Resection of heterotopic ossification around the hip after trauma

Comparative analysis of 'functional excision' of heterotopic ossification around the hip - computed tomography (CT) navigation guided versus conventional excision

PURPOSE

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.

PATIENTS AND 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.

CONCLUSION

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.

Modified Ludloff's medial approach for resection of heterotopic ossification of the hip following severe SARS-CoV-2 infection: a case report

The coronavirus disease 2019 pandemic has significantly affected people worldwide. Herein, we present a case of massive heterotopic ossification (HO) of the right hip following severe SARS-CoV-2 infection. The exact origin of HO development is still unknown, but a critical illness, chronic immobilization and hypoxia are important risk factors. Considering the location and size of the HOs in this case, modified Ludloff's medial approach of the hip was used. This approach allows for good exposure and access to the medial and inferior part of the hip joint and the successful extirpation of the pathologic tissue.

Surgical Resection of Neurogenic Heterotopic Ossification around Hip Joint in Stroke Patients: A Safety and Outcome Report

Purpose

Resection remains the most reliable treatment for established heterotopic ossification, despite questions regarding its effectiveness due to the potential for complications. This study evaluated the clinical outcomes and complications of neurogenic heterotopic ossification (NHO) resection in stroke patients' ankylosed hips.

Materials and Methods

We retrospectively analyzed nine hip NHO resections performed on seven patients from 2010 to 2018. The pre- and postoperative range of motion of the operated hip were compared. Analysis of postoperative complications, including infection, recurrence, iatrogenic fracture, and neurovascular injury was performed.

Results

The mean operative time was 132.78±21.08 minutes, with a mean hemoglobin drop of 3.06±0.82 g/dL within the first postoperative week. The mean duration of postoperative follow-up was 52.08±28.72 months for all patients. Postoperative range of motion showed improvement from preoperative. Flexion and external rotation (mean, 58.89±30.60° and 16.67±18.03°, respectively) showed the greatest gain of motion of the operated hip joint. Postoperative infections resolved in two cases through surgical debridement, and one case required conversion to total hip arthroplasty due to instability. There were no recurrences, iatrogenic fractures, or neurovascular injuries.

Conclusion

Resection is a beneficial intervention for restoring the functional range of motion of the hip in order to improve the quality of life for patients with NHO and neurological disorders. We recommend performance of a minimal resection to achieve a targeted functional arc of motion in order to minimize the risk of postoperative complications.

Computer Navigation-Assisted Resection of Heterotopic Ossification Around the Hip: A Technical Note

Heterotopic ossification is a rare but debilitating situation. It occurs in patients who have undergone paralysis and/or immobilization. Hip osteoma is one of the most frequent locations and is associated with a significant functional handicap. Its treatment is based on surgical resection, which is a risky surgery that is not devoid of complications such as infections, hematoma, and recurrence. We describe in this paper a new surgical technique that adds to the classic hip osteoma resection: guidance with a navigation system coupled to a 3D imaging tool. We performed this technique on two patients (three hips, one bilateral case). We think that this technique makes the surgery safer with fewer complications.

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.

Partial Femoral Diaphysectomy With Vastus Lateralis Interposition in a Paraplegic Patient With Severely Debilitating Hip Ankylosis: Low Risks and High Gains?

We present the case of a 56-year-old male unable to sit because of an ankylosed right hip. This ankylosis originated from combined neurogenic heterotopic ossifications (NHO) and traumatic heterotopic ossifications (THO) as a result of a road traffic accident. Because of multiple ossifications, the proximity of neurovascular structures, and chronic pressure ulcers, a resection was deemed unsafe. We opted for a new articulation distal to the ossifications in unstained tissue. A partial femoral diaphysectomy was performed just distal of the lesser trochanter. and the vastus lateralis was rotated in the new articulation. Postoperatively, the patient was able to sit as his hip could flex again. A partial femoral diaphysectomy with vastus lateralis interposition flap appears to be a valid option in paraplegic patients with extensive heterotopic ossifications (HO) in close proximity to neurovascular structures with a low risk of complications and high gain in hip mobility.

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.

The Impact of Continuous Passive Motion on Heterotopic Ossification Maturation

ABSTRACT

Heterotopic ossification is the formation of pathological bone in soft tissues. It is postulated that continuous passive motion is a helpful adjuvant in the halt of the heterotopic ossification progression and the maintenance or increase of the joint mobility. The purpose of this clinical case study is to present the effectiveness of continuous passive motion. A 46-yr-old male patient experiencing right hemiparesis arrived in our rehabilitation department with limitation on passive flexion of the right hip. On x-ray of the pelvis, immature heterotopic bone formation was found. To halt this ongoing process of heterotopic bone formation, a program of continuous passive motion was implemented. In addition, risedronate was administrated. We started the continuous passive motion at 50 degrees of flexion for 30 mins that was increased to 100 degrees for 3 hrs daily. The final range of motion at the hip was: flexion 85 degrees, extension 0 degrees, internal rotation 10 degrees, external rotation 10 degrees, abduction 10 degrees, and adduction 10 degrees. Based on our results, continuous passive motion plays a role in heterotopic ossification maturation. The effectiveness of continuous passive motion implementation against HO should be further investigated for selected cases.

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.

High Frequency Spectral Ultrasound Imaging Detects Early Heterotopic Ossification in Rodents

Heterotopic ossification (HO) is a devastating condition in which ectopic bone forms inappropriately in soft tissues following traumatic injuries and orthopedic surgeries as a result of aberrant mesenchymal progenitor cell (MPC) differentiation. HO leads to chronic pain, decreased range of motion, and an overall decrease in quality of life. While several treatments have shown promise in animal models, all must be given during early stages of formation. Methods for early determination of whether and where endochondral ossification/soft tissue mineralization (HO anlagen) develop are lacking. At-risk patients are not identified sufficiently early in the process of MPC differentiation and soft tissue endochondral ossification for potential treatments to be effective. Hence, a critical need exists to develop technologies capable of detecting HO anlagen soon after trauma, when treatments are most effective. In this study, we investigate high frequency spectral ultrasound imaging (SUSI) as a noninvasive strategy to identify HO anlagen at early time points after injury. We show that by determining quantitative parameters based on tissue organization and structure, SUSI identifies HO anlagen as early as 1-week postinjury in a mouse model of burn/tenotomy and 3 days postinjury in a rat model of blast/amputation. We analyze single cell RNA sequencing profiles of the MPCs responsible for HO formation and show that the early tissue changes detected by SUSI match chondrogenic and osteogenic gene expression in this population. SUSI identifies sites of soft tissue endochondral ossification at early stages of HO formation so that effective intervention can be targeted when and where it is needed following trauma-induced injury. Furthermore, we characterize the chondrogenic to osteogenic transition that occurs in the MPCs during HO formation and correlate gene expression to SUSI detection of the HO anlagen.

Massive Heterotopic Ossification of the Tensor Fascia Lata in a Bodybuilder Leading to Severe Hip Dysfunction: A Case Report

CASE

A 42-year-old bodybuilder with no history of trauma presented to our clinic with persistent right hip pain and rapidly advancing joint stiffness. Imaging confirmed massive, mature heterotopic ossification predominantly involving the right tensor fascia lata. Six months after a tailored surgical removal, there were no signs of disability, pain, or clinical signs of recurrence, and the patient regained proper joint function.

CONCLUSION

In massive heterotopic ossification, tailored surgical removal of the part of the lesion that is limiting function may result in a complete functional recovery.

Genetic and Acquired Heterotopic Ossification: A Translational Tale of Mice and Men

Heterotopic ossification is defined as an aberrant formation of bone in extraskeletal soft tissue, for which both genetic and acquired conditions are known. This pathologic process may occur in many different sites such as the skin, subcutaneous tissue, skeletal muscle and fibrous tissue adjacent to joints, ligaments, walls of blood vessels, mesentery and other. The clinical spectrum of this disorder is wide: lesions may range from small foci of ossification to massive deposits of bone throughout the body, typical of the progressive genetically determined conditions such as fibrodysplasia ossificans progressiva, to mention one of the most severe and disabling forms. The ectopic bone formation may be regarded as a failed tissue repair process in response to a variety of triggers and evolving towards bone formation through a multistage differentiation program, with several steps common to different clinical presentations and distinctive features. In this review, we aim at providing a comprehensive view of the genetic and acquired heterotopic ossification disorders by detailing the clinical and molecular features underlying the different human conditions in comparison with the corresponding, currently available mouse models.

Pelvic MRI in spinal cord injury patients: incidence of muscle signal change and early heterotopic ossification

STUDY DESIGN

Prospective observational study.

OBJECTIVE

To evaluate pelvic MRI muscle signal changes and their association with early heterotopic ossification (HO) in patients with spinal cord injuries.

SETTING

National Spinal Injuries Unit, Stoke Mandeville, UK.

METHODS

Forty patients were imaged with at least two interval magnetic resonance (MR) studies of the pelvis in the first 6 months following a spinal cord injury. Scans were reviewed and scored for heterotopic ossification, muscle signal change and extent of muscle involvement.

RESULTS

Muscle signal change was present in 28 (70%) on the initial MRI and 31 (77%) by the second study. Six patients developed MR changes of prodromal or immature heterotopic ossification (15%). No restricted diffusion was demonstrated and no patient developed mature HO. Patients developing MR changes of early HO were more likely to have grade 3 muscle changes.

CONCLUSION

Increased T2 muscle signal is common following cord injury, is frequently progressive in the subacute period and is associated with complete injury and early MR signs of heterotopic ossification.

A case of extensive symptomatic lower limb heterotopic ossification in a boy

Heterotopic ossification refers to the abnormal growth of bone in the soft tissue. This report highlighted the case of heterotopic ossification in early childhood. A 3-year-old boy was presented with poor lower limb mobility and rigid left leg. At the age of 10 days, he developed a small lump as large as a quail egg in his left groin. Within 3 months, the lump grew bigger and spread to his leg and feet. His parents claimed no trauma history. It was confirmed by computed tomography scan which revealed multiple ossifications of the soft tissue infiltrating the lower limb muscles and infiltrating the skin, the pathological features showed hard mature trabeculated bone, mature fatty tissue, and loose connective tissue. The patient was treated with a series of soft tissue resections and was still under the care of surgeon with good prognosis.