Trends in avascular necrosis and related arthroplasties in hospitalized patients with systemic lupus erythematosus and rheumatoid arthritis.

OBJECTIVE: Avascular necrosis (AVN) is a devastating complication often necessitating arthroplasty, particularly common in systemic lupus erythematosus (SLE). Limited research exists on arthroplasty trends since new steroid-sparing agents. We analyzed trends and characteristics associated with AVN and AVN-related arthroplasties among SLE and RA hospitalizations using two decades of data from the U.S. National Inpatient Sample (NIS). METHODS: This cross-sectional study used NIS (2000-2019) to identify hospitalized adults with SLE and RA, with or without AVN, using ICD codes. AVN was further grouped by arthroplasty status. Primary outcomes were AVN and AVN-related arthroplasty rates and time trends in SLE and RA. Baseline sociodemographics and comorbidities were compared. Analyses used STATA and Joinpoint regression to calculate annual percent change (APC). RESULTS: Overall, 42,728 (1.3 %) SLE and 43,600 (0.5 %) RA hospitalizations had concomitant AVN (SLE-AVN and RA-AVN). Of these, 16,724 (39 %) and 25,210 (58 %) underwent arthroplasties, respectively. RA-AVN increased (APC: 0.98*), with a decrease in arthroplasties (APC: -0.82*). In contrast, SLE-AVN initially increased with a breakpoint in 2011 (APC 2000-2011: 1.94* APC 2011-2019 -2.03), with declining arthroplasties (APC -2.03*). AVN hospitalizations consisted of individuals who were younger and of Black race; while arthroplasties were less likely in individuals of Black race or Medicaid coverage. CONCLUSION: We report a breakpoint in rising SLE-AVN after 2011, which may relate to newer steroid-sparing therapies (i.e., belimumab). AVN-associated arthroplasties decreased in SLE and RA. Fewer AVN-associated arthroplasties were noted for Black patients and those with Medicaid, indicating potential disparities. Further research should examine treatment differences impacting AVN and arthroplasty rates.

Identifying the causal relationship between immune factors and osteonecrosis: a two-sample Mendelian randomization study.

A wealth of evidence intimates a profound connection between the immune system and osteonecrosis, albeit the specific immune factors underlying this connection remain largely veiled. A bidirectional Mendelian randomization (MR) study was conducted based on genome-wide association study summary data to identify causal links between 731 immune factors and osteonecrosis including drug-induced osteonecrosis. Preliminary MR analysis was accomplished utilizing the inverse-variance weighted method under a multiplicative random effects model, and heterogeneity and potential horizontal pleiotropy were evaluated through Cochrane's Q-test, MR-Egger intercept test, MR-PRESSO global test, and leave-one-out analysis. Upon false discovery rate correction, the gene-predicted level of one immune factor (CD62L - monocyte %monocyte) exhibited a significant positive correlation with osteonecrosis, while eight immune traits associated with monocytes, dendritic cells, and NK cells demonstrated significant causal effects with drug-induced osteonecrosis. Reverse MR revealed no significant correlations. This MR research provides genetic evidence for the causal associations between a broad spectrum of immune factors and osteonecrosis. Such a study aids in unraveling the intricate interaction patterns between the immune and skeletal systems, elucidating the pathogenesis of osteonecrosis, and identifying potential novel therapeutic approaches.

Talar Neck Fractures With Associated Ipsilateral Foot and Ankle Fractures Have a Higher Risk of Avascular Necrosis.

OBJECTIVES: To determine if talar neck fractures with concomitant ipsilateral foot and/or ankle fractures (TNIFAFs) are associated with higher rates of avascular necrosis (AVN) compared with isolated talar neck fractures (ITNs). DESIGN: Retrospective cohort. SETTING: Single level I trauma center. PATIENT SELECTION CRITERIA: Skeletally mature patients who sustained talar neck fractures from January 2008 to January 2017 with at least 6-month follow-up. Based on radiographs at the time of injury, fractures were classified as ITN or TNIFAF and by Hawkins classification. OUTCOME MEASURES AND COMPARISONS: The primary outcome was the development of AVN based on follow-up radiographs, with secondary outcomes including nonunion and collapse. RESULTS: There were 115 patients who sustained talar neck fractures, with 63 (55%) in the ITN group and 52 (45%) in the TNIFAF group. In total, 63 patients (54.7%) were female with the mean age of 39 years (range, 17-85), and 111 fractures (96.5%) occurred secondary to high-energy mechanisms of injury. There were no significant differences in demographic or clinical characteristics between groups ( P > 0.05). Twenty-four patients (46%) developed AVN in the TNIFAF group compared with 19 patients (30%) in the ITN group ( P = 0.078). After adjusting for Hawkins classification and other variables, the odds of developing AVN was higher in the TNIFAF group compared with the ITN group [odds ratio, 2.43 (95% confidence interval, 1.01-5.84); ( P = 0.047)]. CONCLUSIONS: This study found a significantly higher likelihood of AVN in patients with talar neck fractures with concomitant ipsilateral foot and/or ankle fractures compared to those with isolated talar neck fractures after adjusting for Hawkins classification and other potential prognostic confounders. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The association of an elevated Th/Ts ratio and lupus anticoagulant with symptomatic osteonecrosis in systemic lupus erythematosus patients.

Objective: This study aimed to assess the risk factors for symptomatic osteonecrosis (ON) in systemic lupus erythematosus (SLE) and identify clinical characteristics and laboratory markers for predicting symptomatic ON occurrence in SLE patients. Methods: Seventy (6.0%) of 1175 SLE patients diagnosed with symptomatic ON were included in this study. An equal number of SLE patients without symptomatic ON, matched in terms of age and gender, were enrolled in the control group. Clinical symptoms, routine laboratory examinations, lymphocyte subsets, and treatments of these patients were retrospectively reviewed and compared between the two groups. Logistic regression analysis was employed to identify risk factors associated with symptomatic ON in SLE. Results: Among the 70 cases in the symptomatic ON group, 62 (88.6%) patients experienced femoral head necrosis, with bilateral involvement observed in 58 patients. Bone pain was reported in 32 cases (51.6%), and 19 cases (30.6%) presented with multiple symptoms. Univariate analysis revealed significant differences between the two groups in various factors, including disease duration (months), cumulative steroid exposure time, history of thrombosis, neurological involvement, the number of affected organs, myalgia/myasthenia, and the use of medications such as glucocorticoids, immunosuppressants, aspirin, and statins (P<0.05). Moreover, lupus anticoagulant (LA) levels were significantly higher in the symptomatic ON group than in the control group (P<0.05). Furthermore, notable distinctions were observed in peripheral blood immune cells, including an elevated white blood cell count (WBC), a decreased percentage of Ts cells (CD3+CD8+), and an elevated Th/Ts ratio. Logistic regression analysis revealed that a history of thrombosis, LA positivity, and an elevated Th/Ts ratio remained positive factors associated with symptomatic ON (P<0.05). Conclusion: Decreased Ts cells and changes in the T lymphocyte subset play an important regulatory role in the development of symptomatic ON. A history of thrombosis and LA are associated with an increased probability of symptomatic ON in SLE and may serve as potential predictors.

Natural course of talar avascular necrosis during short-term follow-up and factors associated with Disease progression.

BACKGROUND: This retrospective cohort study aimed to investigate the natural history of talar avascular necrosis (AVN) during short-term outpatient follow-up and to identify the risk factors for progression to collapse and arthritic changes. METHODS: Thirty-four cases of talar AVN from 34 patients (15 males, 19 females) were included. The mean age of the patients was 48.9 years (SD 16.0 years) and the mean follow-up period was 39.5 months (SD 42.0 months). The patients were divided into two groups i.e., progression and non-progression groups. The progression group consisted of those who showed aggravation of the Ficat stage during the follow-up period or advanced arthritis of the ankle joint (Ficat stage 4) at presentation. Demographic data and information regarding BMI, medical comorbidities, trauma history, bilaterality, and location of the lesion (shoulder vs. non-shoulder lesions) were collected. Following the univariate analysis, a binary logistic regression analysis was performed. RESULTS: The location of the talar AVN was the only significant factor (p = 0.047) associated with disease progression. A total of 14.3% (2 of 14) of the central (non-shoulder) talar AVN lesions showed progression, while 50% (10 of 20) of shoulder lesions aggravated during follow-up. Age, sex, bilaterality, medical comorbidities, and trauma history were not associated with progressive talar collapse or subsequent arthritic changes in talar AVN. CONCLUSIONS: Conservative treatment should be considered for a central lesion of the talar AVN because it tends to remain stable without progression. A more comprehensive study with a larger study population is required to establish the surgical indications for talar AVN. LEVEL OF EVIDENCE: Prognostic level III.

Obesity impairs revascularization and bone healing in a mouse model of osteonecrosis.

Osteonecrosis of the femoral head (ONFH) is a devastating bone disease that is caused by a disruption of blood supply leading to necrotic cell death. Clinically, it was found that obesity has a high prevalence with ONFH. However, it remains unclear how obesity may directly affect tissue regeneration and bone healing in osteonecrosis (ON). The purpose of this study is to investigate the effects of obesity and weight loss (WL) on ON healing. In this study, we induced obesity and WL in an established surgery-induced ON mouse model via feeding a high-fat diet (HFD) and altering the diet respectively. All mice received a surgical induction of ON of distal femoral epiphysis at the age of 12 weeks. HFD was switched to normal diet (ND) after ON surgery to induce WL. Mouse body weight was recorded weekly. Mouse body composition was scanned by DEXA (Dual-energy X-ray absorptiometry) right after sacrifice at the age of 16 weeks. The distal femoral bone samples were fixed and embedded for histology such as H&E, immunohistochemistry, and TRAP staining. In this study, we found that HFD-induced obesity impaired revascularization and bone remodeling showing decreased vessel areas and reduced osteoblast and osteoclast numbers. WL could rescue obesity-induced bone healing defects. Our study is the first to test the direct effects of obesity and WL on ON bone healing. We believe our work may provide new concepts for osteonecrosis treatment in obese patients.

Risk factors for osteonecrosis of the humeral head after internal fixation of proximal humeral fractures: a systematic review and meta-analysis.

BACKGROUND: Osteonecrosis of the humeral head (ONHH) is a severe complication after the internal fixation of proximal humeral fractures (IFPHF). The risk factors remain controversial though many studies have reported. In this research, meta-analysis was used to evaluate which surgeon-level factors can be modified to lower the risk and we hope to provide evidence-based support for preventing ONHH. METHODS: Literature was retrieved from PubMed, Cochrane Library, Embase, Web of Science, and Scopus for eligible studies published up to January 2023. The pooled odds ratios (ORs) were calculated with their corresponding 95% confidence intervals (CIs) to evaluate. STATA 15.1 software was applied for data synthesis, sensitivity synthesis, and publication bias. RESULTS: 45 articles were published between 2000 and 2022, and 2482 patients were finally included. All articles were observational research, with 7 case-control studies and 38 cohort studies, and the Newcastle Ottawa Scale (NOS) score ranged from 7 to 9. The pooled results suggested that age (OR 0.32, 95% CI 0.14-0.74, P = 0.01), reduction quality (OR 0.08, 95% CI 0.01-0.44, P = 0.00), fracture type (OR 0.44, 95% CI 0.25-0.78, P = 0.01), surgical approach (OR: 4.06, 95% CI 1.21-13.61, P = 0.02) and fixation implant (OR = 0.68, 95% CI = 0.34-1.33, P = 0.02) were risk factors for ONHH after IFPHF. According to sensitivity analysis, Begg (P = 0.42) and Egger (P = 0.68) tests, the results were stable and exhibited no publication bias. CONCLUSIONS: The study showed that age, reduction quality, fracture type, surgical approach and fixation implant were risk factors for ONHH after IFPHF, while gender, varus or valgus, timely operation, injured side, and the existence of medial support have little influence on ONHH, as they could not be considered risk factors and still need further investigations.

A chimeric medial femoral condyle chondro-osseus flap with two thin periosteal flaps to reconstruct partial necrosis of talar body: A case report.

Total talar extrusion is a rare complication of high-energy traumas. A consequence of this injury can be avascular necrosis (AVN) of the talus. Patients are confronted with pain, limited range of motion and post-traumatic arthritis. As AVN progresses the talus is gradually destroyed. This report presents the use of a chimeric medial femoral condyle chondro-osseus flap with two thin periosteal flaps to increase vascular supply to the traumatized area, accelerate bone formation, flap integration, and restore articular surfaces in a patient with partial necrosis of talar body. The patient was a 26-year-old female with open left lateral talar extrusion after a motor-vehicle accident that developed a partial avascular necrosis, at the level of the subtalar and ankle joint with altered talar dome surface with partial depression of 2 cm. The patient was in pain and not able to walk. The medial femoral condyle chondro-osseus portion was placed in the talar dome depression to restore the subtalar joint, the periosteal flaps were placed on top to reconstruct the ankle joint restoring the articular surfaces and the correct weight-bearing distribution. No complications or morbidity of donor site were observed. One year after the operation, the patient walks free, without pain. Post-operatory x-ray performed, evidenced progressive bone healing and reduction of the AVN. In the intent of performing a joint-saving procedure, the presented chimeric flap might be effective in the short-term with excellent clinical and radiographic outcomes.

A prediction model for osteonecrosis of femoral head after internal fixation with multiple cannulated compression screws for adult femoral neck fractures.

OBJECTIVES: This study aims to investigate the high-risk factors for osteonecrosis of the femoral head (ONFH) after internal fixation with multiple cannulated compression screws for adult femoral neck fractures and to construct a prediction model. PATIENTS AND METHODS: Between from January 2012 and December 2020, a total of 268 patients (138 males, 130 females; mean age: 53±10 years; range, 23 to 70 years) with ONFH who had complete follow-up data were included. Closed reduction in combination with open reduction were performed. All patients received internal fixation with multiple cannulated compression screws and were assigned to ONFH and non-ONFH groups. Logistic regression model was utilized to identify independent risk factors for postoperative ONFH, followed by constructing a nomogram prediction model. The predictive ability of the model was evaluated by receiver operating characteristic curve, Hosmer-Lemeshow test, and calibration curve. RESULTS: Multivariate analysis revealed that older age (odds ratio [OR]: 2.307, 95% confidence interval [CI]: 1.295-4.108], Charlson Comorbidity Index (CCI) ≥2 (OR: 2.214, 95% CI: 1.035-4.739), fracture displacement (OR: 2.426, 95% CI: 1.122-5.247), unsatisfactory reduction (OR: 2.629, 95% CI: 1.275-5.423), postoperative removal of internal fixation implant (OR: 2.200, 95% CI: 1.051-4.604) were independent risk factors for postoperative ONFH (p<0.05). The nomogram prediction model constructed based on these clinical characteristics showed high predictive value (AUC=0.807) and consistency (p>0.05). CONCLUSION: Age, comorbidity index, fracture type, reduction quality and postoperative removal of internal fixation implant are of utmost importance for postoperative ONFH in patients with femoral neck fractures. The established nomogram prediction model can accurately predict the occurrence of postoperative ONFH.

Transphyseal Fracture of the Distal Humerus.

Transphyseal fractures of the distal humerus often occur in children younger than 4 years as a result of birth trauma, nonaccidental trauma, or falls from a low height. It is important to identify and treat these injuries in a timely manner to ensure successful management. Most transphyseal fractures of the distal humerus are treated with closed reduction and percutaneous pinning with the aid of an elbow arthrogram. The most common complication following a fracture is cubitus varus caused by growth arrest, malunion, or osteonecrosis of the medial condyle. Normal carrying angles may be restored through corrective lateral closing wedge osteotomy.

Identifying Risk Factors for Osteonecrosis After Talar Fracture.

OBJECTIVE: To identify patient, injury, and treatment factors associated with the development of avascular necrosis (AVN) after talar fractures, with particular interest in modifiable factors. DESIGN: Retrospective chart review. SETTING: 21 US trauma centers and 1 UK trauma center. PATIENT SELECTION CRITERIA: Patients with talar neck and/or body fractures from 2008 through 2018 were retrospectively reviewed. Only patients who were at least 18 years of age with fractures of the talar neck or body and minimum 12 months follow-up or earlier diagnosis of AVN were included. Further exclusion criteria included non-operatively treated fractures, pathologic fractures, pantalar dislocations, and fractures treated with primary arthrodesis or primary amputation. OUTCOME MEASUREMENTS AND COMPARISONS: The primary outcome measure was development of AVN. Infection, nonunion, and arthritis were secondary outcomes. RESULTS: In total, 798 patients (409 men; 389 women; age 18-81 years, average 38.6 years) with 798 (532 right; 264 left) fractures were included and were classified as Hawkins I (51), IIA (71), IIB (113), III (158), IV (40), neck plus body (177), and body (188). In total, 336 of 798 developed AVN (42%), more commonly after any neck fracture (47.0%) versus isolated body fracture (26.1%, P < 0.001). More severe Hawkins classification, combined neck and body fractures, body mass index, tobacco smoking, right-sided fractures, open fracture, dual anteromedial and anterolateral surgical approaches, and associated medial malleolus fracture were associated with AVN ( P < 0.05). After multivariate regression, fracture type, tobacco smoking, open fractures, dual approaches, age, and body mass index remained significant ( P < 0.05). Excluding late cases (>7 days), time to joint reduction for Hawkins type IIB-IV neck injuries was no different for those who developed AVN or not. AVN rates for reduction of dislocations within 6 hours of injury versus >6 hours were 48.8% and 57.5%, respectively. Complications included 60 (7.5%) infections and 70 (8.8%) nonunions. CONCLUSIONS: Forty-two percent of all talar fracture patients developed AVN, with talar neck fractures, more displaced fractures, and open injuries having higher rates. Injury-related factors are most prognostic of AVN risk. Surgical technique to emphasize anatomic reduction, without iatrogenic damage to remaining blood supply appears to be prudent. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Clinical outcomes in patients with scaphoid non-union treated with the vascularized medial femoral condyle technique a case series.

INTRODUCTION: Non-union is a prevalent complication of scaphoid fractures. Late diagnosis is common and has a clinical impact due to functional limitations for the patient. Multiple treatments have been proposed to manage this complication, ranging from conservative (i.e., orthopedic) to surgical treatment. The vascularized medial femoral condyle technique has shown satisfactory clinical and paraclinical results, mainly in presence of avascular necrosis of the proximal pole but data regarding functional outcomes and patient satisfaction is scarce. This case series aims to describe the clinical and patient-reported outcomes in a consecutive series of patients with non-union of the proximal third of the scaphoid treated with vascularized medial femoral condyle technique. METHODS: Case series reporting results for a consecutive - initial cohort of patients who presented with a non united fracture of the proximal pole of the scaphoid, avascular necrosis of the proximal pole was documented by CT od MRI imaging preoperatively in all patients. Measurement instruments include the q-DASH and PRWE questionnaires, radiographic images, goniometry, and assessment of grip strength. RESULTS: Twelve consecutive patients are included and they represent the initial cases for all surgeons involved; bone union was obtained in 10 patients (83%) after a mean follow-up time of 31 months (6-72), successful improvement in the range of motion and grip strength was documented. A high rate of satisfaction expressed by the patient was obtained, with an average score in Q-DASH of 17.3 and 20.1 in PRWE. CONCLUSIONS: The vascularized medial condyle technique in cases of nonunion of scaphoid fracture is a reproducible treatment in clinical terms, both in imaging and functional terms, and in patient satisfaction. The learning curve is flat for a dedicated multi surgeon team.

Postoperative scaphoid alignment, smoking, and avascular necrosis mostly influence union rate after scaphoid reconstruction: Results from a retrospective single center study involving 370 patients.

Current literature does not definitely demonstrate the superiority of any particular scaphoid reconstruction method. The primary goal of this retrospective single center study was to evaluate the influence of reconstruction techniques and other factors on the union rate after reconstruction of scaphoid nonunions. In the study, 370 patients with nonunions classified as stable (Mayo 1) or unstable (Mayo 2) depending on carpal alignment were included. Minimal radiological follow-up was 3 months. Bone healing after scaphoid reconstruction was evaluated using computer tomography scans in 294 and radiograms in 76 patients. Univariate and multivariate logistic regressions were applied in the analysis. Eight statistically significant factors that influenced the union rate were fixation method, type of previous operations, number of all operations, number of reconstructions, smoking, postoperative pathological lateral intrascaphoid angle (LISA>45°), avascular necrosis (AVN), and stability of nonunion. Smoking and postoperative LISA>45° significantly reduced the probability of bone fusion by approximately 4.4 and 9.5 times, respectively. Patients with reduced vascularity in the nonunion site had a 5.2 times lower chance of bone fusion. Our multivariate logistic regression model can explain 32% of failures after scaphoid reconstruction, including postoperative LISA>45°, patients' present record of smoking, and reduced vascularity in the nonunion site. However, bone graft type does not impact the union rate in general; however, in case of AVN, the tendency toward higher union rates was observed for medial femoral condyle free flaps when compared to other types of graft (non-vascularized and pedicled bone grafts considered as one group, p = 0.09).

Clinical and epidemiological features and therapeutic options of avascular necrosis in patients with sickle cell disease (SCD): a cross-sectional study.

BACKGROUND: Avascular necrosis (AVN) is a debilitating complication in sickle cell disease (SCD) patients, and its management is usually challenging. This study aims to evaluate the clinical and epidemiological features and therapeutic options of AVN in sickle cell patients in Qatar. PATIENTS AND METHODS: A cross-sectional study was conducted on a 49 SCD patients who were diagnosed with AVN and attended the hematology clinic at the National Center for Cancer care & research, Hamad Medical Corporation, Qatar between Jan-2011 to Jan2021.  Results: Forty-nine adult patients with SCD who were diagnosed with AVN were studied. The median age of the study population is 32 years, and the median age at the first AVN diagnosis was 26 years (range: 11-44 yr.). 37 (75.5%) patients suffered from multiple joints AVN while 12(24.5%) had single joint involvement. 31 (63.3%) patients had bilateral hip AVN and 18 (36.7%) had shoulder involvement. 30 patients (61%) were on Hydroxyurea treatment. Based on FICAT and Alert classification of AVN, 57 % of patients had stage III and above at first diagnosis. 20 (40.8%) were managed with a conservative approach, 11 (22.4%) received hyperbaric oxygen with good response, 6(12.2%) underwent hip core decompression and 12(24.5%) underwent hip replacement surgery. CONCLUSION: In SCD patients, AVN occurred more during the 3rd and 4th decades of life. The majority of AVN represented with advanced stage and had multiple joint involvements. We recommend adopting a low threshold of joint imaging for early detection and prevention of further complications.

Knee Osteonecrosis After SARS-CoV-2 Virus Infection.

ABSTRACT: Osteonecrosis after COVID-19 infection is a complex pathology with multifactorial origin. Factors such as infection itself with associated coagulopathy, as well as genetic mechanisms, and medications used for its treatment such as corticosteroids, may also be involved. The variability in the presentation makes diagnosis difficult, which, if done soon, can help delay progression and reduce morbidity and the need for surgery.This report presents a case of knee osteonecrosis in a female patient who did not have previous knee pathology on imaging tests. She was diagnosed by magnetic resonance imaging months after hospital admission for SARS-CoV-2 pneumonia, which required high-dose corticosteroid treatment.

Surgical treatment of subchondral osteonecrosis of the humeral head: A case report and literature review.

BACKGROUND: Osteonecrosis of the humeral head is an uncommon subchondral bone disease with many etiologies, and there is currently no definite evidence to support an optimal surgical treatment plan. We report a case of surgical treatment of left humeral head necrosis. To the best of our knowledge, this is the youngest patient with non-drug-induced humeral head necrosis and the largest collapsed area. CASE PRESENTATION: The case involved a 16-year-old male who injured his left shoulder 1 year ago. The patient was admitted to the hospital because of shoulder pain after activity in the year following the injury. During the physical examination, the left glenohumeral joint space was tender, the pain was obvious when the shoulder joint was rotated and squeezed, and the active and passive range of motion was normal. X-ray, magnetic resonance imaging, and computed tomography + 3D computed tomography scans all showed subchondral osteonecrosis of the left humeral head. Left humeral head lesion removal and autologous osteochondral transplantation were performed, and the patient was followed up. CONCLUSION: Non-drug-induced humeral head necrosis is rare. Autologous osteochondral transplantation is currently one of the most mature and effective treatment methods. The short-term curative effect in this patient is satisfactory, but the patient is young and has a large collapsed area, so long-term follow-up is worthwhile.

Increased Risk of In-Hospital Complications and Costs After Total Hip Arthroplasty for Primary and Secondary Osteonecrosis.

BACKGROUND: An increasing proportion of patients are undergoing total hip arthroplasty (THA) for osteonecrosis (ON). Comorbid conditions and surgical risk factors are known to be greater in ON patients compared with patients who have osteoarthritis (OA) alone. The purpose of our study was to quantify the specific in-hospital complications and resource utilization associated with patients undergoing THA for ON versus OA. METHODS: A large national database was queried to identify patients undergoing primary THA from January 1, 2016 to December 31, 2019. A total of 1,383,880 OA, 21,080 primary ON, and 54,335 secondary ON patients were identified. Demographics, in-hospital complications, costs, lengths of stay, and discharge dispositions for primary and secondary ON cohorts were compared to OA only. Age, race, ethnicity, comorbidities, Medicaid, and income status were controlled with binary logistic regression analyses. RESULTS: The ON patients were often younger, African American or Hispanic, and had more comorbidities. Those undergoing THA for primary and secondary ON had a significantly higher risk of perioperative complications, including myocardial infarction, postoperative blood transfusion, and intraoperative bleeding. Total hospital costs and lengths of stay were significantly higher for both primary ON and secondary ON and both cohorts were less likely to be discharged home. CONCLUSION: While rates of most complications have decreased over recent decades in ON patients undergoing THA, the ON patients still have worse outcomes even when controlling for comorbidity differences. Bundled payment systems and perioperative management strategies for these different patient cohorts should be considered separately.