Pars Interarticularis and Pedicle Stress Injuries in Young Athletes With Low Back Pain: A Retrospective Cohort Study of 902 Patients Evaluated With Magnetic Resonance Imaging.

BACKGROUND: Previous studies have reported that spondylolysis occurs predominantly at the L5 and L4 levels, with defects at higher levels occurring in <5% of cases. However, computed tomography and radiography were the primary imaging modalities in these studies. Current evidence regarding diagnostic imaging for pediatric lumbar spondylolysis suggests that magnetic resonance imaging (MRI) is as accurate as computed tomography in detecting early stress reactions of the pars interarticularis or pedicles without fractures while avoiding radiation exposure. The early detection of spondylolysis results in a higher likelihood of bony union and a decreased likelihood of spondylolisthesis. HYPOTHESIS: The increased use of MRI may reveal a larger proportion of spondylolysis in patients who experience an injury at a higher spinal level than previously reported. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The medical records of 902 pediatric and adolescent athletes (364 female, 538 male) diagnosed with symptomatic pars interarticularis and pedicle stress injuries at 2 academic medical centers between 2016 and 2021 were retrospectively reviewed. All patients had MRI scans taken at the time of diagnosis. Only patients with pars/pedicle edema on MRI were included. Data regarding spondylolysis stage, spinal level of injury, unilateral versus bilateral injury, sport participation, and MRI protocol over the 5-year study period were analyzed. RESULTS: Male patients presented at older ages than female patients (P < .001). Soccer was the most common sport at symptom onset and the second most common single-sport activity among those who specialized (participating in 1 sport year-round at the exclusion of others), behind gymnastics. The mean symptom duration was 4.0 months. Although most patients (83.5%) had exclusively lower lumbar stress injuries, 9.1% of injuries occurred at or above the L3 level. Over half of the patients had active single-level pars/pedicle fractures on MRI, with a mean symptom duration before presentation in this subgroup of 4.0 months. Even when pars/pedicle stress reactions were excluded from analysis, 7.1% of patients were injured at or above the L3 level. CONCLUSION: Among male and female athletes aged 8 to 21 years presenting with symptomatic pars interarticularis and pedicle stress injuries evaluated by MRI at the time of initial diagnosis, there was a higher incidence of upper lumbar stress injuries than previously reported.

Effect of High School Showcase Exposures and Timing of Ulnar Collateral Ligament Tear on Professional Baseball Careers in Elite Pitchers.

BACKGROUND: Showcase participation has been considered a risk factor for elbow injuries. It remains unclear whether high school (HS) showcase volume negatively affects pitchers' career paths. Because pitchers are achieving 90 mph thresholds at younger ages, it is unknown whether shorter time intervals between achieving 90 mph thresholds and dates of ulnar collateral ligament reconstruction (UCL-R), known as time to tear (TTT), may affect career trajectory. HYPOTHESIS: Elite pitchers with higher HS showcase volumes would be less likely to reach Major League Baseball (MLB) level compared with elite pitchers with fewer HS showcase appearances. Elite pitchers with longer TTT intervals would be more likely to achieve MLB level. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Demographic, HS showcase and professional performance, and injury data from pitchers selected in the first 5 rounds of the MLB draft (2011-2017) were gathered from publicly available databases. Continuous and categorical variables were compared for the following subgroups: UCL-R group and pitcher group not undergoing UCL-R; "early" and "late" UCL-R groups; and pitchers achieving and pitchers not achieving MLB level. Multivariable analysis was performed using logistic regression. Standard deviations of ±1 SD were used to define early career versus late career UCL-R subgroups after normal distribution was confirmed (Shapiro-Wilk test; P = .227). The early UCL-R group was defined as those pitchers undergoing UCL-R ≤-1 SD from the mean age at first injury (group mean age, 19.43 years), whereas the late UCL-R group was defined as ≥+1 SD from that age (group mean age, 25.19 years). RESULTS: Of 611 pitchers, 455 (74.5%) had HS showcase performance data, and 608 (99.5%) had professional performance data. In total, 184 (30.1%) pitchers underwent UCL-R. Fewer pitchers who underwent early UCL-R achieved the MLB level compared with pitchers who underwent late UCL-R (48.1% vs 86.2%; P = .006). Elite pitchers who pitched in ≥10 showcases in HS had half the odds of achieving the MLB level compared with pitchers who participated in <10 HS showcases (adjusted odds ratio, 0.50; 95% CI, 0.29-0.86; P = .012). For every year longer that an elite pitcher did not tear his UCL after achieving the 90 mph threshold at an HS showcase (TTT after 90 mph [per year]), the likelihood of achieving the MLB level increased by 24% (adjusted odds ratio, 1.24; 95% CI, 1.02-1.52; P = .032). CONCLUSION: Higher HS showcase volume in elite pitchers was associated with a lower likelihood of achieving MLB level. A longer TTT after 90 mph (per year) was significantly associated with achieving MLB level in elite pitchers.

Ulnar Collateral Ligament Tear in Elite Baseball Pitchers: Are High School Showcase Exposures Associated With Injury?

BACKGROUND: Ulnar collateral ligament reconstruction (UCLR) surgeries have increased significantly in amateur and professional baseball pitchers. Although showcase participation has been considered an injury risk factor, limited data are available to corroborate this association. HYPOTHESIS: Elite pitchers achieving fastball velocities ≥90, ≥92, and ≥95 mph at younger ages would be more likely to undergo UCLR earlier in their careers compared with pitchers not achieving these velocity thresholds at younger ages. Elite pitchers participating in high showcase volumes would be more likely to undergo UCLR compared with elite pitchers participating in fewer showcases. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Descriptive, showcase performance, and injury data from pitchers selected in the first 5 rounds of the Major League Baseball draft (2011-2020) were gathered from publicly available databases. Continuous and categorical variables for pitchers undergoing UCLR and those not undergoing UCLR were compared, and multivariable analysis was performed using logistic regression. We used standard deviations (SDs) of ±1 SD of mean age at first UCLR to define early-career versus late-career UCLR subgroups after normal distribution was confirmed (Shapiro-Wilk test; P = .183). The "early" UCLR group was defined as ≤-1 SD (19.09 years), whereas the "late" UCLR group was defined as ≥+1 SD (24.79 years). Trends in time were evaluated using linear regression. RESULTS: Of the 845 pitchers selected, 659 pitchers (78.0%) had retrievable showcase performance data. Of the 845 pitchers, 229 (27.1%) underwent UCLR. Peak fastball velocity recorded at showcases was the strongest predictor of UCLR (adjusted odds ratio, 1.19; 95% CI, 1.02 to 1.39; P = .03). Peak fastball velocity in high school (HS) was significantly higher among pitchers who underwent UCLR compared with pitchers in the no-UCLR group (91.57 vs 90.71 mph, respectively; 95% CI, -1.43 to -0.29; P < .01). Age at which pitchers participated in their first HS showcase was significantly younger for the early versus the late UCLR group (15.53 vs 16.51 years, respectively; 95% CI, -1.53 to -0.41; P < .01). Elite pitchers with early UCLR participated in nearly twice as many showcases compared with the late UCLR group (5.38 vs 2.89, respectively; 95% CI, 0.43 to 4.54; P = .02). The mean number of HS showcases that elite pitchers attended more than doubled during the 2011-2020 study period (from 2.88 to 6.00 total showcases; P < .001). Mean age at which pitchers attended their first HS showcase steadily declined as well over the 10-year period (from 16.52 to 15.63 years; P < .001). CONCLUSION: Peak fastball velocity was the strongest predictor of UCLR in elite pitchers before initiating professional careers. Elite amateur pitchers attended more showcases at younger ages in a decade-long trend. Overall, the variables included in this multivariable analysis were weak predictors, explaining only 3.8% of the variance in UCLR rates.