Damage of the distal radial physis in young gymnasts: can three-dimensional assessment of physeal volume on MRI serve as a biomarker?

To explore the use of quantitative volume assessment to identify the presence and extent of stress-related changes of the distal radial physis in gymnasts with suspected physeal injury, asymptomatic gymnasts, and non-gymnasts. Symptomatic gymnasts with clinically suspected distal radial physeal injury, asymptomatic gymnasts, and non-gymnasts (n = 69) were included and matched on skeletal age and sex. Volume measurements were performed on coronal water selective cartilage MRI images by creating three-dimensional physeal reconstructions semi-automatically using active-contour segmentation based on image-intensity thresholding. Inter- and intra-rater reliability of the measurements were assessed using intra-class correlation coefficients (ICC) for absolute agreement. Twenty-seven symptomatic-, 18 asymptomatic-, and 24 non-gymnasts were included with a median age of 13.9 years (interquartile range (IQR) 13.0–15.0 years). Median physeal volume was significantly increased (p < 0.05) in symptomatic- (971 mm${}^3$, IQR 787–1237 mm${}^3$) and asymptomatic gymnasts (951 mm${}^3$, IQR 871–1004 mm${}^3$) compared with non-gymnasts (646 mm${}^3$, IQR 538–795 mm${}^3$). Inter-rater (ICC 0.96, 95% CI 0.92–0.98) and intra-rater (ICC 0.93, 95% CI 0.85–0.97) reliability of volume measurements were excellent. Of the 10 participants with the highest physeal volumes, nine were symptomatic gymnasts. Increased volume of the distal radial physis can reliably be assessed and is a sign of physeal stress that can be present in both symptomatic- and asymptomatic gymnasts, but gymnasts with suspected physeal injury showed larger volume increases. Future studies should explore if volume assessment can be used to (early) identify athletes with or at risk for physeal stress injuries of the wrist.