A Narrative Review on Avulsion Fractures of the Upper and Lower Limbs

Avulsion and Soft Tissue Injuries of the Ulnar Collateral Ligament in Children and Adolescents

BACKGROUND

Although pediatric medial epicondylar fractures and apophysitis are well studied, patterns of subapophyseal avulsion and ligamentous injuries of the medial elbow in this population merit investigation to inform optimal treatment strategies.

PURPOSE

To describe the occurrence and demographic correlates of ulnar collateral ligament (UCL) avulsion and soft tissue injuries of the pediatric and adolescent elbow.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

An institutional review board-approved review was conducted to identify consecutive patients with medial elbow injuries treated in a tertiary pediatric sports medicine practice between 2016 and 2021. Radiographs were obtained during injury evaluation, and patients with nondisplaced medial epicondylar apophysitis and complete epicondylar fracture were excluded, resulting in 150 patients with soft tissue injuries occurring distal to the medial epicondyle apophysis (subapophyseal) for study. Radiographs were evaluated for bony avulsion of the UCL from either the medial epicondyle proximally or the ulnar sublime tubercle distally. Injuries without radiographic evidence of bony avulsion, but with clinical examination findings consistent with ligamentous injury, were classified as radiographically negative UCL injuries, and magnetic resonance imaging (MRI) was performed to further evaluate these injuries if moderate to severe medial swelling of the elbow or significant concern for medial structural injury was present on examination. These MRI scans were evaluated to classify the UCL injury and assess for periosteal or cartilaginous avulsions.

RESULTS

A total of 150 patients (mean age, 12.5 ± 3.4 years; 70 female), 55% (150/274) of the entire medial elbow injury population, had a subapophyseal injury. Of these patients, 62 had a bony avulsion detected on radiograph, and 88 had a radiographically negative injury. In addition to the 62 radiographic avulsions, the 61 MRI scans obtained on those radiographically negative injuries revealed 33 complete UCL disruptions, resulting in 63.3% (95/150) of patients sustaining a complete ligamentous disruption. With the MRI scans, 37 (61%) cases of cartilaginous or periosteal avulsion of the UCL were diagnosed. Overall, 66% of all 150 subapophyseal injuries had a bony, cartilaginous, or periosteal UCL avulsion. Patients with cartilaginous (mean age, 10.3 years) and bony (mean age, 10.6 years) avulsions were younger than those with central ligament injury (mean age, 14.2 years) or periosteal (mean age, 14.2 years) avulsions (P = .005). There was a significant association between the mechanism of injury and the location of UCL tear identified on MRI scans: traumatic falls were associated with distal tears, and throwing injuries were associated with proximal tears (P < .001).

CONCLUSION

UCL central ligament and avulsion lesions may be frequently diagnosed after injury to the pediatric medial elbow, the majority of which are complete injuries, and may require MRI for diagnosis. The mechanism of injury may predict the location of ligamentous injury, and osteocartilaginous avulsions are more likely to present at younger ages than injuries to the soft tissue of the UCL or periosteum. The prevalence of these injuries merits further investigation into best protocols of nonoperative treatment or surgical repair techniques and outcomes.

Management of Pediatric and Adolescent Sublime Tubercle Injuries: Isolated and Complex Patterns Demonstrate Distinct Etiologies and Radiographic Outcomes

BACKGROUND

The aim of this study was to assess the patient demographics, epidemiology, mechanism of injury, and natural history of sublime tubercle avulsion injuries.

METHODS

A multicenter retrospective study was performed in which sublime tubercle avulsion injuries were identified by surgeon records and database query of radiology reports. Demographic data and imaging were reviewed for each case, and injuries were classified as type 1 (isolated injuries with a simple bony avulsion or periosteal stripping) or type 2 (complex injuries with an associated elbow fracture or dislocation). Treatment modality and evidence of radiographic healing at a minimum of 3 months were collected.

RESULTS

Forty patients (78% male) with a median age of 15 years (range, 8 to 19 years) were identified with sublime tubercle avulsion injuries. Sixty-eight percent of cases (n=27) were determined to be type 1 injuries, and 32% (n=13) were classified as type 2 injuries. The majority of type 1 injuries (59%) occurred via a noncontact mechanism in overhead-throwing athletes, whereas 100% of the type 2 injuries were sustained via a contact mechanism. Type 1 injuries presented in a delayed manner in 19% of cases, whereas no type 2 injuries (0%) were delayed in presentation. Type 1 injuries infrequently underwent surgical intervention (19%), whereas 54% of type 2 injuries required surgery. Of those that did not undergo initial surgical management at a minimum of 3-month radiographic follow-up, 9/11 (82%) of type 1 injuries and 0/4 (0%) of type 2 injuries demonstrated evidence of healing. Only 1 case required reoperation (type 2 injury).

CONCLUSIONS

This series of adolescents with sublime tubercle avulsion injuries expands our understanding of the epidemiology of this rare injury, which was previously only described as a noncontact injury in baseball players. Type 1 injuries are more likely to occur via a noncontact mechanism and generally demonstrate radiographic evidence of healing after a period of rigid immobilization. Conversely, type 2 injuries are more likely to undergo initial surgical intervention, and those managed nonoperatively are less likely to achieve radiographic healing. Further studies are needed to elucidate treatment protocols and long-term functional outcomes.

LEVEL OF EVIDENCE

Level IV-case series.