Exploring the Rotational Instability Spectrum of ACL Deficiency: An Exploratory Phenotype-Based…

Cohort studyJournal of ISAKOS : joint disorders & orthopaedic sports medicine· Aug 2026

Exploring the Rotational Instability Spectrum of ACL Deficiency: An Exploratory Phenotype-Based Classification Integrating Secondary Stabilizer Injury Burden.

Horacio Rivarola, Cristian Collazo, Marcos Palanconi … Francisco Endara Urresta

Sports Medicine & ArthroscopyCohort studyDiagnosisQ1IF 3.7

Greater secondary stabilizer injury burden linked to high-grade pivot shift in anterior cruciate ligament-deficient knees

Exploring the Rotational Instability Spectrum of ACL Deficiency: An Exploratory Phenotype-Based Classification Integrating Secondary Stabilizer Injury Burden.

Horacio Rivarola … Francisco Endara Urresta

Journal of ISAKOS · Aug 2026 · Q1 in Orthopedics

Background

Anterior cruciate ligament (anterior cruciate ligament) deficiency is traditionally viewed as a relatively homogeneous condition in which rotational instability is primarily attributed to anterior cruciate ligament rupture severity and a limited number of clinical risk factors.

Methods

Were not stratified according to time from injury because the objective of the study was exploratory phenotype discovery rather than temporal characterization.

Results

each one-point rise in stabilizer injury raises the odds of severe pivot shift

OR 1.47 (95% CI 1.28 to 1.71)

null 1

1.28

1.71

CI excludes the null - significant

More results

The mean RIBI score was 4.8 ± 2.3.

Hierarchical clustering identified four reproducible phenotypes: Low-Burden anterior cruciate ligament Phenotype (30.7%), Lateral Meniscal-Dominant Phenotype (25.3%), Hyperlaxity-Dominant Phenotype (20.3%), and High Rotational Burden Phenotype (23.7%).

More results

Cluster stability was high (bootstrap coefficient 0.82), and the four-cluster solution demonstrated satisfactory separation (silhouette coefficient 0.61).

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Conclusion · 1 of 2

Within this cohort, anterior cruciate ligament-deficient knees demonstrated reproducible patterns of secondary stabilizer injury that clustered into distinct rotational instability phenotypes.

Conclusion · 2 of 2

Increasing cumulative secondary stabilizer injury burden was independently associated with severe rotational instability.

Exploring the Rotational Instability Spectrum of ACL Deficiency: An Exploratory Phenotype-Based Classification Integrating Secondary Stabilizer Injury Burden.

Exploring the Rotational Instability Spectrum of ACL Deficiency: An Exploratory Phenotype-Based Classification Integrating Secondary Stabilizer Injury Burden.

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