Paper 95: Adolescent Tarsal Navicular Bone Stress Injuries: A Multicenter Retrospective Analysis of 110 Patients.

Objectives: To describe demographic and presenting clinical characteristics, diagnostic features, treatment approaches, and clinical outcomes of adolescent tarsal navicular BSI's. Methods: A retrospective chart review of patients with tarsal navicular BSIs was performed at eight academic centers. Diagnosis was confirmed by radiologic imaging in all cases. The following variables were collected utilizing a REDCap database and analyzed with basic descriptive and comparative statistics: age, sex, primary sport, physical exam (PE) findings, diagnostic imaging modality, treatment modalities, surgical technique (when applicable), time of protected weight-bearing, time to running, and time to return to sport. Results: 110 patients (mean age: 14.7 years +/-2.7 years; 65% female) met inclusion criteria, 103 (94%) of whom reported a primary sport, most commonly cross country/track and field (33%) and gymnastics/dance (27%). Common PE findings included navicular tenderness (96%), pain with walking (89%), and pain with resisted inversion (55%). Both x-ray and MRI were obtained in the majority of patients (91%), while CT was obtained for 30%. A radiologically detectable fracture line was present in 44%, most commonly on the dorsal navicular cortex. Non-operative treatment was successful in 85% of patients, consisting of protective boot (79%) or cast (21%). Operative treatment was pursued for 15% of patients, with 73% treated with open reduction internal fixation and 27% undergoing percutaneous screw fixation. All operative patients underwent fixation with either 1 (50%) or 2 screws (50%). Bone grafting was performed in 5 patients (31%). Significant differences between non-operative and operative cohorts included presence of fracture line (38% vs. 88%, P<0.001), age (14.3 years vs. 17.1, P<0.001), time of protected weightbearing (7 weeks vs 10 weeks, P=0.012), time to running (12 weeks vs 18 weeks, P=0.001), and time to return to sport (14 weeks vs 20 weeks, P=0.001). Conclusions: Adolescent tarsal navicular BSIs occur most commonly in sports involving repetitive loading, such as cross country, track and field, gymnastics, and dance. The most common PE findings are navicular tenderness to palpation, pain with walking, and pain with resisted inversion. Patients that ultimately require surgical treatment were more likely to have a radiologic fracture line, prolonged return to weightbearing, running and sport than those successfully treated non-operatively. Table 1: Total Cohort Demographics of patients with bone stress injury to the tarsal navicular bone from eight institutions across the United States from 2013 to 2021 Table 2: Demographic and clinical characteristics of non-operative vs. operative patients with tarsal navicular bone stress injuries from eight institutions across the United States from 2013 to 2021 [ABSTRACT FROM AUTHOR]