Radiation-Induced Sarcoma After Heterotopic Ossification Prophylaxis: A Case Report

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

CASE

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

CONCLUSION

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

Efficacy of Ibuprofen after Total Hip Arthroplasty to Prevent Heterotopic Ossification: Systematic Review and Meta-Analysis

The objective of this study was to conduct a systematic review and meta-analysis of relevant randomized control trials (RCTs) to determine the role of ibuprofen, as well as the optimum dose and duration of therapy, in preventing the incidence of heterotopic ossification (HO) after primary total hip arthroplasty (THA). A literature search was performed using the PubMed/MEDLINE and Cochrane Library databases for RCTs that compared the use of ibuprofen versus placebo as prophylaxis for HO in patients after THA. The main outcomes for this study were overall occurrence of HO, occurrence according to the Brooker classification, and gastrointestinal complications. A total of 27 potential articles were identified from the database. Eventually, four trials with 1,153 patients were included in the final analysis. When compared with placebo, the use of ibuprofen is associated with a reduction in the incidence of HO at the 3- and 12-month follow-up appointments, as well as the incidence of Brooker II and III HO ( p  < 0.05). However, there was no significant difference between the ibuprofen and placebo groups in terms of treatment discontinuation due to gastrointestinal complications or the incidence of Brooker I and IV HO ( p  > 0.05). The existing data indicates that ibuprofen is safe and efficacious in reducing the total incidence of HO along with Brooker II and III HO at follow-up. However, due to the small number of studies, the conclusions are limited; therefore, more high-quality clinical trials are required to develop guidelines for optimal dose and duration of therapy.

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.

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.

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.

Synostosis of the interphalangeal joint: an uncommon cause of post-fracture digital stiffness

Loss of motion and stiffness after fracture of the digits are most commonly a result of soft tissue contracture and adhesions. However, stiffness can also have a bony etiology. We present a case of synostosis of the thumb interphalangeal joint after non-operative treatment of a closed fracture.