident (adjusted odds ratio 2.04, 95% confidence interval 1.12 to 3.57; P = .014) and deep vein thrombosis (adjusted odds ratio 2.87, 95% confidence interval 1.99 to 4.06; P < .001) as compared to matched controls. No difference in surgical or nonthrombotic medical complications was observed between 2 cohorts. CONCLUSIONS: There were significantly higher rates of stroke and deep vein thrombosis in APS patients. Our study did not find statistical differences in other surgical complications or readmissions between the 2 groups. Orthopaedic surgeons should consider appropriate prophylaxis of thrombosis in this patient population undergoing TKA perioperatively.

Mobile health supported multi-domain recovery trajectories after major arthroplasty or spine surgery: a pilot feasibility and usability study.

BACKGROUND: Recovery after surgery intersects physical, psychological, and social domains. In this study we aim to assess the feasibility and usability of a mobile health application called PositiveTrends to track recovery in these domains amongst participants undergoing hip, knee arthroplasty or spine surgery. Our secondary aim was to generate procedure-specific, recovery trajectories within the pain and medication, psycho-social and patient-reported outcomes domain. METHODS: Prospective, observational study in participants greater than eighteen years of age. Data was collected prior to and up to one hundred and eighty days after completion of surgery within the three domains using PositiveTrends. Feasibility was assessed using participant response rates from the PositiveTrends app. Usability was assessed quantitatively using the System Usability Scale. Heat maps and effect plots were used to visualize multi-domain recovery trajectories. Generalized linear mixed effects models were used to estimate the change in the outcomes over time. RESULTS: Forty-two participants were enrolled over a four-month recruitment period. Proportion of app responses was highest for participants who underwent spine surgery (median = 78, range = 36-100), followed by those who underwent knee arthroplasty (median = 72, range = 12-100), and hip arthroplasty (median = 62, range = 12-98). System Usability Scale mean score was 82 ± 16 at 180 days postoperatively. Function improved by 8 and 6.4 points per month after hip and knee arthroplasty, respectively. In spine participants, the Oswestry Disability Index decreased by 1.4 points per month. Mood improved in all three cohorts, however stress levels remained elevated in spine participants. Pain decreased by 0.16 (95% Confidence Interval: 0.13-0.20, p < 0.001), 0.25 (95% CI: 0.21-0.28, p < 0.001) and 0.14 (95% CI: 0.12-0.15, p < 0.001) points per month in hip, knee, and spine cohorts respectively. There was a 10.9-to-40.3-fold increase in the probability of using no medication for each month postoperatively. CONCLUSIONS: In this study, we demonstrate the feasibility and usability of PositiveTrends, which can map and track multi-domain recovery trajectories after major arthroplasty or spine surgery.

Catastrophic Early Failure and Fragmentation of a Modern Moderately Cross-linked Polyethylene Acetabular Liner.

A 60-year-old man who underwent uncomplicated staged bilateral total hip arthroplasty for femoral head osteonecrosis presented with mechanical catching of his left total hip arthroplasty 3 years after index surgery. Radiographs revealed eccentricity of the left femoral head, concerning the failure of a modern moderately cross-linked polyethylene liner. Catastrophic polyethylene liner failure with significant wear, fragmentation, and femoral head abrasion was noted during revision surgery. The original liner and head were replaced, and the patient has exhibited no complications, pain, or difficulty ambulating 6 months postoperatively. This report highlights one potential novel mechanism for the failure of the Exactech Connexion GXL liner (Exactech Inc., Gainesville, FL), an implant recently reported to have a higher-than-expected failure rate, potentially due to insufficient packaging and increased oxidative processes.

Outcomes Following Total Hip Arthroplasty in Patients Who Have Charcot Neuroarthropathy of the Hip.

BACKGROUND: Historically, Charcot neuroarthropathy hip (CNH) was deemed a contraindication for total hip arthroplasty (THA). However, as implant design and surgical techniques advance, THA for CNH has been performed and documented in literature. Information regarding the outcomes of THA for CNH is limited. The objective of the study was to assess outcomes following THA in patients who have CNH. METHODS: Patients who have CNH underwent primary THA and had at least 2 years of follow-up were identified in a national insurance database. For comparison, a 1:10 matched control cohort of patients who did not have CNH was created based on age, sex, and relevant comorbidities. Eight hundred and ninety-five CNH patients who underwent primary THA were compared to 8,785 controls. Medical outcomes, emergency department visits, hospital readmissions, and surgical outcomes including revisions between cohorts were evaluated using multivariate logistic regressions. RESULTS: The CNH patients were found to have higher risks of 90-day wound complications (P = .014), periprosthetic joint infection (P = .013) (P = .021), dislocation (P < .001) (P < .001), aseptic loosening (P = .040) (P = .002), periprosthetic fracture (P = .003) (P < .001), and revision (P < .001) (P < .001) at 1-year and 2-year follow-up, respectively. CONCLUSION: While patients who have CNH are at a higher risk of wound and implant-related complications, they are comparatively lower than previously reported in literature. Orthopaedic surgeons should be cognizant of the increased risk in this population to provide appropriate preoperative counseling and enhanced perioperative medical management.

Increased rate of complications following total knee arthroplasty in patients with systemic sclerosis.

PURPOSE: Outcomes after total knee arthroplasty (TKA) for patients with systemic sclerosis (SSc) are poorly documented in the literature. The purpose of this study was to evaluate SSc as a potential risk factor for increased rate of complications after TKA. METHODS: Using the PearlDiver Mariner database, 2,002 patients with SSc undergoing primary TKA were identified and compared to matched controls of 19,892 patients without SSc. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to two years. 90-day ED-visit and inpatient readmission were also documented. RESULTS: Compared to the matched controls, patients with SSc demonstrated higher rates of medical complications such as cerebrovascular accident (1.5% vs 0.6%, p < 0.001), myocardial infarction (1.3% vs 0.3%, p < 0.001), and sepsis (1.1% vs 0.4%, p < 0.001). Additionally, patients with SSc displayed elevated rates of surgical complications, including wound complications (3.9% vs 2.2%, p < 0.001) and aseptic loosening at 90 days (0.2% vs 0.1%; OR 3.53 [1.13-9.28]), one year (0.7% vs 0.4%; OR 1.78 [0.96-3.05]), and two years (1.4% vs 0.9%; OR 1.68 [1.10-2.45]). Patients with SSc also had higher rates of emergency department visits (21.2% vs 11.4%, p < 0.001). CONCLUSIONS: Patients with SSc are at higher risks of postoperative complications, encompassing both medical and surgical complications. Specifically, patients with SSc have a significantly higher likelihood of experiencing wound complications, cerebrovascular accident, and myocardial infarction. It is crucial for orthopaedic surgeons and patients alike to consider the elevated risks when determining a course of TKA for patients with SSc.

Outcomes Following Hemiarthroplasty for Femoral Neck Fracture in Patients Who Have Hemiparesis.

BACKGROUND: Hemiparesis increases the risk of femoral neck fracture (FNF) in the elderly, which frequently necessitates hemiarthroplasty. There are limited reports on the outcomes of hemiarthroplasty in patients who have hemiparesis. The purpose of this study was to evaluate hemiparesis as a potential risk factor for medical and surgical complications following hemiarthroplasty. METHODS: Hemiparetic patients who have concomitant FNF and underwent hemiarthroplasty with at least 2 years of follow-up were identified using a national insurance database. A 10:1 matched control cohort of patients who did not have hemiparesis was created for comparison. There were 1,340 patients who have and 12,988 patients who did not have hemiparesis undergoing hemiarthroplasty for FNF. Multivariate logistic regression analyses were used to evaluate rates of medical and surgical complications between the 2 cohorts. RESULTS: Aside from increased rates of medical complications including cerebrovascular accident (P < .001), urinary tract infection (P = .020), sepsis (P = .002), and myocardial infarction (P < .001), patients who have hemiparesis also experienced higher rates of dislocation within 1 and 2 years (Odds Ratio (OR) 1.54, P = .009; OR 1.52, P = .010). Hemiparesis was not associated with higher risk of wound complications, periprosthetic joint infection, aseptic loosening, and periprosthetic fracture, but was associated with higher incidence of 90-day ED-visits (OR 1.16, P = .031) and 90-day readmission (OR 1.32, P < .001). CONCLUSION: While patients who have hemiparesis do not have increased risk of implant-related complications other than dislocation, they are at increased risk of developing medical complications following hemiarthroplasty for FNF.

The impact of Behcet syndrome on total knee arthroplasty outcomes: a retrospective matched cohort study.

PURPOSE: Articu lar involvement is a common manifestation of Behcet syndrome (BS), which can eventually result in significant arthralgia and necessitate total knee arthroplasty (TKA). However, outcomes of BS patients after TKA are still poorly documented in the literature. The purpose of this study was to evaluate BS as a potential risk factor for complications after TKA. METHODS: BS patients undergoing primary TKA were identified from the PearlDiver Mariner database from 2010 to 2021 and compared to 10:1 matched controls. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to two years. Ninety-day emergency department (ED) visit and inpatient readmission were also documented. RESULTS: A total of 4286 patients undergoing primary TKA were queried, of which 390 had BS. Patients with BS demonstrated significantly higher rates of medical complications, including deep venous thrombosis. The rates of surgical complications were similar between the two groups with the exception of periprosthetic instability, aseptic loosening, and wound complications in BS patients. Additionally, a significantly higher rate of ED visits but markedly lower rates of 90-day readmissions were noted in patients with BS. CONCLUSION: Patients with BS undergoing TKA are at higher risks of medical and surgical complications. Special considerations for a unique postoperative course with the higher complications should be made. It is crucial for orthopedic surgeons and patients alike to consider these risks when determining the expected course after TKA for patients with BS.

Anti-inflammatory activities of two new deoxygenated N-acetyl glucosamines in lipopolysaccharide-activated mouse macrophage RAW264.7 cells.

Background: Glucosamine and N-acetyl-glucosamine (NAG) are amino sugars found in human extracellular matrix with previously described anti-inflammatory effects. Despite mixed results from clinical studies, these molecules have been used extensively in supplements. Objective: We investigated the anti-inflammatory properties of two synthesized derivatives of N-acetyl-glucosamine (NAG), bi-deoxy-N-acetyl-glucosamine (BNAG) 1 and 2. Methods: Using mouse macrophage RAW 264.7 cells with lipopolysaccharide (LPS) to induce inflammation, the effects of NAG, BNAG 1, and BNAG 2 on the expression of IL-6, IL-1ß, inducible nitric oxide synthase (iNOS) and COX-2 were studied using ELISA, Western blot and quantitative RT-PCR. Cell toxicity and nitric oxide (NO) production were evaluated using WST-1 assay and the Griess reagent, respectively. Results: Among the three tested compounds, BNAG1 shows the highest inhibition of iNOS, IL-6, TNF α and IL-1ß expression and NO production. All three tested compounds show slight inhibition on cell proliferation of RAW 264.7 cells, except that BNAG1 displays a remarkable toxicity at the tested maximum dose of 5 mM. Conclusion: BNAG 1 and 2 exhibit notable anti-inflammatory effects compared to the parent NAG molecule.

BMP-6 promotes type 2 immune response during enhancement of rat mandibular bone defect healing.

Introduction: Bone morphogenetic proteins (BMPs) are used as key therapeutic agents for the treatment of difficult fractures. While their effects on osteoprogenitors are known, little is known about their effects on the immune system. Methods: We used permutations of BMP-6 (B), vascular endothelial growth factor (V), and Hedgehog signaling pathway activator smoothened agonist (S), to treat a rat mandibular defect and investigated healing outcomes at week 8, in correlation with the cellular landscape of the immune cells in the fracture callus at week 2. Results: Maximum recruitment of immune cells to the fracture callus is known to occur at week 2. While the control, S, V, and VS groups remained as nonunions at week 8; all BMP-6 containing groups - B, BV, BS and BVS, showed near-complete to complete healing. This healing pattern was strongly associated with significantly higher ratios of CD4 T (CD45+CD3+CD4+) to putative CD8 T cells (CD45+CD3+CD4-), in groups treated with any permutation of BMP-6. Although, the numbers of putative M1 macrophages (CD45+CD3-CD11b/c+CD38high) were significantly lower in BMP-6 containing groups in comparison with S and VS groups, percentages of putative - Th1 cells or M1 macrophages (CD45+CD4+IFN-γ+) and putative - NK, NKT or cytotoxic CD8T cells (CD45+CD4-IFN-γ+) were similar in control and all treatment groups. Further interrogation revealed that the BMP-6 treatment promoted type 2 immune response by significantly increasing the numbers of CD45+CD3-CD11b/c+CD38low putative M2 macrophages, putative - Th2 cells or M2 macrophages (CD45+CD4+IL-4+) cells and putative - mast cells, eosinophils or basophils (CD45+CD4-IL-4+ cells). CD45- non-haematopoietic fractions of cells which encompass all known osteoprogenitor stem cells populations, were similar in control and treatment groups. Discussion: This study uncovers previously unidentified regulatory functions of BMP-6 and shows that BMP-6 enhances fracture healing by not only acting on osteoprogenitor stem cells but also by promoting type 2 immune response.

Fewer Than One in 20 Current Academic Orthopaedic Surgeons Have Obtained National Institutes of Health Funding.

BACKGROUND: National Institutes of Health (NIH) funding is a key driver of orthopaedic research, but it has become increasingly difficult to obtain in recent years. An understanding of the types of grants that are commonly funded, how productive they are, and the factors associated with obtaining funding may help orthopaedic surgeons better understand how to earn grants. QUESTIONS/PURPOSES: In this study, we sought to determine (1) the proportion of current academic orthopaedic surgeons who have obtained NIH grant funding, (2) the productivity of these grants by calculating grant productivity metrics, and (3) the factors (such as gender, subspecialty, and additional degrees) that are associated with obtaining grant funding. METHODS: Current academic orthopaedic surgeons at the top 140 NIH-funded institutions were identified via faculty webpages; 3829 surgeons were identified. Demographic information including gender (men constituted 88% of the group [3364 of 3829]), academic rank (full professors constituted 22% [856 of 3829]), additional degrees (those with MD-PhD degrees constituted 3% [121 of 3829]), leadership positions, and orthopaedic subspecialty was collected. Funding histories from 1985 through 2021 were collected using the NIH Research Portfolio Online Reporting Tools Expenditures and Results. Grant type, funding, publications, and citations of each article were collected. A previously used grant impact metric (total citations per USD 0.1 million) was calculated to assess grant productivity. Multivariable binomial logistic regression was used to evaluate factors associated with obtaining funding. RESULTS: Four percent (150 of 3829) of academic orthopaedic surgeons obtained USD 338.3 million in funding across 301 grants, resulting in 2887 publications over the entire study period. The R01 was the most commonly awarded grant in terms of the total number awarded, at 36% (108 of 301), as well as by funding, publications, and citations, although other grant types including T32, F32, R03, R13, and R21 had higher mean grant impact metrics. There was no difference between men and women in the by-gender percentage of academic orthopaedic surgeons who obtained funding (4% [135 of 3229] versus 3% [15 of 450]; odds ratio 0.9 [95% confidence interval 0.5 to 1.7]; p = 0.80). A department having a single funded PhD researcher may be associated with surgeon-scientists obtaining grant funding, but with the numbers available, we could not demonstrate this was the case (OR 1.4 [95% CI 0.9 to 2.2]; p = 0.12). CONCLUSION: Fewer than one in 20 academic orthopaedic surgeons have received NIH funding. R01s are the most commonly awarded grant, although others demonstrate increased productivity metrics. Future studies should investigate the role of co-principal investigators on productivity and the role of different funding sources. CLINICAL RELEVANCE: Individuals should pursue both R01 and non-R01 grants, and departments should consider cultivating relationships with funded PhDs. The specific research infrastructure and departmental policies of the most productive institutions and grants should be surveyed and emulated.

Formyl peptide receptors in bone research.

PURPOSE/AIM OF THE STUDY: The formyl peptide receptor (FPR) participates in the immune response, with roles in infection and inflammation. In this review article, we summarize the current literature on these roles before discussing the function of FPRs in the pathogenesis of musculoskeletal disorders including osteoarthritis (OA), degenerative disc disease (DDD), and rheumatoid arthritis (RA). Additionally, we discuss the potential diagnostic and therapeutic roles of FPRs in these domains. METHODS: PubMed and Ovid MEDLINE searches were performed from 1965 through March 2022. Keywords included "FPR, tissue expression, inflammation, infection, musculoskeletal disorder, bone, rheumatoid arthritis, osteoarthritis, degenerative disc disease, mitochondria." RESULTS: Sixty-nine studies were included in this review article. FPRs appear to be ubiquitous in the pathogenesis, diagnosis, and treatment of common musculoskeletal disorders. They can potentially be utilized for the earlier diagnosis of OA and DDD. They may be employed with mesenchymal stem cells (MSCs) to reverse OA and DDD pathologies. With anti-inflammatory, anti-osteolytic, and pro-angiogenic functions, they may broaden treatment options in RA. CONCLUSIONS: FPRs appear to be heavily involved in the pathogenesis of common musculoskeletal conditions, including arthritis, degenerative disc disease, and rheumatoid arthritis. Furthermore, they demonstrate much promise in the diagnosis and treatment of these conditions. Their roles should continue to be explored.

Higher cost of arthroplasty for hip fractures in patients transferred from outside hospitals vs primary emergency department presentation.

BACKGROUND: In 2016 Centers for Medicare and Medicaid Services proposed bundled payments for hip fractures to improve the quality and decrease costs of care. Patients transferred from other facilities may be imposing a financial risk on the hospitals that accept these patients. AIM: To determine the costs associated with patients that either presented to the emergency department or were transferred from another hospital or skilled nursing facility (SNF) with the diagnosis of a hip fracture requiring operative intervention. METHODS: A retrospective single institution review was conducted for all arthroplasty patients from 2010 to 2015. Inclusion criteria included a total or partial hip replacement for a hip fracture. Exclusion criteria included pathologic, periprosthetic, and fracture non-union. Data was collected to compare total observed costs for patients from the emergency department, patients from skilled nursing facilities, and patients from an outside hospital. RESULTS: A total of 223 patients met the inclusion criteria. 135 (60.54%) of these patients presented primarily to the emergency department, 58 patients (26.01%) were transferred from an outside hospital, and 30 patients (13.43%) were transferred from a SNF. Cost data analysis showed that outside hospital patients demonstrated significantly greater total cost for their hospitalization ($43302) compared to emergency department patients ($28875, P = 0.000) and SNF patients ($28282, P = 0.000). CONCLUSION: Patients transferred from an outside hospital incurred greater costs for their hospitalization than patients presenting from an emergency department or SNF. This is a strong argument for risk-adjustment models when bundling payments for the care of hip fracture patients.

Outcomes following Total Hip Arthroplasty for Femoral Head Osteonecrosis in Patients with History of Solid Organ Transplant.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) is a potentially debilitating condition, often requiring total hip arthroplasty (THA). Patients with solid organ transplant (SOT) are at increased risk of postoperative complications after THA for osteoarthritis. The objective of the present study is to evaluate SOT as a potential risk factor for complication after THA for ONFH. METHODS: This is a retrospective study that identified patients with SOT who underwent THA for ONFH from 2005 to 2014 in a national insurance database and compared them to 5:1 matched controls without transplant. Subgroup analyses of patients with renal transplant (RT) and those with non-RT were also analyzed. A logistic regression analysis was used to compare rates of mortality, hospital readmission, emergency room (ER) visits, infection, revision, and dislocation while controlling for confounders. Differences in hospital charges, reimbursement, and length of stay (LOS) were also compared. RESULTS: 996 patients with SOT who underwent THA were identified and compared to 4,980 controls. SOT patients experienced no increased risk of early postoperative complications compared to controls. Solid organ transplant was associated with higher resource utilization and LOS. Renal transplant patients were found to have significantly higher risk of hospital readmission at 30 days (odds ratio [OR] 1.77; p = 0.001) and 90 days (OR 1.62; p < 0.001) and hospital LOS (p < 0.001), but had lower risk of infection (OR 0.65; p = 0.030). Non-RT patients had higher rate of ER visits at 30 days (OR 2.26; p = 0.004) but lower rates of all-cause revision (OR 0.22; p = 0.043). CONCLUSIONS: Patients with history of SOT undergoing THA for ONFH utilize more hospital resources with longer LOS and greater risk of readmission but are not necessarily at an increased risk of early postoperative complications.