A systematic review of the therapeutic interventions for heterotopic ossification after spinal cord injury. Spinal Cord. 2010;48:512-521. [PMID: 20048753 DOI: 10.1038/sc.2009.175]

Angiogenesis in heterotopic ossification: From mechanisms to clinical significance

Heterotopic ossification (HO) refers to the formation of pathologic bone in nonskeletal tissues (including muscles, tendons or other soft tissues). HO typically occurs after a severe injury and can occur in any part of the body. HO lesions are highly vascularized. Angiogenesis, which is the formation of new blood vessels, plays an important role in the pathophysiology of HO. Surgical resection is considered an effective treatment for HO. However, it is difficult to completely remove new vessels, which can lead to the recurrence of HO and is often accompanied by significant problems such as intraoperative hemorrhage, demonstrating the important role of angiogenesis in HO. Here, we broadly summarize the current understanding of how angiogenesis contributes to HO; in particular, we focus on new insights into the cellular and signaling mechanisms underlying HO angiogenesis. We also review the development and current challenges associated with antiangiogenic therapy for HO.

A Novel Surgical Technique for the Management of Large-Volume Neurogenic Heterotopic Ossification Following a Spinal Cord Injury: The Sashimi Technique

This case series investigates the efficacy of the "sashimi technique," a novel surgical approach utilizing a curved chisel for the resection of heterotopic ossification (HO). The main focus is on reducing resection margins and preventing excessive bone removal while maintaining optimal functional outcomes and preventing recurrence. Two cases illustrate successful outcomes in patients with spinal cord injuries and severe HO of the hip, emphasizing the precision of using the curved chisel-based technique in improving patient mobility while still achieving a desired resection margin. The study highlights the effectiveness of using a curved chisel in protecting neurovascular structures and maintaining resection precision. Additionally, the integration of postoperative radiotherapy and pharmacological treatment is emphasized as a strategy to prevent recurrence. The goal of this procedure is to improve functional outcomes and patient quality of life.

Trauma patient heterotopic ossification diagnosis is associated with increased hospital length of stay

BACKGROUND

Traumatic heterotopic ossification (tHO) refers to the development of extra-skeletal bone in muscle and soft tissues following tissue insult secondary to surgery or trauma. This presents a persistent clinical concern associated with significant patient morbidity and expense to diagnose and treat. Traumatic HO is a substantial barrier to rehabilitation for trauma-injured patients. As such, the development of tHO after burn and other trauma is hypothesised to prolong inpatient length of stay (LOS) and thus increase health care costs.

OBJECTIVE

To investigate the association between an inpatient tHO diagnosis and hospital LOS in trauma patients.

METHODS

A retrospective audit of trauma patients over a 14-year period was completed using data from four WA hospitals. Burn and neurological trauma patients diagnosed with tHO as an inpatient (tHO+) and control subjects (tHO-), matched (1:3) by age, gender, and injury severity factors, were identified using medical diagnostic codes. Data relating to patient and injury-related determinants of LOS from tHO+ and tHO- subjects were analysed to model the association of tHO on total hospital length of stay.

RESULTS

188 identified patients were hospitalised due to traumatic injury; 47 patients with tHO following burn injury (n = 17), spinal cord injury (n = 13) and traumatic brain injury (n = 17), and 141 control patients. Those who developed tHO during hospitalisation had a significantly higher median LOS than matched trauma patients who did not develop tHO (142 days vs. 61 days). Multivariate regression analyses identified the following independent predictive factors of a prolonged hospital LOS: tHO diagnosis, mechanical ventilation hours, injury to the hip region and thigh area, other ossification disorder, pressure injury, admission to intensive care unit and deep vein thrombosis. Trauma patients diagnosed with tHO during their hospital admission stayed 1.6 times longer than trauma patients matched for injury severity without a tHO diagnosis (IRR 1.56, 95% CI 1.35-1.79, p<0.001).

CONCLUSION

Traumatic heterotopic ossification is an independent explanatory factor for increased hospital LOS in patients following burns, spinal cord, and traumatic brain injury. Early diagnosis may assist in reducing the impact of tHO on acute hospital stay after trauma.

Heterotopic ossification in right popliteal fossa causing arterial insufficiency

Heterotopic ossification (HO) is the abnormal formation of extra-skeletal bone in soft tissue, which can occur after trauma or surgery. HO in joints can cause pain, hinder mobility, and compress surrounding nerves and blood vessels. We present an unusual case of arterial insufficiency caused by HO in the right popliteal fossa.

Basilar tubercles and eminences of the clivus: Novel anatomical entities

BACKGROUND

The clivus forms the central skull base between the dorsum sellae and the foramen magnum. Although bony variations of the inferior surface of the clivus are well-recognized and have been well studied, studies of bony variations of the basilar (superior) surface of the clivus are scarce. Therefore, the present study was performed to investigate bony anatomical variations on the basilar part of the clivus.

METHODS

Computed tomography scans belonging to 407 Indian subjects from the CQ500 open-access dataset were retrospectively reviewed.

RESULTS

Bony tubercles on the basilar surface of the clivus were found in 40 cases (9.83%). They were classified into three types including single, double and triple. A single tubercle was found in 35 cases (8.60%) including 12 on the left (2.95%), 10 on the right (2.46%) and 13 in the center (3.19%). The tubercles were doubled in four cases (0.98%) and tripled in one case (0.25%). The average width and height of the tubercles were 4.4 ± 1.5 mm (range 1.4-7.9 mm) and 1.7 ± 0.7 mm (range 0.8-4.2 mm), respectively. Ninety-five (95%) percent of the tubercles were located on the lower half of the clivus.

CONCLUSIONS

To our knowledge, these tubercles have not been previously described. Therefore, we suggest the terms "basilar tubercles of the clivus" and "basilar eminences of the clivus", depending on their sizes. Knowledge of these newly described structures is important when interpreting radiological images of the skull base.

HETEROTOPIC OSSIFICATION AFTER SPINAL CORD INJURY: PREVENTION AND TREATMENT - A SISTEMATIC REVIEW

Trauma configures the main cause of spinal cord injuries. Patients with traumatic spinal cord injury often develop severe and debilitating outcomes that require multidisciplinary care to adapt patients to their new reality. Heterotopic ossification (HO) is one of the frequent comorbidities in these patients but it still lacks well-established treatments or a gold standard one. Thus, this systematic review aimed to search the current literature for HO treatment and prevention. This study was conducted following PRISMA recommendations (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) and searches were conducted in three databases (PubMed, Embase, and Web of Science). A total of 193 articles were found in an initial search. After screening following the established criteria, eight articles were included in this review; of these, two reported prevention and the others, treatments. Based on data analysis, the use of non-steroidal anti-inflammatory drugs in the acute post-traumatic period proved to be the best method of prevention. In cases of mature HO or accompanied by ankylosis, surgical resection proved to be the most effective treatment despite the high rate of postoperative infections. Level of Evidence III, Systematic Review.

The interplay between the nerves and skeleton: a 30-year bibliometric analysis

Background

The mechanisms and effects of the interplay between the nerves and skeleton remain a popular research topic. This study aimed to analyze and evaluate publications on nerve-bone interactions using bibliometrics and to identify the state of the art of current research, hotspots, and future directions.

Methods

This study included 1989 articles and reviews from the Web of Science Core Collection (WoSCC) published from January 1, 1991, to June 22, 2022. The Bibliometrix package of R 4.2.0 (The R Foundation for Statistical Computing, Vienna, Austria) was used to analyze basic information about the publications, including the annual number of publications, institution analysis, author influence analysis, journal analysis, and the national cooperation network. We also used CiteSpace 5.8.R3 for bibliometric analysis, including co-occurrence, co-citation, and cluster analysis.

Results

We discovered a significant increase in the number of articles on nerve-bone interactions published over the last 10 years. The most active country and institution were the United States and the University of Minnesota, respectively. In terms of journals and cocited journals, Bone was ranked highest with respect to the number of publications, while Journal of Bone and Mineral Research was ranked highest among cited journals. Wang Lei was the author with the most publications, and Bjurholm A was the most cited author. The analysis of references and keywords revealed that the impact of nerve- and neuromodulation-related factors on stem cell differentiation was a persistently hot topic. Osteoarthritis, neuropeptide Y, and osteoclastogenic process are likely to be the next era of research hotspots. The neurovascular crosstalk within bone has received great attention, especially in skeletal diseases, which may provide potential targets for future treatments.

Conclusions

We used a bibliometric method to provide an efficient, objective, and comprehensive assessment of existing research about the interplay between the skeletal and nervous systems and to accurately identify hotspots and research frontiers, providing valuable information for future research.

Preoperative Arterial Embolization for Heterotopic Ossification of the Hip

PURPOSE

To investigate the efficacy and safety of preoperative arterial embolization for neurogenic heterotopic ossification (NHO) of the hip.

MATERIALS AND METHODS

This single-center retrospective study reviewed outcomes in 16 consecutive patients who had surgical resection of NHO of the hip: 8 of whom underwent preoperative arterial embolization and 8 of whom did not. Both patient cohorts had similar baseline characteristics. A mean of 2.62 ± 1.9 arteries per patient, including the gluteal, lateral circumflex femoral, and deep circumflex iliac branches, were embolized using an n-butyl cyanoacrylate (NBCA)-ethiodized oil mixture. Data from both cohorts regarding intraoperative blood loss, volume of blood transfused, complications, and duration of hospitalization were compared.

RESULTS

A mean of 2.6 ± 1.9 arteries were embolized with NBCA-ethiodized oil, mainly the gluteal arteries, lateral circumflex femoral artery, and deep circumflex iliac artery. In the embolization group, mean intraoperative blood loss was 875 mL ± 320, mean number of units of blood used was 0.5 ± 0.7, and average number of days of hospitalization was 6.4 days ± 1.6. In the control group, mean intraoperative blood loss was 1,350 mL ± 120, mean number of units of blood used was 2 ± 1.1, and average number of days of hospitalization was 11.5 days ± 1.4. The embolization group had an average reduction in blood loss of 40.7% (P = 0.035), reduction in units of blood administered of 75% (P = 0.021), and reduction in days of hospitalization of 44.7% (P = 0.014). No procedural complications were recorded.

CONCLUSIONS

Preoperative arterial embolization is effective and safe in reducing intraoperative blood loss, number of hospitalization days, and need for blood transfusions in surgical resection of NHO of the hip.

Heterotopic Ossification after a Prolonged Course of COVID-19: A Case Report and Review of the Literature

We report the case of a 20-year-old male who developed severe HO of the left hip secondary to a prolonged course of COVID-19 pneumonia. Upon extubation, he was found to have debilitating left hip pain and significant functional deficits with regard to his range of motion and functional status. There are numerous known causes of heterotopic ossification (HO), including trauma, surgery, and traumatic brain or spinal cord injuries. An increased incidence of HO has also been reported in patients who undergo prolonged intubation. While the COVID-19 virus has many known respiratory and medical complications, it has also resulted in unforeseen complications that present long-term challenges for patients. When treating patients with coronavirus, physicians should be aware of HO as a possible complication and consider it as a cause of musculoskeletal pain.

Identification of Risk Factors in the Development of Heterotopic Ossification After Primary Total Hip Arthroplasty

PURPOSE

Heterotopic ossification (HO) is a process by which bone forms abnormally in soft tissues. Known risk factors for developing HO include male sex, spinal cord injury, trauma, and surgery. We investigated additional risk factors in the development of HO after hip arthroplasty.

METHODS

We performed a retrospective review of electronic medical records of 4070 individuals who underwent hip arthroplasty from September 2010 to October 2019 at the University of California, San Francisco Hospital. Demographics, anthropometrics, medications, and comorbid conditions were used in logistic regression analysis to identify factors associated with the development of HO.

RESULTS

A total of 2541 patients underwent primary hip arthroplasty in the analyzed timeframe (46.04% men, mean age at procedure: 62.13 ± 13.29 years). The incidence of postsurgical HO was 3% (n = 80). A larger proportion of individuals who developed HO had underlying osteoporosis (P < 0.001), vitamin D deficiency (P < 0.001), spine disease (P < 0.001), type 1 or 2 diabetes (P < 0.001), amenorrhea (P = 0.037), postmenopausal status (P < 0.001), parathyroid disorders (P = 0.011), and history of pathologic fracture (P = 0.005). Significant predictors for HO development were Black/African American race [odds ratio (OR) 2.97, P = 0.005], preexisting osteoporosis (OR 2.72, P = 0.001), spine disease (OR 2.04, P = 0.036), and low estrogen states (OR 1.99, P = 0.025). In the overall group, 75.64% received perioperative nonsteroidal anti-inflammatory drugs (NSAIDs), which negatively correlated with HO formation (OR 0.39, P = 0.001).

CONCLUSIONS

We identified new factors potentially associated with an increased risk of developing HO after primary hip arthroplasty, including African American race, osteoporosis, and low estrogen states. These patients may benefit from HO prophylaxis, such as perioperative NSAIDs.

Effectiveness of Prophylactic Interventions in Neurogenic Heterotopic Ossification (NHO): A Systematic Review

Neurogenic heterotopic ossification (NHO) is the formation of mature lamellar bone in peri-articular tissues following a neurological insult, most commonly traumatic brain injury (TBI) or spinal cord injury (SCI). NHO is a debilitating condition associated with significant morbidity and reduced quality of life. However, its pathophysiology remains poorly understood. While surgery is the mainstay of treatment once NHO has been diagnosed, prophylactic options are limited and not well studied. This review aimed to determine the efficacy of various interventions used in the primary prevention of NHO. We conducted an electronic literature search using five databases (PubMed, Embase, ScienceDirect, Cochrane Library, and Cumulative Index to Nursing and Allied Health Literature (CINAHL)) for records published until April 10, 2022. We identified 2,610 potentially eligible records across all databases. Nine reports met our eligibility criteria and were included in this review. Four were clinical trials (three randomized control trials, one nonrandomized trial), four were observational studies, and one was a systematic review/meta-analysis. The medications/interventions used included: warfarin, pulse low-intensity electromagnetic field therapy (PLIMF), bisphosphonates, and nonsteroidal anti-inflammatory drugs (NSAIDs). We did not find conclusive evidence to recommend the use of bisphosphonates and warfarin in the prevention of NHO. On the contrary, we found NSAIDs and PLIMF as effective prophylactic options based on the results of high-quality randomized control trials. Further prospective randomized studies with prolonged follow-ups are needed to confirm the long-term efficacy of these preventive interventions.

Case Report: Unusual Heterotopic Ossification of the Hindfoot

Heterotopic ossification (HO) is a pathologic condition in which aberrant lamellar bone deposits in soft tissues, outside of the normal skeleton. Pathogenesis is still unclear, but different risk factors are known. Here we report a case of a 14 year-old girl presenting with pain in the medial calcaneal region and evidence of a rapidly growing, firm and solid neoformation. The lesion was diagnosed 6 years earlier, but it was consistently smaller and asymptomatic so that the patient did not undergo any follow up. The patient had no previous trauma or surgery, no other risk factors for HO and did not show any clinically evident HO in other districts. Xray and CT showed a heterogeneous bony lesion in the context of soft tissues, isolated from the calcaneus. After complete excision, histological analysis confirmed the diagnosis of HO. In conclusion, lone non congenital HO can occur regardless of known risk factors. Small HO lesion may also enter a proliferative phase without evidence of triggering events. More studies are required to better understand etiopathogenesis of HO in these clinical settings.

Sustained local ionic homeostatic imbalance caused by calcification modulates inflammation to trigger heterotopic ossification

Heterotopic ossification (HO) is a condition triggered by an injury leading to the formation of mature lamellar bone in extraskeletal soft tissues. Despite being a frequent complication of orthopedic and trauma surgery, brain and spinal injury, the etiology of HO is poorly understood. The aim of this study is to evaluate the hypothesis that a sustained local ionic homeostatic imbalance (SLIHI) created by mineral formation during tissue calcification modulates inflammation to trigger HO. This evaluation also considers the role SLIHI could play for the design of cell-free, drug-free osteoinductive bone graft substitutes. The evaluation contains five main sections. The first section defines relevant concepts in the context of HO and provides a summary of proposed causes of HO. The second section starts with a detailed analysis of the occurrence and involvement of calcification in HO. It is followed by an explanation of the causes of calcification and its consequences. This allows to speculate on the potential chemical modulators of inflammation and triggers of HO. The end of this second section is devoted to in vitro mineralization tests used to predict the ectopic potential of materials. The third section reviews the biological cascade of events occurring during pathological and material-induced HO, and attempts to propose a quantitative timeline of HO formation. The fourth section looks at potential ways to control HO formation, either acting on SLIHI or on inflammation. Chemical, physical, and drug-based approaches are considered. Finally, the evaluation finishes with a critical assessment of the definition of osteoinduction. STATEMENT OF SIGNIFICANCE: The ability to regenerate bone in a spatially controlled and reproducible manner is an essential prerequisite for the treatment of large bone defects. As such, understanding the mechanism leading to heterotopic ossification (HO), a condition triggered by an injury leading to the formation of mature lamellar bone in extraskeletal soft tissues, would be very useful. Unfortunately, the mechanism(s) behind HO is(are) poorly understood. The present study reviews the literature on HO and based on it, proposes that HO can be caused by a combination of inflammation and calcification. This mechanism helps to better understand current strategies to prevent and treat HO. It also shows new opportunities to improve the treatment of bone defects in orthopedic and dental procedures.

Successful Total Knee Arthroplasty in a Patient With Contralateral Ankylosis Due to Severe Heterotopic Ossification

A 63-year-old woman with ankylosis of the left knee due to severe heterotopic ossification (HO) following total knee arthroplasty (TKA) underwent right TKA with preoperative radiation and postoperative chemical prophylaxis for HO. At the one-year follow-up, the patient had no evidence of HO in the right knee. To our knowledge, there are no reports of successful arthroplasty in patients with a history of ankylosis due to severe HO. We present the first case of successful TKA in a patient with ankylosis of the contralateral knee. TKA can be safely performed in patients at high risk for developing ankylosis.

Long-term radial extracorporeal shock wave therapy for neurogenic heterotopic ossification after spinal cord injury: A case report

Context: Heterotopic ossification is characterized by abnormal growth of bone in soft tissues. Neurogenic heterotopic ossification is also closely related to central nervous system injuries and has been reported to respond to radial extracorporeal shock wave therapy.Findings: In this case, a radial extracorporeal shock wave therapy (five times per week, lasted for almost one year) was applied to a patient with neurogenic heterotopic ossification on the left hip as a result of spinal cord injury. Throughout the treatment session, the heterotopic ossification lesion was gradually diminished, associated with the increase in joint range of motion, pain mitigation and decrease in serum alkaline phosphatase level.Conclusion/clinical relevance: Long-term radial extracorporeal shock wave therapy offers a promising therapeutic alternative for neurogenic heterotopic ossification.

[Research progress of traumatic heterotopic ossification]

OBJECTIVE

To review and evaluate the research progress of traumatic heterotopic ossification (HO).

METHODS

The domestic and foreign related research literature on traumatic HO was widely consulted, and its etiology, pathogenesis, pathological progress, diagnosis, prevention, and treatment were summarized.

RESULTS

Traumatic HO is often caused by severe trauma such as joint operation, explosion injury, nerve injury, and burn. At present, it is widely believed that the occurrence of traumatic HO is closely related to inflammation and hypoxia. Oral non-steroidal anti-inflammatory drugs and surgery are the main methods to prevent and treat traumatic HO.

CONCLUSION

Nowadays, the pathogenesis of traumatic HO is still unclear, the efficiency of relevant prevention and treatment measures is low, and there is a lack of specific treatment method. In the future, it is necessary to further study the pathogenesis of traumatic HO and find specific prevention and treatment targets.

Spinal cord injury reprograms muscle fibroadipogenic progenitors to form heterotopic bones within muscles

The cells of origin of neurogenic heterotopic ossifications (NHOs), which develop frequently in the periarticular muscles following spinal cord injuries (SCIs) and traumatic brain injuries, remain unclear because skeletal muscle harbors two progenitor cell populations: satellite cells (SCs), which are myogenic, and fibroadipogenic progenitors (FAPs), which are mesenchymal. Lineage-tracing experiments using the Cre recombinase/LoxP system were performed in two mouse strains with the fluorescent protein ZsGreen specifically expressed in either SCs or FAPs in skeletal muscles under the control of the Pax7 or Prrx1 gene promoter, respectively. These experiments demonstrate that following muscle injury, SCI causes the upregulation of PDGFRα expression on FAPs but not SCs and the failure of SCs to regenerate myofibers in the injured muscle, with reduced apoptosis and continued proliferation of muscle resident FAPs enabling their osteogenic differentiation into NHOs. No cells expressing ZsGreen under the Prrx1 promoter were detected in the blood after injury, suggesting that the cells of origin of NHOs are locally derived from the injured muscle. We validated these findings using human NHO biopsies. PDGFRα⁺ mesenchymal cells isolated from the muscle surrounding NHO biopsies could develop ectopic human bones when transplanted into immunocompromised mice, whereas CD56⁺ myogenic cells had a much lower potential. Therefore, NHO is a pathology of the injured muscle in which SCI reprograms FAPs to undergo uncontrolled proliferation and differentiation into osteoblasts.

Heterotopic Ossification: Clinical Features, Basic Researches, and Mechanical Stimulations

Heterotopic ossification (HO) is defined as the occurrence of extraskeletal bone in soft tissue. Although this pathological osteogenesis process involves the participation of osteoblasts and osteoclasts during the formation of bone structures, it differs from normal physiological osteogenesis in many features. In this article, the primary characteristics of heterotopic ossification are reviewed from both clinical and basic research perspectives, with a special highlight on the influence of mechanics on heterotopic ossification, which serves an important role in the prophylaxis and treatment of HO.

Treatment of Temporomandibular Joint Heterotopic Ossificans: A Novel Protocol With Multimodal Therapy Based on Literature Review and Presentation of a Unique Case Reportc

PURPOSE

The purpose of this study was to create a treatment protocol for cases of heterotopic ossification (HO) of the temporomandibular joint (TMJ), particularly those refractory to current TMJ HO protocols. In addition, we demonstrate the success of this protocol on a unique case of recurrent HO that failed multiple TMJ HO protocols in the setting of an improvised explosive device (IED) blast in a wounded warrior.

METHODS

An electronic literature review was conducted via PubMed and Web of Science. Twenty-five studies were identified to provide supporting evidence for a proposed, up-to-date protocol for the treatment of refractory TMJ HO. The authors present a case report of a wounded warrior with HO ankylosis of bilateral TMJs in the setting of IED blast and demonstrate successful use of our surgical and pharmacotherapeutic protocol.

RESULTS

Based on the literature review, our proposed protocol consists of pharmacotherapy with celecoxib and etidronate, with weekly forced dilation (brisement) and home physical therapy with the TheraBite Jaw Motion Rehab System. Surgically, the TMJ should be treated with two-stage reconstruction using initial polymethyl methacrylate spacers and subsequent total joint reconstruction with custom prostheses, fat grafting, and 3-dimensional-navigated total resection of HO. This protocol was successfully utilized in our patient's refractory HO ankylosed TMJ secondary to IED blast, and the patient's maximal incisal opening was regained and has remained stable 2 years after surgery without recurrent HO.

CONCLUSIONS

Our method for treatment in this case deviated from the standard TMJ Concepts HO protocol in that it included multimodal pharmacotherapy with celecoxib and etidronate. Based on our literature review and experience, we advise that clinicians utilize our protocol for the management of all craniofacial HO cases, particularly in cases of recurrent HO that fail conventional therapies and/or involving high-order blast trauma.

Heterotopic Ossification of the Inferior Vena Cava Wall: A Case Report and Literature Review

Masses of the inferior vena cava (IVC) are very diverse, most of which are thrombus and tumor thrombus, whereas heterotopic ossification of IVC has never been reported. Heterotopic ossification (HO) is the formation of mature lamellar bone outside normal bones and in soft tissues. Some researchers believe that HO is a manifestation of vascular calcification. Here we present a case of HO of the inferior vena cava (IVC) wall. A 68 year old female patient complaining hypertension and palpitation and diagnosed with a retroperitoneal mass was found to have a primary mass of the inferior vena cava wall during surgery. Histopathological examination after surgical resection revealed that the mass was mainly composed of mature bone tissues and hematopoietic tissues of bone marrow, there was no recurrence and the patient was symptom-free 15 months after the surgery. HO of the inferior vena cava wall is very rare, with large volume it can affect the circulation, and this case remind us that it can be cured by surgical resection.

Surgical excision of heterotopic ossification associated with anti-N-methyl-d-aspartate receptor encephalitis: A case report

INTRODUCTION AND IMPORTANCE

Heterotopic ossification (HO) associated with Anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis is rare and the treatment strategy is unclear.

CASE PRESENTATION

We report the case of a 31-year-old female diagnosed with anti-NMDA receptor encephalitis from Osaka General Medical Center, Osaka, JAPAN that developed heterotopic ossification of the knees during prolonged coma. She was unable to walk because of pain and limited range of motion in both knees. Thirty months after the onset of the coma, surgical excision of the heterotopic bone in both knees was performed. The range of motion of both the knees improved markedly and she had no recurrence of heterotopic ossification on a three-year follow-up. Thus, this case can be used as a guide for surgeons with such patients.

CONCLUSIONS

We reported a case of heterotopic bone formation in the periarticular region of both bilateral knees in a patient who suffered a 2-month coma following anti-NMDA receptor encephalitis. Surgical excision of the heterotopic bones significantly improved the passive range of motion in both knees. Three years after the operation, the patient had no complaints about her knees, and there was no recurrence of HO.

Neurogenic heterotopic ossification in the upper limb

Neurogenic heterotopic ossifications (NHOs) are periarticular ectopic ossifications that frequently develop after a central nervous system injury, most often a traumatic one. They limit range of motion and cause pain, interfering with limb positioning and function, whether active or passive. Highly described in the lower limbs, NHOs can also develop in the upper limb, with specific characteristics depending on their location. This article provides a summary of the diagnostic and therapeutic management of NHOs in the upper limb, based on the current literature.

NGF-TrkA signaling dictates neural ingrowth and aberrant osteochondral differentiation after soft tissue trauma

Pain is a central feature of soft tissue trauma, which under certain contexts, results in aberrant osteochondral differentiation of tissue-specific stem cells. Here, the role of sensory nerve fibers in this abnormal cell fate decision is investigated using a severe extremity injury model in mice. Soft tissue trauma results in NGF (Nerve growth factor) expression, particularly within perivascular cell types. Consequently, NGF-responsive axonal invasion occurs which precedes osteocartilaginous differentiation. Surgical denervation impedes axonal ingrowth, with significant delays in cartilage and bone formation. Likewise, either deletion of Ngf or two complementary methods to inhibit its receptor TrkA (Tropomyosin receptor kinase A) lead to similar delays in axonal invasion and osteochondral differentiation. Mechanistically, single-cell sequencing suggests a shift from TGFβ to FGF signaling activation among pre-chondrogenic cells after denervation. Finally, analysis of human pathologic specimens and databases confirms the relevance of NGF-TrkA signaling in human disease. In sum, NGF-mediated TrkA-expressing axonal ingrowth drives abnormal osteochondral differentiation after soft tissue trauma. NGF-TrkA signaling inhibition may have dual therapeutic use in soft tissue trauma, both as an analgesic and negative regulator of aberrant stem cell differentiation.

Extracorporeal shock wave therapy to treat neurogenic heterotopic ossification in a patient with spinal cord injury: A case report

Objective: To evaluate the efficacy and safety of treatment for neurogenic heterotopic ossification (NHO) using extracorporeal shock wave therapy (ESWT) in persons with spinal cord injury (SCI).Design: Single case report.Setting: Department of Physical Medicine and Rehabilitation, Veterans Health Service Medical Center.Participants: A 55-year-old male with cervical SCI, who developed painful NHO around the right hip joint.Interventions: Ultrasound-guided ESWT that used 4,000 shocks at the rate of 3 Hz and the energy flux density between 0.056 and 0.068 mJ/mm² was applied to the NHO region a total of 7 times, weekly.Outcome Measures: We assessed the treatment outcomes using a visual analog scale (VAS) score, wheelchair sitting time and size of NHO.Result: After 7 weeks of ESWT treatment, his pain reduced from a VAS score of 7-8 to 3 and his wheelchair sitting time increased. However, there was no significant change of size of NHO.Conclusion: The application of ESWT could be a possible alternative to other treatments for NHO in persons with SCI.Clinical Trial Registry Number: 2019-03-003.

Myositis ossificans revisited - The largest reported case series

INTRODUCTION

Myositis ossificans (MO) is a condition characterised by the formation of non-neoplastic heterotropic ossification in extraskeletal soft tissues.

MATERIAL AND METHODS

We performed a retrospective study of our radiology databases within our tertiary orthopaedic centre to identify all cases of MO, reported on X ray, Magnetic resonance imaging (MRI) and Computed tomography (CT) over the past 13 years (2007-2020).

RESULTS

We identified 68 cases of MO, which were included into our cohort. The average age of our patients was 36 years (range 4-84 years). 73% of cases (n = 50) were found to affect the lower limb muscles with the majority in the quadriceps.

CONCLUSION

We report the largest case series of MO and discuss the demographics, diagnoses and management.

Development of a rodent high-energy blast injury model for investigating conditions associated with traumatic amputations

AIMS

In recent conflicts, most injuries to the limbs are due to blasts resulting in a large number of lower limb amputations. These lead to heterotopic ossification (HO), phantom limb pain (PLP), and functional deficit. The mechanism of blast loading produces a combined fracture and amputation. Therefore, to study these conditions, in vivo models that replicate this combined effect are required. The aim of this study is to develop a preclinical model of blast-induced lower limb amputation.

METHODS

Cadaveric Sprague-Dawley rats' left hindlimbs were exposed to blast waves of 7 to 13 bar burst pressures and 7.76 ms to 12.68 ms positive duration using a shock tube. Radiographs and dissection were used to identify the injuries.

RESULTS

Higher burst pressures of 13 and 12 bar caused multiple fractures at the hip, and the right and left limbs. Lowering the pressure to 10 bar eliminated hip fractures; however, the remaining fractures were not isolated to the left limb. Further reducing the pressure to 9 bar resulted in the desired isolated fracture of the left tibia with a dramatic reduction in the fractures to other sites.

CONCLUSION

In this paper, a rodent blast injury model has been developed in the hindlimb of cadaveric rats that combines the blast and fracture in one insult, necessitating amputation. Experimental setup with 9 bar burst pressure and 9.13 ms positive duration created a fracture at the tibia with total reduction in non-targeted fractures, rendering 9 bar burst pressure suitable for translation to a survivable model to investigate blast injury-associated diseases. Cite this article: Bone Joint Res 2021;10(3):166-172.

Residual limb pain: An evidence-based review

Acquired limb loss, whether from accident or amputation, occurs with an incidence of greater than 175,000 per year in the United States. Current prevalence is estimated at greater than 1.5 million and is expected to double within 30 years. While many patients with amputations may have no significant pain or sensory issues after healing from the initial loss, one-quarter to one-half of patients may have ongoing difficulties with residual limb pain, phantom limb pain, or phantom limb sensation. This review explores the potential etiologies of those symptoms, as well as a variety of treatment options that a practitioner may consider when approaching this condition.

Activin A promotes the development of acquired heterotopic ossification and is an effective target for disease attenuation in mice

Heterotopic ossification (HO) is a common, potentially debilitating pathology that is instigated by inflammation caused by tissue damage or other insults, which is followed by chondrogenesis, osteogenesis, and extraskeletal bone accumulation. Current remedies are not very effective and have side effects, including the risk of triggering additional HO. The TGF-β family member activin A is produced by activated macrophages and other inflammatory cells and stimulates the intracellular effectors SMAD2 and SMAD3 (SMAD2/3). Because HO starts with inflammation and because SMAD2/3 activation is chondrogenic, we tested whether activin A stimulated HO development. Using mouse models of acquired intramuscular and subdermal HO, we found that blockage of endogenous activin A by a systemically administered neutralizing antibody reduced HO development and bone accumulation. Single-cell RNA-seq analysis and developmental trajectories showed that the antibody treatment reduced the recruitment of Sox9+ skeletal progenitors, many of which also expressed the gene encoding activin A (Inhba), to HO sites. Gain-of-function assays showed that activin A enhanced the chondrogenic differentiation of progenitor cells through SMAD2/3 signaling, and inclusion of activin A in HO-inducing implants enhanced HO development in vivo. Together, our data reveal that activin A is a critical upstream signaling stimulator of acquired HO in mice and could represent an effective therapeutic target against forms of this pathology in patients.

Diverse manifestations of a sickle cell crisis

We describe the case of a 21-year-old man with a background of sickle cell disease (SCD) who was on acute presentation in a sickle cell crisis required immediate intensive care admission with red blood cell exchange and ventilatory support. He had right frontal lobe infarcts and extensive bilateral deep white matter lesions most likely secondary to fat embolism. Inpatient investigations demonstrated a patent foramen ovale, explaining the route of spread of the fat embolus. He then had a transcatheter closure of the atrial defect. The patient needed prolonged inpatient rehabilitation. He was discharged from hospital in a wheelchair secondary to severe lower limb neurology and bilateral knee heterotopic ossification. He lives with the possibility of early onset dementia and cognitive decline, requiring constant care. The case highlights the multiple manifestations of SCD and their diverse and debilitating consequences.

Early diagnosis of heterotopic ossification among patients admitted to a neurological Post-Intensive Care Rehabilitation Unit

BACKGROUND

Heterotopic ossification (HO) is defined as the formation of endochondral bone within soft tissue. Non-genetic forms, mainly corresponding to a consequence of bone, brain or spinal cord injury, are the most common. HO leads to important functional limitations and alteration of quality of life. To our knowledge, the time between brain, bone, or spinal cord injury and clinical suspicion of HO has never been studied. By admitting patients with severe neurological disorders, we hypothesized that the prevalence of HO in neurological post-intensive care rehabilitation units (PICRU) might be significant as these patients have recognized risk factors for HO.

AIM

This study aimed to investigate HO among patients admitted to a neurological PICRU with two objectives: 1) to describe the prevalence of HO in PICRU; 2) to assess the time between neurological disorder, clinical suspicion of HO and radiological diagnosis.

DESIGN

A monocentric retrospective cohort study.

SETTING

PICRU in our public university teaching hospital. This inpatient referral department is specifically dedicated to the early discharge from Intensive Care Units (ICU) of patients with severe neurological impairment who need rehabilitation.

POPULATION

We study all patients admitted between April 2016 and January 2019. One hundred twenty-five subjects were admitted for a rehabilitation program after neuro-trauma or stroke. We included all first-time stays in PICRU lasting 7 days or longer.

METHODS

Retrospective data extraction using administrative data from an electronic patient management program was done to select eligible subjects. Included subjects were then identified by a retrospective review of electronic inpatient medical records after patient discharge. Data of interest were collected from these same medical records.

RESULTS

Forty-four HO were diagnosed in 24 subjects (24/125; 19%), with a median number of 2 [1; 2] HO per subject. Neurological trauma was the main reason for admission to ICU (89/125; 71%) and half of patients had a traumatic brain injury (TBI) (67/125; 54%). The diagnosis of HO was made in PICRU in 75% of cases. Clinical suspicion of HO (autonomic dysfunction, local inflammatory signs, pain, or reduced joint range of motion) was made 6 [5; 7] weeks after admission to ICU. Radiological confirmation of clinical suspicion or fortuitous diagnosis by imaging (50% of the cases) occurred 8 [7; 12] weeks after admission to ICU. The median time of clinical suspicion or radiological diagnosis was 1 week after admission to PICRU.

CONCLUSIONS

HO is a sub-acute complication which develops in patients admitted to ICU for severe central nervous system disorders as clinical suspicion or radiological confirmation of diagnosis was made within the first week after admission in neurological PICRU (i.e. 6 to 8 weeks after ICU admission).

CLINICAL REHABILITATION IMPACT

As treatment for HO may at least partially improves rehabilitation and quality of life, we recommend a systematic screening in PICRU patients for HO by clinical examination supplemented by imaging in case of suspicion.

Enhanced Spinal Therapy: Extracorporeal Shock Wave Therapy for the Spine

Extracorporeal shock wave therapy (ESWT) is a non-invasive therapeutic method used for pain management and muscle strength improvement through the use of shock waves. In vitro studies have demonstrated that shockwave therapy induces fluctuation in redox reaction regulation and increases in Mitogen-Activated Protein Kinase (MAPK) signal transduction pathways, stimulating increased gene expression in the nucleus. ESWT has also been shown to upregulate angiogenesis and growth factors through activation of endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF). The use of ESWT in the treatment of various musculoskeletal disorders was widely adopted throughout Europe, South America, and Asia before being introduced in the United States in 2000. Within the past 20 years, the clinical application of ESWT in the treatment of musculoskeletal and bone disorders has grown. This paper provides a comprehensive narrative review of applications and outcomes of ESWT in clinical spinal pathology and assesses reported efficacy as it relates to the pathology. A review of the literature yielded studies describing the use of ESWT in degenerative osteoporotic neuro-spinal pathology, heterotopic ossification due to spinal cord injury, cervical spondylosis, scoliosis, sacroiliitis, and coccydynia. The efficacy of ESWT as an adjunct treatment in patients with spinal cord pathologies varied with the specific pathology, however, all pathologies discussed in this review provided evidence of potential benefits with minimal adverse effects. While the use of ESWT for pain management has widely been established, further literature should aim to identify the long-term benefits of ESWT.

Severe Heterotopic Ossification with Proximal Entrapment of the Ulnar Nerve following Primary Anterior Shoulder Dislocation

Heterotopic ossifications (HO) in the shoulder are rare. The effectiveness of conservative treatment is limited, and therefore, symptomatic cases are usually treated surgically. However, there are no guidelines for the surgical treatment of HO. Herein, we report the case of a 45-year-old man with severe HO and proximal entrapment of the ulnar nerve following primary anterior shoulder dislocation without concomitant injuries (e.g., fracture and rotator cuff tears). Surgical intervention was indicated, including resection of HO and neurolysis of the brachial plexus. Nine months after surgery, the patient presented with restored shoulder function, pain relief, and good patient satisfaction. The case shows that the ulnar nerve can also be impaired due to HO following shoulder dislocation.

Heterotopic ossification with femoral vein compression mimicking deep vein thrombosis

Heterotopic ossification (HO) in patients with spinal cord injury could lead to local tissue swelling and sometimes mimic the clinical presentation of deep vein thrombosis. Recognition and effective management is critical. We report the case of a bedridden patient with spinal cord injury presenting with diffuse right lower limb swelling caused by external venous compression from HO. The patient underwent surgery and local radiation therapy. Postoperative venography disclosed a marked improvement in the blood flow, and symptoms were alleviated. We discuss the role of venography in the diagnosis and treatment of venous compression in the setting of HO.

Heterotopic ossification of tendon and ligament

Much of the similarities of the tissue characteristics, pathologies and mechanisms of heterotopic ossification (HO) formation are shared between HO of tendon and ligament (HOTL). Unmet need and no effective treatment has been developed for HOTL, primarily attributable to poor understanding of cellular and molecular mechanisms. HOTL forms via endochondral ossification, a common process of most kinds of HO. HOTL is a dynamic pathologic process that includes trauma/injury, inflammation, mesenchymal stromal cell (MSC) recruitment, chondrogenic differentiation and, finally, ossification. A variety of signal pathways involve HOTL with multiple roles in different stages of HO formation, and here in this review, we summarize the progress and provide an up‐to‐date understanding of HOTL.

Risk factors for heterotopic ossification in operatively treated proximal humeral fractures

AIMS

Heterotopic ossification (HO) is a potentially devastating complication of the surgical treatment of a proximal humeral fracture. The literature on the rate and risk factors for the development of HO under these circumstances is lacking. The aim of this study was to determine the incidence and risk factors for the development of HO in these patients.

METHODS

A retrospective analysis of 170 patients who underwent operative treatment for a proximal humeral fracture between 2005 and 2016, in a single institution, was undertaken. The mean follow-up was 18.2 months (1.5 to 140). The presence of HO was identified on follow-up radiographs.

RESULTS

The incidence of HO was 15% (n = 26). Our multivariate model revealed that male sex (odds ratio (OR) 3.57, 95% confidence interval (CI) 1.30 to 9.80 compared to female) and dislocation as the initial injury (OR 5.01, 95% CI 1.31 to 19.22) were significantly associated with the formation of HO (p < 0.05) while no significant associations were seen for the age of the patient, the characteristics of the injury, or the type of operative treatment.

CONCLUSION

This retrospective radiological study is the first to investigate the association between the method of surgical treatment for a proximal humeral fracture and the formation of HO postoperatively. We found that male sex and dislocation as the initial injury were risk factors for HO formation, whereas the method of surgical treatment, the age of the patient, and the pattern of the fracture were not predictive of HO formation. While additional studies are needed, these findings can help to identify those at an increased risk for HO formation under these circumstances. Cite this article: Bone Joint J 2020;102-B(4):539-544.

Painful Proximally Oriented Large Heterotopic Spur Formation in an Active Adult With a Nontraumatic Amputation

Heterotopic ossification (HO) is excess bone growth in soft tissues, typically juxta-articular and interfascicular, with varying incidence. This excess bone growth has been well-documented in cases of traumatic amputation but less frequently observed in cases of nontraumatic amputation. Symptomatic heterotopic ossification usually includes pain during prosthetic use with management involving prosthetic adjustments for comfort. This atypical case highlights a patient with a nontraumatic amputation and a proximal-oriented large spur formation that was not painful with ambulation but with doffing his prosthesis.

Heterotopic ossification: a preventable case of gossypiboma in spinal cord injury

OBJECTIVE

Heterotopic ossification is the formation of ectopic bone in soft tissues. It has three established aetiologies: genetic, traumatic and neurogenic. A gossypiboma is defined as a retained foreign body, such as a mass or sponge, usually after a surgical procedure. In this article, we present a unique, preventable case of a patient admitted for newly developed heterotopic ossification in the gluteus maximus muscle caused by a retained piece of foam from negative pressure wound therapy (NPWT). The heterotopic ossification lesion, together with the retained foreign body, was completely excised and reconstructed using a posterior thigh fasciocutaneous advancement flap. This is the first reported case of heterotopic ossification caused by a retained foreign body and may be helpful to better understanding of the aetiology of heterotopic ossification.

Pharmacologic prophylaxis for heterotopic ossification following spinal cord injury: A systematic review and meta-analysi

Heterotopic ossification(HO) is a common complication following spinal cord injury(SCI); however, its underlying pathophysiology remains relatively unknown. Although there are options for treating HO, prophylactic treatment is limited. Additionally, evidence supporting the effectiveness of these prophylactic treatments is scarce. Electronic literature search was conducted using four databases. Studies comparing prophylactic medication for HO versus placebo for patients with acute spinal cord injury were included. A meta-analysis comparing the incidence of HO between the two groups was conducted, with a subgroup analysis of non-steroidal anti-inflammatory drugs (NSAIDs) and non-NSAIDs. A total of 5 studies and 815 patients were included. Overall incidence of HO was 9.73 % (n = 25) in the medication group versus 16.5 %(n = 92) in the placebo group. However, the two groups do not statistcally differ(p = 0.21). In the subgroup analysis for NSAIDs, those who received prophylactic treatment with NSAIDs had a lower incidence of HO compared to those who received placebo (RR[95 % CI]:0.32[0.15, 0.68]; p = 0.003). As for studies that used bisphosphonates, a statistically significant difference in incidence of HO was not found (RR[95 % CI]:1.30[0.52, 3.24];p = 0.58) and the overall evidence was inconclusive. In present systematic review and meta-analysis comparing prophylactic medications to placebo for prevention of HO, we found similar incidence rates for both groups. However, subgroup analysis showed a significantly lower incidence rate for those who recevied NSAIDs for HO prophylaxis. Altough this finding is promising for secondary prevention of HO among patients suffering from SCI, further prospective studies with longer follow-ups are required to assess other appropriate medications for HO prevention.

Celecoxib cannot inhibit the progression of initiated traumatic heterotopic ossification

BACKGROUND AND HYPOTHESIS

Heterotopic ossification (HO) is a recognized sequela after trauma and arthroplasty. The purpose of this study was to evaluate the therapeutic effect of celecoxib on HO. We hypothesized that celecoxib may inhibit the progression of initiated HO.

METHODS

We performed a retrospective review of 37 patients who underwent elbow joint surgery between January 2014 and June 2018. Seventeen patients were prescribed orally administered celecoxib (200 mg/dose, twice daily) for 2 months after the diagnosis of HO, whereas the remaining 20 patients were administered celecoxib for 1 month starting immediately after surgery. HO progression was evaluated by plain radiographs. By use of an Achilles tendon puncture-induced HO mouse model, the curative effect of celecoxib was illustrated at different HO progression stages. The mice were assigned to 1 of 4 groups: sham group, vehicle group, group receiving celecoxib on day 1, and group receiving celecoxib in week 6. Achilles tendons were analyzed by micro-computed tomography and histochemistry after 12 weeks.

RESULTS

Celecoxib did not inhibit the progression of initiated HO in the patients in whom HO was diagnosed, whereas those who received celecoxib after surgery had lower morbidity. Achilles tendon puncture effectively induced typical HO in mice. The ectopic bone volume was significantly reduced in the day 1 celecoxib group compared with the vehicle group; however, the difference was not statistically significant in the week 6 celecoxib group.

CONCLUSIONS

Administration of celecoxib starting immediately after surgery can significantly inhibit the formation of HO. Once HO is visible on plain radiographs or micro-computed tomography, celecoxib cannot effectively attenuate further progression of HO in humans and mice.

Heterotopic Ossification: A Comprehensive Review

Heterotopic ossification (HO) is a diverse pathologic process, defined as the formation of extraskeletal bone in muscle and soft tissues. HO can be conceptualized as a tissue repair process gone awry and is a common complication of trauma and surgery. This comprehensive review seeks to synthesize the clinical, pathoetiologic, and basic biologic features of HO, including nongenetic and genetic forms. First, the clinical features, radiographic appearance, histopathologic diagnosis, and current methods of treatment are discussed. Next, current concepts regarding the mechanistic bases for HO are discussed, including the putative cell types responsible for HO formation, the inflammatory milieu and other prerequisite “niche” factors for HO initiation and propagation, and currently available animal models for the study of HO of this common and potentially devastating condition. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Gαs signaling in skeletal development, homeostasis and diseases

Skeletal development is exquisitely controlled both spatially and temporally by cell signaling networks. Gα_s is the stimulatory α-subunit in a heterotrimeric G protein complex transducing the signaling of G-protein-coupled receptors (GPCRs), responsible for controlling both skeletal development and homeostasis. Gα_s, encoded by the GNAS gene in humans, plays critical roles in skeletal development and homeostasis by regulating commitment, differentiation and maturation of skeletal cells. Gα_s-mediated signaling interacts with the Wnt and Hedgehog signaling pathways, both crucial regulators of skeletal development, remodeling and injury repair. Genetic mutations that disrupt Gα_s functions cause human disorders with severe skeletal defects, such as fibrous dysplasia of bone and heterotopic bone formation. This chapter focuses on the crucial roles of Gα_s signaling during skeletal development and homeostasis, and the pathological mechanisms underlying skeletal diseases caused by GNAS mutations.

Clinical Prediction Rule for Heterotopic Ossification of the Hip in Patients with Spinal Cord Injury

STUDY DESIGN

A case-control study; clinical prediction rule.

OBJECTIVE

The aim of this study was to construct and internally validate a clinical prediction rule to identify patients at high risk of developing heterotopic ossification (HO) after spinal cord injury (SCI).

SUMMARY OF BACKGROUND DATA

HO after SCI can lead to loss of joint mobility, loss of function, peripheral nerve entrapment, and pressure sores. HO is usually diagnosed on the basis of clinical symptoms, as no laboratory tests are yet available to identify patients with early HO formation. Risk factors include a complete SCI; patient age; spasticity; urinary tract infection (UTI); pneumonia; pelvic trauma; cervical or thoracic injury; and pressure sores.

METHODS

We analyzed a total of 558 patients with SCI, of whom 221 developed HO of the hip. A parametric survival model was fitted to estimate the probability of developing HO of the hip within 3 months of a SCI. Hazard ratios (HRs) calculation, internal validation, calibration, and model reduction were performed over 200 bootstrapped resamples. A risk score for clinical used was developed.

RESULTS

Risk factors contributing to the risk score were completeness of the injury, age, sex, UTI, spasticity, and pneumonia. The model demonstrated good discrimination (AUC = 0.72). According to the risk score quintiles, the risk of developing HO after SCI was 1.0 for persons with a score of 0 to 17 and increased 2.47-fold for persons with a score of 1 to 21, 4.75-fold for persons with a score of 22 to 27, 6.95-fold for persons with a score of 28 to 31, and 9.23-fold for persons with a score of 32-35.

CONCLUSION

The risk score demonstrated good discrimination in predicting the occurrence of HO within 3 months of a SCI. Further development and validation of the model in other populations is warranted.

LEVEL OF EVIDENCE

3.