Research Article: Varus shearing force is a main injury mechanism of pediatric trampoline-related injury in addition to compressive axial loading

Date Published: June 5, 2019

Publisher: Public Library of Science

Author(s): Keong-Hwan Kim, Han-Soo Kim, Michael Seungcheol Kang, Soo-Sung Park, Gianluigi Forloni.


Many case studies have been published about trampoline-related injury (TRI); however, a comparative study could allow a more specific analysis of the characteristics of TRI, and enable more differentiated approaches to prevent such injuries. We investigated the injury mechanism of TRI in children compared with other pediatric trauma.

Of 35,653 children (age 0–18 years) who visited the pediatric emergency department after traumatic injuries from January 2011 to June 2017, 372 patients with TRI (TRI group) were retrospectively identified. Among the remaining 35,281 patients with other trauma (non-TRI group), 372 were 1:1 matched to the TRI group according to sex, age, injured body part, and body weight (matched-control group). The patients’ data, injured site, and injury patterns were compared between the groups.

The most frequently injured body part was the knee/lower leg in the TRI group and the head in the non-TRI group. The most frequent injury types were fractures in the TRI group and open wounds in the non-TRI group. In the comparison between the TRI and matched-control groups, the most common lower-extremity fractures were proximal tibial fractures with varus angulation in the TRI group and tibial shaft spiral fractures in the matched-control group. For the upper extremities, the risk of lateral condylar humeral fracture was higher in the TRI group. The TRI group presented more physeal involvements.

The risks of varus stress injury (proximal tibial fracture with varus angulation in lower extremity and lateral condylar humeral fracture in upper extremity) were higher in the TRI group than in matched-control group. Thus, varus shearing force seems to be an important injury mechanism in TRI in addition to compressive force. This varus force may increase the risk of physeal injury by generating additional shear force on the physis.

Partial Text

The incidence of trampoline-related injuries (TRIs) in children has increased over decades [1–4]. The patterns of TRI have been described in previous studies [5, 6], including a large-scale study using a national electronic surveillance system [7]. Consequently, several injury patterns of TRI and recommendations to prevent such injuries in relation to the design of trampolines and the behavior of the jumpers have been introduced and updated [7, 8].

The present study protocol was reviewed and approved by the Institutional Review Board of Asan Medical Center (approval No. 2017–0384). Informed consent was waived because the data were gathered retrospectively and analyzed anonymously.

The demographic data of the TRI and non-TRI groups are shown in Table 1. Most injuries occurred in the head in the non-TRI group; however, the TRI group showed more frequent injuries in the extremities, especially the shoulder/upper arm, knee/lower leg, and ankle/foot. The most common types of injury were open wounds in the non-TRI group and fractures in the TRI group. There was no case with significant multiple injuries in the TRI and matched-control groups.

We investigated the characteristics of children with TRI (TRI group) and compared them with those of children with a traumatic injury other than TRI (non-TRI group). The most frequent injured body part was the head in the non-TRI group and the knee/lower leg in the TRI group. The most frequent kinds of injuries were open wounds in the non-TRI group and fractures in the TRI group.




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