Growth plate fractures in children’s ankle injuries are much rarer than previously thought

By Emily de Medeiros

A new study led by The Hospital for Sick Children (SickKids) found that lateral ankle injuries in children without X-ray evidence of a fracture are most often sprains that can be easily treated with a removable splint.

The study looked at 135 children with lateral ankle injuries and normal X-rays; of these, only four cases (three per cent) showed evidence of a growth plate fracture with magnetic resonance imaging (MRI), two of which only had partial growth plate injuries. The majority of children in the study had ankle sprain injuries. This study was published on January 4 in JAMA Pediatrics.

According to current standards, the most commonly presumed lateral ankle injury for children is a Salter-Harris I fracture of the distal fibula (SH1DF), a type of growth plate fracture. This fracture can only be seen using MRI since the growth plate is a layer of soft growing tissue not visible on X-rays. The growth plate is traditionally thought to be the weakest part of a child’s musculoskeletal system, so when a child “twists” an ankle, the injury is more likely to result in a growth plate fracture rather than a sprained ligament like adults.

Based on these facts, doctors often assume there is typically a fracture and traditionally treat these injuries with a restrictive cast for three to six weeks and advise follow-up by an orthopaedic surgeon. However, lead author Dr. Kathy Boutis notes that a growth plate fracture is actually quite rare in children’s ankle injuries; thus, many less-serious ankle injuries such as sprains, are being overtreated.

The study compared the healing process of a fracture and sprain injury by using the same supportive treatment of a removable brace and allowing patients to use crutches as needed. “Patients were permitted to use supportive treatments in accordance with their symptoms rather than prescribed immobilization for three to six weeks, regardless of the specific injury of sprain or fracture. The two types of injuries healed in the same amount of time, which supports the previous research in this area,” says Boutis, Staff Physician in Paediatric Emergency Medicine and Senior Associate Scientist at SickKids.

Based on these findings, as well as the goals of the Choosing Wisely campaign, a Canadian effort to help clinicians and patients engage in conversations about unnecessary tests and treatments, Boutis says, "we advocate for a less conservative approach focusing on a treatment strategy that minimizes a patient's discomfort with a removable splint and allows for a return to activities as allowed by the patient's symptoms.”

Boutis explains it’s unnecessary to immobilize these injuries with a cast or walking boot as casting may also reduce speed of recovery. She adds that orthopaedic consultation and radiographic follow-up are not routinely necessary and should be reserved for patients that are not recovering as expected. These findings may improve the diagnosis and treatment of the most common paediatric ankle injuries for both patients and health-care providers.

This research was funded by Physician Services Incorporated and was supported by DJO Global and the Paediatric Research Academic Initiative at SickKids Emergency (PRAISE) program.