[Research progress in surgical treatment of avascular necrosis of talus].

Objective: To summarize the surgical treatment methods for avascular necrosis of the talus. Methods: The recent domestic and international literature related to avascular necrosis of the talus was extensively conducted. The pathogenesis, surgical treatment methods, and prognosis were summarized. Results: The clinical symptoms of avascular necrosis of the talus at early stage are not obvious, and most patients have progressed to Ficat-Arlet stages Ⅲ-Ⅳ and require surgical treatment. Currently, surgical treatments for this disease include core decompression, vascularized bone flap transplantation, arthroplasty, and arthrodesis, etc. Early avascular necrosis of the talus can be treated conservatively, and if treatment fails, core decompression can be considered. Arthrodesis is a remedial surgery for patients with end-stage arthritis and collapse, and in cases of severe bone loss, tibiotalocalcaneal arthrodesis and bone grafting are required. Vascularized bone flap transplantation is effective and plays a role in all stages of avascular necrosis of the talus, but the appropriate donor area for the flap still needs further to be studied. Conclusion: The surgical treatment and the system of treatment for different stages of avascular necrosis of the talus still need to be refined.

Medication-related osteonecrosis of the jaw: evolving research for multimodality medical management.

PURPOSE: Medication-related osteonecrosis of the jaw (MRONJ) is a debilitating side effect of antiresorptive and antiangiogenic agents that can lead to progressive bone destruction in the maxillofacial region. Dental surgery, including tooth extractions, commonly trigger the onset of MRONJ. While guidelines suggest avoiding extraction when possible, complete avoidance is not always feasible, as necrosis can develop from dental and periodontal disease without dental procedures. The goal of this article is to provide an update review of current preventive and therapeutic approaches for MRONJ. METHODS: A comprehensive electronic search was conducted on PubMed/MEDLINE, Embase, and Scopus databases. All English articles encompassing randomized controlled trials, systematic reviews, observational studies, and case studies were reviewed. The current medical treatments and adjuvant therapies for managing MRONJ patients were critically assessed and summarized. RESULTS: Pentoxifylline and alpha tocopherol (PENT-E), teriparatide, photobiomodulation (PBM), photodynamic therapy (PDT), and the use of growth factors have shown to enhance healing in MRONJ patients. Implementing these methods alone or in conjunction with surgical treatment has been linked to reduced discomfort and improved wound healing and increased new bone formation. DISCUSSION: While several adjuvant treatment modalities exhibit promising results in facilitating the healing process, current clinical practice guidelines predominantly recommend antibiotic therapy as a non-surgical approach, primarily addressing secondary infections in necrotic areas. However, this mainly addresses the potential infectious complication of MRONJ. Medical approaches including PENT-E, teriparatide, PBM, and PDT can result in successful management and should be considered prior to taking a surgical approach. Combined medical management for both preventing and managing MRONJ holds potential for achieving optimal clinical outcomes and avoiding surgical intervention, requiring further validation through larger studies and controlled trials.

[Role and mechanism of macrophage-mediated osteoimmune in osteonecrosis of the femoral head].

Objective: To summarize the research progress on the role of macrophage-mediated osteoimmune in osteonecrosis of the femoral head (ONFH) and its mechanisms. Methods: Recent studies on the role and mechanism of macrophage-mediated osteoimmune in ONFH at home and abroad were extensively reviewed. The classification and function of macrophages were summarized, the osteoimmune regulation of macrophages on chronic inflammation in ONFH was summarized, and the pathophysiological mechanism of osteonecrosis was expounded from the perspective of osteoimmune, which provided new ideas for the treatment of ONFH. Results: Macrophages are important immune cells involved in inflammatory response, which can differentiate into classically activated type (M1) and alternatively activated type (M2), and play specific functions to participate in and regulate the physiological and pathological processes of the body. Studies have shown that bone immune imbalance mediated by macrophages can cause local chronic inflammation and lead to the occurrence and development of ONFH. Therefore, regulating macrophage polarization is a potential ONFH treatment strategy. In chronic inflammatory microenvironment, inhibiting macrophage polarization to M1 can promote local inflammatory dissipation and effectively delay the progression of ONFH; regulating macrophage polarization to M2 can build a local osteoimmune microenvironment conducive to bone repair, which is helpful to necrotic tissue regeneration and repair to a certain extent. Conclusion: At present, it has been confirmed that macrophage-mediated chronic inflammatory immune microenvironment is an important mechanism for the occurrence and development of ONFH. It is necessary to study the subtypes of immune cells in ONFH, the interaction between immune cells and macrophages, and the interaction between various immune cells and macrophages, which is beneficial to the development of potential therapeutic methods for ONFH.

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.

Bisphosphonates and osteonecrosis of the jaws: Clinical and forensic aspects.

OBJECTIVE: This manuscript aims to provide a comprehensive review of the current knowledge in the pathophysiology, diagnosis, prevention, and other relevant clinical and forensic aspects of a potentially severe complication known as medication-related osteonecrosis of the jaw (MRONJ) while synthesizing state-of-the-art information on bisphosphonates and introducing a possible differential diagnosis. DESIGN: An extensive search was conducted in PubMed (U.S. National Library of Medicine) without a time or language constraint, focusing on the epidemiology, pathophysiology, risk factors, site specificity, signs and symptoms, differential diagnosis, prevention, and forensic aspects of MRONJ. All types of original articles, reviews, case reports, short communications, opinion articles, guidelines, and letters to editors were considered to produce a complete review on this subject. RESULTS: MRONJ prevention relies on a multidisciplinary approach and is critical since truly effective treatments are lacking. This therapeutic challenge is partly due to uncertainty regarding this condition's pathophysiology. Differential diagnosis of osteonecrosis of the jaws associated with krokodil abuse, one of the most dangerous and homemade psychoactive illicit substances, should be considered. CONCLUSIONS: Further research into the etiology and site specificity of MRONJ is encouraged, aiming to develop novel treatment prospects. Indeed, comprehending this would allow for increased efficacy and therapeutic options while emphasizing the importance of prevention. In addition, we advocate for greater consensus among the various societies regarding MRONJ's treatment and management.

Osteonecrose dos maxilares relacionada ao uso demedicamentos: características patológicas, diagnóstico,prevenção e estratégias terapêuticas / Medication-related osteonecrosis of the jaws: pathological characteristics, diagnosis, prevention and therapeutic strategies

Objetivo: Este trabalho tem como propósito fornecer uma análise abrangente das características clínicas, etiológicas, radiográficas e histopatológicas da osteonecrose dos maxilares relacionada ao uso de medicamentos, além de abordar os métodos de diagnóstico, prevenção e estratégias terapêuticas. Materiais e métodos: foi realizada uma busca por artigos científicos publicados no período de 2015 a 2023, utilizando as bases de dados Scientific Electronic Library Online (SciELO), US National Library of Medicine (PubMed) e ScienceDirect. Conclusão: Embora infrequente, há um considerável potencial de ocorrência de osteonecrose dos maxilares em pacientes submetidos a terapia prolongada com medicamentos antirreabsortivos e antiangiogênicos, especialmente quando não são adotadas medidas preventivas adequadas. A implementação de práticas preventivas, a vigilância das condições bucais e a colaboração de uma equipe multidisciplinar são fundamentais para reduzir os riscos associados a essa condição patológica.(AU)

Objective: This work aims to provide a comprehensive analysis of the clinical, etiological, radiographic and histopathological characteristics of Medication-Related Jaw Osteonecrosis, in addition to addressing diagnostic methods, prevention and therapeutic strategies. Materials and methods: A search was carried out for scientific articles published between 2015 and 2023, using the Scientific Electronic Library Online (SciELO), US National Library of Medicine (PubMed) and ScienceDirect databases. Conclusion: Although infrequent, there is a considerable potential for osteonecrosis of the jaw to occur in patients undergoing prolonged therapy with antiresorptive and antiangiogenic medications, especially when adequate preventive measures are not adopted. The implementation of preventive practices, surveillance of oral conditions and the collaboration of a multidisciplinary team are essential to reduce the risks associated with this pathological condition.(AU)

Humeral Head Avascular Necrosis: Pathophysiology, Work-up, and Treatment Options.

¼ Avascular necrosis (AVN) of the humeral head is the result of ischemic injury to the epiphyseal bone leading to humeral head collapse and arthritis.¼ Common causes include trauma, chronic corticosteroid use, or systemic disease processes, such as sickle cell disease, systemic lupus erythematosus, or alcohol abuse.¼ Nonoperative treatment consists of risk factor management, physical therapy, anti-inflammatory medications, and activity modification.¼ Surgical treatment options include arthroscopic debridement, core decompression, vascularized bone grafts, and shoulder arthroplasty.

Current management of avascular necrosis of the metacarpal head: a comprehensive literature review.

BACKGROUND: Avascular necrosis (AVN) of the metacarpal head is a rare disease that may lead to progressive destruction of the metacarpophalangeal joint and hand function. This study aimed to describe the epidemiology, possible risk factors, clinical presentation, diagnostic workup, and treatment of the rare condition of avascular necrosis of the metacarpal head. METHODS: Articles were searched using the subject words "Dieterich disease","Mauclaire's disease", and "avascular necrosis of metacarpal head" in the PubMed and Scopus databases. Studies were retained for review after meeting the inclusion criteria. Those outcomes relevant to diagnose and assessing AVN of the metacarpal head and those related to curative management were extracted. RESULTS: The literature search revealed 45 studies with 55 patients. Although the aetiology of osteonecrosis has not been clearly delineated, AVN of the metacarpal head most commonly arises from trauma but other risk factors may also be involved. Plain radiographs are often negative and therefore likely to be missed. Early-stage osteonecrosis of the metacarpal head was best assessed using MRI. Given the rarity of this condition, there is no clear consensus on the treatment. CONCLUSIONS: Avascular necrosis of the metacarpal head should be considered in the differential diagnosis of painful metacarpophalangeal joints. An early understanding of this unusual disease will provide an optimal clinical outcome, restoring joint activity, and resolving pain. Nonoperative treatment cannot cure all patients. Surgical management is based on the patient and lesion characteristics.

Prognosis of hip osteonecrosis after cell therapy with a calculator and artificial intelligence: ten year collapse-free survival prediction on three thousand and twenty one hips.

PURPOSE: Several reports have identified prognostic factors for hip osteonecrosis treated with cell therapy, but no study investigated the accuracy of artificial intelligence method such as machine learning and artificial neural network (ANN) to predict the efficiency of the treatment. We determined the benefit of cell therapy compared with core decompression or natural evolution, and developed machine-learning algorithms for predicting ten year collapse-free survival in hip osteonecrosis treated with cell therapy. Using the best algorithm, we propose a calculator for "prognosis hip osteonecrosis cell therapy (PHOCT)" accessible for clinical use. METHODS: A total of 3145 patients with 5261 osteonecroses without collapses were included in this study, comprising 1321 (42%) men and 1824 (58%) women, with a median age of 34 (12-62) years. Cell therapy was the treatment for 3021 hips, core decompression alone for 1374 hips, while absence of treatment was the control group of 764 hips. First, logistic regression and binary logistic regression analysis were performed to compare results of the three groups at ten years. Then an artificial neural network model was developed for ten year collapse-free survival after cell therapy. The models' performances were compared. The algorithms were assessed by calibration, and performance, and with c-statistic as measure of discrimination. It ranges from 0.5 to 1.0, with 1.0 being perfect discrimination and 0.5 poor (no better than chance at making a prediction). RESULTS: Among the 3021 hips with cell therapy, 1964 hips (65%) were collapse-free survival at ten years, versus 453 (33%) among those 1374 treated with core decompression alone, and versus 115 (15%) among 764 hips with natural evolution. We analyzed factors influencing the prediction of collapse-free period with classical statistics and artificial intelligence among hips with cell therapy. After selecting variables, a machine learning algorithm created a prognosis osteonecrosis cell therapy calculator (POCT). This calculator proved to have good accuracy on validation in these series of 3021 hip osteonecroses treated with cell therapy. The algorithm had a c-statistic of 0.871 suggesting good-to-excellent discrimination when all the osteonecroses were mixed. The c-statistics were calculated separately for subpopulations of categorical osteonecroses. It retained good accuracy, but underestimated ten year survival in some subgroups, suggesting that specific calculators could be useful for some subgroups. This study highlights the importance of multimodal evaluation of patient parameters and shows the degree to which the outcome is modified by some decisions that are within a surgeon's control, as the number of cells to aspirate, the choice of injecting in both the osteonecrosis and the healthy bone, the choice between unilateral or bilateral injection, and the possibility to do a repeat injection. CONCLUSION: Many disease conditions and the heterogeneities of patients are causes of variation of outcome after cell therapy for osteonecrosis. Predicting therapeutic effectiveness with a calculator allows a good discrimination to target patients who are most likely to benefit from this intervention.

Necrosis avascular de la epífisis proximal del primer metatarsiano en la infancia. Evolución a largo plazo. / Necrosis avascular de la epífisis proximal del primer metatarsianoen la infancia. Evolución a largo plazo

Paciente varón de 10 años edad con cojera de 8 meses de evolución por dolor en la zona dorsomedial del antepie derecho. Presentaba inflamación local, dolor local y marcha antiálgica con rotación interna. No existían signos de flogosis, erosiones, eritema o fiebre. La radiografía mostraba ensanchamiento de la epifisis proximal del primer metatarsiano. Un mes después se podía observar fragmentación, esclerosis y colapso en radiografía y en resonancia magnética compatible con necrosis avascular de la epífisis proximal del primer metatarsiano. Se prescribió evitar actividades físicas con carga en el pie. Los síntomas remitieron espontáneamente en las siguientes seis semanas y el dolor local lo hizo tras cuatro meses. Cuatro años más tarde permanece asintomático, realizando deporte. Es una causa excepcional de cojera en la infancia. Se necesita un alto índice de sospecha para evitar realizar pruebas complementarias superfluas dado que es una entidad autoresoluble.(AU)

Paciente varón de 10 años edad con cojera de 8 meses de evolución por dolor en la zona dorsomedial del antepie derecho. Presentaba inflamación local, dolor local y marcha antiálgica con rotación interna. No existían signos de flogosis, erosiones, eritema o fiebre. La radiografía mostraba ensanchamiento de la epifisis proximal del primer metatarsiano. Un mes después se podía observar fragmentación, esclerosis y colapso en radiografía y en resonancia magnética compatible con necrosis avascular de la epífisis proximal del primer metatarsiano. Se prescribió evitar actividades físicas con carga en el pie. Los síntomas remitieron espontáneamente en las siguientes seis semanas y el dolor local lo hizo tras cuatro meses. Cuatro años más tarde permanece asintomático, realizando deporte.Es una causa excepcional de cojera en la infancia. Se necesita un alto índice de sospecha para evitar realizar pruebas complementarias superfluas dado que es una entidad autoresoluble.(AU)

The efficiency of genetically modified mesenchymal stromal cells combined with a functionally graded scaffold for bone regeneration in corticosteroid-induced osteonecrosis of the femoral head in rabbits.

Core decompression (CD) with mesenchymal stromal cells (MSCs) is an effective therapy for early-stage osteonecrosis of the femoral head (ONFH). Preconditioning of MSCs, using inflammatory mediators, is widely used in immunology and various cell therapies. We developed a three-dimensional printed functionally graded scaffold (FGS), made of ß-TCP and PCL, for cell delivery at a specific location. The present study examined the efficacy of CD treatments with genetically modified (GM) MSCs over-expressing PDGF-BB (PDGF-MSCs) or GM MSCs co-over-expressing IL-4 and PDGF-BB and preconditioned for three days of exposure to lipopolysaccharide and tumor necrosis factor-alpha (IL-4-PDGF-pMSCs) using the FGS for treating steroid-induced ONFH in rabbits. We compared CD without cell-therapy, with IL-4-PDGF-pMSCs alone, and with FGS loaded with PDGF-MSCs or IL-4-PDGF-pMSCs. For the area inside the CD, the bone volume in the CD alone was higher than in both FGS groups. The IL-4-PDGF-pMSCs alone and FGS + PDGF-MSCs reduced the occurrence of empty lacunae and improved osteoclastogenesis. There was no significant difference in angiogenesis among the four groups. The combined effect of GM MSCs or pMSCs and the FGS was not superior to the effect of each alone. To establish an important adjunctive therapy for CD for early ONFH in the future, it is necessary and essential to develop an FGS that delivers biologics appropriately and provides structural and mechanical support.

Frequency of osteonecrosis in bisphosphonate users submitted to dental procedures: A systematic review.

OBJECTIVE: To determine the frequency of osteonecrosis of the jaw in bisphosphonate users submitted to dental procedures. METHODS: This systematic review searched the sources: MEDLINE, EMBASE, Web of Science, Scopus, and Virtual Health Library, with no restriction on language or publication date. Reviewers, in pairs and independently, selected the studies, extracted their data, and assessed the risk of bias. Meta-analyses were pooled using the DerSimonian and Laird random effects model. RESULTS: A total of 27 studies (5391 participants) were included. The most reported bisphosphonates were zoledronate (n = 17 studies) and alendronate (n = 19) for treating cancers (n = 11) and osteoporosis (n = 16), respectively. Twelve studies were of low methodological quality. The frequency of osteonecrosis was 2.7% (95% CI: 0.9-5.2%) and proved higher for intravenous [6.9% (0.7-17.3%)] than oral [0.2% (0.9-5.2%)] bisphosphonate use. No association between longer treatment duration and greater frequency of osteonecrosis was observed. CONCLUSIONS: Higher frequency of osteonecrosis was observed in intravenous bisphosphonate users submitted to dental extraction. Further studies collecting more detailed information on the bisphosphonates used and of greater methodological rigor are warranted to confirm these findings and better inform prescribers, dental surgeons, and other professionals on risks of bisphosphonate use in this patient group.

A systematic review on the management of idiopathic avascular necrosis of the scaphoid (Preiser's disease).

BACKGROUND: Treatment options for patients with Preiser's disease are challenging and varied. This article thus provides a systematic review of existing studies on the outcomes of the treatments for patients suffering from Preiser's disease in order to investigate the most appropriate management of Preiser's in each stage of the disease. METHODS: We followed PRISMA guidelines while performing the study, and reviewed 107 papers in all languages from 1981 till November 2020 and included 42 studies that met the eligibility criterion. Studies investigating the outcome of one or more treatment options for Preiser's disease were eligible. Besides, quantitative analysis on 130 individuals (135 wrists) of the included studies was performed. RESULTS: The results show that in stages II and III, pain score reduces more in surgical approach than in conservative treatment. In stage II of the Preiser's, Vascularized Bone Grafting (VBG) was more effective in pain alleviation and improvement in wrist range of motion (ROM) and Mayo Modified Wrist Score (MMWS) than immobilization. Proximal Row Carpectomy (PRC) in stage III causes more pain relief and ROM improvement than VBG and conservative treatments like prescribing NSAIDs. Inconsistent evidence was found in case studies of stage IV; however, they generally favour PRC and SILASTIC implants. Surgical studies of stage I are not yet enough for making a conclusive assessment. CONCLUSION: Surgical treatment outcomes seem more satisfactory in all Preiser's disease stages. Specifically, VBG for patients of stage II provided they have no scaphoid degenerative changes, and PRC seems more satisfactory for stage III. LEVEL OF EVIDENCE: IV; systematic review of case reports and case series on Preiser's disease.

Ex vivo study of detergent-assisted intraosseous bone wash treatment of osteonecrosis.

Avascular necrosis (AVN) involves ischemic cell death of the bone. AVN leaves an abundance of necrotic lipids and debris in the bone marrow, which instigates inflammatory bone repair. Consequently, the necrotic bone microenvironment stimulates excessive bone resorption, leading to joint deformities and osteoarthritis. Here, we performed a detergent-assisted bone wash using poloxamer 407 (P407) to clean the necrotic bone environment by removing lipids and necrotic debris. The new concept was tested using an established ex vivo AVN model of porcine cadaver humeral heads. The P407 wash was performed using P407 solution and followed with saline via two intraosseous needles. Visual inspection and image analyses of average pixel light intensity showed that the P407 wash produced a better-cleaned bone than the saline wash. Analyses of the collected bone wash solution showed a two-fold increase in triglycerides (101 vs. 53 mmol/head, p = 0.006) and a 10-fold increase in the dry weight of the removed debris (1.34 vs. 0.13 g/head, p = 0.02) with the P407 wash compared to saline. The histological evaluation showed significantly decreased Oil-Red-O (fats) staining in the P407-washed bone compared with the saline-washed bone. The in vitro assays of Alizarin red and qPCR showed the P407 wash neither altered the osteogenic behaviors of porcine bone marrow-derived mesenchymal cells (pBMMCs) nor raised inflammatory responses of porcine bone marrow-derived macrophages (pBMMs). In conclusion, detergent-assisted bone wash using P407 produced a better removal of nonsoluble debris from the bone marrow space than the saline wash without causing changes to osteogenesis or inflammatory reactions.

The role of immune cells in modulating chronic inflammation and osteonecrosis.

Osteonecrosis occurs when, under continuous stimulation by adverse factors such as glucocorticoids or alcohol, the death of local bone and marrow cells leads to abnormal osteoimmune function. This creates a chronic inflammatory microenvironment, which interferes with bone regeneration and repair. In a variety of bone tissue diseases, innate immune cells and adaptive immune cells interact with bone cells, and their effects on bone metabolic homeostasis have attracted more and more attention, thus developing into a new discipline - osteoimmunology. Immune cells are the most important regulator of inflammation, and osteoimmune disorder may be an important cause of osteonecrosis. Elucidating the chronic inflammatory microenvironment regulated by abnormal osteoimmune may help develop potential treatments for osteonecrosis. This review summarizes the inflammatory regulation of bone immunity in osteonecrosis, explains the pathophysiological mechanism of osteonecrosis from the perspective of osteoimmunology, and provides new ideas for the treatment of osteonecrosis.

Clinical Vignettes, Part II: Eyes, Teeth, and Bone.

Microvascular occlusions caused by sickle cell disease (SCD) can affect all ocular and orbital structures. Sickle cell retinopathy (SCR) is the most common ophthalmic manifestation of SCD. Fortunately, most individuals with SCR are visually asymptomatic. Vision loss in SCD most commonly occurs as a consequence of proliferative sickle cell retinopathy (PSR), in which pathologic retinal neovascularization occurs. To prevent significant vision loss and blindness, which can occur from complications of PSR, regular retinopathy surveillance screening examinations and consistent follow-up with a retina specialist are recommended. Scatter laser photocoagulation is the current gold-standard treatment to prevent vision threatening progression of PSR. Patients with sickle cell disease should have regular checkups with their dental care provider. Patients should be educated on the importance of proper dental care, a healthy diet, and the need for early intervention if they suspect any dental problems or are having dental pain. If any dental procedures that involve surgery or sedation are planned, it is critical to consult with the hematologist before the procedure is started. Prophylactic antibiotics may have to be prescribed before invasive dental procedures, such as extractions or periodontal surgery but is best determined by discussions between the dental care provider and the hematologist. Osteonecrosis is a highly prevalent skeletal complication of sickle cell disease that affects all genotypes. Risk factors for osteonecrosis include older age, HbSS genotype with concomitant alpha-thalassemia trait, frequent vaso-occlusive episodes, history of acute chest syndrome, elevated body mass index, and low white blood cell counts. Osteonecrosis causes progressive joint damage and associates with chronic pain, frequent acute care visits, and overall poor health-related quality of life. Current consensus guidelines recommend analgesics, physical therapy, and early consideration of joint arthroplasty in sickle cell-related osteonecrosis, although surgery may be deferred until late adolescence after growth plates have fused.

Preiser's Disease-Current Concepts of Etiology and Management.

The term Preiser's disease typically is used to describe idiopathic avascular necrosis of the scaphoid, but there have been a number of putative etiologies considered. It is rare and the natural history is not fully understood. Management of the condition should be based on patient factors as well as the stage of disease with regard to the scaphoid and the surrounding wrist. This chapter appraises the available evidence and aims to provide the reader with a framework to manage this rare condition.

Bioactivation of scaffolds in osteonecrosis.

Avascular osteonecrosis (AVN) due to local ischemia leads to an inhomogeneous osseous defect, which can be treated by resection and with bone substitute materials in a joint-preserving treatment. Due to the underlying risk profile of AVN, the mostly subchondral localization and the size of the local bone defect, bone regeneration is impaired. Therefore, bioactivation of the applied bone substitute materials prior to application is highly desirable. Apart from the use of growth factors and other soluble substances, the autologous application of location-typical cells and tissue is a useful alternative to support the bone healing properties of scaffolds. This article presents various methods to activate scaffolds for bone stimulation and discusses these techniques with respect to recent data from the literature.

Transient spontaneous osteonecrosis of the knee (SONK) shortly after SARS-CoV-2 infection: A report of 2 cases.

BACKGROUND: This article describes 2 cases of post-coronavirus disease 2019 (COVID-19) transient spontaneous osteonecrosis of the knee (PCT-SONK) observed in patients who had previously recovered from COVID-19 without corticosteroid administration. OBJECTIVES: The possible pathomechanisms by which a recent SARS-CoV-2 infection may contribute as a causative factor for osteonecrosis are reviewed, and the differential diagnosis and treatment are discussed. MATERIAL AND METHODS: Two patients (males, 45- and 47-year-old) presented with sudden onset knee pain with no trauma history. The pain persisted during rest and at night. On magnetic resonance imaging (MRI), no subchondral bone thickening was observed; bone edema was diffusely distributed in the whole femoral condyle, in contrast to the more focal edema that is typically concentrated mainly around the subchondral region in classic SONK. Both patients were treated nonoperatively with no weight bearing and pharmacological agents, and complete resolution of symptoms was achieved. RESULTS: A follow-up MRI 10 weeks after presentation revealed a near-complete loss of signal in the medial femoral condyle in both patients. CONCLUSION: Orthopedic surgeons should be cautious when sudden knee pain without concurrent trauma or a history of injury occurs shortly after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, even with mild COVID-19 illness. While some studies report the development of post-COVID-19 osteonecrosis after lower doses of corticosteroids and sooner after their administration than in comparable non-COVID-19 cases, our study is the first to report 2 cases with no corticosteroid administration at all. Therefore, the authors believe it adds to the body of knowledge on the potential connections between COVID-19 and PCT-SONK. The transient nature of symptoms and radiological findings suggest that aggressive surgical treatment of non-injury local bone edema occurring shortly after SARS-CoV-2 infection should be avoided.