Proximal Tibial Fracture Sustained During Trampoline Use

A 2.5-year-old, previously healthy boy presented to the emergency department (ED) with left leg pain. One day prior to presentation, the boy was jumping on a trampoline with an 11-year-old child, when he suddenly dropped to his knees and began to scream. He then refused to walk and was brought to the ED for refusal to walk and persistent left leg pain.

The child’s vital signs were normal, and the results of the full body examination were unremarkable except for his left lower extremity. There was significant pain with movement in the left lower extremity, along with tenderness to palpation and mild swelling over the proximal tibia. Neurovascular examination results were unremarkable, and right lower extremity examination demonstrated full range of motion, without any tenderness, swelling, or bruising. The boy’s strength was rated 5/5 bilaterally, and his shoulders, elbows, wrists, and hands were normal for strength and neurovascular status.

A 2-view radiograph of the left tibia and fibula demonstrated an acute Salter-Harris type II fracture of the proximal tibia (Figures 1A and 1B). A skeletal survey was performed, which was significant only for the left proximal tibia fracture. The patient was placed in a posterior long leg splint, and follow up was arranged with the orthopedic department in one week for conversion to a long leg cast.

Discussion

Between 8% and 12% of all pediatric injuries are fractures, making fractures one of the most common injuries encountered during childhood.¹ Approximately 20% of fractures are intentional and are indicative of child abuse,¹ but many fractures are caused for other reasons, including trampoline use. Trampoline injury cases doubled between 1991 and 1996, leading to a peak of injuries in 2004. Sales of trampolines also reached their peak in 2004. As noted in a 2012 study, injuries were shown to have decreased as a result of less use of trampolines at home.² However, public trampoline parks have gained popularity in recent years, and from 2010 to 2014 ED visits resulting from injuries at trampoline parks increased.³ Trampoline injuries are also on the rise also because of use by children younger than 6 years, which accounts for 22% to 37% of trampoline-related injuries presenting to ED.²

Most trampoline injuries are sprains, strains, contusions, or other soft tissue injuries. Ankle sprain is the most common type of trampoline-associated injury.² Younger children are more prone to bony injuries, with 29% of injuries in children aged 6 to17 years resulting in fractures or dislocations versus 48% of injures in children aged 5 years and younger resulting in fractures or dislocations.² Higher rates of hospitalization for trampoline injuries are seen in children less than 4 years of age compared with older children.²

Lower extremity injuries are the most common injuries, comprising 34% to 50% of trampoline injuries. Injuries of the upper extremities comprise 24% to 36% of cases.² Head and neck injuries account for 10% to 17% of all trampoline-related injuries, with 0.5% of injuries resulting in permanent neurologic damage.² Proximal tibial fractures are a more specific type of fracture seen in trampoline injuries, and they can be either a transverse or torus-type fracture.² They occur more frequently when young children share the trampoline with larger individuals. Other types of injuries include manubriosternal dislocations/sternal injuries, thoracic hyperflexion injuries, vertebral artery dissections, and atlanto-axial subluxations.²

There are different mechanisms of trampoline injuries. Approximately 75% of injuries occurred when there was simultaneous usage of the trampoline with multiple people.² The smaller participant is 14 times more likely to sustain injury than the heavier counterparts due to greater recoil of the mat, in combination with the smaller participant’s less developed motor skills.² Falls from a trampoline account for 27% to 39% of all trampoline-associated injuries,^, while impact with trampoline frame/springs accounts for approximately 20% of trampoline injuries.²

Clinicians must always include child abuse in the differential diagnosis when a child presents with a fracture. Of the injuries caused by physical child abuse, fractures are the second most common type of injury and bruises are the most common injury.¹ In children under the age of 3 years, as many as 20% of fractures caused by abuse may be misdiagnosed as nonintentional if not approached with a high index of suspicion.¹ Some clues in the history and physical examination that point to a child abuse diagnosis include a care giver’s delay in seeking medical treatment, the presence of multiple fractures in various stages of healing, and other organ injuries.

The American Academy of Pediatrics continues to recommend against recreational trampoline use at home.² Current implementation of safety measures have not appeared to substantially mitigate risks, especially for children younger than 5 years.²

Jin Seon Kim, MD and Shabnam Zargar, MD, are resident physician and attending physician, respectively, at the University of California Riverside School of Medicine, Palm Springs, California.

References

1. Flaherty EG, Perez-Rossello JM, Levine MA, et al. Evaluating children with fractures for child physical abuse. Pediatrics. 2014;133(2):477-489.

2. Council On Sports Medicine and Fitness. Trampoline safety in childhood and adolescence. Pediatrics. 2012;130(4):774-779.

3. Kasmire KE, Rogers SC, Strum JJ. Trampoline park and home trampoline injuries. Pediatrics. 2016;138(3). pii: e20161236.