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. 2025 Aug 5;12(3):e70280.
doi: 10.1002/jeo2.70280. eCollection 2025 Jul.

Creation and validation of a treatment algorithm for skeletally immature patients with acute anterior cruciate ligament injury based on MRI and patient characteristics

Alberto Grassi  1   2 , Kyle Borque  3 , Martijn Dietvorst  4 , Emanuele Altovino  2 , Claudio Rossi  2 , Luca Ambrosini  2 , Alice Bondi  5 , Stefano Zaffagnini  1   2
Affiliations

Creation and validation of a treatment algorithm for skeletally immature patients with acute anterior cruciate ligament injury based on MRI and patient characteristics

Alberto Grassi et al. J Exp Orthop. .

Abstract

Purpose: This study aimed to develop and validate a clinical decision-making algorithm, the 'Best ACL-treatment Based on the Years of the Knee' (BABY-Knee) Algorithm, for treating acute anterior cruciate ligament (ACL) injuries in skeletally immature patients. The algorithm integrates magnetic resonance imaging (MRI) findings and patient-specific characteristics to differentiate cases suitable for conservative management from those requiring surgical intervention.

Methods: A prospective cohort of 75 skeletally immature patients (mean age: 13.9 ± 2.2 years) diagnosed with ACL rupture at a single institution between February 2022 and October 2024 was evaluated. Patients were categorized as surgical or non-surgical candidates based on the BABY-Knee Algorithm, which incorporates six weighted criteria: MRI-detected meniscal tears, lateral tibiofemoral bone bruises, skeletal age, injury mechanism and rotatory laxity. Outcomes of initial management were retrospectively analyzed for algorithm validation.

Results: Of the 75 patients, 55 (73.3%) underwent surgical reconstruction, while 20 (26.7%) were managed conservatively. Conservative treatment failed in 12 cases (60%), necessitating surgical intervention. Retrospective application of the algorithm yielded a positive predictive value of 91.7% for identifying surgical candidates and a negative predictive value of 87.5% for successful conservative treatment.

Conclusion: The BABY-Knee Algorithm demonstrated high reliability in guiding treatment decisions for skeletally immature patients with acute ACL injuries, predicting outcomes of conservative treatment in nearly 90% of cases. Further studies are required to confirm its applicability in additional prospective case series.

Level of evidence: Level IV, case series.

Keywords: ACL; MRI; algorithm; paediatric; physeal sparing; skeletally immature.

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Conflict of interest statement

Alberto Grassi: not‐paid consultant for Smith & Nephew. Kyle Borque: paid consultant for Mitek and Xiros Inc.; receives research support from CONMED Linvatec and Xiros Inc. Stefano Zaffagnini: paid consultant for De Puy Synthes and Smith & Nephew; Board member of European Society of Sports Traumatology Knee Surgery and Arthroscopy (ESSKA) and International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine (ISAKOS); Editor in Chief of Journal of Experimental Orthopaedics (JEO). The remaining authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
BABY‐Knee Algorithm. BABY‐Knee, Best ACL‐treatment Based on the Years of the Knee.
Figure 2
Figure 2
Knee joint laxity in males (blue line) and females (pink line) according to age, showing a progressive decrease of laxity with growth (Chart adapted from data by Baxter [4] and Seil [30] et al.).
See this image and copyright information in PMC

References

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