Heterotopic Ossification After Elbow Fractures

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Classification and Incidence of Heterotopic Ossifications in Relation to NSAID Prophylaxis after Elbow Trauma

Heterotopic ossification (HO) after elbow trauma can be responsible for significant motion restrictions. The study's primary aim was to develop a new X-ray-based classification for HO of the elbow. This retrospective study analyzed elbow injury radiographs from 138 patients aged 6-85 years (mean 45.9 ± 18) who underwent operative treatment. The new classification was applied at 6 weeks, 12 weeks, and 6 months postoperatively. The severity of HO was graded from 0 to 4 and localization was defined as r (radial), p (posterior), u (ulnar) or a (anterior) by two observers. The patients were categorized based on injury location and use of non-steroidal anti-inflammatory drugs (NSAIDs) for HO prophylaxis. The correlations between the generated data sets were analyzed using Chi-square tests (χ2) with a significance level of p < 0.05. The inter- and intraobserver reliability was assessed using Cohen's Kappa. In 50.7% of the evaluated X-rays, the formation of HO could be detected after 12 weeks, and in 60% after 6 months. The analysis showed a significant correlation between the injury's location and the HO's location after 12 weeks (p = 0.003). The use of an NSAID prophylaxis did not show a significant correlation with the severity of HO. The classification showed nearly perfect inter- (κ = 0.951, p < 0.001) and intrareliability (κ = 0.946, p < 0.001) according to the criteria of Landis and Koch. Based on the presented classification, the dimension and localization of HO in the X-ray image can be described in more detail compared to previously established classifications and, thus, can increase the comparability of results across studies.

The Incidence of Heterotopic Ossification in Surgically and Non-surgically Treated Elbow Fractures at a Municipal Hospital in Japan

Background: Heterotopic ossification (HO) is a well-recognised complication of after elbow trauma. The prevalence and risk factors of HO have been previously reported. However, these reports were based on elbow trauma that had undergone surgical treatment and most of them were from Western countries. This study aimed to assess the incidence of HO in patients with elbow fractures who were treated surgically and non-surgically in Japan. Methods: We retrospectively identified consecutive patients who were treated of elbow fractures and fracture-dislocations at our institution in recent consecutive 3-year periods. We extracted patient demographics, injury mechanisms and treatment details from the medical records. Furthermore, we reviewed radiographs to classify the fracture pattern and identify the presence or absence of HO. Results: HO was identified in 6/97 (6%) patients. Fracture-dislocation was noted in 4/6 patients. The fracture types with HO included terrible triad injury (n = 2), isolated coronoid process fractures (n = 2), distal humerus A-type fractures (n = 1) and radial head fracture (n = 1). According to the Hastings and Graham classification, HO was classified as Class I in five patients and Class II B in one patient who underwent additional surgery for HO resection. Conclusions: The incidence of HO was relatively low in our patients. However, of the 20 conservatively treated elbows, one patient developed clinically relevant HO and required excision of HO. Even patients with elbow fractures treated conservatively should be informed of the potential risk of developing severe HO requiring surgical excision. In addition, surgeons in this region could use these data to inform patients about the risk of HO development after an elbow injury. Level of Evidence: Level IV (Therapeutic).

Heterotopic Ossification after Trauma

Heterotopic ossification (HO) refers to benign ectopic bone formation in soft tissue and is common following trauma surgery. HO bone can restrict movement and progress into ankylosis that may necessitate surgical intervention. This article discusses the current literature on the pathophysiology, prophylaxis, treatment, and epidemiology of postoperative HO following orthopedic trauma.

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.

Heterotopic ossification formation after fractures about the elbow

INTRODUCTION

Heterotopic ossification (HO) is a well-known sequela after an elbow injury and is widely studied given the associated morbidity. The anatomic location of HO development for specific elbow injuries has not been reported. The purpose of this study was to describe the precise, anatomic location of HO development after different peri-articular elbow injuries.

METHODS

A retrospective chart review was performed for patients with peri-articular elbow fracture and/or dislocation who underwent an elbow contracture release. The injuries were grouped into coronal shear distal humerus/AO 13.B3 (CSDH), distal humerus/AO 13.A, 13.B1, B2 or 13.C (DH), olecranon/AO 21.B1 (OL), radial head/AO 21.B2 (RH), extra-articular proximal radius and ulna/AO 21.A (EAPRU) fractures and elbow dislocations (DL). The HO location was determined by reviewing elbow radiographs and CT scans and were classified as anterior capsule, medial or lateral collateral ligaments, and posterior capsule/triceps insertion.

RESULTS

The study consisted of 49 patients, such as 6 CSDH, 13 DH, 6 OL, 21 RH, 4 EAPRU fractures and 20 elbow DL. All CSDH and RH fractures and 19/20 elbow DL developed HO in the collateral ligaments, while 12/13 DH fractures developed an anterior capsule HO. All 6 OL fractures developed HO posteriorly, and 3/4 EAPRU fractures developed a proximal radioulnar synostosis.

CONCLUSIONS

Our findings suggest that the location of HO development is specific to the injury type and is influenced by the soft tissues involved. This is consistent with the understanding that HO is the abnormal ossification of normal structures.