A long term outcomes analysis of severe haemophilia A boys receiving 4 years prophylaxis on the Chinese Haemophilia Individualized escalating low dose Prophylaxis (CHIPS).

BACKGROUND: The Chinese Haemophilia Individualized Prophylaxis Study (CHIPS), which was launched in 2016, reported a significant reduction in haemarthrosis over a one-year study. However, its long-term efficacy requires verification. This paper summarizes the clinical outcomes of 18 severe haemophilia A (SHA) patients who completed one year on the CHIPS and 3 more years of follow-up. METHODS: Clinical follow-up was based on the CHIPS protocol (from July 2018 to July 2021). Escalation was based on index joint bleeding, and serial ultrasound (greyscale and colour Doppler) examinations of the index joints (both sides of the ankles, knees and elbows) were conducted every 6 months via a scoring system. RESULTS: A total of 18 SHA patients completed the 3-year study. Fifteen patients dropped out due to the financial crisis during the COVID-19 pandemic in China. The median age was 5.4 (range 4.3-6.9) years. A significant reduction in haemarthrosis was achieved, with mean annual bleeding rates reduced from 18.9 ± 2.8 to 1.7 ± 0.4 (p < 0.001), annual joint bleeding rates from 3.1 ± 0.7 to1.2 ± 0.3 (p < 0.028). 5 out of 8 target joint resolved. Sixteen doses were escalated. At study exit, the heterogeneous treatment outcomes of the SHA boys were 5 at step 4 (20-25 lU/kg, every other day), 10 at step 3 (15-20 IU/kg, 3×/week), 2 at step 2 (10-15 lU/kg, 3×/week) and 1 at step 1 (10-15 lU/kg, 2×/week). The mean FVIII consumption was 2964 IU/kg/year, with savings. The quality of life improved, with Canadian Haemophilia Outcomes-Kids Life Assessment Tool (CHO-KLAT, Chinese Version 2.0) scores ranging from 68.8 to 78.8. There was no change in the ultrasound score. CONCLUSION: Our follow-up data on the 18 SHA boys after completing one year on the CHIPS verify the long-term efficacy of the CHIPS for haemarthrosis reduction, joint health preservation, improvement in the quality of life of the boys and cost savings.

TKR in Hemophilic Arthropathy: A Combination of Special Surgical Considerations and Novel Nonacog Beta Pegol: A Case Report.

CASE: A 29-year-old man with hemophilia B presented with advanced arthropathy of the right knee, resulting in poor knee functional scores and difficulties in his livelihood. The patient underwent total knee replacement while receiving nonacog beta pegol factor IX by a multidisciplinary approach. CONCLUSION: Hemophilias commonly result in end-stage hemophilic arthropathy of the joints at a young age that may warrant joint replacement surgeries. This case report illustrates the surgical protocol of total knee arthroplasty in a patient who received a long-acting factor IX preparation.

Joint health and pain in the changing hemophilia treatment landscape.

INTRODUCTION: Hemophilia is an inherited bleeding disorder. Bleeding, and in particular joint hemorrhage results in chronic arthropathy and disability. Acute and chronic pain are frequent and limit activity and participation and result in decreased health-related quality of life. Remarkable progress has been made in the diagnosis and treatment of hemophilia but bleeding continues to prove recalcitrant to currently available treatments and joint disease remains problematic. Physiotherapy and pain management are mainstays of current multidisciplinary integrated care of people with hemophilia (PWH). The focus of this review is on preservation of joint health in the era of new and innovative therapies. AREAS COVERED: A search of the PubMed Central was conducted on 1 February 2024 using the MeSH Major Topic terms identified as keywords for the manuscript. This review will highlight what is known and unknown about joint bleeding and arthropathy, including insights on pain as a related complication. EXPERT OPINION: Recent advances in therapeutic interventions aimed at promoting healthy joints in PWH will be discussed, including both the pharmacological treatment landscape and related strategies to promote joint health.

Ultrasound-guided joint procedures in hemophilia: technique, indications and tips.

INTRODUCTION: The therapeutic approach to pain in hemophilia should be multimodal. Intra-articular injections are a good option when joint lesions do not respond to hematological treatment or rehabilitation and orthopedic surgery is not yet indicated. Performing these procedures under ultrasound guidance has been shown to improve their accuracy and efficacy. AREAS COVERED: This article provides a practical overview of the most frequently employed ultrasound-guided intra-articular procedures on the joints of people with hemophilia. The article describes the key elements for performing the technique on the elbow, knee and ankle as the most affected joints. The particularities of the most frequent indications, arthrocentesis, synoviorthesis and analgesic injections with various products are detailed. EXPERT OPINION: Current hematological treatments have made it possible to incorporate new therapeutic tools for pain relief for people with hemophilia, including ultrasound-guided joint procedures, which offer excellent results.

The advantages of using tranexamic acid in anterior cruciate ligament reconstruction: a randomized controlled trial.

OBJECTIVE: The number of participants in sports or some form of recreation globally has led to an increase in the incidence of anterior cruciate ligament (ACL) injuries and the number of surgeries performed. Although it does not belong to risky surgical interventions, this operation is accompanied by complications that slow down post-operative rehabilitation. The objective is to analyze the effects of intra-articular (IA) injection of tranexamic acid (TXA) on the reduction of post-operative drained blood volume, pain intensity, and incidence of hemarthrosis after ACL reconstruction. METHODS: This prospective research included 124 patients undergoing ACL reconstruction surgery, randomly divided into two groups. The TXA group received IA TXA, whereas an equal amount of placebo was administered using the same route in the control group. RESULTS: The research has shown that IA injection of TXA effectively reduces post-operative blood loss (TXA group 71.29 ± 40.76 vs. control group 154.35 ± 81.45), reducing the intensity of post-operative pain (p < 0.001) and the incidence of hemarthrosis. CONCLUSION: The application of TXA significantly reduced post-operative bleeding and pain intensity, which accelerated the post-operative period.

OBJETIVO: El mayor número de participantes en deportes o alguna forma de recreación en todo el mundo ha llevado a un aumento en la incidencia de lesiones del ligamento cruzado anterior (LCA) y de las cirugías realizadas. Aunque no es una intervención quirúrgica de riesgo, esta operación va acompañada de complicaciones que ralentizan la rehabilitación posoperatoria. El objetivo es analizar los efectos de la inyección intraarticular de ácido tranexámico (TXA) sobre la reducción del volumen sanguíneo drenado posoperatorio, la intensidad del dolor y la incidencia de hemartrosis tras la reconstrucción del LCA. MÉTODO: Esta investigación prospectiva incluyó 124 pacientes sometidos a cirugía de reconstrucción del LCA, divididos aleatoriamente en dos grupos: uno recibió TXA intraarticular y otro (grupo de control) una cantidad igual de placebo por la misma vía. RESULTADOS: La investigación ha demostrado que la inyección intraarticular de TXA reduce efectivamente la pérdida de sangre posoperatoria (grupo TXA 71.29 ± 40.76 vs. grupo control 154.35 ± 81.45), reduciendo la intensidad del dolor posoperatorio (p < 0.001) y la incidencia de hemartrosis. CONCLUSIONES: La aplicación de TXA redujo significativamente el sangrado posoperatorio y la intensidad del dolor, lo que aceleró el posoperatorio.

A qualitative study on the perioperative experiences and demands of haemophilic arthropathy patients undergoing total joint replacement.

INTRODUCTION: Total joint replacement is the optimal treatment option for patients with severe haemophilic arthritis. Current research emphasizes patient-reported outcomes as a vital measure for evaluating surgical outcomes and patient satisfaction. Nevertheless, very limited information about the subjective experience of perioperative haemophiliacs in the literature, highlighting the need for exploration in this area. AIM: To investigate the psychological experiences and health demands of haemophilic arthropathy patients during the perioperative period of total joint replacement. DESIGN: Qualitative descriptive research with semistructured individual interviews. METHODS: From June to September 2023, nine patients with severe haemophilic arthropathy who underwent total joint replacement at a Haemophilia Diagnosis and Treatment Centre in China were interviewed for average 37 min per person. Data were analysed using the traditional content analysis method and reported following the consolidated criteria for reporting qualitative research. The study is reported according to the COREQ checklist. RESULTS: Interviews described two main themes: (1) emotional decline which involves preoperative overoptimism, early postoperative anxiety and disease uncertainty during the early independent rehabilitation. (2) wellness aspiration which includes rehabilitation support and spiritual healing. CONCLUSION: This study reveals the patients' significant psychological changes and their well-being aspiration, particularly out-of-hospital rehabilitation needs. Strengthening communication between multidisciplinary teams and patients, enhancing the involvement of nurses, broadening the scope of functions at primary Haemophilia Treatment Centres, and developing telerehabilitation, these concerted efforts may improve the overall treatment experience for patients.

Crohn's disease in hemophilic arthropathy patient: a case report.

Crohn's disease (CD) is an inflammatory bowel disease affecting the digestive tract, the incidence of which is on the rise worldwide. The most common clinical manifestation of hemophilia is arthropathy secondary to recurrent joint effusions and chronic synovitis. This article reports on a rare 25-year-old male patient with both hemophilic arthropathy and Crohn's disease who was at risk for pathogenic gastrointestinal bleeding. After undergoing endoscopic pathologic testing and genetic testing, a multidisciplinary expert work-up of a treatment and nutritional plan was performed. The patient improved clinically and adhered to conservative treatment. This case report is the first report of this rare co-morbidity, demonstrating the highly pathogenic mutation locus and summarizing the clinical experience of early diagnosis and treatment.

30-sit-to-stand power is a better tool than isometric knee extensor strength to detect motor impairment in people with haemophilic arthropathy.

INTRODUCTION: Regular assessment of motor impairments is crucial in people with haemophilic arthropathy (PwHA). This study aimed to determine if there are differences in 30-seconds sit-to-stand (30-STS) power and maximal voluntary isometric contraction (MVIC) of the knee extensors between PwHA and healthy control group (CG). The secondary aims were to investigate the correlation between 30-STS power and MVIC of knee extensors with clinical characteristics and to assess their effectiveness in identifying motor impairment in PwHA. METHODS: A cross-sectional study was conducted by collecting data from PwHA (n = 17) and a sedentary CG (n = 15). MVIC (torque) and 30-STS power were normalised to body mass. Correlation analysis and simple linear regression adjusted for age were used to assess the association between tests and clinical variables. Using z-scores derived from the mean and standard deviation of the CG, we compared the MVIC and the 30-STS power in PwHA. RESULTS: PwHA showed lower MVIC and 30-STS power compared to CG (p < .001; large effect size d > .8). Lower 30-STS power was associated with greater joint impairment and greater fear of movement, whereas MVIC showed no association with clinical variables. 30-STS power showed a lower z-score compared to MVIC (p < .001). In addition, 30-STS power detected 47% of PwHA with motor impairment compared to 0% for MVIC (p = .002). CONCLUSIONS: Our results suggest that 30-STS power may be more effective than knee extensors MVIC in detecting motor impairment in PwHA. Consequently, lower limb skeletal muscle power, rather than maximum knee extensor strength, appears to be more affected in PwHA.

Assessing joint health in haemophilia patients: The combined value of physical examination and ultrasound imaging.

INTRODUCTION: Early diagnosis of joint damage is pivotal in haemophilia to prevent the occurrence and progression of haemophilic arthropathy thus providing optimal personalised management. The haemophilia joint health score version 2.1 (HJHS) is based on a physical examination of the mainly affected joints. Musculoskeletal ultrasound has demonstrated the capability to detect early changes in terms of synovitis and osteochondral damage. The haemophilia early detection with ultrasound (HEAD-US) score has been proposed as a simple and reliable evaluation tool. AIM: This study aims to investigate the correlation between the HJHS and the HEAD-US scores performed by two independent operators (physical therapist and musculoskeletal ultrasound expert) for the evaluation of the joint health status of patients with haemophilia. METHODS: Consecutive adult patients independent of the severity degree were included. Elbows, knees and ankles were evaluated by a physical therapist by HJHS and by a musculoskeletal ultrasound expert following the HEAD-US protocol. RESULTS: We observed a good positive correlation between HJHS and HEAD-US (Spearman's rho 0.72). The main discrepancy in conceptually similar domains was found between the HJHS swelling and the HEAD-US synovitis (rho 0.17), as ultrasound was able to detect even mild synovitis when HJHS swelling was scored 0 in up to 40% of cases. CONCLUSIONS: The HJHS and HEAD-US correlate well even when performed by two independent operators. Musculoskeletal ultrasound is particularly useful for the early detection of synovitis. The routine assessment of both scores helps clinicians define the stage and extension of joint involvement and set up a personalised treatment.

Anti-inflammatory effect of a novel piperazino-enaminone delivered by liposomes in a mouse model of hemophilic arthropathy.

Hemophilic arthropathy (HA) is a condition caused by recurrent intra-articular bleeding in patients with hemophilia. Pro-inflammatory cytokines play a crucial role in the pathogenesis of HA. Our previous research demonstrated that a novel compound, piperazino-enaminone (JODI), effectively inhibited pro-inflammatory cytokines, including IL-6, MCP-1, MIP-1α, and MIP-1ß, in a mouse model of hemarthrosis. This study aims to enhance the anti-inflammatory effect of JODI by employing nanoparticle delivery systems, which could potentially improve its poor water solubility. Here, we developed liposomes modified with polyethylene glycol (PEG) for the delivery of JODI (JODI-LIP), and found that JODI-LIP exhibited uniform size, morphology, good stability and in vitro release degree. JODI-LIP mitigated cytotoxicity of JODI, and significantly suppressed the production of pro-inflammatory cytokines (TNF-α and IL-1ß) and nitric oxide (NO) release in RAW 264.7 cells stimulated by lipopolysaccharide (LPS), as well as the proliferation of human fibroblast-like synovial (HFLS) cells. In a murine model of HA, JODI-LIP demonstrated superior efficacy in ameliorating joint swelling and synovitis, compared to JODI. Importantly, JODI-LIP markedly reduced pro-inflammatory cytokines (TNF-α, IFN-γ, IL-33, and MCP-1) in injured joints. No hepatic or hematological toxicity was observed in mice treated with JODI-LIP. In summary, our results suggest that JODI-LIP holds promise as a therapeutic intervention for HA by attenuating pro-inflammatory cytokine levels.

A pathological joint-liver axis mediated by matrikine-activated CD4+ T cells.

The knee joint has long been considered a closed system. The pathological effects of joint diseases on distant organs have not been investigated. Herein, our clinical data showed that post-traumatic joint damage, combined with joint bleeding (hemarthrosis), exhibits a worse liver function compared with healthy control. With mouse model, hemarthrosis induces both cartilage degeneration and remote liver damage. Next, we found that hemarthrosis induces the upregulation in ratio and differentiation towards Th17 cells of CD4+ T cells in peripheral blood and spleen. Deletion of CD4+ T cells reverses hemarthrosis-induced liver damage. Degeneration of cartilage matrix induced by hemarthrosis upregulates serological type II collagen (COL II), which activates CD4+ T cells. Systemic application of a COL II antibody blocks the activation. Furthermore, bulk RNAseq and single-cell qPCR analysis revealed that the cartilage Akt pathway is inhibited by blood treatment. Intra-articular application of Akt activator blocks the cartilage degeneration and thus protects against the liver impairment in mouse and pig models. Taken together, our study revealed a pathological joint-liver axis mediated by matrikine-activated CD4+ T cells, which refreshes the organ-crosstalk axis and provides a new treatment target for hemarthrosis-related disease. Intra-articular bleeding induces cartilage degradation through down-reulation of cartilage Akt pathway. During this process, the soluble COL II released from the damaged cartilage can activate peripheral CD4+ T cells, differention into Th17 cells and secretion of IL-17, which consequently induces liver impairment. Intra-articular application of sc79 (inhibitor of Akt pathway) can prevent the cartilage damage as well as its peripheral influences.

Efficacy of rehabilitation interventions on functioning in patients with hemophilic arthropathy: A systematic review with meta-analysis.

BACKGROUND: Hemophilic arthropathy is a detrimental condition that crucially affects functional outcomes in hemophilic patients. In recent years, due to the advances in systemic therapies, growing attention has been raised in the rehabilitation field in order to improve functional outcomes of hemophilic patients. However, the optimal rehabilitation modalities in these patients are far from being fully characterized. OBJECTIVE: The present study aimed to assess the effects of different rehabilitation interventions on physical functioning and health-related quality of life of hemophilic arthropathic patients. METHODS: The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Five databases were systematically searched for randomized controlled trials (RCTs) published until June 22nd, 2023. The selection criteria included adult patients with hemophilia A and B receiving rehabilitation interventions. The outcomes were muscle strength, physical function, pain intensity, physical performance, and health-related quality of life. RESULTS: Out of 1,743 identified records, 17 studies were included in the qualitative synthesis. Rehabilitation interventions were categorized into exercise intervention, fascial therapy, and multimodal intervention. The findings suggested positive outcomes in terms of muscle modifications, range of motion improvements, joint health enhancements, pain intensity reduction, and quality of life improvements. More in detail, meta-analyses showed significant improvements in pain intensity [ES: -1.10 cm (-1.37, -0.82), p< 0.00001], joint health [ES: -1.10 (-1.38, -0.82), p< 0.00001], In accordance, exercise interventions showed significant benefits in terms of joint health [ES: -2.54 (-3.25, -1.83), p< 0.00001)] and quality of life [ES: 1.17 (0.48, 1.86), p< 0.0000)]. CONCLUSION: Rehabilitation interventions have a positive impact on functional outcomes and health-related quality of life of hemophilic arthropathic patients. Further studies are needed to better elucidate the role of a comprehensive intervention combining different rehabilitation approaches to treat hemophilic arthropathy.

Artificial intelligence for detection of effusion and lipo-hemarthrosis in X-rays and CT of the knee.

BACKGROUND: Traumatic knee injuries are challenging to diagnose accurately through radiography and to a lesser extent, through CT, with fractures sometimes overlooked. Ancillary signs like joint effusion or lipo-hemarthrosis are indicative of fractures, suggesting the need for further imaging. Artificial Intelligence (AI) can automate image analysis, improving diagnostic accuracy and help prioritizing clinically important X-ray or CT studies. OBJECTIVE: To develop and evaluate an AI algorithm for detecting effusion of any kind in knee X-rays and selected CT images and distinguishing between simple effusion and lipo-hemarthrosis indicative of intra-articular fractures. METHODS: This retrospective study analyzed post traumatic knee imaging from January 2016 to February 2023, categorizing images into lipo-hemarthrosis, simple effusion, or normal. It utilized the FishNet-150 algorithm for image classification, with class activation maps highlighting decision-influential regions. The AI's diagnostic accuracy was validated against a gold standard, based on the evaluations made by a radiologist with at least four years of experience. RESULTS: Analysis included CT images from 515 patients and X-rays from 637 post traumatic patients, identifying lipo-hemarthrosis, simple effusion, and normal findings. The AI showed an AUC of 0.81 for detecting any effusion, 0.78 for simple effusion, and 0.83 for lipo-hemarthrosis in X-rays; and 0.89, 0.89, and 0.91, respectively, in CTs. CONCLUSION: The AI algorithm effectively detects knee effusion and differentiates between simple effusion and lipo-hemarthrosis in post-traumatic patients for both X-rays and selected CT images further studies are needed to validate these results.

Predicting joint involvement through tailored prophylaxis in severe haemophilia A, is it possible?

INTRODUCTION: Tailored prophylaxis is the current treatment regimen for patients with severe haemophilia A. Recently, published guidelines describe two possible approaches, based on clinical characteristics or estimation of pharmacokinetic parameters. However, both have strengths and weaknesses, and their characteristics need to be integrated to optimize treatment appropriately. In this paper, we present a model that considers together the characteristics of prophylaxis and the relevance of each. METHODS: The age at initiation of prophylaxis, number of bleeding events, treatment regimen, therapeutic adherence, FVIII trough levels, and joint status were analyzed in 59 patients followed at La Paz University Hospital between January 2000 and December 2019. RESULTS: The mean duration of primary prophylaxis of 113.37 ± 57.79 months. Eighty-three percent (n = 49) had no joint status involvement at the end of follow-up (HJHS and HEAD-US = 0). The median ABR was 0.7 (IQR 0.2 -1.0) and 54.2% presented trough levels of FVIII during follow-up >1 IU/dL. 72,9% engaged in some type of physical activity and overall adherence was over 85% in all patients evaluated. The regression analysis performed, considering all these factors, showed that the initiation of prophylaxis before 21 months of age was the most relevant protective factor against the appearance of joint involvement (OR 88.33 p.031 CI 95% 1.49-5224.40) CONCLUSION: Early initiation of prophylaxis was the most relevant factor in the protection of joint status. More comprehensive analysis models adapted to the characteristics of each population, are needed to adequately individualize treatment.

Primary prophylaxis implementation and long-term joint outcomes in Swedish haemophilia A patients.

INTRODUCTION: Primary prophylaxis is the gold standard in severe haemophilia A (SHA) but time to escalate the prophylaxis regimen varies. AIM: Assess prophylaxis implementation and long-term joint health outcomes in SHA with primary prophylaxis. METHODS: Adult male patients born after 1980, with SHA on primary prophylaxis, started before the age of 3 years and second joint bleed, and no history of FVIII inhibitors, were enrolled. Repeated joint-health examinations were performed with HJHS or HEAD-US; VERITAS-PRO assessed adherence. RESULTS: Thirty patients were enrolled with, at inclusion, median age 33.5 years, annualized bleed rate and joint bleed rate 0, and FVIII consumption 4232 IU/kg/year, respectively. The median age was 1.2 years, at prophylaxis start once weekly with a median FVIII dose of 47.7 IU/kg, and 1.7 years, by the time escalation to a final regimen had occurred, with a median infusion frequency of thrice weekly and FVIII dose 41.7 IU/kg, respectively. Older age correlated with later transition to escalated prophylaxis (p < .001). Longer time to escalated prophylaxis correlated to more bleeds (p < .001). Median HJHS increased slowly, reaching 4 at 35-40 years. HJHS at 15-20 years correlated with higher HJHS afterwards. Median total HEAD-US score was 1 and correlated with HJHS (p < .001). Median VERITAS-PRO score was 36, indicating good treatment adherence. CONCLUSION: Primary prophylaxis is effective but does not completely prevent the gradual development of arthropathy in SHA. Joint assessments with HJHS should start at an early age, as they correlate with arthropathy in later life. Prophylaxis escalation should proceed expeditiously to prevent bleeds.

Haemophilic arthropathy: Diagnosis, management, and aging patient considerations.

Gene therapy and universal use of safer, more effective, and personalised prophylactic regimens (factor, and nonfactor) are expected to prevent joint bleeding and promote joint health in persons with haemophilia (PwH). Growing evidence suggests that subclinical bleeding, with active and inactive synovial proliferation, continues and haemophilic arthropathy remains a major morbidity in PwH despite early institution of joint prophylaxis. Joint health assessment is evolving with physical examination scores complementing imaging scores. Point-of-care ultrasound is emerging as a safe, cost-effective, and readily available tool for acute determination of musculoskeletal abnormalities, serial evaluation of joints for sonographic markers of haemophilic arthropathy, and in providing objective insight into the efficacy of new therapies. In acute haemarthrosis, arthrocentesis expedites recovery and prevent the vicious cycle of bleed-synovitis-rebleed. When synovial proliferation develops, a multidisciplinary team approach is critical with haematology, orthopaedics, and physiotherapy involvement. Synovectomy is considered for patients with chronic synovitis that fail conservative management. Non-surgical and minimally invasive procedures should always be offered and considered first. Careful patient selection, screening and early intervention increase the success of these interventions in reducing bleeding, pain, and improving joint function and quality of life. Chemical synovectomy is practical in developing countries, but radioactive synovectomy appears to be more effective. When surgical synovectomy is considered, arthroscopic/minimally invasive approach should be attempted first. In advanced haemophilic arthropathy, joint replacement and arthrodesis can be considered. While excited about the future of haemophilia management, navigating musculoskeletal challenges in the aging haemophilia population is equally important.

Predictive parameters for spontaneous joint bleeding during emicizumab prophylaxis.

ABSTRACT: Emicizumab is approved for prophylaxis of patients with hemophilia A (HA). Despite its efficacy in reducing bleeding, some patients on emicizumab still experience hemarthrosis, but no tool is yet available to identify those at a higher risk of spontaneous joint bleeding. This study aimed to evaluate whether laboratory measurements (global coagulation assays and emicizumab concentration) and/or arthropathy scores can distinguish patients at higher risk of spontaneous joint bleeding while on emicizumab prophylaxis. A thrombin generation assay was performed upon the addition of tissue factor and synthetic phospholipids. Nonactivated thromboelastography was performed on citrated whole blood. Emicizumab concentrations were measured using a modified 1-stage factor VIII assay. The degree of hemophilic arthropathy was assessed using the Hemophilia Joint Health Score and Hemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) score. A Cox proportional hazards model was used to evaluate the association between variables and bleeding. The predictive power of these variables was investigated using receiver operating characteristic (ROC) analysis. Forty patients with severe HA, with or without inhibitors, on emicizumab prophylaxis were enrolled in an observational cohort study. Ten of 40 developed spontaneous joint bleeding. None of the laboratory parameters were able to distinguish patients with a higher risk of spontaneous joint bleeding. ROC analysis showed that during emicizumab prophylaxis, only the presence of synovitis and a higher HEAD-US score were associated with spontaneous joint bleeding (area under the curve, 0.84). A greater degree of arthropathy and the presence of synovitis could help predict the risk of spontaneous joint bleeding in patients with HA on emicizumab prophylaxis.