Stress Fractures in Adolescent Athletes Andrew D. Goodwillie, MD, Eric Nussbaum, ATC and Charles J. Gatt Jr., MD University of Medicine and Dentistry of New Jersey - Robert Wood Johnson Medical School None of the authors listed above have any conflicts of interest Between September 2007 and December 2009, stress fractures in adolescent athletes were prospectively submitted to an online database by local high-school athletic trainers. For every radiographically confirmed stress fracture, a standardized online form that detailed each athlete’s demographics, fracture pattern, clinical presentation, sport, level of participation, training intensity and dietary habits was completed. The database created is reported and analyzed within this study. Adolescent stress fractures are an underappreciated entity in the athletic community and sports literature, especially in the adolescent athlete. Significant gender differences highlight the importance of understanding more about this injury. Furthermore, our data suggests that the intensity of training protocols and level of participation may place adolescents at a significantly higher risk of developing a stress injury. Tibia, 48% Metatarsal, 19% Fibula, 10% Spine, 6% Pelvis, 6% Hindfoot, 4% Femur, 4% This study reports the epidemiology of stress fractures in the adolescent athlete. To date, there are no comprehensive studies published on this injury in patients under the age of 18. We conducted a community surveillance of stress fractures in high school athletes to highlight the importance of this injury as well as reporting significant gender differences that exist within this age group. 230 stress fractures were reported in 189 athletes (74 males; 115 females) from 57 high-schools. The tibia (48%) was the most frequently involved bone, followed by the metatarsal (19%), fibula (10%), spine (6%), pelvis (6%), hindfoot (4%), and femur (4%). Varsity athletes sustained the majority of the fractures (64%) within this study. The most common sports that caused fractures in males were track (26%), football (23%) and cross-country (19%), and in females track (28%) and cross country (23%). Male athletes sustained fractures at an older age (15.97 yrs vs. 15.46 yrs, P<0.005), higher grade (10.56 vs. 10.14, P<0.01), and at a higher body-mass index (BMI) (22.5 vs. 20.8, P<0.001) than female athletes. Males also got more sleep (P=0.001) and had more intense weight lifting schedules (1.50 vs. 0.78 sessions a week, P<0.001) than their female counterparts. Figure 2: Distribution of adolescent stress fractures by anatomic location and level of sport participation. Male athletes have a statistically higher proportion of stress fractures located within the spine than compared with female athletes (9.4% vs. 2.6%; P<0.05). In addition, almost twice as many stress fractures were observed at the varsity level than all other competitive levels combined (64% vs. 36%). Males Females P value Patient Demographics N 74 115 *Age (yrs) 16 (SD + 1.22) 15.5 (SD + 1.16) P < 0.005 *Grade 10.6 (SD + 1.09) 10.1 (SD + 1.07) P < 0.01 *BMI (kg/cm2) 22.5 (SD + 4.06) 20.8 (SD + 2.6) P < 0.001 Pain Scale (0-10) 7.2 (SD + 1.36) 7.3 (SD + 1.47) P = 0.69 Prior Stress Fx (%) 5.4 8.7 NS Training Regimen Middle School/Freshman/Sophmore (%) 15.1 12.3 NS Junior Varsity (%) 21.9 22.8 NS Varsity (%) 63.1 64.9 NS Year schedule (# seasons/yr) 2.3 (SD + 0.74) 2.4 (SD + 0.76) P = 0.65 Weekly schedule (# sessions/wk) 6.1 (SD + 0.59) 5.9 (SD + 0.62) P = 0.46 Duration (# hrs/wk) 15.1 (SD + 3.68) 14.6 (SD + 3.51) P = 0.49 *Weight schedule (# weights/wk) 1.5 (SD + 1.61) 0.78 (SD + 1.09) P < 0.001 Hardwood training (%) 31.10% 38.30% NS Dietary Habits Supplements (Y/N) 41.9% / 58.1% 30.4% / 69.6% NS Balanced meals (Y/N) 87.8% / 12.2% 88.7% / 11.3% NS *Dairy intake (# servings/day) 2.97 (SD + 1.88) 2.3 (SD + 0.01) P = 0.01 Caffeine (# servings/day) 0.9 (SD + 1.08) 0.9 (SD + 1.34) P = 0.79 *Sleep (# hrs/night) 7.6 (SD + 0.81) 7.11 (SD + 0.91) P = 0.001 Table 1: Patient demographics, training regimen and dietary habits of adolescent patients with documented stress fractures. Gender differences at a statistically significant value of P < 0.01 are highlighted. Male athletes sustain stress fractures at an older age, at a higher BMI, sleep for longer and participate in a more intense lifting schedule than female athletes. Figure 3: X-ray radiographs and MRI T2-sequences of a 13-year-old baseball player showing a right proximal tibial posterior metaphyseal stress fracture with circumferential periosteal reaction and surrounding soft tissue edema. 0 10 20 30 40 50 60 19 14 5 6 17 0 2 4 0 1 0 1 1 0 0 0 32 27 14 12 0 14 5 0 4 2 2 0 0 1 1 1 Male Female Figure 1: Distribution of adolescent stress fractures by type of sport and gender. The tendency is for stress fractures to occur in more ‘running intense’ sports. The sports most associated with stress fractures in male athletes are track (26%), football (23%) and cross country (19%). For female athletes the sports most associated with stress fracture are track (28%) and cross country (23%). Middle School 1% Freshman 11% Sophmore 2% Junior Varsity 22% Varsity 64%