Heterotopic Ossification: A Challenging Complication of Total Hip Arthroplasty: Risk Factors, Diagnosis, Prophylaxis, and Treatment

Severe heterotopic ossification after total hip arthroplasty in male patients under 70 years of age: effectiveness of prophylactic protocol

BACKGROUND

This study aims to evaluate the incidence of clinically significant heterotopic ossification (HO) in primary total hip arthroplasty (THA), comparing outcomes with and without the adoption of an HO prophylactic protocol in male patients under 70 years of age.

METHODS

The prophylactic protocol involved the administration of 50 mg of Indomethacin twice daily for 3 weeks. HO presence was classified according to the Brooker classification system, considering "severe" clinically significant HO (Brooker grade 3 and 4).

RESULTS

Two hundred and seventy-nine patients were included in our study, and an overall HO rate of 68.2% versus a rate of 61.5% was found respectively in patients not subjected and subjected to prophylactic protocol, without significant difference (PR 0.062). However, patients not subjected to the HO prophylactic protocol exhibited a severe HO rate of 22.4% compared to 7.7% in the prophylactic group, with a statistically significant difference (P = 0.008).

CONCLUSIONS

Our study demonstrated that prophylactic protocol adoption is significantly associated with lower rate of severe HO in male patients under 70 years of age. Currently, there are no orthopedic guidelines for the prevention and management of HO after THA, but in the absence of contraindications, the adoption of a prophylactic protocol for HO should always be considered in high-risk patients.

Heterotopic ossification following total wrist arthroplasty: a case report

BACKGROUND

Total wrist arthroplasty as a procedure in patients with advanced osteoarthritis has gained more popularity in recent years. As early implants had high rates of complications and newer implants have only slowly gained traction, some sequelae have not been reported yet.

CASE PRESENTATION

This study presents the case of a male German patient, 57 years old, with advanced osteoarthritis who received arthroplasty and presented with severely restricted range of motion 6 weeks after surgery. Radiographs revealed signs of heterotopic ossification that could be confirmed during the revision surgery. Intraoperatively, ossifications were removed and the mobile parts of the implant were changed. In the further course of the healing process, no further signs of ossifications have been reported for 1 year, but range of motion remains reduced.

CONCLUSION

This is the first reported case of heterotopic ossification of the wrist following arthroplasty. Heterotopic ossification should be taken into consideration in cases of restricted range of motion after arthroplasty to be able to handle this complication adequately.

Radiation Therapy for Heterotopic Ossification: A Systematic Review

PURPOSE

Heterotopic ossification (HO) is a benign disorder characterized by ectopic bone formation in soft tissues that can lead to functional loss in patients. We conducted a systematic review of the evidence on the use of radiation therapy (RT) for the prevention or treatment of HO.

METHODS AND MATERIALS

Literature searches were conducted using Medline (via PubMed), Embase, and ClinicalTrials.gov until April 1, 2023. Medical subject headings and free text terms relevant to HO and RT were used. In brief, eligible study participants were ≥18 years of age with HO and were treated with low-dose external RT. Two reviewers screened relevant abstracts and extracted full-text data for analysis. The review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.

RESULTS

Ten studies evaluating the effect of RT for either the prevention or treatment of HO met the inclusion for evidence synthesis. Nine randomized controlled trials did not clearly report their methods and had a medium risk of bias. The studies were conducted between 1988 and 2008, with follow-up ranging on average from 3 to 59 months posttreatment. A total of 1530 participants were analyzed, and 566 were treated with RT following fracture fixation, total hip arthroplasty, or total hip replacement. In pooled data from 8 randomized controlled trials, there was a nonsignificant but clinically meaningful reduction in the presence of HO at follow-up for patients who received RT versus comparators (pooled odds ratio, 0.47; 95% CI, 0.19, 1.17). There was minimal evidence of adverse events.

CONCLUSIONS

This systematic review found a clinically, but not statistically, significant benefit of prophylactic RT for HO at follow-up. These findings are tempered by a moderate risk of bias. While practice patterns vary, RT for HO prophylaxis in high-risk patients may have benefits that outweigh the risks.

Heterotopic ossification (HO) prophylaxis in total hip arthroplasty (THA): A systematic review of level I and level II evidence since 2000

Introduction

Heterotopic ossification (HO) is a somewhat common occurrence after total hip arthroplasty (THA), particularly with certain approaches. This complication can be detrimental to the success of the surgical outcome. Indomethacin and radiotherapy remain common treatment modalities; however, no true gold-standard treatment is universally agreed upon. This study aims to evaluate Level I and Level II evidence for treatment practices of HO prophylaxis since 2000.

Methods

To evaluate HO prophylaxis in total hip arthroplasty, a search was conducted across MEDLINE/Pubmed, Cochrane, and Embase databases using keywords and Medical Subject Heading (MeSH) terms. Titles and abstracts were screened for eligibility for inclusion criteria. Full texts were screened and included if they met eligibility criteria.

Results

HO chemical prophylaxis was more effective than no HO prophylaxis, except for aspirin. Multiple NSAIDs showed equivalence and better side effect profiles than indomethacin. No one superior NSAID was found, and numerous modalities showed efficacy. The most effective dosages of radiation therapy and combination therapy remain unclear. Additionally, both etidronate and salmon calcitonin showed benefit in preventing HO in one study each.

Conclusion

Radiation, NSAIDs, and combination therapy all showed efficacy as HO prophylaxis modalities. HO prophylaxis treatment and modalities should be guided upon patient and surgical factors such as surgical approach, side effects and tolerability of modalities, comorbidities, and available facility resources to optimize the prevention of HO.Level of evidence: Level IV Therapeutic.

Mid- to Long-Term Outcomes and Complications of Total Hip Arthroplasty in Patients Who Have Crowe IV Developmental Dysplasia of the Hip: A Systematic Review and Meta-Analysis

BACKGROUND

Severe forms of developmental dysplasia of the hip (DDH) in adulthood often lead to total hip arthroplasty (THA). This study aimed to evaluate the mid-term to long-term outcomes of THA in Crowe type IV DDH cases, which represent a technically challenging and complex patient group.

METHODS

PubMed, EMBASE, Web of Science, and Scopus were searched for observational studies and case series with over 100 months of mean follow-up on adult patients who had Crowe type IV DDH treated with THA. A total of 3,710 records were initially identified, leading to the inclusion of 24 studies in the final analysis. These studies were subjected to quality assessment using the National Institutes of Health Quality Assessment tool. Various outcomes including revision rates, leg-length discrepancy, Harris Hip Score, and complications like periprosthetic joint infections, dislocations, and nerve injuries were analyzed. A random effects model was employed for statistical analysis, with sensitivity analysis and metaregression applied in cases of high heterogeneity.

RESULTS

The included studies assessed 1,024 hips with a mean follow-up of 11 years, revealing improvements in Harris Hip Score and reductions in leg length discrepancy post-THA. However, notable challenges were noted, including a 10.7% rate of intraoperative fractures, a 1.8% periprosthetic joint infection rate, and a 5.8% dislocation rate. Osteolysis and aseptic loosening revisions were observed in 9.1 and 8% of cases, respectively. Heterotopic ossification occurred in 11.1% of patients. Nerve injury was reported in 4.2% of cases. With the use of metaregression, some factors for observed heterogeneity were identified.

CONCLUSIONS

Total hip arthroplasty (THA) in Crowe type IV DDH patients presents notable challenges, but can lead to substantial long-term improvements in patient-reported outcomes.

LEVEL OF EVIDENCE

IV.

Engineered myeloid precursors differentiate into osteoclasts and resorb heterotopic ossification in mice

Introduction

Heterotopic ossification (HO) occurs following orthopedic trauma, spinal cord injuries, brain trauma and limb amputations. Once symptomatic, HO causes pain, limited mobility and decreased quality of life. Current treatments are limited and have significant complications with high recurrence rates, underscoring the need for improved therapeutic interventions. Osteoclasts (OCs) are physiological bone resorptive cells that secrete enzymes and protons to degrade bone.

Methods

In this study, we describe the use of genetically engineered OCs as a novel cell therapy approach to treat HO. Inducible, engineered myeloid precursors (iRANK cells) treated with a chemical inducer of dimerization (CID) differentiated into TRAP+ multinucleated OCs and resorbed mineralized tissues in vitro.

Results

In vivo, BMP-2-induced murine HO lesions were significantly regressed following treatment using iRANK cells with concomitant systemic administration of CID. Moreover, many OCs were TRAP+, MMP9+, and GFP+, indicating that they differentiated from delivered iRANK cells.

Discussion

In summary, these data con rm the ability of engineered myeloid precursors to differentiate into OCs and resorb HO in vivo paving the way for OC delivery as a promising approach for HO treatment.

Heterotopic ossification following total hip arthroplasty. Which is the predominant risk factor: surgical approach or post-operative prophylaxis?

PURPOSE

To investigate the impact of surgical approach and post-operative prophylaxis on heterotopic ossification (HO) development after total hip arthroplasty (THA).

METHODS

A retrospective analysis of 312 patients who underwent THA between January 2009 and April 2016. Patients were categorized by surgical approach (direct lateral or posterolateral), prosthesis type, and post-operative prophylaxis (Etoricoxib 60 mg daily for two weeks). Two orthopaedic surgeons independently assessed radiographs at serial intervals, and HO was graded as per Brooker classification. Bivariate analysis and regression modelling were performed to assess the associations and confounding effects of different variables, RESULTS: Bivariate analysis identified factors correlated with higher HO incidence: absence of prophylaxis, older age, longer symptom evolution, and lower pre-surgery physical activity. Regression modelling showed a correlation between the direct-lateral approach, post-operative prophylaxis, symptom evolution, and higher HO incidence.

CONCLUSION

Patients with longer symptom evolution before surgery and without post-operative prophylaxis are at higher risk of developing HO. While the direct lateral approach showed higher HO rates, the difference was insignificant. A two-week prophylactic regimen of Etoricoxib 60 mg daily after THA effectively reduced HO formation. Pharmacological prophylaxis should be evaluated case-by-case, considering patient characteristics and risk factors.

Effectiveness of indomethacin in preventing Heterotopic Ossification: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Heterotopic ossification (HO) is a frequent complication of joint trauma or surgery, commonly occurring after hip replacements, acetabular or other joint injuries, or surgeries. Indomethacin has long been used to prevent HO and is considered the first-line therapy. However, its effectiveness and necessity for HO prevention are still debated due to mixed evidence about its efficacy and potential side effects.

METHODS

Following PRISMA guidelines, this systematic review and meta-analysis evaluated randomized controlled trials using the PICO framework. Searches were conducted across PubMed, Embase, Cochrane Library, and Web of Science. Data were extracted and assessed based on the evidence levels of the selected articles. This study was registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY).

RESULTS

This analysis included 665 patients, with 347 in the Indomethacin group and 318 in the No Indomethacin group. The outcomes analyzed-HO, Gastrointestinal Side Effects, and Bone Ununion-indicated that indomethacin effectively prevents HO. The meta-analysis revealed that the Indomethacin group experienced a significant reduction in the occurrence of grade I-II HO compared to the No Indomethacin group, but not for grade III-IV HO. Gastrointestinal side effects were notably higher in the Indomethacin group. The incidence of bone nonunion was higher in the Indomethacin group, although not statistically significant.

CONCLUSIONS

The meta-analysis suggests that indomethacin is effective in preventing HO, particularly for Brooker grade I-II, rather than Brooker grade III-IV. Special attention should be given to gastrointestinal complications when using indomethacin. Further prospective randomized controlled studies are required to confirm these findings.

Heterotopic Ossifications Following Intramedullary Stabilization of Femoral Fractures in Polytraumatized Patients

INTRODUCTION

Heterotopic ossifications (HOs) are a well-known complication following total hip arthroplasty. Yet only little is known about the development of HOs following a femoral fracture and intramedullary stabilization in polytraumatized patients. Thus, the present study aimed to investigate whether the development of HOs is being observed more frequently in patients suffering polytrauma compared to those with single-extremity trauma.

MATERIALS AND METHODS

The retrospective outcome study was conducted at our level I trauma center. All patients admitted from 2010 to 2020 were included if they (1) presented with multiple injuries (≥2 body regions), (2) had an Injury Severity Score ≥16, (3) suffered a femoral fracture, and (4) were treated with intramedullary stabilization. Furthermore, a control group was established to match the polytrauma group (sex, age), who were suffering from single-extremity trauma (femoral fracture) which was treated with intramedullary stabilization. Subsequently, X-rays of the hip were performed and evaluated for up to one-year post-trauma.

RESULTS

Our study group consisted of 36 patients in total (91.7% male; mean age 39.4 ± 17.4 years, range: 18-82 years). The polytrauma (PT) group included 12 patients (mean age 39.5 years, median ISS 28), whereas the control group (single-extremity-trauma) included 24 patients (mean age 39.3 years). We documented HOs in nine (75%) patients in the PT group vs. five (20.8%) patients in the single-extremity group (p = 0.03).

CONCLUSION

In this study, we were able to demonstrate that heterotopic ossifications are being observed significantly more frequently in patients suffering from polytrauma in comparison to patients with single-extremity trauma following intramedullary stabilization after a femoral fracture.

Development and validation of a nomogram for predicting heterotopic ossification following spinal cord injury

OBJECTIVE

Heterotopic ossification (HO) following spinal cord injury (SCI) can severely compromise patient mobility and quality of life. Precise identification of SCI patients at an elevated risk for HO is crucial for implementing early clinical interventions. While the literature presents diverse correlations between HO onset and purported risk factors, the development of a predictive model to quantify these risks is likely to bolster preventive approaches. This study is designed to develop and validate a nomogram-based predictive model that estimates the likelihood of HO in SCI patients, utilizing recognized risk factors to expedite clinical decision-making processes.

METHODS

We recruited a total of 145 patients with SCI and presenting with HO who were hospitalized at the China Rehabilitation Research Center, Beijing Boai Hospital, from June 2016 to December 2022. Additionally, 337 patients with SCI without HO were included as controls. Comprehensive data were collected for all study participants, and subsequently, the dataset was randomly partitioned into training and validation groups. Using Least Absolute Shrinkage and Selection Operator regression, variables were meticulously screened during the pretreatment phase to formulate the predictive model. The efficacy of the model was then assessed using metrics including receiver-operating characteristic (ROC) analysis, calibration assessment, and decision curve analysis.

RESULTS

The final prediction model incorporated age, sex, complete spinal cord injury status, spasm occurrence, and presence of deep vein thrombosis (DVT). Notably, the model exhibited commendable performance in both the training and validation groups, as evidenced by areas under the ROC curve (AUCs) of 0.756 and 0.738, respectively. These values surpassed the AUCs obtained for single variables, namely age (0.636), sex (0.589), complete spinal cord injury (0.681), spasm occurrence (0.563), and DVT presence (0.590). Furthermore, the calibration curve illustrated a congruence between the predicted and actual outcomes, indicating the high accuracy of the model. The decision curve analysis indicated substantial net benefits associated with the application of the model, thereby underscoring its practical utility.

CONCLUSIONS

HO following SCI correlates with several identifiable risk factors, including male gender, youthful age, complete SCI, spasm occurrence and DVT. Our predictive model effectively estimates the likelihood of HO development by leveraging these factors, assisting physicians in identifying patients at high risk. Subsequently, correct positioning to prevent spasm-related deformities and educating healthcare providers on safe lower limb mobilization techniques are crucial to minimize muscle injury risks from rapid iliopsoas muscle extension. Additionally, the importance of early DVT prevention through routine screening and anticoagulation is emphasized to further reduce the incidence of HO.

Fulminant Heterotopic Ossification of the Lower Extremity After Gunshot Injury and Blunt Trauma: A Case Report

Traumatic heterotopic ossification (HO) of the lower extremity is relatively rare but is of major importance in clinical practice. They are defined as posttraumatic abnormal formations of bone within soft tissue outside of the skeletal system. This article describes the clinical case of a 31-year-old male patient who suffered 2 traumatic events within 12 months-a gunshot wound in the lumbar spine/gluteal region followed by a severe traumatic brain injury with intracranial hemorrhage in a traffic accident as a pedestrian. Clinically, the patient was bedridden because of complete stiffening of the lumbar spine, both hip joints, and the left knee joint. After preoperative diagnosis, 3 surgical ablations of the HO were performed on both the hip joints and the left knee joint. In addition, physiotherapeutic exercise, postoperative nonsteroidal anti-inflammatory drug administration (25 mg of indomethazine for 6 weeks, 3 times a day), and perioperative radiation with 7 Gy for each operation were advised. After 4 years of follow-up, the patient showed significant improvement. In HO treatment, prophylactic local radiotherapy (pre- and postoperative radiation with a local single dose of 7 Gy) and postoperative administration of nonsteroidal anti-inflammatory drugs are often recommended. For therapeutic purposes, surgical resection is still indicated for pronounced cases.

Myositis Ossificans of the Psoas Major Muscle After XLIF With Preoperative Administration of Romosozumab: A Case Report

CASE

A 62-year-old woman receiving romosozumab for 3 months underwent extreme lateral interbody fusion (XLIF) for lumbar degenerative spondylolisthesis. From 1 week after surgery, she experienced gradually increasing pain from the right groin to the front of the thigh. Examination revealed ossifying myositis in bilateral psoas major muscles. Etidronate treatment was initiated, improving pain after 4 days. Computed tomography showed lesion disappearance by 3 months after surgery.

CONCLUSION

We report a rare case of myositis ossificans in bilateral psoas major muscles following XLIF surgery, possibly influenced by intraoperative manipulation and romosozumab treatment. Etidronate administration may be effective, as with heterotopic ossification.

Enhanced Surgical Techniques in Orthopedics: A Comprehensive Guide for Surgeons Based on Modification of the McFarland and Osborne Approach to the Hip

INTRODUCTION

The implementation of various approaches in hip arthroplasties introduces distinct advantages and complications. Notably, widely adopted methods such as the posterior approach have been linked to elevated rates of posterior hip dislocations and iatrogenic sciatic nerve injuries, while the lateral approach has been associated with superior gluteal nerve injuries. In this study, we propose a refined modification of the McFarland and Osborne approach, aiming to amalgamate the most favorable aspects of prior modifications of the lateral approach to the hip. Additionally, our contribution extends to providing a comprehensive stepwise guide for the exposure and closure processes in cases of bipolar hemiarthroplasty or total hip replacement. This modification not only offers potential advantages to seasoned orthopedic surgeons but also serves as a valuable resource for young Turks venturing into hip surgeries.

MATERIAL AND METHODS

14 patients with femoral neck fractures underwent surgery using the modified McFarland and Osborne approach and were followed up for a period of six months. The functional outcome was analyzed by the Modified Mobility and Aids Scoring Matrix.

RESULTS

Seven of the 14 patients attained pre-injury status with respect to the Mobility and Aids scoring matrix. six patients had a fall of 1, and one patient had a fall of 2, as compared to pre-injury status.

CONCLUSION

Our research suggests that this method serves as a superior alternative to conventional approaches, demonstrating notable advantages in terms of dissection difficulty, reduced risk to neurovascular structures, and minimized post-operative hip dislocations. Additionally, it exhibits a favorable outcome, enabling a return to pre-injury levels of activity.

Personalizing Prophylactic Radiotherapy for Hip Heterotopic Ossification: An AMSTAR-2 Compliant Review of Meta-analyses

BACKGROUND/AIM

Heterotopic ossification (HO) is a common complication following total hip arthroplasty. Various prophylactic treatments have been proposed, including radiotherapy (RT). This review summarizes the evidence from meta-analyses on the efficacy of RT in preventing hip HO.

MATERIALS AND METHODS

A literature search was conducted on PubMed. The quality of the meta-analyses was assessed using the AMSTAR-2 tool.

RESULTS

Seven meta-analyses were included. One meta-analysis reported a significant reduction in HO occurrence after RT compared to the control group. Comparing RT and non-steroidal anti-inflammatory drugs, one and two meta-analyses showed significantly greater efficacy of RT in preventing severe HO and better outcomes in patients receiving drugs, respectively. Regarding RT settings, the postoperative and preoperative RT were each supported by one meta-analysis. Furthermore, two meta-analyses showed an advantage of multi-fractionated RT over single fraction RT. The overall confidence rate of the meta-analyses was moderate, low, and critically low in one, three, and three meta-analyses, respectively.

CONCLUSION

RT is a confirmed prophylactic intervention for HO. However, the precise optimization of timing, dosage, and fractionation requires elucidation. Future research should focus on the development of predictive models through large-scale data collection and advanced analytics to refine individualized treatment strategies and assess RT comparative effectiveness with drugs.

Incidence of heterotopic ossification following total hip arthroplasty by approach: a systematic review

BACKGROUND

Heterotopic ossification (HO) formation has been increasingly recognized as a complication of major orthopedic surgeries, particularly total hip arthroplasty (THA). Though, the overall incidence of HO following THA has been well-documented, it is often not reported by severity or by surgical approach.

QUESTIONS/PURPOSES

(1) What are the demographics of patients with HO? (2) What is the severity of HO following THA using the Brooker classification? (3) What is the incidence and class of HO following different THA approaches (anterior, posterior, posterolateral, anterolateral, superior, lateral, trans-gluteal)? (4) What are the number and training level of surgeons who performed each procedure?

METHODS

The PubMed, Embase, and Web of Science databases were queried, and PRISMA guidelines were followed. Qualitative and quantitative analyses were performed using Microsoft Excel.

RESULTS

We isolated 26 studies evaluating 6512 total hip arthroplasties (THA). The mean HO percentage overall was 28.8%, mostly Class I (54.2%) or Class II (29.6%). The highest percentage of HO was associated with the modified direct lateral (57.2%) and the traditional lateral (34.6%) approaches. The lowest HO percentages were identified following posterolateral (12.8%) and direct superior approaches (1%). Most studies reported a singular senior surgeon operating within the same approach for all patients.

CONCLUSIONS

The traditional lateral and modified direct lateral approaches to THA resulted in the highest percentage of HO postoperatively. However, most ossification cases were not clinically significant and did not strongly affect overall patient morbidity. Further studies are warranted to identify an association between severity of ossification and different arthroplasty approaches.

Heterotopic Ossification Secondary to Motor Vehicle Collision Trauma Leading to Femoroacetabular Impingement Syndrome: A Case Report

Introduction

A patient presented for recalcitrant right hip pain secondary to femoroacetabular impingement (FAI) after blunt motor vehicle trauma and following the development of a 12 cm heterotopic ossification (HO). FAI is an increasingly recognized diagnosis where the hip joint is exposed to repeated femoral microtrauma from high-level physical activity or trauma, often causing labral ossification, and perhaps underlying a similar biological mechanism to HO.

Case Report

In this case report, we have an otherwise healthy 49-year-old male who was involved in a high-speed motor vehicle collision who was diagnosed with right hip FAI secondary to HO (Brooker's Class IV) and indicated for surgical excision of the HO anterior to the right proximal femur. The care team and patient initially trialed non-operative conservative treatment with non-steroidal anti-inflammatories drugs (NSAIDs) and hypothesized therapeutic success using a non-surgical approach. Surgical resection was pursued with the patient after a failure of conservative measures. The patient reported a zero out of ten on a ten-point numerical rating scale for pain, he also stated improved quality of life, satisfaction with the procedure, and subsequent rehabilitation at 1-month post-operative follow-up.

Conclusion

HO with near complete ankylosis of the hip joint may be causative of FAI when untreated. Although this case demonstrates a rarely studied traumatic etiology of impingement secondary to HO, initial standard conservative anti-inflammatory treatment can still be pursued. By analyzing the periarticular impact of HO secondary to non-surgical trauma, we can utilize and make inferential correlations from the literature, studying HO and impingement in the setting of prior hip surgery to guide treatment and prognosis in those presenting with FAI symptoms secondary to blunt force trauma.

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.

[Effectiveness of combined anteversion angle technique in total hip arthroplasty for treatment of ankylosing spondylitis affecting hip joint]

Objective

To explore the effectiveness of the combined anteversion angle technique in total hip arthroplasty (THA) for treating ankylosing spondylitis (AS) affecting the hip joint.

Methods

A retrospective analysis was conducted on the clinical data of 73 patients with AS affecting the hip joint who underwent THA between August 2018 and August 2021. According to whether the combined anteversion angle technique was used in THA, the patients were divided into study group (37 cases, combined anteversion angle technique was used in THA) and control group (36 cases, traditional THA). There was no significant difference in baseline data such as gender, age, body mass index, disease duration, preoperative Harris score, range of motion (ROM), acetabular anteversion angle, acetabular abduction angle, femoral anteversion angle, and combined anteversion angle between the two groups ( P>0.05). The operation time, hospital stay, and complications of the two groups were recorded and compared. The Harris score and hip ROM were compared between the two groups before operation, at 1, 3, 6, 12 months after operation, and at last follow-up. The acetabular component anteversion angle, femoral component anteversion angle, acetabular component abduction angle, and component combined anteversion angle were measured postoperatively.

Results

The operation time in the study group was significantly shorter than that in the control group ( P<0.05), and there was no significant difference in hospital stay between the two groups ( P>0.05). There was no intraoperative complication such as acetabular and proximal femoral fractures, neurovascular injuries in both groups, and the incisions healed by first intention. All patients were followed up 2-3 years, with an average of 2.4 years; there was no significant difference in the follow-up time between the two groups ( P>0.05). During the follow-up period, there was no complication such as hip dislocation, wound infection, delayed wound healing, deep venous thrombosis, and hip dislocation in both groups. The hip Harris score and ROM of the two groups gradually increased with time after operation, and the differences were significant when compared with those before operation ( P<0.05); the above two indicators of the study group were significantly better than those of the control group at each time point after operation ( P<0.05). Extensive bone ingrowth on the surface of the components could be observed in the anteroposterior X-ray films of the hip joint of the two groups at 12 months after operation, and the acetabular components was stable without femoral stem subsidence, osteolysis around the components, and heterotopic ossification. At last follow-up, the acetabular component anteversion angle, femoral component anteversion angle, and component combined anteversion angle in the study group were significantly superior to those in the control group ( P<0.05), except that there was no significant difference in the acetabular component abduction angle between the two groups ( P>0.05).

Conclusion

For patients with AS affecting the hip joint, the use of the combined anteversion angle technique during THA effectively promotes the recovery of hip joint function and enhances the postoperative quality of life of patients when compared to traditional THA.

Total Hip Arthroplasty Outcomes in Patients Who Have a History of Prior Radiation

BACKGROUND

The purpose of this study was to assess the odds of developing medical and surgical adverse events following total hip arthroplasty (THA) in patients who have a history of radiation therapy (RT) for cancer.

METHODS

A retrospective cohort study was conducted using a national database to identify patients who underwent primary THA (Current Procedural Terminology code 27130) from 2002 to 2022. Patients who had a prior RT were identified by International Classification of Diseases, Tenth Revision, Clinical Modification codes Z51.0 (encounter for antineoplastic RT), Z92.3 (personal history of irradiation), or Current Procedural Terminology code 101843 (radiation oncology treatment). One-to-one propensity score matching was conducted to generate 3 pairs of cohorts: 1) THA with/without a history of RT; 2) THA with/without a history of cancer; and 3) THA patients who have a history of cancer treated with/without RT. Surgical and medical complications were assessed at the 30-day, 90-day, and 1-year postoperative periods.

RESULTS

Patients who have a history of RT had higher odds of developing anemia, deep vein thrombosis, pneumonia, pulmonary embolism, and prosthetic joint infection at all intervals. When controlling for a history of cancer, RT was associated with an increased risk of pulmonary embolism, heterotrophic ossification, prosthetic joint infection, and periprosthetic fracture at all postoperative time points. There was additionally an increased risk of aseptic loosening at 1 year (odds ratio: 2.0, 95% confidence interval: 1.2 to 3.1).

CONCLUSION

These findings suggest that patients who have a history of antineoplastic RT are at an increased risk of developing various surgical and medical complications following THA.

Role of aspirin in the prevention of heterotopic ossification following total hip replacement: a systematic review and meta-analysis

BACKGROUND

To systematically investigate if aspirin (ASA), used as venous thromboembolism (VTE) prophylaxis, plays a role in the prevention of heterotopic ossification (HO) following total hip arthroplasty (THA) and if ASA dosage impacted the rate of HO.

METHODS

Eligible studies published from January 2000 to July 2022 were identified from the computerized searching of PubMed, Scopus and Web of Science. HO was defined according to Brooker Classification. Pooled risk ratios (OR) and 95% confidence interval (CI) were estimated under a random-effect model. Additionally, combined HO incidences were compared according to ASA dosage (a regular dose of 325 bid vs. a low dose of 81 mg bid/162 mg qd).

RESULTS

Thirteen studies were included. ASA administered for VTE prophylaxis was significantly associated with a reduced risk of all-grade HO following THA (univariate, OR: 0.50, 95% CI: 0.34-0.74, P < 0.001; multivariate, OR: 0.60, 95% CI: 0.49-0.73, P < 0.001). Similar results could be observed for high-grade HO (univariate, OR: 0.57, 95% CI: 0.36-0.89, P = 0.015; multivariate, OR: 0.50, 95% CI: 0.27-0.92, P = 0.026). There was a non-significant trend towards a higher incidence of HO formation for low-dose ASA (31%, 95% CI: 29-34%), compared with regular-dose ASA (21%, 95% CI: 11-33%) (P = 0.069 under test of interaction).

CONCLUSIONS

ASA can be an effective option for HO prophylaxis. More well-designed trials with long-term follow-ups are encouraged to confirm the current findings and to investigate the effect of ASA dosage on HO reduction.

Heterotopic ossification in primary total hip arthroplasty: risk factor analysis

BACKGROUND

Aim is to identify if age, sex, type of posterolateral approach (mini vs standard), surgical time and time from surgery to drainage removal were independent risk factors for heterotopic ossifications after total hip arthroplasty.

MATERIALS AND METHODS

Patients who underwent a THA with posterolateral approach during a 15 years period were included. The exclusion criteria were absence of X-rays follow-up or HO prophylaxis protocol adoption. The following data were collected: age, sex, type of approach (classical/minimal-invasive), surgical time, time from surgery to drainage removal. Two orthopedic surgeons independently reviewed the 2 years follow-up X-rays and classified the HO according to Brooker classification. Severe HO was defined if HO were classified as major than grade 2. Correlation between severe HO and risk factor has been tested with multivariable analysis.

RESULTS

About 1225 patients were included: mean age of 63.8 years, 504 were men. HO were found in 67.6%. Men showed higher severe HO rate than woman (44.1% vs 29.1%, p = 0.001). Patients older than 65 years showed higher severe HO rate (30.3% vs 39.9%, p = 0.002). Standard posterolateral approach was performed in 75.4% and severe HO rate was 32.8% versus 27.1% in those treated with the minimally invasive approach (p = 0.067). In 75.6% of cases surgery lasted less than 90 min and this group showed a severe HO rate in 29.1%, while patient with longer surgical time showed a rate of 35.7% (p = 0.033). In 47.4% of patients, the drainage was removed in the first post-operative day, in this group severe HO rate was significantly lower than the others: 24.8 versus 36.2% (p = 0.001).

DISCUSSION

Male sex, age older than 65 years, surgical time longer than 90 min and delayed drainage removal are risk factors for severe HO. Patients with one or more of those risk factors should be identified as good candidates for HO prophylaxis.

Heterotopic Ossification After Modern Total Hip Arthroplasty: Predisposing Factors, Prophylaxis, and Surgical Treatment

Heterotopic ossification (HO) is a common radiographic finding and potentially serious complication after modern total hip arthroplasty. Although historically associated with the posterolateral approach, HO has been noted in 10% to 40% of patients having direct anterior or anterior-based muscle sparing approaches. The available data are uncertain whether robotic arm-assisted procedures are associated with this complication. Current prophylaxis for patients considered high risk of this complication includes postoperative, nonsteroidal, anti-inflammatory medication for several weeks or low-dose perioperative irradiation. The surgical treatment of symptomatic HO associated with severely restricted motion or ankylosis of the hip should be individualized but may include wide excision of bone, acetabular revision to prevent instability, and prophylaxis to prevent recurrence.

The role of miRNA and lncRNA in heterotopic ossification pathogenesis

Heterotopic ossification (HO) is the formation of bone in non-osseous tissues, such as skeletal muscles. The HO could have a genetic or a non-genetic (acquired) background, that is, it could be caused by musculoskeletal trauma, such as burns, fractures, joint arthroplasty (traumatic HO), or cerebral or spinal insult (neurogenetic HO). HO formation is caused by the differentiation of stem or progenitor cells induced by local or systemic imbalances. The main factors described so far in HO induction are TGFβ1, BMPs, activin A, oncostatin M, substance P, neurotrophin-3, and WNT. In addition, dysregulation of noncoding RNAs, such as microRNA or long noncoding RNA, homeostasis may play an important role in the development of HO. For example, decreased expression of miRNA-630, which is responsible for the endothelial-mesenchymal transition, was observed in HO patients. The reduced level of miRNA-421 in patients with humeral fracture was shown to be associated with overexpression of BMP2 and a higher rate of HO occurrence. Down-regulation of miRNA-203 increased the expression of runt-related transcription factor 2 (RUNX2), a crucial regulator of osteoblast differentiation. Thus, understanding the various functions of noncoding RNAs can reveal potential targets for the prevention or treatment of HO.

Preoperative Arterial Embolization for Heterotopic Ossification of the Hip

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Does drainage affect development of heterotopic ossification after total hip arthroplasty?

OBJECTIVE

To investigate the effect of drainage on heterotopic ossification (HO) after total hip arthroplasty (THA) and to evaluate other postoperative complications and joint dysfunction between patients with and without drainage.

METHODS

In this retrospective cohort study, the medical records of patients who underwent THA from 2017 to 2019 were reviewed. The patients were divided into a drainage group and non-drainage group. Standard preoperative anteroposterior and lateral radiographs were assessed by senior radiologists for HO analysis. Clinical indicators included the hemoglobin concentration, superficial infection, blood transfusion, hematoma formation, hip range of motion (ROM), erythrocyte sedimentation rate, C-reactive protein concentration, dressing changes, visual analogue scale score, and Harris Hip Score (HHS).

RESULTS

The incidence of HO was significantly higher in the drainage than non-drainage group (32.0% vs. 16.3%). The presence of severe HO (Brooker grade III or IV) was also different between the groups. Patients in the non-drainage group had smaller ROM early after surgery, but the final ROM and HHS did not differ significantly between the groups.

CONCLUSIONS

The rate and degree of HO after THA were significantly different between patients with and without drainage. There is no added advantage of closed suction drainage over no drainage in primary THA.

Heterotopic ossification after total hip arthroplasty: radiological comparison between a direct anterior approach without an orthopaedic table and a posterior approach

INTRODUCTION

Heterotopic ossification (HO) occurs in almost ⅓ of total hip arthroplasties (THAs). A direct anterior approach (DAA) with an orthopaedic table is less likely to cause HO than a posterior approach. Without an orthopaedic table, the exposure of the femur requires additional soft tissue release. Soft tissue trauma leads to the production of HO inductors. Our study evaluated the incidence of HO 6 months after THA and compared the results between DAAs without an orthopaedic table and posterior approaches.

METHODS

Retrospectively, 164 consecutive, primary THAs were included: 76 through a posterior approach and 88 through a DAA. The main objective was to measure the presence of HO on pelvis radiography 6 months after surgery.

RESULTS

The incidence of HO was significantly higher in the DAA group than in the posterior approach group (47.7% vs. 27.6%, respectively; p < 0.01). The overall incidence of HO was 38.4%. No significant difference was found between the 2 approaches regarding the severity of HO. No significant risk factor for HO was identified other than the surgical approach.

DISCUSSION

In our study, the incidence of HO after THA in patients undergoing DAA without an orthopaedic table was higher than in patients undergoing a posterior approach after 6 months of follow-up. This result is closely related to the surgical trauma. It suggests that the minimally invasive feature of a surgical approach cannot be dissociated from the overall conditions in which it is performed.

Risk Factors for the Development of Heterotopic Ossification Following Acetabular Fractures: A Systematic Review

BACKGROUND

Heterotopic ossification (HO) following acetabular fractures is a common complication that may affect clinical outcomes. However, the effects of prophylactic treatment with nonsteroidal anti-inflammatory drugs or radiation therapy remain controversial. While several factors have been related to the development of HO, there is considerable uncertainty regarding their importance or effect size in the setting of acetabular surgery. Therefore, this systematic review aims to summarize the risk factors for HO following the operative fixation of acetabular fractures and clarify their interrelationships.

METHODS

In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, PubMed, MEDLINE, Embase, and CINAHL databases were searched from inception to February 2021. Studies that assessed factors related to HO development among patients with operatively repaired acetabular fractures were included. Outcomes were risk factors and their effect size (p values, odds ratios, and 95% confidence intervals).

RESULTS

Twenty-five studies and 1 conference abstract with a total of 3,940 patients were included. The following risk factors for HO were identified. Patient factors were increased body mass index, male sex, and increased age. Injury factors were intensive care unit (ICU) admission and length of stay, non-ICU hospitalization for &gt;10 days, the need for mechanical ventilation for ≥2 days, abdominal and/or chest injuries, the number and type of associated fractures, traumatic brain injuries, T-type acetabular fractures, pelvic ring injuries, and hip dislocation. Care factors were a delay to surgery, extensile and posterior surgical approaches to the hip, trochanteric osteotomy, postoperative step-off of &gt;3 mm, and a delay to prophylaxis following injury or surgery. Ethnicity, Injury Severity Score, cause of the fracture, femoral head injuries, degloving injuries, comminution, intra-articular debris, the type of bone void filler, gluteus minimus muscle preservation, prolonged operative time, and intraoperative patient position were not risk factors for developing HO.

CONCLUSIONS

HO following operative fixation of acetabular fractures is not uncommon, with severe-grade HO associated with substantial disability. Careful consideration of the risk factor effect sizes and interdependencies could aid physicians in identifying patients at risk for developing HO and guide their prophylactic management. The results of this study could establish a framework for future studies.

LEVEL OF EVIDENCE

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

Human osteoprogenitor cells obtained from traumatic heterotopic ossification samples showed enhanced osteogenic differentiation potential and ERK/Hedgehog signaling than that from normal bone

Traumatic heterotopic ossification (HO) refers to the abnormal ectopic osteogenesis following trauma, causing limb dysfunction and seriously lowering the life quality of patients. Aberrant osteogenic behavior of progenitor cells that ectopically accumulated within the soft tissues are believed to be responsible for HO formation. However, the detailed mechanism still remained to be clarified. Here in this study, we successfully isolated osteoprogenitors from human heterotopic ossification tissues (HO-ops) and identified their stemness and multi-directional differentiation potential. Using alkaline phosphatase staining together with alizarin red staining, we confirmed that the HO-ops in the heterotopic ossified tissues gained greater osteogenic potential than the normal human bone marrow mesenchymal stem cells (HBMSCs). RT-qPCR also indicated that HO-ops obtained more gene transcriptions of critical osteogenic determinators than HBMSCs. In addition, through Western blot, we proved that ERK signaling pathway and Hedgehog signaling pathway were significantly activated in the HO-ops. When U0126 and cyclopamine were used to inhibit ERK and hedgehog signaling respectively, the osteogenic potential of HO-ops decreased significantly. The hedgehog signaling and ERK signaling also showed cross-talk in HO-ops during osteogenic differentiation in HO-ops during osteogenic differentiation. The elevated ERK and hedgehog signaling was further confirmed in the human traumatic HO sample sections by immunohistochemical staining. In sum, our results showed that the activation of ERK and Hedgehog signaling pathway jointly enhanced the osteogenic potential of HO-ops to induce the formation of traumatic HO, which provides novel insights into the molecular basis of HO formation and offers promising targets for future therapeutic strategy. This article is protected by copyright. All rights reserved.

Selective versus non-selective NSAIDs as prophylaxis for heterotopic ossification following hip arthroplasty: a meta-analysis

Background

Some patients have demonstrated evidence of heterotopic ossification (HO) following total hip arthroplasty (THA). Selective and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) are used as prophylaxis for HO following THA. This meta-analysis compared selective versus non-selective NSAIDs as prophylaxis for HO following THA.

Material and methods

The present study was conducted according to the PRISMA 2020 guidelines. All the clinical investigations comparing selective versus non-selective NSAIDs as prophylaxis for HO following THA were accessed in February 2022. An assessment of the methodological quality and statistical analyses were performed through the risk of bias summary tool of the Review Manager 5.3 software (Cochrane Collaboration, Copenhagen). The modified Brooker staging system was used to rate the efficacies of the interventions.

Results

Data from 8 studies and 1526 patients were collected. 60.8% were female. No difference was found in the sample size, mean age, and percentage of females between the two groups at baseline. No statistically significant difference was found between selective and non-selective NSAIDs in term of efficacy. 72% (1078 of 1502) of the patients were classified as Brooker 0, 21% (322 of 1502) as Brooker I, 5% (80 of 1502) as Brooker II, 1% (16 of 1502) as Brooker III, and 0.1% (2 of 1502) as Brooker IV.

Conclusion

Selective and non-selective NSAIDs were equally effective when used as prophylaxis for HO following THA.

Level of evidence

Level III, systematic review and meta-analysis.

Heterotopic ossification after alloplastic temporomandibular joint replacement: a case cohort study

Background

Heterotopic ossification (HO) is one of the serious complications leading to the failure of alloplastic temporomandibular joint replacement (TJR). However, there was few research on its exact incidence and occurrence. Severe HO might result in pain and limited mouth opening after surgery. Therefore, it is necessary to clarify its clinical and imaging manifestations. The purpose of this study was to study the occurrence and classify HO after the alloplastic TJR.

Method

Patients who underwent standard TJR (Zimmer Biomet stock prostheses or Chinese stock prostheses) with fat graft and at least 1-year-follow-up were included. HO was classified into 4 types according to postoperative computed tomography (CT) scans. Type and occurrence in different TMJ disease were compared. Joint space within 1 week after operation was measured and compared between HO and non-HO TJRs. Maximum incisal opening (MIO), pain, and quality of life (QoL) were recorded and their relevance with HO was analyzed statistically.

Result

81cases with 101 joints were included in the study. The mean follow-up time was 22.9 months (12 ~ 56 months). Among the 48 joints, 27 (56.3%) were type I (bone islands); 16 (33.3%) were type II (bone spurs from the mandibular ramus); 3 (6.3%) were type III (bone spurs from the fossa); and 2 (4.2%) were type IV (bone spurs from both the mandibular ramus and fossa). In HO patients, joint space in type IV was smaller than the other 3 types. Pain scores in HO were significantly greater than non-HO patients before and after operations (p < 0.05). 1 patient in Type IV HO developed ankylosis and had prosthesis revision which accounted for 2.1% in HO patients and 1.0% in all TJR patients.

Conclusion

HO after alloplastic TJR with fat graft was not severe except for type IV, which was easy to cause ankylosis. Preserving sufficient TJR space was important for ankylosis prevention.

Are there really specific risk factors for heterotopic ossifications? A case report of 'non-risk factor' after total hip replacement

Femoral neck fractures are one of the most common fractures in the elderly population. Due to frequent complications of the fixation of these fractures, patients are more and more often eligible for hip replacement surgery. One of the most frequently mentioned postoperative complication is the formation of heterotopic ossification. This case report describes as a 70-year-old male patient that presented with an old hip fracture accompanied by a mild craniocerebral trauma. The patient underwent total cementless hip arthroplasty followed by rehabilitation. At 8 months after surgery, the patient was diagnosed with Brooker IV° heterotopic ossification in the area of the operated hip joint. Due to the persistent pain and complete loss of mobility in the operated joint, computed tomography imaging was performed and the patient was recommended for a revision surgery. The procedure was performed 14 months after the original surgical treatment, resulting in a significant improvement in the range of motion and reduction of pain.

Palovarotene inhibits the NF-κB signaling pathway to prevent heterotopic ossification

Heterotopic ossification (HO) is a common disease characterized by pain, dysfunction, and calcification. The mechanisms underlying HO have not been completely elucidated. Palovarotene, a retinoic acid receptor gamma agonist, significantly inhibits the formation of HO in vivo. However, its specific mechanism of action remains unclear. Therefore, we aimed to evaluate the signaling pathways related to the formation of HO as well as the mechanism of Palovarotene action. We constructed in vitro and in vivo models of HO. Osteogenic differentiation of bone mesenchymal stem cells (BMSCs) was observed by alizarin red and alkaline phosphatase staining assays in vitro. X-ray and hematoxylin-eosin staining were performed in vivo. Western blots and reverse transcription-polymerase chain reaction were performed to determine the levels of osteogenic- and inflammation-related genes. Immunofluorescence and immunocytochemistry were used to assess the levels of p65, the core molecule of the nuclear factor kappa-B (NF-κB) signaling pathway. We demonstrated that, in vitro, under inflammatory stimulation, pathological calcium deposition increased in BMSCs. The levels of osteogenesis- and inflammation-related genes were also upregulated, along with an enhanced expression of p65. Immunofluorescence assays revealed that p65 entered the nucleus, thereby stimulating the downstream effectors of the NF-κB pathway. The above trends were reversed after Palovarotene treatment. In conclusion, the NF-κB signaling pathway played an important role in HO and Palovarotene could alleviate HO by blocking the NF-κB cascade. Our results may provide a theoretical basis for Palovarotene in the treatment of HO. Further studies on the side effects of Palovarotene are warranted in the future.

The Treatment of Heterotopic Ossification With a Dual Mobility Total Hip Replacement System: A Case Report

Heterotopic ossification (HO) is the formation of bone within extraskeletal soft tissue. The development of mature lamellar bone within soft tissues can be acquired in cases like trauma. Clinical manifestations of HO primarily include pain at the site of the extraskeletal ossification and limited range of motion or function when it involves a joint. This case report presents a 56-year-old man with severe HO. His past medical history included a traumatic hip dislocation in 1996. He denied any other past medical, family, or surgical history. This patient had severely limited range of motion and difficulty performing activities of daily living like going up and down the stairs and getting up from a seated position. After failing conservative therapy with non-steroidal anti-inflammatory drugs (NSAIDs) and physical therapy, a non-cemented dual mobility hip replacement system was used to treat this patient. A non-cemented dual mobility hip replacement system was chosen because the patient had significant bone loss and was relatively young. The dual mobility system significantly reduces the risk of dislocation and is a good option for younger patients who require more stability in their hips. The patient progressed well with a full range of motion and no pain. There was no evidence of HO recurrence. Treatment of HO with a total hip replacement, let alone a dual mobility system, is not prevalent throughout the literature. Furthermore, cemented total hip arthroplasty has been associated with increased recurrence of HO, which is why we elected to use a non-cemented technique. Osteoplasty is typically the mainstay of treatment for HO. The purpose of this case report is to introduce an incident of HO treated with a non-cemented dual mobility system and emphasize its use in young, middle-aged, or active patients who have bone loss and require increased stability.

Heterotopic ossification after total hip arthroplasty: When is development completed?

Background

Heterotopic ossifications (HO) are a common complication after total hip arthroplasty (THA). Nonsteroidal anti-inflammatory drugs have proven to reduce the occurrence of HO. It is still unclear when the formation of HO is finished. Aim of our study was to answer this question.

Methods

In a prospective study, the occurrence of periarticular HO was checked during the follow-up (FU) examinations. In total, 75 consecutive patients who underwent THA were included. To ensure a high follow-up rate, only patients with a life expectancy of at least 10 years were included. A medical ossification prophylaxis with mostly etoricoxib (90 mg once daily) was administered. Follow-up examinations were performed at 3 months, 1 year, 3, 5, and 10 years postoperatively. Each time, a clinical and radiological examination was carried out. The HO was graded according to Brooker’s method.

Results

Low-grade HO classified by Brooker grade I and II occurred significantly more frequent than HO grade III. In patients with present HO, a possible increase in Brooker stage could further be observed within 3 years postoperatively. After 3 years, the formation of HO was completed in all patients.

Conclusion

Three years after THA, the formation of HO is complete. After more than 3 years postoperatively, if HO occurs or increases, other triggering causes such as new trauma, periarticular infection, or implant loosening should be considered.

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.

Burn-induced heterotopic ossification from incidence to therapy: key signaling pathways underlying ectopic bone formation

Burn injury is one of the potential causes of heterotopic ossification (HO), which is a rare but debilitating condition. The incidence ranges from 3.5 to 5.6 depending on body area. Burns that cover a larger percentage of the total body surface area (TBSA), require skin graft surgeries, or necessitate pulmonary intensive care are well-researched risk factors for HO. Since burns initiate such complex pathophysiological processes with a variety of molecular signal changes, it is essential to focus on HO in the specific context of burn injury to define best practices for its treatment. There are numerous key players in the pathways of burn-induced HO, including neutrophils, monocytes, transforming growth factor-β1-expressing macrophages and the adaptive immune system. The increased inflammation associated with burn injuries is also associated with pathway activation. Neurological and calcium-related contributions are also known. Endothelial-to-mesenchymal transition (EMT) and vascularization are known to play key roles in burn-induced HO, with hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) as potential initiators. Currently, non-steroidal anti-inflammatory drugs (NSAIDs) and radiotherapy are effective prophylaxes for HO. Limited joint motion, ankylosis and intolerable pain caused by burn-induced HO can be effectively tackled via surgery. Effective biomarkers for monitoring burn-induced HO occurrence and bio-prophylactic and bio-therapeutic strategies should be actively developed in the future.

Mortality After Revision Total Hip Arthroplasty

BACKGROUND

In counseling patients about the complications of revision total hip arthroplasty (revTHA), it is imperative that mortality be considered. The actual mortality rate by indication of revision is ill-defined. The purpose of this study is to determine the mortality rate after revTHA.

METHODS

An institutional database identified 596 patients who had undergone revTHA between 2012 and 2018. Medical records, national, state, and local death indexes were queried for mortality status and indication for revTHA. For survivors, the last clinical visit date was used for censoring in the mortality analysis. Mortality rates were calculated for all clinical patients and then by specific indication for revision.

RESULTS

The overall 2-year mortality rate following revTHA was 19.5 deaths per 1000 or 1 in 51 patients. Patients presenting with a periprosthetic fracture had a significantly higher 2-year mortality rate of 74.5 deaths per 1000 or 1 in 13 patients (P < .001), while an indication of dislocation or instability had a slightly higher 2-year mortality rate of 50.3 per 1000 (1 in 20) but this difference was not significant (P = .531). Other indications such as mechanical loosening or infection did not have a significantly different mortality rate.

CONCLUSION

The overall 2-year mortality rate following revTHA was 19.5 deaths per 1000 which was largely attributed to patients with a periprosthetic fracture (74.5 per 1000) with other indications not significantly impacting mortality. Mortality rates and specific rates by indication for revision should be considered when counseling patients prior to revTHA.

Myositis ossificans of the hip joint causing sciatic nerve palsy following Guillain-barré syndrome: A case report

INTRODUCTION AND IMPORTANCE

Myositis ossificans of the hip is a rare entity caused by trauma and neurological conditions which lead to lamellar bone formation around the joint.

CASE PRESENTATION

We present a 47 years old patient with myositis ossificans of the left and the piriformis muscle following Guillain Barré syndrome causing sciatic nerve palsy (Piriformis syndrome).

CLINICAL DISCUSSION

Clinical assessment revealed global limitation of the left hip movements and palpable bony mass on the lateral aspect of the left hip. Radiographs and computed tomography showed extensive myositis ossificans of the left hip and non-bridging calcification noted on the asymptomatic right side. During initial medical management and physiotherapy patient developed sciatic nerve palsy due to piriformis syndrome and ankylosis of the hip on the left side. Surgical exploration of the sciatic nerve and debridement of the hip. The left hip was found ankylosed and not salvageable. Uncemented total hip arthroplasty was carried out in the session. The patient recovered completely from sciatic nerve palsy and regained the range of motion of the hip. He is under follow-up for the recurrence of myositis ossificans.

CONCLUSION

Guillain-barré syndrome causing piriformis syndrome is a rare entity. Extensive myositis ossificans causing sciatic nerve palsy is even rarer. An awareness of this entity, early detection, and intervention of this condition may help to preserve the native hip.

How Can We Differentiate Local Recurrence From Heterotopic Ossification After Resection and Implantation of an Oncologic Knee Prosthesis in Patients with a Bone Sarcoma?

BACKGROUND

Heterotopic ossification (HO) is common after total joint arthroplasty and usually does not cause diagnostic problems. However, the occurrence of HO after oncologic prostheses implantation can be troublesome as it may mimic a locally recurrent tumor. Because this distinction could have a profound impact on the surgeon and patient, it is important to distinguish the two entities; to our knowledge, no study has evaluated this after oncologic endoprosthetic reconstruction around the knee after tumor resection.

QUESTIONS/PURPOSES

(1) How common is the occurrence of HO compared with local recurrence (LR) after resection of bone sarcoma and the use of an oncologic knee prosthesis? (2) Are there any factors associated with the development of HO after limb salvage procedures with an endoprosthesis? (3) What features allow the surgeon to differentiate HO from a locally recurrent tumor in this setting?

METHODS

Between 2002 and 2018, we performed 409 resections of primary bone tumors followed by reconstructions with oncologic endoprostheses. Of these, 17% (71 of 409) died before 2 years and did not have HO at that time, 2% (8 of 409) were lost to follow-up before 2 years, and another 2% (10 of 409) did not have radiographs available at a minimum of 2 years after surgery (and had not developed HO before then), and so could not be analyzed, leaving 320 patients for analysis in this retrospective study. Forty-two patients were excluded; 2% (5 of 320) for a history of failed allograft reconstruction, 3% (8 of 320) for pathologic fracture at presentation, 2% (6 of 320) for inadequate or complicated biopsy, 1% (2 of 320) for stem fractures, 2% (7 of 320) for stem loosening, and 4% (14 of 320) for extracortical bone bridging, leaving 278 patients for final evaluation. Two observers analyzed AP and lateral radiographs for signs of HO at a mean follow-up of 63 ± 33 months after surgery. We defined HO as extraskeletal bone formation in soft tissues. The primary study endpoint was survivorship free from HO, as ascertained by a competing-risks estimator. To identify factors associated with HO appearance, the demographic, radiographic, clinical, pathologic, and surgical characteristics were compared between patients with HO and those who had no lesion. Characteristic features were also compared between patients with HO and those with LR to help their differentiation. Univariate analysis was used for all statistical evaluations.

RESULTS

HO developed in 8% (21 of 278) of patients in whom oncologic knee prosthesis was implanted. LR developed in 10% (28 of 278) of the patients. According to survivorship estimates, the HO-free survival rate was not different from the LR-free survival rate at 2 years after oncologic knee reconstruction (76 ± 5% [95% CI 63 to 87] versus 74 ± 5% [95% CI 62 to 88]; p = 0.19). History of infection was more common in patients with HO than in patients with no lesion (19% [4 of 21] versus 5% [12 of 229], Odds ratio [OR] 6 [95% CI 2 to 17]; p < 0.001). The male sex was more common in the HO group as well (76% [16 of 21] versus 55% [128 of 229], OR 2 [95% CI 1 to 5]; p = 0.03). The Modular Universal Tumor and Revision System prosthesis was more frequently used in patients with HO (67% [14 of 21]) compared to those with no lesions (40% [92 of 229]; OR 2 [95% CI 1 to 5]; p = 0.02). The lesion border in radiographs was ill-defined in 19% (4 of 21) of patients with HO and 100% (28 of 28) of patients with LR (OR 8 [95% CI 3 to 20]; p < 0.001). The median time to the appearance of HO was shorter than the time to LR (8 months [3 to 13] versus 16 months [11 to 21], [95% CI 10 to 13]; p < 0.001). Pain at presentation was more frequent in patients with LR than in those with HO (86% [24 of 28] versus 14% [3 of 21], OR 36 [95% CI 7 to 181]; p < 0.001).

CONCLUSION

HO may occur after the use of oncologic knee prostheses for reconstruction after tumor resection. In most patients, HO could be differentiated from local recurrence through identifying a well-defined border on radiographs. Otherwise, factors such as an earlier time of presentation and absence of pain could suggest an HO, rather than an LR.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Low-Dose Aspirin Administered for Venous Thromboembolism Prophylaxis Reduces the Incidence of Heterotopic Ossification in Total Joint Arthroplasty

BACKGROUND

Heterotopic ossification (HO) is a common complication following total joint arthroplasty (TJA). However, the pathophysiology of HO is not entirely understood. Inflammation may play a significant role in the pathogenesis of HO as nonsteroidal anti-inflammatory drugs are effective in the prevention of HO. The purpose of this study is to examine if aspirin (ASA), when used as venous thromboembolism (VTE) prophylaxis, influenced the rate of HO formation following TJA.

METHODS

We queried our longitudinally maintained database to identify all patients who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) for osteoarthritis between January 2016 and June 2018 with at least 3-month radiographic follow-up. In total, 1238 THAs and 1051 TKAs were included for analysis. Radiographs were reviewed and HO formation graded according to the Brooker classification. Patient demographic and VTE prophylaxis data were collected and reviewed for accuracy. Univariate and multivariate analysis was performed to evaluate the effect of ASA on HO formation.

RESULTS

The overall rate of HO was 37.5% after THA and 17.4% after TKA. Patients receiving ASA were less likely to develop HO after THA (34.8% vs 45.5%; P < .001), as well as HO after TKA (13.4% vs 18.4%; P = .047) compared to patients receiving non-ASA VTE prophylaxis. The rate of HO formation trended to be lower, albeit not statistically significantly, in patients receiving low-dose ASA (81 mg) vs high-dose ASA (325 mg).

CONCLUSION

Patients undergoing primary TJA receiving ASA for VTE prophylaxis were less likely to develop HO compared to patients who were administered non-ASA VTE prophylaxis.

Evaluation of the Impact of Different Pain Medication and Proton Pump Inhibitors on the Osteogenic Differentiation Potential of hMSCs Using 99mTc-HDP Labelling

First-line analgetic medication used in the field of musculoskeletal degenerative diseases, like Nonsteroidal anti-inflammatory drugs (NSAIDs), reduces pain and prostaglandin synthesis, whereby peptic ulcers are a severe adverse effect. Therefore, proton pump inhibitors (PPI) are frequently used as a concomitant medication to reduce this risk. However, the impact of NSAIDs or metamizole, in combination with PPIs, on bone metabolism is still unclear. Therefore, human mesenchymal stem cells (hMSCs) were cultured in monolayer cultures in 10 different groups for 21 days. New bone formation was induced as follows: Group 1 negative control group, group 2 osteogenic differentiation media (OSM), group 3 OSM with pantoprazole (PAN), group 4 OSM with ibuprofen (IBU), group 5 OSM with diclofenac (DIC), group 6 OSM with metamizole (MET), group 7 OSM with ibuprofen and pantoprazole (IBU + PAN), group 8 OSM with diclofenac and pantoprazole (DIC + PAN), group 9 OSM with metamizole and pantoprazole (MET + PAN) and group 10 OSM with diclofenac, metamizole and pantoprazole (DIC + MET + PAN). Hydroxyapatite content was evaluated using high-sensitive radioactive ^99mTc-HDP labeling. Within this study, no evidence was found that the common analgetic medication, using NSAIDs alone or in combination with pantoprazole and/or metamizole, has any negative impact on the osteogenic differentiation of mesenchymal stem cells in vitro. To the contrary, the statistical results indicate that pantoprazole alone (group 3 (PAN) (p = 0.016)) or diclofenac alone (group 5 (DIC) (p = 0.008)) enhances the deposition of minerals by hMSCS in vitro. There is an ongoing discussion between clinicians in the field of orthopaedics and traumatology as to whether post-surgical (pain) medication has a negative impact on bone healing. This is the first hMSC in vitro study that investigates the effects of pain medication in combination with PPIs on bone metabolism. Our in vitro data indicates that the assumed negative impact on bone metabolism is subsidiary. These findings substantiate the thesis that, in clinical medicine, the patient can receive every pain medication needed, whether or not in combination with PPIs, without any negative effects for the osteo-regenerative potential.

Clinical and radiological outcomes of total hip arthroplasty in patients affected by Paget's disease: a combined registry and single-institution retrospective observational study

BACKGROUND

Total hip arthroplasty (THA) in patients with Paget's disease can be associated with technical difficulties related to deformities and altered mechanical bone properties, and hypervascularity leads to significative intra-operative bleeding. The purpose of this registry and single-institution study was to investigate overall survival and causes of failure of THA in pagetic patients, together with an analysis of the clinical and radiological complications.

MATERIAL AND METHODS

Registry-based survival and complication analysis, type of fixation, intra- and post-operative complications, clinical (pharmacological history, blood transfusions, Harris hip score [HHS]) and radiographic (cup orientation, stem axial alignment, osteolysis around the cup and the stem and heterotopic ossification [HO]) data were reviewed.

RESULTS

In total, 66 patients (27 males and 39 females, mean age at surgery 71.1 years for males and 74.8 years for female) from the registry study presented a 10-year survival of 89.5%. In the institutional study, involving 26 patients (14 males and 12 females, 69 years average) and 29 THAs, hip function improved significantly. Average cup orientation was 40.5°, while varus stem alignment was 13.8%. In total, 52% of hips had heterotopic ossifications. Peri-acetabular osteolysis was in 13.8% of implants and in 45% of hips was found around the stem. Allogenic and autologous blood transfusion rate were 68.2% and 31.8%, respectively, with an average transfusion of 2 units of blood (range 1-6 units). HHS improved by an average of 34 points, with excellent result in 64.3% of patients. Two implants failed, one due to traumatic ceramic head fracture 64 months after surgery, and one due to mobilization of the cup on the second post-operative day.

CONCLUSION

THA surgery in Paget's patients is a safe procedure, and implant survival is only partly affected by bone remodelling and choice of fixation. The post-operative functional outcome is largely similar to that of other patients. Bleeding-related complications are the main complications; a careful pharmacological strategy should be recommended to decrease the risk of transfusions and of HO development.

LEVEL OF EVIDENCE

Level III.

Direct Anterior Approach for Revision Total Hip Arthroplasty: Anatomy and Surgical Technique

There has been increased interest and literature on the efficacy of direct anterior approach (DAA) for total hip arthroplasty (THA). Developments in surgical technique and instrumentation, along with exposure earlier in orthopaedic residency training, may augment the adoption of this approach among practicing orthopaedic surgeons. With the increasing number of primary THA performed through the DAA, understanding the indications and techniques associated with revision THA via the DAA has proved increasingly important. Patient positioning, understanding surgical anatomy and extensile maneuvers, and applying key reconstructive methods are essential for obtaining adequate exposure and fixation. Acetabular exposure can be facilitated through capsular and soft-tissue release, along with extensile approaches to the pelvis and acetabulum. Extensile distal extension can be performed for safe access to the femur, including extended femoral osteotomies. The purpose of this review is to describe indications, surgical anatomy, intraoperative tips, clinical outcomes, and complications after DAA for revision THA.

NSAIDs for Prophylaxis for Heterotopic Ossification After Total Hip Arthroplasty: A Bayesian Network Meta-analysis

Non-steroidal anti-inflammatory drugs (NSAID) have been recommended to prevent of heterotopic ossification (HO) after total hip arthroplasty (THA), but debates are still ongoing. The present Bayesian network meta-analysis of randomized clinical trials (RCTs) compared all available pathways of NSAID treatment as prophylaxis for HO after THA. The present Bayesian network meta-analysis was conducted according to The PRISMA Extension Statement for Reporting of Systematic Reviews Incorporating Network Meta-analyses of Health Care Interventions guidelines. All randomized clinical trials comparing two or more interventions to prevent HO after THA were considered for analysis. HO was classified according to Brooker. The quality of the methodological assessment was performed through the risk of bias summary tool of the Review Manager Software 5.3 (The Cochrane Collaboration, Copenhagen). The network meta-analysis was performed through a STATA routine for Bayesian hierarchical random-effects model analysis, with log odd ratio (LOR) effect measure. Data from 26 studies (6396 THAs; 58% females) were collected. The mean follow-up was 10.50 ± 5.7 months. ANOVA showed good comparability among mean age and gender (P > 0.5). Celecoxib demonstrated the highest rate of Brooker class 0 (LOR 6.96), followed by diclofenac (LOR 6.94). Naproxen demonstrated the lowest rate of Brooker I HO (LOR 2.82), followed by celecoxib (LOR 3.52). Celecoxib demonstrated lowest rate of Brooker class II HO (LOR 1.66), class III (LOR), and class IV (LOR 0.25). The equation for global linearity detected no statistically significant inconsistency (P > 0.5) in all the comparisons. The present Bayesian network meta-analysis encourages the use of celecoxib as a prophylaxis for HO. These conclusions must be interpreted in light of the limitations of the present study. Future investigations are required to establish more definitely the role of celecoxib.Level of Evidence: I, Bayesian network analysis of RCTs.

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.