Soft tissue aneurysmal bone cysts (STABCs) are rare neoplasms histopathologically identical to aneurysmal bone cysts. These benign lesions are characterized by thin, peripheral ossification and no skeletal continuity. STABC may be difficult to distinguish from myositis ossificans (MO) and malignant entities from imaging and fine needle aspiration, due to rarity and overlapping features. We present a case of a STABC occurring in the paraspinal cervical muscles. The imaging, histopathology, molecular analysis, and treatment are discussed. Four other published cases of STABC of the head and neck are reviewed.

There are few animal models for heterotopic ossification of the temporomandibular joint (TMJ-HO). This scoping review provides an overview of current knowledge on the induction methods and specific conditions required to produce TMJ-HO in various animal models. Two independent reviewers selected papers from the PubMed, Web of Science, and Cochrane Library databases. The inclusion criteria were articles in English, in vivo studies, and a TMJ-HO induction method. Observational, in vitro, human studies, reviews, and book chapters were excluded. Twenty-four publications were included. HO was surgically, genetically, or chemically induced through single or combined defects in the condyle, articular disc, and temporal bone in animal models (sheep=9 studies, mouse=5, rat=4, rabbit=2, pig=2, goat=1, dog=1, monkey=1) specific for traumatic TMJ-HO (n=4), ankylosis (n=9), osteoarthritis (n=8), experimental disc perforation (n=1), status post-TMJ replacement (n=1), and status post bilateral sagittal split osteotomy (n=1). TMJ-HO remains challenging to study due to its multifactorial etiology and largely unknown pathogenesis, which varies between species. There is a need for more accurate, reproducible animal models that can be extrapolated to human TMJ-HO and a consolidated clinical classification system to allow for meaningful future research.

Heterotopic ossification refers to the pathological formation of extra-skeletal bone. It is a common complication of trauma or surgery that can cause disability and has no definitive cure. Furthermore, the mechanisms underlying chronic inflammation during ossification remain unclear. Therefore, this study aimed to elucidate the systemic immune microenvironment status of heterotopic ossification and identify biomarkers of therapeutic efficacy and recurrence. A combination of stereoarthrolysis with prophylactic radiotherapy and non-steroidal anti-inflammatory drugs was used to treat patients with heterotopic ossification. Changes were observed in peripheral blood lymphocyte levels after treatment. The number of IFNγ+CD8+T cells (3.753 % vs 12.90 %, P < 0.0001) and IL17+CD4+T cells (3.420 % vs 5.560 %, P = 0.0281) were was higher in the peripheral blood of relapsed patients with heterotopic ossification than in that of non-relapsed patients. Similarly, the number of these cells was elevated in patients who developed heterotopic ossification after posttraumatic elbow surgery. Peripheral CD8+T cells derived from patients with this pathology promoted osteogenesis through IFNγ expression in vitro. Our findings demonstrate that IFNγ+CD8+T cells and IL17+CD4+T cells are potential biomarkers of heterotopic ossification after posttraumatic elbow surgery. Furthermore, these cells can be used to predict therapeutic efficacy and relapse after combination therapy.

UNASSIGNED: This case report describes the occurrence of a rare heterotopic ossification of the elbow joint in a child, caused by inappropriate movement after trauma. A successful operation to remove heterotopic ossification was described in the report with satisfactory results.
UNASSIGNED: A 7-year-old boy suffered a supracondylar fracture of the humerus after an accidental fall, and after immobilization with a cast, improper movement resulted in heterotopic ossification of the elbow joint, which severely affected joint function. The heterotopic ossification was surgically removed and a complete recovery was demonstrated at 18 months follow-up. The heterotopic ossification was successfully removed with good elbow function and no recurrence at 18 months follow-up.
UNASSIGNED: The purpose of this report is to show the good results with surgical treatment of heterotopic ossification of the elbow joint in children,when conservative treatment does not work.

OBJECTIVE: We aim to analyse and compare the efficacy of the excision of HO around the hip with and without CT-guided navigation. We also aim to compare the functional outcome between CT navigation guided versus conventional excision of HO.
METHODS: This study is a retrospective analysis of prospectively collected data from 2015 to 2022. There were 23 patients (24 hips) in the final cohort. Intraoperative CT navigation guided excision was performed in 7 hips and conventional excision of HO was done in 17 hips. The HO was classified by Brooker\'s grading in radiographs. CT scan was taken preoperatively in all patients to exactly identify the volume, location and preoperative planning. The functional outcome was analysed according to Harris Hip Score (HHS) and International Hip Outcome Tool (iHOT) for self-ambulatory patients and improvement in the sitting or nursing care was assessed in patients mobilising with wheelchair or walker support. Any complications or recurrence noted postoperatively and in follow-up were recorded.
RESULTS: The mean follow-up was 41.2 months in the CT navigation-guided excision group and 55 months in the conventional excision group. According to Brooker\'s grading, grade IV was present in 20 hips and grade III in four hips. Twelve patients were self-ambulatory and the other 12 patients were requiring support for mobilisation. There was a significant improvement in the HHS from 21.3 ± 3.7, 18.3 ± 2.5 preoperatively to 75.2 ± 8.3, 72.2 ± 4.3 postoperatively in the CT navigation guided and conventional group respectively (p < 0.001) in the self-ambulatory group. There was one anterior wall and one partial posterior wall fracture in the conventional group. One patient in the conventional group had a deep infection and recurrence. One patient had a superficial infection and another had superficial vein thrombosis in the CT guided excision group.
CONCLUSIONS: Intraoperative CT navigation helps to exactly localize the HO and facilitates safe excision. Functional excision of the HO leads to better nursing care and functional outcomes between both groups.

Anterior cruciate ligament and meniscus tears are common among sports injuries. There are different techniques for addressing anterior cruciate ligament and meniscus tears, with distinct indications, advantages, and disadvantages. We present the case of a 23-year-old male who underwent right anterior cruciate ligament reconstruction and posterior horn medial meniscus repair using an all-inside technique via superficial medial collateral ligament (sMCL) pie-crusting. Clinical examination and radiological investigations a few months later identified calcifications on the medial side of the right knee. We diagnosed the patient with heterotopic ossification post-sMCL pie-crusting; no apparent causal factors were present. To our knowledge, there have been no documented instances of heterotopic ossification following sMCL pie-crusting. In conclusion, heterotopic ossification may occur after sMCL pie-crusting; further studies are needed on this subject.

Myositis ossificans (MO) is characterized by benign heterotopic ossificans in soft tissues like muscles, which can be classified into nonhereditary MO and fibrodysplasia ossificans progressiva (FOP). Although MO has been studied for decades, no research reviewed and analyzed the features of publications in this field quantitatively and qualitatively. Using bibliometrics tools (bibliometrix R package, VOSviewer, and CiteSpace), we conducted a bibliometric analysis of 1280 articles regarding MO in the Web of Science Core Collection database from 1993 to 2022. The annual number of publications and related research areas in the MO field increased gradually in the past 20 years. The USA contributed the most percentage (42.58%) of articles. The University of Pennsylvania (UPenn) and the Journal Bone published the most articles among all institutions and journals. Kaplan FS and Shore EM from UPenn were the top two scholars who made the largest contributions to this field. Keyword analysis showed that research hotspots changed from traumatic MO and clinical management of MO to the genetic etiology, pathogenesis, and treatment of FOP. This study can provide new insights into the research trends of MO and helps researchers grasp and determine future study directions more easily.

OBJECTIVE: Heterotopic ossification (HO) is a common complication following total hip arthroplasty. Various prophylactic treatments have been proposed, including radiotherapy (RT). This review summarizes the evidence from meta-analyses on the efficacy of RT in preventing hip HO.
METHODS: A literature search was conducted on PubMed. The quality of the meta-analyses was assessed using the AMSTAR-2 tool.
RESULTS: Seven meta-analyses were included. One meta-analysis reported a significant reduction in HO occurrence after RT compared to the control group. Comparing RT and non-steroidal anti-inflammatory drugs, one and two meta-analyses showed significantly greater efficacy of RT in preventing severe HO and better outcomes in patients receiving drugs, respectively. Regarding RT settings, the postoperative and preoperative RT were each supported by one meta-analysis. Furthermore, two meta-analyses showed an advantage of multi-fractionated RT over single fraction RT. The overall confidence rate of the meta-analyses was moderate, low, and critically low in one, three, and three meta-analyses, respectively.
CONCLUSIONS: RT is a confirmed prophylactic intervention for HO. However, the precise optimization of timing, dosage, and fractionation requires elucidation. Future research should focus on the development of predictive models through large-scale data collection and advanced analytics to refine individualized treatment strategies and assess RT comparative effectiveness with drugs.

UNASSIGNED: Radioulnar synostosis is an uncommon complication of forearm fractures and presents with varying degrees of restricted forearm movement. The diaphysial distal third synostosis is less common and excision of the synostosis is fraught with risk of re-ossification. Use of inert or biological interposing material has thus been accompanied with the synostosis excision and various methods have been described. There is still no consensus on the ideal treatment method.
UNASSIGNED: We, hereby, report a case of a long-standing radioulnar synostosis with rotational restriction of movement. Despite the movement restriction, the patient could perform basic activities of daily living and wanted to improve the movements. The presence of diaphyseal radioulnar synostosis was conformed on the radiographs and computerized tomography scan. A volar forearm approach was used and the bony bridge was excised. The ipsilateral native palmaris longus (PL) tendon was extracted from distal wrist crease and with its proximal attachment intact, circumferentially wrapped around the ulnar raw surface as an interposing material. Apart from this, free fat was also placed at the synostosis site. In the long-term follow-up of 10 years, there was no radiological evidence of re-ossification noted. The clinical improvement was not much but the patient was performing activities of daily living with no discomfort.
UNASSIGNED: The use of an encircling loop of the native PL tendon, over the raw surface of one of the forearm bones, may be another useful method to decrease the chances of recurrence following the excision of the synostosis.

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.