Ulnar variance in youth sport

Ulnar variance is a radiographic measurement that describes the relative heights of the distal ulna and radius. Youth athletes who repetitively load their wrist can develop stress injury at the distal radial physis, which may alter longitudinal growth resulting in positive ulnar variance (PUV). This dynamic bony relationship may predilect athletes for wrist pain and/or ulnar-sided pathology; however, the prevalence and clinical significance of ulnar variance in youth athletes is not completely understood.

PubMed, CINAHL, EMBASE, and SPORTDiscus were queried in November 2025 without time constraints.

Ulnar variance is best measured in skeletally immature athletes on posteroanterior radiographs using Hafner's method. Youth athletes exhibit more PUV values on average than non-athlete predicted norms. Its magnitude is not significantly associated with training volume or wrist pain. Positive ulnar variance is a potential end stage of stress injury to the radial growth plate complex. Symptomatic PUV becomes clinically meaningful and may warrant surgical intervention in select cases.

Reported prevalence of PUV in youth athletes varies widely across studies (0%-50%), reflecting substantial heterogeneity in the existing literature. Inconsistent associations of ulnar variance with multiple anthropometric variables, biological data, and training characteristics prevent clear delineation between the effects of genetics vs repetitive mechanical stress to the distal radial physis on its development. Treatment of symptomatic PUV remains controversial.

Body composition may uniquely impact ulnar variance magnitude. Distal radial physis stress injury, rather than PUV, may be a primary driver of wrist pain.

Newer prospective investigations incorporating dynamic imaging techniques are warranted to evaluate ulnar variance under physiologic weight-bearing conditions. Future work should include athletes from multiple upper extremity weight-bearing sports (gymnastics, cheerleading, diving, and wrestling) across all levels of participation to better account for the effects of training exposure on ulnar variance. Serial radiographic evaluation may also help define the relationship between progressive PUV and the development of wrist pain and dysfunction.