Journal of Pediatric Orthopaedics - 2026-07-21 - Journal Article
The Relationship Between Boxer's Fracture and Aggression, Hyperactivity, and 2D:4D Finger Ratio in Children and Adolescents: A Prospective Case-Control Study.
Özel V, Günaydin F, Dağlar Ş, Dursun G, Yilmaz M
Topics
Key Takeaway
Children with boxer's fractures had a significantly lower 2D:4D digit ratio (0.888 vs. 0.939, P<0.001) and higher aggression scores, with ADHD subtypes independently associated with fist-mechanism fifth metacarpal neck fractures.
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Summary
This prospective case-control study compared 2D:4D digit ratio, aggression scores (Buss-Perry and Violence Propensity Scales), and DSM-5-TR ADHD symptom burden between 100 pediatric boxer's fracture patients and 100 age-, sex-, and socioeconomic-status-matched controls presenting with non-aggression-related trauma. The boxer's fracture cohort demonstrated a lower 2D:4D ratio (0.888 vs. 0.939), higher scores across all aggression subscales, and strong ADHD subtype associations on penalized logistic regression (all P<0.001). A low 2D:4D ratio and high total aggression score were independently predictive of boxer's fracture on multivariate analysis, though the 2D:4D–aggression correlation was weak (r=−0.23).
Key Limitation
The cross-sectional single-assessment design cannot establish whether ADHD symptoms and elevated aggression scores preceded the fracture or were acutely influenced by the injury and its circumstances, precluding causal inference.
Original Abstract
BACKGROUND
Boxer's fracture (fifth metacarpal neck fracture associated with the fist mechanism) is a common outcome of aggression-related intentional injuries, particularly in children and adolescents. This study aimed to compare the second-to-fourth digit ratio (2D:4D), aggression level, and attention deficit hyperactivity disorder (ADHD) symptoms in children and adolescents with a boxer's fracture against a healthy control group, and to evaluate possible relationships among these variables.
METHOD
In this prospective case-control study, 100 children and adolescents (mean age: 13 y; range: 6 to 17) with a fist-mechanism fifth metacarpal neck fracture (group 1) and 100 patients presenting with nonaggression-related trauma (group 2) were enrolled at 2 hospitals over a 1-year period. All variables were assessed at presentation; as the design involved a single assessment point, no follow-up period was applicable. The 2D:4D finger ratio was measured in all participants using conventional hand radiographs. Aggression was evaluated using the Buss-Perry Aggression Scale and the Violence Propensity Scale, while ADHD symptoms were evaluated using the Level 2 ADHD Assessment Scale based on DSM-5-TR. Intergroup comparisons, correlation analyses, and multivariate logistic regression analyses were performed.
RESULTS
The case and control groups were similar in terms of age, sex, and socioeconomic status (all P >0.05). The 2D:4D finger ratio was significantly lower in patients with a boxer's fracture compared with the control group (0.888 vs. 0.939, P <0.001). Physical aggression, anger, hostility, and total aggression scores were significantly higher in the case group (all P <0.001).A weak but significant negative correlation was found between the 2D:4D ratio and physical aggression ( r =-0.23, P =0.001) and total aggression score ( r =-0.23, P =0.001). In multivariate logistic regression analysis, a low 2D:4D ratio and a high total aggression score were independently associated with a boxer's fracture. ADHD subtypes (predominantly inattentive, predominantly hyperactive, and combined type) were strongly associated with a boxer's fracture in penalized logistic regression analysis.
CONCLUSION
This study demonstrates that children and adolescents with a boxer's fracture exhibit a risk profile characterized by a lower 2D:4D finger ratio, increased aggression, and pronounced ADHD symptoms. The findings suggest that a boxer's fracture in childhood and adolescence may not only be an orthopaedic injury but also a clinical reflection of associated behavioral and neurodevelopmental risks. Therefore, multidisciplinary assessment and appropriate psychosocial screening approaches in children presenting with a boxer's fracture may contribute to clinical practice.
LEVEL OF EVIDENCE
Level
III
prospective case-control study.