Radiation therapy for heterotopic ossification prophylaxis acutely after elbow trauma: a prospective randomized study

Regional distribution prevalence of heterotopic ossification in the elbow joint: a 3D study of patients after surgery for traumatic elbow injury

BACKGROUND

Heterotopic ossification (HO) is a common complication after elbow fracture surgery and can lead to severe upper extremity disability. The radiographic localization of postoperative HO has been reported previously. However, there is no literature examining the distribution of postoperative HO at the three-dimensional (3D) level. This study aimed to investigate 1) the distribution characteristics of postoperative HO and 2) the possible risk factors affecting the severity of postoperative HO at a 3D level.

METHODS

A retrospective review was conducted of patients who presented to our institution with HO secondary to elbow fracture between 13 January 2020 and 16 February 2023. Computed tomography scans of 56 elbows before elbow release surgery were reconstructed in 3D. HO was identified using density thresholds combined with manual identification and segmentation. The elbow joint and HO were divided into six regions according to three planes: the transepicondylar plane, the lateral ridge of the trochlear plane, and the radiocapitellar joint and coronoid facet plane. The differences in the volume of regional HO associated with different initial injuries were analyzed.

RESULTS

Postoperative HO was predominantly present in the medial aspect of the capsule in 52 patients (93%), in the lateral aspect of the capsule in 45 patients (80%), in the medial supracondylar in 32 patients (57%), and in the lateral supracondylar, radial head, and ulnar region in the same number of 28 patients (50%). The median and interquartile range volume of total postoperative HO was 1683 (777-4894) mm3. The median and interquartile range volume of regional postoperative HO were: 584 (121-1454) mm3 at medial aspect of capsule, 207 (5-568) mm3 at lateral aspect of capsule, 25 (0-449) mm3 at medial supracondylar, 1 (0-288) at lateral supracondylar, 2 (0-478) at proximal radius and 7 (0-203) mm3 at the proximal ulna. In the subgroups with Injury Severity Score > or = 16, Gustilo-Anderson II, normal uric acid levels, elevated alkaline phosphatase, and body mass index > or = 24, the median HO volume exceeds that of the respective control groups.

CONCLUSION

The medial aspect of the capsule was the area with the highest frequency and median volume of postoperative HO among all initial elbow injury types. Patients with higher Gustilo-Anderson grade, Injury Severity Score, alkaline phosphatase or Body Mass Index had higher median volume of postoperative HO.

Embolization followed by resection of the heterotopic hip joint ossification with spinal cord injury

BACKGROUND

Heterotopic ossification of large joints, such as knees and hips, has been reported after spinal cord injury, possibly leading to decreased activity of daily living due to a limited range of motion of the affected joint. Therefore, heterotopic ossification resection is performed to improve the range of motion, but it might cause massive bleeding as a complication.

METHODS

In this case, the patient had a history of spinal cord injury and developed heterotopic ossification after the left hip injury. He had left hip ankylosis and could not transfer to a wheelchair by himself; therefore, heterotopic ossification resection was planned. On conducting contrast-enhanced computed tomography, the supplying arteries extending to the heterotopic ossification could be identified. A day before the surgery, embolization of the branches by interventional radiology was performed.

RESULTS

Heterotopic ossification resection was performed with an 820-ml blood loss. Postoperative rehabilitation was continued, and range of motion continued to improve without heterotopic ossification recurrence 2 years post-surgery.

CONCLUSIONS

The combination of preoperative contrast-enhanced computed tomography and embolization was useful in treating heterotopic ossification.

Neutrophil and NETosis Modulation in Traumatic Heterotopic Ossification

OBJECTIVE

To characterize the role of neutrophil extracellular traps (NETs) in heterotopic ossification (HO) formation and progression and to use mechanical and pharmacological methods to decrease NETosis and mitigate HO formation.

BACKGROUND

Traumatic HO is the aberrant osteochondral differentiation of mesenchymal progenitor cells after traumatic injury, burns, or surgery. While the innate immune response has been shown to be necessary for HO formation, the specific immune cell phenotype and function remain unknown. Neutrophils, one of the earliest immune cells to respond after HO-inducing injuries, can extrude DNA, forming highly inflammatory NETs. We hypothesized that neutrophils and NETs would be diagnostic biomarkers and therapeutic targets for the detection and mitigation of HO.

METHODS

C57BL6J mice underwent burn/tenotomy (a well-established mouse model of HO) or a non-HO-forming sham injury. These mice were either (1) ambulated ad libitum, (2) ambulated ad libitum with daily intraperitoneal hydroxychloroquine, ODN-2088 (both known to affect NETosis pathways), or control injections, or (3) had the injured hind limb immobilized. Single-cell analysis was performed to analyze neutrophils, NETosis, and downstream signaling after the HO-forming injury. Immunofluorescence microscopy was used to visualize NETosis at the HO site and neutrophils were identified using flow cytometry. Serum and cell lysates from HO sites were analyzed using enzyme-linked immunosorbent assay for myeloperoxidase-DNA and ELA2-DNA complexes to identify NETosis. Micro-computerized tomography was performed on all groups to analyze the HO volume.

RESULTS

Molecular and transcriptional analyses revealed the presence of NETs within the HO injury site, which peaked in the early phases after injury. These NETs were highly restricted to the HO site, with gene signatures derived from both in vitro NET induction and clinical neutrophil characterizations showing a high degree of NET "priming" at the site of injury, but not in neutrophils in the blood or bone marrow. Cell-cell communication analyses revealed that this localized NET formation coincided with high levels of toll-like receptor signaling specific to neutrophils at the injury site. Reducing the overall neutrophil abundance within the injury site, either pharmacologically through treatment with hydroxychloroquine, the toll-like receptor 9 inhibitor OPN-2088, or mechanical treatment with limb offloading, results in the mitigation of HO formation.

CONCLUSIONS

These data provide a further understanding of the ability of neutrophils to form NETs at the injury site, clarify the role of neutrophils in HO, and identify potential diagnostic and therapeutic targets for HO mitigation.

Pediatric Heterotopic Ossification: A Comprehensive Review

PURPOSE OF REVIEW

The purpose of this review is to provide a comprehensive analysis of heterotopic ossification (HO) in pediatric patients, including an in-depth examination of the risk factors associated with this condition, current prophylactic measures, and available management strategies.

RECENT FINDINGS

HO is a medical disorder in which bone tissue inexplicably develops in soft tissues such as muscles and tendons. It involves the formation of mature, lamellar bone in extra-skeletal soft tissue, and its formation is influenced by oxygen tension, pH, the availability of micronutrients, and mechanical stimulation. HO has many cellular origins, with the most common theory being multipotent cells in local tissue. The diagnosis of HO is typically made based on exam, radiographs, and CT. Management includes both prophylactic nonsurgical options and surgical resection for severe or recalcitrant cases. The review highlights the incidence, risk factors, and management strategies associated with HO in pediatric patients. HO is a rare condition in children, with severe neurologic injury being the most common cause. Pediatric patients most commonly develop HO following severe neurologic injury, followed by trauma and surgery. Current prophylactic measures, include nonsteroidal anti-inflammatory drugs and radiation therapy though limited literature on their use in the pediatric population exists. For recalcitrant symptomatic cases, wide surgical resection can be considered but has a higher risk profile and associated morbidity. This review highlights the need for further pediatric specific research to inform guidelines and management strategies for this debilitating condition.

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.

[Elbow joint dislocation : Frequent concomitant injuries and current treatment concepts]

Dislocations of the elbow joint are among the most prevalent dislocation injuries in the human body after shoulder joint dislocations and represent a challenge in the clinical routine because of the concomitant injuries and complications. They predominantly affect young adults who become injured during athletic or daily activities. A distinction is generally made between a simple elbow dislocation and a dislocation fracture of the elbow; however, a uniform classification or treatment algorithm has not yet been established, especially for simple elbow dislocations with associated ligamentous, muscular and capsular concomitant injuries. Due to this and the complexity of this injury, a standardized approach is needed to initiate the optimal treatment at an early stage and to correctly select the narrow treatment pathway between impending chronic instability and elbow stiffness.

Pathophysiology and Emerging Molecular Therapeutic Targets in Heterotopic Ossification

The term heterotopic ossification (HO) describes bone formation in tissues where bone is normally not present. Musculoskeletal trauma induces signalling events that in turn trigger cells, probably of mesenchymal origin, to differentiate into bone. The aetiology of HO includes extremely rare but severe, generalised and fatal monogenic forms of the disease; and as a common complex disorder in response to musculoskeletal, neurological or burn trauma. The resulting bone forms through a combination of endochondral and intramembranous ossification, depending on the aetiology, initiating stimulus and affected tissue. Given the heterogeneity of the disease, many cell types and biological pathways have been studied in efforts to find effective therapeutic strategies for the disorder. Cells of mesenchymal, haematopoietic and neuroectodermal lineages have all been implicated in the pathogenesis of HO, and the emerging dominant signalling pathways are thought to occur through the bone morphogenetic proteins (BMP), mammalian target of rapamycin (mTOR), and retinoic acid receptor pathways. Increased understanding of these disease mechanisms has resulted in the emergence of several novel investigational therapeutic avenues, including palovarotene and other retinoic acid receptor agonists and activin A inhibitors that target both canonical and non-canonical signalling downstream of the BMP type 1 receptor. In this article we aim to illustrate the key cellular and molecular mechanisms involved in the pathogenesis of HO and outline recent advances in emerging molecular therapies to treat and prevent HO that have had early success in the monogenic disease and are currently being explored in the common complex forms of HO.

A comprehensive update on the pharmacological management of heterotopic ossification following hip arthroplasty: a level I evidenced based expert opinion

INTRODUCTION

Heterotopic ossification (HO) of the hip joint may happen accompanying skeletal muscle trauma or surgical procedures. The pharmacological prophylaxis of heterotopic ossification (HO) following total hip arthroplasty (THA) is debated.

AREAS COVERED

This expert opinion aims to systematically investigate the efficacy of current pharmacological options as prophylaxis for HO following THA.

EXPERT OPINION

The current evidence identified celecoxib, naproxen, and diclofenac as best option for the prevention of HO in patients who undergo primary THA. The most appropriate pharmacotherapy for the prevention of HO is still debated and should be customized according to patients' comorbidities and medical history. For patients with cardiovascular comorbidities, naproxen, or diclofenac should be considered along with proton pump inhibitors to prevent gastrointestinal complications. For patients with history of gastrointestinal disease, celecoxib can be recommended. These conclusions must be considered within the limitations of the present investigation. Between studies, heterogeneities in the administration protocols were evident. In some RCTs, the length of the follow-up was shorter than 12 months. The current clinical practice would benefit of high-quality recommendations and the development of the shared official guidelines.

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.

Primary Versus Secondary Radiotherapy for Heterotopic Ossification Prevention About the Elbow

OBJECTIVES

To examine the efficacy and safety of radiotherapy for the prevention of heterotopic ossification (HO) about the elbow.

DESIGN

Retrospective chart review.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Two hundred and twenty-nine patients who received prophylactic radiotherapy (XRT) over a 15-year period were identified. Patients were included if they received XRT to the elbow joint and had at least 12 weeks of follow-up after XRT. Fifty-four patients were ultimately included.

INTERVENTION

All patients were treated with a single dose of 7 Gy. Ninety-eight percentage of patients received XRT within 24 hours after surgery, and all patients received XRT within 72 hours after surgery.

MAIN OUTCOMES MEASUREMENTS

The primary study measures evaluated were the presence or absence of clinically symptomatic HO and the presence of radiographic HO after XRT to the elbow joint.

RESULTS

Eighteen patients were treated with XRT after a traumatic injury requiring surgery (primary prophylaxis), and 36 were treated with XRT after excision surgery to remove HO which had already formed (secondary prophylaxis). In the primary cohort, 16.7% developed symptomatic HO after XRT and 11.1% required surgery to resect the heterotopic bone. In the secondary cohort, 11.1% developed symptomatic HO after surgery and XRT and 5.5% required resection surgery. No secondary malignancies were identified.

CONCLUSIONS

Our findings suggest that XRT for elbow HO may be safe and effective for both primary and secondary HO. XRT for HO was not shown to be associated with radiation-induced sarcoma in this series, at least in the short term. Further study in a large patient population with extended follow-up is required to better characterize populations at high risk for development of HO and secondary malignancy.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

Surgical Management of Complex Adult Monteggia Fractures

Monteggia fractures classically involve a proximal ulna fracture with an associated radial head dislocation. The presence of radial head/neck fracture and comminution of the proximal ulna with coronoid involvement elevates the complexity of surgical reconstruction considerably. The Jupiter classification captures this injury pattern as a subgroup of Bado posterior Monteggia lesions. Access to the critical coronoid fragment can be problematic from the posterior approach and may result in tenuous reduction and fixation, directly affecting the functional outcome. Multiple operative techniques have been described to address the broad spectrum of injuries seen in Monteggia fractures. This article will cover commonly used fixation techniques for Monteggia fractures with a comprehensive literature review, including technical tips, outcomes, and complications.

Comparing Options for Heterotopic Ossification Prophylaxis following Elbow Trauma: A Systematic Review and Meta-Analysis

Introduction  Heterotopic ossification (HO) can be a potentially serious and devastating complication following traumatic injury to the elbow. HO prophylaxis options include nonsteroidal anti-inflammatory drugs (NSAIDs) and radiation therapy (RT) but neither has been proven more effective. The purpose of this review is to compare effectiveness and outcomes between NSAID and RT prophylaxis for HO about the elbow following a traumatic injury. Materials and Methods  We performed a systematic review of PubMed and Cochrane Library for cases of HO prophylaxis following elbow trauma utilizing PRISMA guidelines to determine the most effective form of prophylaxis. Outcomes of interest included recurrence of HO, range of motion (ROM), and Mayo elbow performance index (MEPI). A total of 36 articles and 826 elbows of which 203 received RT and 623 received NSAID were identified and included in the final analysis. Results  Rates of HO formation or recurrence following elbow trauma were similar between radiation and NSAID prophylaxis (15.6% vs. 22.2%, respectively p = 0.457). ROM was similar in flexion and extension arc (109.0 degrees in radiation vs. 112.8 in NSAIDs, p = 0.459) and in pronation and supination arc (118.9 degrees radiation vs. 134.7 degrees NSAIDs, p = 0.322). MEPI scores were 79.19 in the radiation group and 88.82 in the NSAIDs group at the final follow-up. Conclusion  There is no statistical difference in HO development, recurrence, or final ROM between NSAIDs and RT prophylaxis following trauma to the elbow. We recommend the choice of modality based on patient characteristics, cost, and surgeon preference. Level of Evidence  Level III.

The efficacy of nonsteroidal anti-inflammatories in the prevention of heterotopic ossification following elbow trauma surgery

Background

Heterotopic ossification (HO) is common following surgery for elbow trauma and can have a significant impact on elbow function. The use of nonsteroidal anti-inflammatories (NSAIDs) for HO prophylaxis following total hip arthroplasty is well described, with the gold standard of indomethacin 25 mg tid for 6 weeks. However, there is sparse evidence relating to the elbow joint, particularly after elbow trauma surgery. We aim to investigate the efficacy of NSAIDs in the primary prevention of HO amongst all adult patients undergoing surgery for elbow trauma and identify risk factors for HO formation.

Methods

A search of the Fiona Stanley Hospital electronic theater database for procedures undertaken for elbow trauma from January 2015 to June 2020 was performed. Electronic medical records and radiographs were reviewed to determine the incidence of HO, prescription of NSAIDs, biographical data, and complications.

Results

One hundred and fifty-three patients were identified of which 78 patients received NSAIDs postoperatively, compared to 72 who did not. The prescribing history of the remaining 3 patients was unknown. In the NSAID group, the typical patient was prescribed 3-7 days of NSAIDs. Ten patients received a prophylactic course (4-6 weeks). The incidence of HO was similar in both groups (24% in those taking NSAIDs vs. 21% in those not taking NSAIDs). Of those specifically prescribed a prophylactic course, 50% developed HO and 50% did not. Statistical analysis demonstrated that patients with increased body mass index and high energy injuries were more likely to develop HO. Overall complications were low within the cohort. Only 1 patient, who was prescribed NSAIDs, suffered a fracture nonunion (1.3%).

Conclusion

NSAIDs did not affect the incidence of HO about the elbow following surgery for trauma amongst our cohort. There was no appreciable difference in the rates of HO amongst those prescribed NSAIDs and those who were not. Increased body mass index and high energy trauma were predictive for higher incidence of HO. Risks of NSAID therapy were low, with only 1 (1.3%) patient suffering a nonunion.

Patient Outcomes After Transolecranon Fracture-Dislocation

INTRODUCTION

There are few small case series that discuss patient outcomes after a transolecranon fracture-dislocation, and they suggest that patients have reasonable function after injury. The purpose of this study was to describe the injury pattern and clinical outcomes of transolecranon fracture-dislocations.

METHODS

After Institutional Review Board approval, transolecranon fracture-dislocations treated at two academic level 1 trauma centers between 2005 and 2018 were retrospectively reviewed. Fracture characteristics and postsurgical complications were recorded. Radiographs were reviewed for arthrosis, and Quick Disabilities of Arm, Shoulder, and Hand (QuickDASH) scores were obtained at a minimum of 12 months after injury.

RESULTS

Thirty-five patients with a mean follow-up of 28 months (range, 12 to 117 months) were included. Nine patients had associated radial head fracture, 23 patients had associated coronoid fracture, four patients had ligamentous injury, and two patients had capitellum fracture. Four patients (11%) developed infection and required irrigation and débridement with intravenous antibiotics. Thirteen patients (13 of 35, 37%) developed radiographic arthrosis with most (11 of 13) having grade 2 or three changes. Patients who had associated radial head fracture, coronoid fracture, capitellum fracture, and/or ligamentous injury had significant arthrosis (10 of 24, 42%) more commonly than patients with olecranon fracture alone (1 of 11, 9%) (P = 0.05). Twenty-eight patients completed patient outcomes instrument and achieved a mean QuickDASH score of 9 (range, 0 to 59). Patients with isolated transolecranon fracture had a significantly better QuickDASH score (0.93, 0 to 4) than patients with transolecranon fracture variant with associated coronoid fracture, radial head fracture, distal humeral fracture, or ligamentous injury (11.74, 0 to 59) (P = 0.04).

DISCUSSION

Patients with transolecranon fracture-dislocation had excellent return to function based on the QuickDASH outcome assessment. Patients with transolecranon fracture with associated radial head fracture, coronoid fracture, humeral condyle fracture, and/or ligamentous injury tend to have worse functional outcome than patients with simple transolecranon fracture.

LEVEL OF EVIDENCE

Level IV-case series.

Risk Factors for the Occurrence and Progression of Posttraumatic Elbow Stiffness: A Case-Control Study of 688 Cases

Background: Elbow stiffness is a severe complication after trauma. Surgical or conservative treatments may be ineffective for restoring functional elbow motion. We aim to evaluate intrinsic and extrinsic factors for the occurrence and severity of elbow stiffness.

Methods: This retrospective case–control study included mild/moderate stiffness, severe stiffness, and non-stiffness groups between January 2011 and December 2017 at a single orthopedic center. Multivariable logistic regression analysis and subgroup analysis were used to evaluate age, gender, body mass index, muscle strength, fracture type and site, injury mechanism, immobilization time, elbow dysfunction time, multiple surgeries, nerve symptoms, physical therapy, smoking and alcohol abuse, and dominant hand of stiff elbow as potential risk factors for the occurrence and severity of elbow stiffness.

Results: There were 461 patients in the stiffness group and 227 patients in the non-stiffness group. The odds ratios (ORs) of the age, muscle strength, and injury mechanism were 0.960, 0.333, and 0.216 for the occurrence of elbow stiffness. In subgroup evaluation, increased cast immobilization time might be a risk factor for patients receiving conservative therapies (OR = 2.02; p = 0.014). In the evaluation on factors for progression of elbow stiffness, “multiple surgeries” might be a risk factor in surgical treatment by subgroup analysis (OR = 1.943; p = 0.026). Nevertheless, alcohol abuse might increase severity of elbow stiffness in conservatively treated patients (OR = 3.082; p = 0.025).

Conclusion: Increased cast immobilization time in the conservative therapy might be a risk factor for stiffness occurrence. Multiple surgeries might be risk factors for stiffness progression. Alcohol abuse potentially increased stiffness severity after conservative treatment.

Neurological heterotopic ossification: novel mechanisms, prognostic biomarkers and prophylactic therapies

Neurological heterotopic ossification (NHO) is a debilitating condition where bone forms in soft tissue, such as muscle surrounding the hip and knee, following an injury to the brain or spinal cord. This abnormal formation of bone can result in nerve impingement, pain, contractures and impaired movement. Patients are often diagnosed with NHO after the bone tissue has completely mineralised, leaving invasive surgical resection the only remaining treatment option. Surgical resection of NHO creates potential for added complications, particularly in patients with concomitant injury to the central nervous system (CNS). Although recent work has begun to shed light on the physiological mechanisms involved in NHO, there remains a significant knowledge gap related to the prognostic biomarkers and prophylactic treatments which are necessary to prevent NHO and optimise patient outcomes. This article reviews the current understanding pertaining to NHO epidemiology, pathobiology, biomarkers and treatment options. In particular, we focus on how concomitant CNS injury may drive ectopic bone formation and discuss considerations for treating polytrauma patients with NHO. We conclude that understanding of the pathogenesis of NHO is rapidly advancing, and as such, there is the strong potential for future research to unearth methods capable of identifying patients likely to develop NHO, and targeted treatments to prevent its manifestation.

A Retrospective Analysis of 287 Patients Undergoing Prophylactic Radiation Therapy for the Prevention of Heterotopic Ossification

Purpose

Heterotopic ossification (HO) is a potentially disabling disorder of ectopic bone formation secondary to orthopedic surgery or trauma. In this retrospective analysis we evaluated the outcomes of patients who received radiation therapy (RT) for HO prophylaxis.

Methods and Materials

A total of 287 patients who received RT for HO prophylaxis at a major trauma center from 2007 to 2018 were analyzed. Data collected included types of injury, surgery, time intervals between key events, development of postprophylaxis HO, and secondary malignancies. Associations between various factors and the risk of developing HO were analyzed. Kaplan-Meier analysis was used to estimate failure rates.

Results

The most common indication for RT was traumatic acetabular fracture (83.3%). Twelve patients (4.2%) developed postprophylaxis HO with a median time to failure of 8.6 months (2.8-24.5). Kaplan-Meier 1-, 2-, and 5-year failure rates were 3.7%, 4.4%, and 7.4%, respectively. Injury type and timing of RT were not associated with the risk of failure, but we observed a trend of increased risk of failure in patients with longer time between surgery and RT (odd ration [OR] 1.68, P = .056). Current or former smokers (51.7%) were less likely to fail (OR 0.10, P = .03). There was no incidence of in-field secondary malignancy.

Conclusions

There was no significant association between injury and fracture type, surgical approach, or timing of RT and development of HO, contrary to published reports of increased HO risk with certain surgical approaches and longer time intervals between injury and surgery, suggesting that prophylactic RT might play a role in mitigating these effects. Decreased risk of postprophylaxis HO among former or current smokers was unexpected. No secondary malignancy in the RT field was identified, although the median follow-up was only 17 months. Compared with published HO incidences (17%-39%) in patients who receive no prophylaxis after traumatic acetabular fractures, our results are highly suggestive of the efficacy of prophylactic RT.

Elbow Fracture-Dislocations: Determining Treatment Strategies

Elbow dislocations represent common injuries. A quarter of these injuries involve at least 1 fracture. The sequel of elbow fracture-dislocations can be fraught with complications, including recurrent instability, posttraumatic arthritis, elbow contracture, and poor functional results. The 3 main patterns of injury are valgus posterolateral rotatory instability, varus posteromedial rotatory instability, and transolecranon fracture-dislocation. This article discusses each pattern individually, including the anatomy, the typical injury pattern, and treatment strategies. It also discusses common complications that can occur.

An Assessment of Randomized Controlled Trial Quality in The Journal of Bone & Joint Surgery: Update from 2001 to 2013

BACKGROUND

The quality of reporting of randomized controlled trials (RCTs) published in The Journal of Bone & Joint Surgery (JBJS) from 1988 to 2000 was previously analyzed. The purpose of this current study was to analyze the quality of reporting of RCTs published in JBJS from 2001 to 2013 to identify trends over time and potential areas of improvement for future clinical trials.

METHODS

A manual search of the JBJS database identified RCTs published between January 2001 and December 2013. Quality assessments, using the Detsky quality-of-reporting index (Detsky score), a modified Cochrane risk-of-bias tool, and abstraction of relevant data identifying predictors of quality, were conducted.

RESULTS

A total of 5,780 publications were identified in JBJS from 2001 to 2013, with 285 RCTs (4.9%), representing an increase from the prior 13-year period. The overall mean transformed Detsky score (and standard error) increased significantly (p < 0.001) from 68.1% ± 1.67% to 76.24% ± 0.72%. The percentage of multicenter RCTs decreased from 67% to 31%. The percentage of positive trials also decreased from 80% to 50.5%, as did the mean sample size (212 to 166). Regression analysis indicated that trials with an epidemiologist as the first author and nonsurgical trials were significantly associated (p = 0.001) with a higher overall trial quality score. The categories of the lowest mean methodology scores were randomization and concealment, eligibility criteria, and reasons for patient exclusion, as identified with the Detsky score, and patient and assessor blinding, as identified with the risk-of-bias assessment.

CONCLUSIONS

The quantity and quality of published RCTs in JBJS have increased in the 2001 to 2013 time period compared with the previous time period. Although these improvements are encouraging, trends to smaller, single-center trials were also observed. To efficiently determine the efficacy of orthopaedic treatments and limit bias, high-quality randomized trials of appropriate sample size and rigorous design are needed.

Investigation into Possible Association of Oxandrolone and Heterotopic Ossification Following Burn Injury

Oxandrolone, a testosterone analog, is used to counteract the catabolic effects of burn injury. Recent animal studies suggest a possible hormonal association with heterotopic ossification (HO) development postburn. This work examines oxandrolone administration and HO development by exploring historical clinical data bridging the introduction of oxandrolone into clinical practice. Additionally, we examine associations between oxandrolone administration and HO in a standardized mouse model of burn/trauma-related HO. Acutely burned adults admitted between 2000 and 2014, survived through discharge, and had a HO risk factor of 7 or higher were selected for analysis from a single burn center. Oxandrolone administration, clinical and demographic data, and elbow HO were recorded and were analyzed with logistic regression. Associations of oxandrolone with HO were examined in a mouse model. Mice were administered oxandrolone or vehicle control following burn/tenotomy to examine any potential effect of oxandrolone on HO and were analyzed by Student's t test. Subjects who received oxandrolone had a higher incidence of elbow HO than those that did not receive oxandrolone. However, when controlling for oxandrolone administration, oxandrolone duration, postburn day oxandrolone initiation, HO risk score category, age, sex, race, burn size, and year of injury, there was no significant difference between rates of elbow HO between the two populations. In agreement with the review, in the mouse model, while there was a trend toward the oxandrolone group developing a greater volume of HO, this did not reach statistical significance.

Do Indomethacin or Radiation for Heterotopic Ossification Prophylaxis Increase the Rates of Infection or Wound Complications After Acetabular Fracture Surgery?

OBJECTIVES

To compare the rates of infection and wound complications in patients undergoing operative fixation (ORIF) of acetabular fractures receiving heterotopic ossification (HO) prophylaxis using indomethacin or external beam radiation therapy (XRT) versus no prophylaxis.

DESIGN

Retrospective cohort.

SETTING

Level I trauma center.

PATIENTS

We reviewed 473 patients undergoing ORIF of acetabular fractures through posterior, combined, or extensile surgical approaches from 2012 to 2017, with a median follow-up of 13 months (0.5-77 months).

MAIN OUTCOME MEASUREMENT

Rates of infection and wound complications were stratified according to their HO prophylaxis method into three groups as indomethacin, XRT, and no prophylaxis.

RESULTS

Overall, 167 patients (35.3%) received indomethacin, 104 patients (22.0%) received postoperative XRT, and 202 patients (42.7%) received no prophylactic treatment. There was no difference between the 3 groups for the risk of surgical site infection (P = 0.280). The XRT group had a significantly increased risk of noninfectious wound complications (20.2%) compared with the indomethacin group (6.6%, P = 0.002) and the no prophylaxis group (5.0%, P < 0.0001). Multivariate analysis revealed XRT remained a significant risk factor for noninfectious wound complications compared with no prophylaxis (odds ratio 5.39; 95% confidence interval 2.37-12.22; P < 0.0001).

CONCLUSIONS

Although there is no difference between XRT, indomethacin, and no HO prophylaxis for the risk of surgical site infection, the use of XRT results in more than 5 times increased risk of noninfectious wound complications compared with no prophylaxis. This increased risk should be considered when contemplating XRT for HO prophylaxis in acetabular fracture patients.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Local injection of a hexametaphosphate formulation reduces heterotopic ossification in vivo

Heterotopic ossification (HO), the pathological formation of ectopic bone, is a debilitating condition which can cause chronic pain, limit joint movement, and prevent prosthetic limb fitting. The prevalence of this condition has risen in the military population, due to increased survivorship following blast injuries. Current prophylaxes, which aim to target the complex upstream biological pathways, are inconsistently effective ​and have a range of side-effects that make them unsuitable for combat-injured personnel. As such, many patients must undergo further surgery to remove the formed ectopic bone. In this study, a non-toxic, U.S. Food and Drug Administration (FDA) -approved calcium chelator, hexametaphosphate (HMP), is explored as a novel treatment paradigm for this condition, which targets the chemical, rather that biological, ​bone formation pathways. This approach allows not only prevention of pathological bone formation ​but also uniquely facilitates reversal, which current drugs cannot achieve. Targeted, minimally invasive delivery is achieved by loading HMP into an injectable colloidal alginate. These formulations significantly reduce ​the length of the ectopic bone formed in a rodent model of HO, with no effect on the adjacent skeletal bone. This study demonstrates the potential of localized dissolution as a new treatment ​and an alternative to surgery ​for pathological ossification and calcification conditions.

The Fragility Index in Hand Surgery Randomized Controlled Trials

PURPOSE

Randomized controlled trials (RCTs) are the gold standard for comparing clinical interventions. Statistical significance as reported via a P value has been used to determine if a difference between clinical interventions exists in an RCT. However, P values do not clearly convey information about the robustness of a study's conclusions. An emerging metric, called the fragility index (the number of subjects who would need to change outcome category to raise the P value above the .05 threshold), is an indirect measure of how likely a repeat of the trial would reach the same conclusions. This study addressed the fragility of RCTs using dichotomous outcomes in hand surgery.

METHODS

Using systematic searching of the MEDLINE database, we identified hand surgery RCTs published in 11 high-impact journals published in the last decade (2007-2017). Studies were identified that involved 2 parallel arms, allocated patients to treatment and control in a 1:1 ratio, and reported statistical significance for a dichotomous variable. The fragility index was calculated using Fisher's exact test, using previously published methods.

RESULTS

Five hand surgery RCTs were identified for inclusion reporting a range of fragility indices from 0 to 26. Two of the trials (40%) had a fragility index of 2 or less. Two of the trials (40%) reported that the number of patients lost to follow-up exceeded the fragility index, meaning that results of the patients lost to follow-up could theoretically completely reverse the study conclusions.

CONCLUSIONS

The range of fragility indices reported in the recent hand surgery literature is consistent with previous reporting within orthopedic surgery.

CLINICAL RELEVANCE

The fragility index is a useful metric to analyze the robustness of the study conclusions that should complement other methods of critical evaluation including the P value or effect sizes. Our results emphasize the need for future efforts to strengthen the robustness of RCT conclusions.

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.

Post-traumatic stiff elbow

Post-traumatic and post-operative stiffness of the elbow joint is relatively common and may in pronounced cases markedly interfere with normal upper extremity function.Soft-tissue contractures and heterotopic bone formation are two major causes of limited movement.Extensive recent research has elucidated many of the pathways contributing to these conditions, but the exact mechanisms are still unknown.In the early phase of soft-tissue contractures conservative treatment may be valuable, but in longstanding cases operative treatment is often necessary.Several different options are available depending on the severity of the condition and the underlying offending structures. Surgical treatment may allow significant gains in movement but rarely complete restoration, and complications are not uncommon.The following presentation reviews the recent literature on pathomechanisms and treatment alternatives. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170062.

Post-Traumatic Heterotopic Ossification: An Old Problem in Need of New Solutions

Heterotopic ossification (HO) is the formation of pathological bone in ectopic sites and it can have serious consequences for functional outcomes. For many years, its main clinical relevance was as a rare complication of elective joint arthroplasty or CNS injury and a number of prophylaxes were developed to mitigate against it in these settings. As a consequence of changes in patterns of wounding and survival in conflicts since the turn of the century, post-traumatic HO has become much more common and case severity has increased. It represents one of the main barriers to rehabilitation in a large cohort of combat-injured patients. However, extant prophylaxes have not been shown to be effective or appropriate in this patient cohort. In addition, the lack of reliable early detection or means of predicting which patients will develop HO is another barrier to effective prevention. This review examines the current state of understanding of post-traumatic HO including the historical context, epidemiology, pathophysiology, clinical issues, currently prophylaxis and detection, management, and potential future approaches. Our aims are to highlight the current lack of effective means of early detection and prevention of HO after major trauma and to stimulate research into novel solutions to this challenging problem. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1061-1068, 2018.

Heterotopic ossification and the elucidation of pathologic differentiation

Tissue regeneration following acute or persistent inflammation can manifest a spectrum of phenotypes ranging from the adaptive to the pathologic. Heterotopic Ossification (HO), the endochondral formation of bone within soft-tissue structures following severe injury serves as a prominent example of pathologic differentiation; and remains a persistent clinical issue incurring significant patient morbidity and expense to adequately diagnose and treat. The pathogenesis of HO provides an intriguing opportunity to better characterize the cellular and cell-signaling contributors to aberrant differentiation. Indeed, recent work has continued to resolve the unique cellular lineages, and causative pathways responsible for ectopic bone development yielding promising avenues for the development of novel therapeutic strategies shown to be successful in analogous animal models of HO development. This review details advances in the understanding of HO in the context of inciting inflammation, and explains how these advances inform the current standards of diagnosis and treatment.

Heterotopic Ossification After the Arthroscopic Treatment of Lateral Epicondylitis

BACKGROUND

Heterotopic ossification (HO) is a well-known complication following the surgical treatment of fractures and dislocations about the elbow but it is not commonly discussed as a complication following arthroscopy. We present a case of a young athlete who developed HO after the arthroscopic treatment of lateral epicondylitis.

METHODS

This is a case report chart review of a 24 year old male with lateral epicondylitis. After failing conservative measures, arthroscopic debridement of the extensor carpi radialis brevis (ECRB) origin ensued. The treatment and patient's final disposition were reported.

RESULTS

The patient developed heterotopic ossification of the elbow follow arthroscopic debridement of the ECRB origin. Further surgery was required to excise the heterotopic ossification. Good recovery of motion was achieved.

CONCLUSION

To our knowledge, we present the first case of HO development after elbow arthroscopy for lateral epicondylitis. As the use of elbow arthroscopy continues to grow, there is a need for identification of the risk factors and primary prophylaxis for HO.

Posttraumatic stiff elbow

Posttraumatic stiff elbow is a frequent and disabling complication and poses serious challenges for its management. In this review forty studies were included to know about the magnitude of the problem, causes, pathology, prevention, and treatment of posttraumatic stiff elbow. These studies show that simple measures such as internal fixation, immobilization in extension, and early motion of elbow joint are the most important steps that can prevent elbow stiffness. It also supports conservative treatment in selected cases. There are no clear guidelines about the choice between the numerous procedures described in literature. However, this review article disproves two major beliefs-heterotopic ossification is a bad prognostic feature, and passive mobilization of elbow causes elbow stiffness.

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.

[Primary radial head arthroplasty in trauma : Complications]

Radial head fractures are common injuries in elbow trauma. Non-displaced fractures are best treated conservatively. Simple but displaced fractures require anatomic reduction and fixation, typically using screws. The treatment course for complex fractures with multiple fragments is still being debated, as results are less predictable. Radial head resection is not advised if concomitant injuries of the coronoid process or the collateral ligaments with instability are present. Favorable outcomes following open reduction and fixation using plates were reported recently. However, complication rates are very high. Radial head replacement is a valuable tool in treating complex fractures of the radial head with predominantly good and excellent results. Patients who suffer radial head fractures are typically of a younger age, resulting in high functional demands. Certainly, unspecific and specific complications related to radial head arthroplasty were reported in up to 40 % of cases in an acute fracture setting. This article highlights common complications in radial head arthroplasty and aims to present strategies to avoid them.

The clinical implications of heterotopic ossification in patients treated with radial head replacement for trauma: A case series and review of the literature

Radial head arthroplasty (RHA) is an acceptable treatment for comminuted radial head fractures (RHF). Fourteen patients with no postop HO prophylaxis were treated with RHA for comminuted RHF. A 50% incidence in HO was seen following RHA with a statistically increased risk (p ≤ 0.05) of reoperation compared to those without HO. Decreased ROM was seen on the affected side (p ≤ 0.05); patients without HO showed no statistical difference (p ≥ 0.05) in ROM or grip strength. HO following RHA increases patient risk for reoperation and decreases ROM. We recommend HO prophylaxis with NSAIDs and/or radiotherapy if no direct patient contraindications are found.

Fibrocytes participate in the development of heterotopic ossification

Heterotopic ossification (HO) is a complication of musculoskeletal injury characterized by the formation of mature bone in soft tissues. The etiology of HO is unknown. We investigated the role of bone marrow derived progenitor cells in HO pathophysiology. We isolated the cells from HO specimens by cell explantation. Using flow cytometry and immunofluorescence microscopy, we found that 35 to 65% of the HO cells exhibit a bone marrow derived fibrocyte profile consisting in spindle-shaped morphology associated with type 1 pro-collagen and LSP1 expression. When cultured in osteogenic differentiation medium, active machinery for bone mineralization (high gene expression of Anx2, TNAP, and Pit-1), and calcium/phosphate deposits were found. Interestingly, interferon-alpha 2b significantly reduced the proliferation rate and COL1 gene expression in HO cells. We have characterized a novel subset of bone marrow derived progenitor cells in the HO specimens. The findings from this research study will provide new insights into the development of HO in burn patients.

Comparative clinical study of the prophylaxis of heterotopic ossifications after total hip arthroplasty using etoricoxib or diclofenac

PURPOSE

This study investigated whether etoricoxib (COX-II blocker) has a superior efficacy of preventing heterotopic ossification (HO) after total hip arthroplasty (THA) compared to diclofenac (non-selective NSAID).

METHODS

One hundred patients were included (50 in each group) in this single centre, prospective, double-blinded, randomized, controlled trial. Etoricoxib (90 mg) was administered once and diclofenac (75 mg) twice per day for a perioperative period of nine days. The incidence of HO was evaluated on radiographs of the pelvis six months after surgery.

RESULTS

Eighty nine of 100 (89 %) patients could be analysed. The overall HO incidence was 37.8 %. There was no significant difference between both study groups. Twelve patients (27.3 %) of the DIC group and 13 patients (28.9 %) of the ETO group showed Brooker grade I ossifications. Five patients (11.4 %) of the DIC and four patients of the ETO (8.9 %) group showed grade II HO formations. No class III or IV HO formations occured in both groups. Ad hoc analysis detected a negative correlation between HO incidence and limited abduction and internal rotation of the hip.

CONCLUSIONS

Etoricoxib and diclofenac are equally effective for oral HO prophylaxis after primary cementless THA when given for nine peri-operative days to ensure a full recovery and high patient satisfaction.

Management of Adult Elbow Fracture Dislocations

Elbow fracture dislocations are complicated injuries that are difficult to manage and fraught with complications. A complete series of radiographs is typically complemented with CT scan to evaluate the elbow and assist preoperative planning. Typically, operative intervention is necessary and a systematic approach to the elbow injuries should be chosen. This article addresses the coronoid and proceeds to the radial head, lateral soft tissues, and finally the medial ligaments if elbow instability persists. With a focused, systematic surgical approach, improved outcomes have been demonstrated and patients may recover full function and range of motion in the affected elbow.

Olecranon Fractures

Olecranon fractures are common upper extremity injuries, with all but nondisplaced fractures treated surgically. There has been a recent shift in the surgical management of these fractures from tension band wiring to locking plate fixation and intramedullary nailing; however, this comes with increased implant cost. Although most patients can expect good outcomes after these various techniques, there is little information to guide a surgeon's treatment plan. This article reviews the epidemiology, classification, treatment, and outcomes of olecranon fractures.

Malpositioned olecranon fracture tension-band wiring results in proximal radioulnar synostosis

Background

Tension-band wiring (TBW) is a well-established fixation technique for two-part, transverse fracture types of the olecranon. However, complication rates up to 80 % are reported. By reporting on the enormous impact on the patient if failed the aim of the present report was to emphasize the importance of correct K wire positioning in TBW.

Case presentation

We present the case of a 49-year-old woman who suffered from a radioulnar synostosis of the forearm due to malpositioned K wires after TBW treatment. The patient was treated by heterotopic bone resection supported by ossification prophylaxis (radiotherapy and Indomethacin). At follow-up of 12 months after revision surgery, elbow motion was unrestricted with a strength grade 5/5. The patient was free of pain and reported no restrictions in daily as well as sporting activities. Radiologic assessment showed no recurrence of heterotopic bone tissue.

Conclusion

Intraoperative radiographic and clinical examination of the elbow is highly recommended to identify incorrect hardware positioning and, therefore, to avoid serious postoperative complications in TBW.

Coronoid Fractures

Fractures of the coronoid process of the ulna are usually part of a more complex injury. The type of coronoid fracture corresponds with a specific pattern of injury with known pitfalls and recommended treatments. Tip fractures usually correspond with dislocation of the elbow and fracture of the radial head (the so-called terrible triad of the elbow because it is prone to redislocation, subluxation, and arthrosis) and are best repaired with a suture passed through drill holes along with repair or replacement of the fractured radial head and reattachment of the lateral collateral ligament to the lateral epicondyle. Anteromedial fractures are usually part of a subluxation injury and are best addressed with a medial buttress plate and reattachment of the lateral collateral ligament. Large basilar coronoid fractures are usually part of an olecranon fracture-dislocation and are usually repaired with 1 or 2 plates and screws. Tenuous fixation is protected with temporary external fixation or cross-pinning of the joint because healing of the coronoid with concentric elbow alignment is critical.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Incidence and risk factors for heterotopic ossification after total hip arthroplasty: a meta-analysis

BACKGROUND

This study aims to quantitatively summarize risk factors associated with heterotopic ossification after total hip arthroplasty.

METHODS

The computerized and additional manual searches were performed in Medline, Embase, CNKI, and Cochrane central database (all through March 2014) for potential studies. Studies eligible had to meet the quality assessment criteria by Newcastle-Ottawa Scale and to evaluate the risk factors for heterotopic ossification after total hip arthroplasty. Two reviewers independently extracted the relevant data and any disagreement was solved by consensus. Stata11.0 was used to perform all the statistical analyses.

RESULTS

Fourteen studies involving 6468 cases with total hip arthroplasty and 1939 heterotopic ossification (HOs) (30.0 %) were eligible and included in this meta-analysis. Our meta-analysis identified the significant increased risk factors for HO were male gender [odds ratio (OR) 2.11; 95 % confidence interval (CI) 1.80-2.48)], cemented implant (OR 1.48; 95 % CI 1.00-2.17), bilateral operations (OR 1.74; 95 % CI 1.24-2.45), ankylosing spondylitis (OR 1.90; 95 % CI 1.07-3.37) and ankylosed hip (OR 9.85; 95 % CI 2.61-37.24). Rheumatoid arthritis was protective for the development of HO (OR 0.51; 95 % CI 0.33-0.80). The other variables including age, use of NSAIDs, femoral neck fracture, previous hip fracture, hypertrophic osteoarthritis and osteophytes were identified not as the risk factors for development of HO (P > 0.05).

CONCLUSION

Patients involved with the above-mentioned medical conditions should be carefully paid close attention by surgeons to reduce HO after total hip arthroplasty.

LEVEL OF EVIDENCE

Level II, meta-analysis.

Radiotherapy for the prophylaxis of heterotopic ossification: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Heterotopic ossification (HO) involves the formation of lamellar bone in nonosseous tissue. For HO, radiotherapy has been shown to be an effective prophylactic modality.

OBJECTIVE

To compare HO outcomes following radiotherapy and to investigate the comparative efficacy of preoperative versus postoperative radiotherapy.

METHODS

A systematic search was conducted on Ovid MEDLINE, EMBASE and Cochrane CENTRAL. Studies were included if they were randomized controlled trials (RCTs) that included patients who were prescribed prophylactic radiation for whom relevant HO progression outcomes were reported.

RESULTS

From a literature search of 528 articles, 12 RCTs were included. There was a statistically significant reduction in HO prevalence with multiple as opposed to single fraction radiotherapy (p=0.04), however there was no statistically significant difference when examining HO progression (p=0.34). There was no statistically significant difference in HO progression when comparing a biologically effective radiation dose (BED) of >2500cGy versus ⩽2500cGy (p=0.28). As well, no statistically significant difference existed in HO progression between postoperative versus preoperative radiation (p=0.43).

CONCLUSION

There was no difference between postoperative or preoperative radiotherapy in preventing HO progression. There seems to be no relationship between BED greater or less than 2500cGy and the efficacy of HO prophylaxis. Multiple fractions seem to be more effective than single fraction radiotherapy in preventing HO progression.

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.

Is cross-screw fixation superior to plate for radial neck fractures?

This study compares the outcomes of two methods of fixation of displaced fractures of the radial neck. The 58 patients with a mean age of 38.5 years (18 to 56), were treated in a non randomised study with screws (n = 29) or a plate and screws (n = 29) according to the surgeon’s preference.

The patients were reviewed at one year. Radiographs and functional evaluations were carried out up to one year post-operatively, using the Broberg and Morrey functional evaluation score, range of movement, and assessment of complications.

The mean functional scores did not differ significantly between groups (90 (55 to 100) vs 84; 50 to 100, p = 0.09), but the mean range of forearm rotation in screw group was significantly better than in the plate group (152°; 110° to 170° vs 134°; 80° to 170°, p = 0.001). Although not statistically significant, the screw group had a lower incidence of heterotopic ossification than the plate group (n = 1) than the plated group (n = 3) and the pathology was graded as less severe.

Cite this article: Bone Joint J 2015;97-B:830–5

External beam radiation therapy for orthopaedic pathology

External beam radiation therapy is essential in the management of a wide spectrum of musculoskeletal conditions, both benign and malignant, including bony and soft-tissue sarcomas, metastatic tumors, pigmented villonodular synovitis, and heterotopic ossification. Radiation therapy, in combination with surgery, helps reduce the functional loss from cancer resections. Although the field of radiation therapy is firmly rooted in physics and radiation biology, its indications and delivery methods are rapidly evolving. External beam radiation therapy mainly comes in the form of four sources of radiotherapy: protons, photons, electrons, and neutrons. Each type of energy has a unique role in treating various pathologies; however, these energy types also have their own distinctive limitations and morbidities.

Heterotopic ossification after surgery for distal humeral fractures

We retrospectively reviewed 89 consecutive patients (45 men and 44 women) with a mean age at the time of injury of 58 years (18 to 97) who had undergone external fixation after sustaining a unilateral fracture of the distal humerus. Our objectives were to determine the incidence of heterotopic ossification (HO); identify risk factors associated with the development of HO; and characterise the location, severity and resultant functional impairment attributable to the presence of HO. HO was identified in 37 elbows (42%), mostly around the humerus and along the course of the medial collateral ligament. HO was hazy immature in five elbows (13.5%), mature discrete in 20 (54%), extensive mature in 10 (27%), and complete bone bridges were present in two elbows (5.5%). Mild functional impairment occurred in eight patients, moderate in 27 and severe in two. HO was associated with less extension (p = 0.032) and less overall flexion-to-extension movement (p = 0.022); the flexion-to-extension arc was < 100º in 21 elbows (57%) with HO compared with 18 elbows (35%) without HO (p = 0.03). HO was removed surgically in seven elbows. The development of HO was significantly associated with sustaining a head injury (p = 0.015), delayed internal fixation (p = 0.027), the method of fracture fixation (p = 0.039) and the use of bone graft or substitute (p = 0.02).HO continues to be a substantial complication after internal fixation for distal humerus fractures.

Radiation therapy for recurrent heterotopic ossification prophylaxis after partial metatarsal amputation

The formation of heterotopic ossification is a relatively common, yet rarely discussed, cause of re-ulceration after previous partial metatarsal amputation. Excessive bone growth at the amputation site has the potential to create an unwanted prominence on the weightbearing surface of the foot, intuitively increasing plantar pressure and placing the neuropathic patient at greater risk of re-ulceration and limb loss. The aim of the present study was to assess the efficacy of single-dose radiation therapy in preventing recurrent heterotopic ossification. The inclusion criteria consisted of a history of clinically relevant heterotopic ossification formation after partial metatarsal amputation with subsequent partial metatarsal amputation for heterotopic ossification resection, followed by prophylactic single-dose radiation therapy. Eleven consecutive patients meeting the inclusion criteria were identified for the present study. Before the intervention, 10 (91%) patients demonstrated formation of mid- to high-grade heterotopic ossification, and 9 (82%) patients exhibited an associated neuropathic ulceration. On follow-up at least 6 weeks after intervention, 2 (18%) patients exhibited low-grade heterotopic ossification reformation that was not clinically relevant and 9 (82%) did not show signs of heterotopic recurrence. Single-dose radiation therapy can help prevent the formation of heterotopic ossification in high-risk patients, acting as an effective adjunct to surgery in minimizing the risk of re-ulceration and re-amputation in the neuropathic patient.

Characterization of heterotopic ossification in burn patients

Heterotopic ossification (HO) is a clinical condition of ectopic bone formation in soft tissue. This clinical entity has been associated with genetic disorders, traumatic injuries, and musculoskeletal surgeries. In this regard, functional impairments secondary to scar contractures seen in burn injuries may be exacerbated with underlying HO. The appropriate prevention or management of this complication is crucial to optimize outcome in burn patients. This clinical study reviews the incidence of HO in our burned patients, diagnostic methods, therapeutic approaches including surgical timing and techniques.