Objective To develop and internally validate a field-side triage model to support early specialist referral decisions in young athletes with acute lower extremity sports injuries, where diagnostic resources are often limited.

Design Retrospective cohort study.

Setting Single-center sports medicine clinic.

Participants Athletes aged ≤22 years presenting with acute lower extremity sports injuries between January 2017 and November 2025.

Independent Variables Age, sex, functional severity, injury site, and injury mechanism assessed at initial presentation.

Results A total of 2,129 athletes were included, with 276 (13.0%) undergoing surgery. Independent predictors were older age, female sex, greater functional severity, knee involvement, and high-energy deceleration mechanisms. The full model showed good performance (AUC 0.890; Brier score 0.073; calibration slope 1.00), and the simplified model also demonstrated high discrimination (AUC 0.883). Risk stratification showed increasing surgical rates across low-, intermediate-, and high-risk groups. Decision curve analysis demonstrated greater net benefit than treat-all and treat-none strategies across clinically relevant thresholds.

Conclusions A field-side prediction model based on readily obtainable clinical variables demonstrated good performance for identifying young athletes at risk of requiring surgical intervention and may support early specialist referral decisions in resource-limited settings.

Clinical Relevance This model provides a practical tool for early risk stratification using simple clinical information, supporting timely and appropriate referral decisions in field-side and initial clinical settings.

The authors have declared no competing interest.

This study did not receive any funding.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Ethics Committee of Ashiya Central Hospital approved this study.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors