Thanks very much to AOSSM and my co-authors. Our disclosures are in the program. So tarsal navicular bone stress injuries or stress fractures are considered high-risk bone stress injuries in adults due to prolonged healing times and higher rates of nonunion. But this really has not been previously examined in comprehensive fashion in adolescent athletes. These injuries are relatively rare in this age group but probably increasing due to youth sports popularity, specialization, and increases in intensity of training. But we really just have case reports and almost no applicable case series, so treatment principles are largely derived from adult papers. So our goal was to investigate in multicenter fashion the demographic, clinical, and radiographic characteristics of navicular bone stress injuries in a large cohort and their response to both operative and nonoperative treatment. We hypothesized the majority would heal with nonoperative treatment, but those who failed might have identifiable risk factors that could help guide treatment in the future, and the clinical results of operative treatment would be good to excellent with lower rates of nonunion than reported for adults. So this is a retrospective Level 4 clinical series, but derived from eight different academic centers over a nine-year study period. All were radiologically confirmed fractures in the 10- to 19-year-old age group with the overuse pattern. And so we excluded any traumatic, discrete mechanisms of injury-type navicular fractures, os naviculari, tarsal coalitions, pathologic fractures, and those without a definitive diagnosis radiologically. We looked at demographic characteristics, the clinical presentation, radiologic characteristics, the surgical technique when applicable, and the clinical outcomes, but it was not a patient outreach study with PROs. So our mean age was just under 15. Sixty-five percent of the patients were female, which is flipped from the typical adult finding of more males in most of the series in the literature. We had 88 percent were white, mostly from a single center without great diversity representing half of the cohort, and all the geographic regions were represented, but largely in the Northeast. In terms of primary sports, 60 percent of patients were either cross-country track and field runners or gymnastics or dance athletes. So really this is in the lean sport category in which lower body weight is thought to improve performance. And so this is an important thing to note for future research. And then 30 percent were in high-impact cutting and pivoting sports with a variety of other sports represented in the final 10 percent. So in terms of clinical presentation, almost all patients had navicular tenderness, 90 percent or so had pain with walking. Over half had pain with resisted inversion. And then a third had prior bone stress injury elsewhere, with just over 10 percent having a prior navicular bone stress injury. Over 90 percent had both x-rays and MRIs, so 30 percent had CTs. And then 44 percent had a Grade 4 BSI, so a visible fracture line, the most common site of which was a dorsal navicular and the body of the navicular. All patients underwent initial non-operative treatment with crutches and then about 80% walking boots, 20% short-leg casts with two-thirds having physical therapy out of the gates. The mean duration of weight-bearing protection was 7 weeks. Mean time to return to running, 12 weeks. And mean time to full return to sport, 14 weeks. Fifteen percent ended up needing surgery, three-quarters of whom had open surgery with debridement or curettage at the fracture site. About half of those were bone grafted as well. One-quarter underwent percutaneous screw fixation. And then we had an even split between a single screw fixation and a dual screw fixation. In terms of risk factors amongst the operative cohort, this is an older subgroup, so 17 compared to 14 in the non-operative group. They also had a higher BMI. As you'd expect, there's a higher ratio of grade 4 BSIs or visible fracture lines, though almost 40% of the effectively non-operative treatment group had grade 4 injuries. And then a couple had grade 3 injuries in the operative group. In terms of the return to activities, the operative group starting from the time of surgery had a higher time to return to weight-bearing at 10 weeks compared to 7 weeks. Return to running was more like 4 months compared to 3 months in the non-op group and return to sports 5 months compared to 4 months. So in summary, adolescent tarsal navicular BSIs most commonly occur in females and those participating in lean sports. The primary diagnostic tool should be MRI, which is warranted for staging as well as potential future comparisons if there's a lack of healing or continued symptoms. The gold standard treatment should be non-operative in this age group as 75% of our highest grade injuries healed without surgery, but be prepared for potential need for surgery in the operative patients are more likely to be the older adolescents, those with a higher BMI, grade 4 fracture lines. And surgery is successful with low rates of non-union, but they do require longer periods of weight-bearing protection, return to running and return to sports. Thanks very much.

tarsal navicular bone stress injuries

adolescent athletes

multicenter study

fractures

overuse patterns