Surgical resection of severe heterotopic ossification after open reduction and internal fixation of acetabular fractures: a case series of 18 patients

Heterotopic hip ossification resection: monocentric experiences of associated factors, outcomes, and complications

PURPOSE

The exponential increase in total hip arthroplasty (THA) has led to acute and chronic surgery-related complications. Common chronic and local complications are represented by hip ossification (HO). The aim of our study was to assess the clinical and radiological correlates of patients undergoing surgical removal of heterotopic ossifications after THA and the possible association between HO and prosthetic joint infection.

METHODS

Data of 26 patients who underwent surgical removal of periprosthetic calcifications after THA from 2000 to 2022 were analyzed and compared with characteristics of 156 subjects without HO.

RESULTS

The preoperative radiographs of patients showed a high-grade Brooker, 3 or 4, later reduced to 1 or 2 in the postoperative radiographs. Ten (38.5%) patients underwent radiotherapy prophylaxis, administered as a single dose 24 h before surgery. In 19 (73%) patients, pharmacological prophylaxis with indomethacin was added in the 30 postoperative days. Only one patient who underwent radiotherapy had a recurrence, while new ossifications were found in three patients without prophylaxis (11.5%). Intraoperative cultures were performed for suspected periprosthetic infection in 8 study group patients. In logistic regression, the presence of HO was significantly and inversely associated with the ASA score (OR = 0.27, 95% CI = 0.09-0.82; P = 0.021) after adjusting.

CONCLUSION

Surgical HO removal in symptomatic patients with high-grade disease produces good clinical and radiographic results. Radiotherapy was a good perioperative and preventive strategy for recurrence, also associated with NSAIDs and COX-2 inhibitors.

Surgical Treatment of Severe Heterotopic Ossification After Total Hip Arthroplasty Over the Last 25 Years: A Systematic Review of the Literature and a New Case Series

BACKGROUND

Severe heterotopic ossification (HO) (grades III and IV) after total hip arthroplasty (THA) over the last 25 years requiring excision is very uncommon. We performed a systematic review of the literature and reported a new case series with operative treatment after primary uncemented THA.

METHODS

A systematic review identified papers describing patients who had excision of HO after THA performed after 1988. Concepts of hip arthroplasty, HO, and surgical excision were searched in MEDLINE, Embase, and Scopus from database inception to November 2022. The inclusion criteria were articles that included specific patient data on the grade of HO, operative procedure, and prophylaxis. Studies were screened for inclusion by 2 independent reviewers. The extracted data included demographic data, the interval from index surgery to excision, clinical results, and complications. There was one surgeon who performed reoperation for ankylosis of primary THA in 3 men who had severe pain and hip deformity.

RESULTS

Data from 7 studies were included. There were 41 patients who had grade III or IV HO who had excision, and in 5 patients, revision of a component was also performed. Perioperative prophylaxis was irradiation alone in 10 patients, irradiation and indomethacin in 10 patients, and indomethacin alone in 21 patients. At a mean follow-up time of 14.8 months, the definition of the results was not uniform, and range of motion was improved, but relief of pain was inconsistent. There was one dislocation after resection without revision, one gastrointestinal complication, and 2 recurrences. Treatment of the 3 new patients, with wide excision of periarticular bone, selective exchange of components, and perioperative irradiation prophylaxis, was successful in improving pain, motion, and deformity.

CONCLUSIONS

There is insufficient good-quality data on the operative treatment of severe symptomatic HO after THA performed over the last 25 years. Prophylaxis with low-dose irradiation prevented a recurrence. Multicenter studies are needed to determine the optimum timing and prognosis for treatment.

3D-Printed Model in Preoperative Planning of Sciatic Nerve Decompression Because of Heterotopic Ossification: A Case Report

CASE

A 31-year-old patient presented with an encapsulated sciatic nerve secondary to extensive hip heterotopic ossification (HO), which prevented visualization of a safe osteotomy site to avoid nerve damage. The 3D-printed model demonstrated an easily identifiable osseous reference point along the inferior aspect of the heterotopic mass, allowing for a vertical osteotomy to be safely performed.

CONCLUSION

HO is associated with loss of normal anatomic topography. The current case report illustrates the use of a 3D-printed model to identify pertinent anatomic landmarks required for safe decompression of an encapsulated sciatic nerve within the anatomic region of the hip.

A microCT-based platform to quantify drug targeting

BACKGROUND

Heterotopic ossification (HO) is a frequent and debilitating complication of traumatic musculoskeletal injuries and orthopedic procedures. Prophylactic dosing of botulinum toxin type A (BTxA) holds potential as a novel treatment option if accurately distributed throughout soft-tissue volumes where protection is clinically desired. We developed a high-resolution, microcomputed tomography (microCT)-based imaging strategy to assess drug distribution and validated this platform by quantifying distribution achieved via a prototype delivery system versus a single-bolus injection.

METHODS

We injected an iodine-containing contrast agent (iodixanol 320 mg I/mL) into dissected rabbit musculature followed by microCT imaging and analysis. To contrast the performance of distributed versus bolus injections, a three-dimensional (3D) 64-cm3-printed soft-tissue holder was developed. A centered 2-cm3 volume of interest (VOI) was targeted with a single-bolus injection or an equal volume distributed injection delivered via a 3D-printed prototype. VOI drug coverage was quantified as a percentage of the VOI volume that was < 1.0 mm from the injected fluid.

RESULTS

The microCT-based approach enabled high-resolution quantification of injection distribution within soft tissue. The distributed dosing prototype provided significantly greater tissue coverage of the targeted VOI (72 ± 3%, mean ± standard deviation) when compared to an equal volume bolus dose (43 ± 5%, p = 0.031) while also enhancing the precision of injection targeting.

CONCLUSIONS

A microCT-based imaging technique precisely quantifies drug distribution within a soft-tissue VOI, providing a path to overcome a barrier for clinical translation of prophylactic inhibition of HO by BTxA.

RELEVANCE STATEMENT

This platform will facilitate rapid optimization of injection parameters for clinical devices used to effectively and safely inhibit the formation of heterotopic ossification.

KEY POINTS

• MicroCT provides high-resolution quantification of soft-tissue drug distribution. • Distributed dosing is required to maximize soft-tissue drug coverage. • Imaging platform will enable rapid screening of 3D-printed drug distribution prototypes.

Heterotopic Ossification Remodeling After Acetabular Surgery: A Natural History Case Report

CASE

A 30-year-old woman presented with a transverse plus posterior wall acetabular fracture and underwent operative fixation through a Kocher-Langenbeck approach. Shared decision was made for no heterotopic ossification (HO) prophylaxis. The patient developed symptomatic HO and was scheduled for resection, which was delayed because of the pandemic. She returned with interval remodeling of HO and symptom resolution. No surgery was required.

CONCLUSION

HO is a common complication after acetabular injury. Resection is the treatment of choice for symptomatic HO. We are not aware of other reports of spontaneous remodeling of symptomatic HO such that it no longer required surgery.

The impact of heterotopic ossification prophylaxis after surgical fixation of acetabular fractures: national treatment patterns and related outcomes

BACKGROUND

Heterotopic ossification (HO) is a common complication after surgical fixation of acetabular fractures. Numerous strategies have been employed to prevent HO formation, but results are mixed and optimal treatment strategy remains controversial. The purpose of the study was to describe current national heterotopic ossification (HO) prophylaxis patterns among academic trauma centers, determine the association between prophylaxis type and radiographic HO, and identify if heterogeneity in treatment effects exist based on outcome risk strata.

METHODS

We used data from a subset of participants enrolled in the Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities (PREPARE) trial. We included only patients with closed AO-type 62 acetabular fractures that were surgically treated via a posterior (Kocher-Langenbeck), combined anterior and posterior, or extensile exposure. PREPARE Clinical Trial Registration Number: NCT03523962 Patient population This cohort study was nested within the Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities (PREPARE) trial. The PREPARE trial is a multicenter cluster-randomized crossover trial evaluating the effectiveness of two alcohol-based pre-operative antiseptic skin solutions. All PREPARE trial clinical centers that enrolled at least one patient with a closed AO-type 62 acetabular fracture were invited to participate in the nested study.

RESULTS

277 patients from 20 level 1 and level 2 trauma centers in the U.S. and Canada were included in this study. 32 patients (12%) received indomethacin prophylaxis, 100 patients (36%) received XRT prophylaxis, and 145 patients (52%) received no prophylaxis. Administration of XRT was associated with a 68% reduction in the adjusted odds of overall HO (OR 0.32, 95% CI, 0.14 - 0.69, p = 0.005). The overall severe HO (Brooker classes III or IV) rate was 8% for the entire cohort; XRT reduced the rate of severe HO in high-risk patients only (p=0.03).

CONCLUSION

HO prophylaxis patterns after surgical fixation of acetabular fractures have changed dramatically over the last two decades. Most centers included in this study did not administer HO prophylaxis. XRT was associated with a marked reduction in the rate of overall HO and the rate of severe HO in high-risk patients. Randomized trials are needed to fully elucidate the potential benefit of XRT. PREPARE Clinical Trial Registration Number: NCT03523962.

Factors influencing functional outcomes following open reduction internal fixation of acetabular fractures

INTRODUCTION

Recent large series of patient-reported outcomes after acetabulum fracture are limited, and potentially modifiable risk factors may be unidentified. The goal of this study was to describe patient and injury factors which negatively influence functional outcomes following operative management of acetabular fractures.

METHODS

699 patients with acetabular fractures were treated with open reduction and internal fixation (ORIF). Musculoskeletal Function Assessment (MFA) questionnaire was completed after a minimum 12 months post-injury by 283 adults. MFA scores range from 1 to 100 and higher scores represent greater dysfunction. Factors were assessed for potential association with MFA scores, and univariate and multiple linear regression analyses were performed.

RESULTS

Survey respondents were more severely injured than non-respondents, with more chest injury (38% vs 22%, p<0.001) and higher Injury Severity Score (19.3 vs 16.8, p=0.003). Patients were 69% male with mean age 44.0 years. Approximately one-third were smokers (31%), while 14% had comorbid diabetes mellitus type II. The majority of injuries occurred during a motor vehicle collision (65%); low-energy mechanisms were rare (4.2%). The most common fracture pattern was isolated posterior wall (23%), followed by transverse/posterior wall (21%). Heterotopic ossification (HO) was noted in 22%: Brooker 1: 29.5%, 2: 23.0%, 3: 32.8%, and 4: 14.8%. Tobacco use (β = 18.4, p<0.001), obesity (β = 0.39, p=0.009), diabetes (β = 8.2, p=0.029), post-traumatic arthrosis (PTA) (β = 5.94 p=0.035), and increasing HO severity (β = 8.93, p<0.001) were independently associated with worse MFA scores. Tobacco use had the strongest association, followed by the severity of HO.

CONCLUSION

In a large series of patient-reported functional outcomes following fixation of acetabular fractures, tobacco use, obesity, comorbid diabetes, PTA, and HO were associated with worse MFA scores. Further study to mitigate HO should be considered.

LEVEL OF EVIDENCE

III.

A Rare Case of Extremely Severe Heterotopic Ossification after Primary Total Hip Arthroplasty due to Persistent Mild Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) caused by coagulase-negative staphylococci (CNS) can be a mild, persisting infection. Although heterotopic ossification (HO) is common following total hip arthroplasty (THA), the etiology of severe HO remains unclear. Herein, we describe a rare case of extremely severe HO after a PJI associated with a Staphylococcus caprae infection in a 78-year-old male patient. The patient had poorly controlled diabetes mellitus with no diabetic complications. The patient had no previous history of hip surgery, hip injury, or systemic bacterial infection. Immediately after the initial THA, he developed intermittent low-grade fever (37°C), which persisted for 3 months; consequently, he also reported mild hip pain during walking. He experienced a gradual decrease in hip range of motion within 5 years after the surgery, with progressive gait impairment. Two revision surgeries were required for the successful treatment of this difficult case. The patient's hip function improved, and the PJI was controlled following the second revision surgery. Based on the clinical course, CNS-caused PJI may lead to severe HO. This possibility warrants verification from an accumulated number of cases.

Early resection of ectopic bone in patients with heterotopic ossification about the hip after trauma

OBJECTIVES

Heterotopic ossification (HO) is a common complication in patients who have sustained high-energy trauma to the hip region. Traditionally, resection is performed after ectopic bone maturation. We hypothesized that early HO resection in patients with hip ankylosis after trauma can be performed with little chance of recurrence.

DESIGN

Retrospective clinical cohort.

SETTING

Level I Trauma Center PATIENTS/PARTICIPANTS: 14 patients with resection of HO about the hip performed by the senior author during a six-year period.

INTERVENTION

Early resection of Brooker Class III or IV HO.

MAIN OUTCOME MEASUREMENTS

The original injuries, risk factors for HO, post-traumatic clinical course including the workup for HO, times from fixation to resection, surgical approach, and complications were recorded. Records were reviewed to document pre and postoperative hip motions. Pre and post-operative x-rays and CT scans were reviewed to classify the HO and localize the ectopic mass.

RESULTS

Mean injury to resection interval was 6.8-months. Nine of 14 (64%) patients were followed for a mean of 32.9-months post-resection. Indications for resection included pain, stiffness, and evolving sciatic nerve lesions. Risk factors were male gender, brain injury, and extended iliofemoral and Kocher-Langenbeck surgical approaches. Complications included gluteal vein laceration, draining wounds, and recurrence. Mean flexion-extension arc of motion was 18° (range = 0-70°) preoperatively, 100° (range = 85-125°) intra-operatively, and 94° (range = 20-110°) at final follow-up. HO recurred in nine patients; functionally significant in one.

CONCLUSION

Early resection of HO around the hip may be performed with little chance of symptomatic recurrence.

LEVEL OF EVIDENCE

This is a Level IV retrospective case series.

Imaging Acetabular Fractures

Acetabular fractures are encountered by radiologists in a wide spectrum of practice settings. The radiologist's value in the acute and long-term management of acetabular fractures is augmented by familiarity with systematic computed tomography-based algorithms that streamline and simplify Judet-Letournel fracture typing, together with an appreciation of the role of imaging in initial triage, operative decision making, postoperative assessment, prognostication, and evaluation of complications. The steep increase in incidence of acetabular fractures in the elderly over the past several decades places special emphasis on familiarity with geriatric fracture patterns.

Therapeutic advances for blocking heterotopic ossification in fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease in which heterotopic bone forms in muscle and soft tissue, leading to joint dysfunction and significant disability. FOP is progressive and many patients are wheelchair-bound by the 3rd decade of life. FOP is caused by an activating mutation in the ACVR1 gene, which encodes the activin A Type 1 receptor. Aberrant signalling through this receptor leads to abnormal activation of the pSMAD 1/5/8 pathway and triggers the formation of bone outside of the skeleton. There is no curative therapy for FOP; however, exciting advances in novel therapies have developed recently. Here, we review the clinical and translational pharmacology of three drugs that are currently in clinical trials (palovarotene, REGN 2477 and rapamycin) as well as other emerging treatment strategies for FOP.

Rescue of ankylosing hip following open reduction and internal fixation of acetabular fracture by surgical resection of heterotopic ossification: A case report

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Heterotopic ossification is a major complication after surgical treatment of acetabular fractures.

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Whether delayed or early surgical resection of heterotopic ossification is more effective remains controversial.

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Early surgical resection is not necessarily contraindication.

Introduction

Heterotopic ossification is a major complication after surgical treatment of acetabular fractures. Heterotopic ossification generally involves the large joints, often limits the range of motion, and may cause ankylosis.

Presentation of case

This case report describes a 59-year-old man with severe heterotopic ossification who developed an acetabular fracture and resultant hip ankylosis, which was rescued by surgical resection of the heterotopic ossification. He had accompanying head injury and multiple other fractures, which were treated conservatively. Open reduction with internal fixation of the acetabular fracture was performed through the ilioinguinal and Kocher–Langenbeck combined approach. The patient unexpectedly returned to our hospital 7.5 months after the fracture surgery. We found that his left hip joint was completely ankylosed by severe heterotopic ossification. We performed surgical resection of the heterotopic ossification through a direct lateral approach 9.5 months after the initial surgery. At the final follow-up, 5.5 years after the heterotopic ossification resection surgery, the hip function including the range of motion was satisfactory. Radiographs showed no signs of recurrence, and he could walk with no support.

Discussion

The only effective treatment for established HO is surgical excision. Whether delayed or early surgical resection of heterotopic ossification is more effective remains controversial.

Conclusion

We considered that waiting for a long time before surgical resection of the heterotopic ossification would lead to more disability, and early resection of the heterotopic ossification was not a contraindication despite the fact that the uptake on the bone scan was still intense.

Posttraumatic Heterotopic Ossification of the Hip

INTRODUCTION

Posttraumatic heterotopic ossification (HO) of the hip frequently follows acetabular fracture and hip surgery and can become symptomatic, with significant pain and limited range of motion (ROM). Definitive treatment may require surgical excision, which can result in serious complications if not planned and executed appropriately.

METHODS

Surgical excision of posttraumatic hip HO requires appropriate indications, preoperative planning, and intraoperative guidance using fluoroscopy to maximize excision of HO and minimize complications. This video presents a case of severe posttraumatic hip HO, indications and technique of surgical excision using fluoroscopic guidance, postoperative protocol, and the patient's clinical follow-up.

RESULTS

Surgical excision along with appropriate postoperative HO prophylaxis and immediate mobilization resulted in significant improvement in hip ROM and return to activities of daily living without complications or recurrence. Intraoperative blood loss can be significant and should be appropriately planned for preoperatively.

CONCLUSIONS

Posttraumatic hip HO can cause significantly limited hip ROM and pain with resulting disability. Surgical excision of posttraumatic hip HO in a preserved hip joint can be successful in restoring hip ROM and function. Appropriate postoperative HO prophylaxis can prevent recurrence.

Ankylosing Neurogenic Myositis Ossificans of the Hip: A Case Series and Review of Literature

Purpose

Neurogenic myositis ossificans (NMO) in patients with traumatic spinal cord or brain injuries can cause severe joint ankylosis or compromise neurovascularture. The purpose of this study was to evaluate the clinical and radiological outcomes of and review considerations relevant to surgical resection of NMO of the hip joint.

Materials and Methods

Six patients (9 hips) underwent periarticular NMO resection between 2015 and 2017. The medical records of these patients were retrospectively reviewed. Preoperative computed tomography including angiography was performed to determine osteoma location and size. Improvement in hip motion allowing sitting was considered the sole indicator of a successful surgery. The anterior approach was used in all patients. The ranges of motion (ROM) before and after surgery were compared.

Results

The mean time from accident to surgery was 3.6 years. Average ROM improved from 24.3°(flexion and extension) to 98.5°(flexion and extension) after surgery, and improvement was maintained at the last follow-up. No commom complications (e.g., deep infection, severe hematoma, deep vein thrombosis) occurred in any patient. Improvement in ROM in one hip in which surgical resection was performed 10 years after the accident was not satisfactory owing to the pathologic changes in the joint.

Conclusion

Surgical excision of periarticular NMO of the hip joint can yield satisfactory results, provided that appropriate preoperative evaluation is performed. Early surgical intervention yields satisfactory results and may prevent the development of intra-articular pathology.

Results from the surgical resection of severe heterotopic ossification of the hip: a case series of 26 patients

INTRODUCTION

Surgical resection of heterotopic ossification (HO) around the hip joint is often challenging. The aim of this study is to evaluate the clinical and radiological outcomes following surgical resection of Brooker's type III and IV HO of the hip.

METHODS

We retrospectively reviewed clinical and radiological data, between November 2006 and January 2013, of all patients who underwent surgical resection of severe HO of the hip. Brooker's grading, range of motion and the Harris Hip Score before and after surgery were recorded in all cases. The combined radiation (700 cGy preoperatively) and indomethacin regimen was used to prevent heterotopic ossification recurrence.

RESULTS

Twenty-six patients (22 males and 4 females) were included in our study. Mean patient age was 47.38 years (range 24-72). The HO was graded as Brooker grade III in 3 patients (11.5%) and Brooker grade IV in 23 patients (88.5%). Mean time interval between HO development and resection was 40.8 months (range 13-156 months). All patients had CT scans prior to surgery. Mean follow-up was 31.4 months (range 24-40 months). There was no severe HO recurrence. Complications included one intraoperative injury of a femoral artery branch, one intraoperative femoral neck fracture treated with intramedullary nailing, one sciatic nerve injury and one superficial infection treated conservatively.

CONCLUSIONS

Surgical resection of severe HO of the hip along with preoperative radiation and indomethacin provides excellent results; however, the complication rate is relatively high. Careful evaluation of the preoperative CT scan and wide exposure are required in order to identify all the involved neurovascular structures.

Heterotopic Ossification in Acetabular Fracture Surgery

Heterotopic ossification (HO) is a common complication of the surgical treatment of acetabular fractures. HO is the formation of trabecular bone in soft tissues where bone does not usually occur. Over the last decade, many risk factors have been identified for HO after surgical fixation of acetabular fractures; however, prophylaxis and treatment of this condition are controversial. Potential preventive measures range from NSAIDs to external beam irradiation, but recent studies have questioned the utility of these measures. The Brooker classification system, which has been correlated with patient function and outcomes, is most commonly used to describe HO severity. Advances will assist in the diagnosis, prevention, and management of HO as well as the assessment of risk factors that could affect outcomes.

Heterotopic Ossification in Trauma

Better understanding of the biology of heterotopic ossification (HO) formation will lead to treatment and prevention modalities that can be directed specifically at the cellular level. Early identification of HO precursor cells and target genes may provide prognostic value that guides individualized prophylactic treatment. Better understanding of molecular signaling and proteomics variability will allow surgeons to individualize preemptive treatment to suppress inflammation and formation of HO. Careful surgical technique to avoid muscle damage is important. Damaged muscle should be debrided as a prophylactic measure. Hemostasis and avoidance of a postoperative hematoma may decrease the chance of formation of HO.

Heterotopic Ossification following acetabular fixation: Incidence and risk factors: 10-year experience of a tertiary centre

BACKGROUND

Heterotopic Ossification (HO) is a well-recognized complication following acetabular fracture fixation and its presence is prognostic for suboptimal clinical outcome. There are many controversies pertaining to its aetiology, including surgical approach, associated injuries and the use of HO prophylaxis. Long term data from high volume centres is necessary to address these issues.

AIM

To determine the incidence of HO post open reduction and internal fixation (ORIF) of acetabular fractures and to examine the associated risk and prognostic factors.

METHOD

We studied a cohort of 369 consecutive acetabular fractures that underwent ORIF at our institution over a 10 year period. Data was analyzed using univariate and multivariate logistic regression.

RESULTS

The existence of HO was evident in 65 patients (17.62%), of these 39 (60.0%) were Class I, 16 (24.6%) were Class II, 8 (12.3%) were Class III, and 2 (3.1%) were Class IV according to Brooker Classification. We found a significant association between admission to an Intensive Care Unit (ICU) (P-value=0.039), chest injury (P-value=0.013), multiple fractures (P-value=0.005), and the time lapse between injury and operation (P-value=0.025), and some statistical significance with surgical approach, ipsilateral fractures, open fractures, tibial and patellar fractures. Age over 30 years as the only prognostic factor for severe HO. Prophylaxis with Indomethacin did not appear to confer any benefit in our patient group.

CONCLUSION

The risk factors for developing HO following acetabular fracture fixation are multifactorial and include admission to ICU, associated chest injuries, multiple fractures and delay between injury and surgery. Surgical approach, ipsilateral fractures and tibia and patellar fractures may also play a role. Age over thirty years was the only prognostic factor for developing severe HO.

Heterotopic Ossification: Basic-Science Principles and Clinical Correlates

➤ Heterotopic ossification occurs most commonly after joint arthroplasty, spinal cord injury, traumatic brain injury, blast trauma, elbow and acetabular fractures, and thermal injury.➤ The conversion of progenitor cells to osteogenic precursor cells as a result of cell-mediated interactions with the local tissue environment is affected by oxygen tension, pH, availability of micronutrients, and mechanical stimuli, and leads to heterotopic ossification.➤ Radiation and certain nonsteroidal anti-inflammatory medications are important methods of prophylaxis against heterotopic ossification.➤ Well-planned surgical excision can improve patient outcomes regardless of the joint involved or the initial cause of injury.➤ Future therapeutic strategies are focused on targeted inhibition of local factors and signaling pathways that catalyze ectopic bone formation.