Meniscal Tears, Posterolateral and Posteromedial Corner injuries, Increased Coronal Plane and Increased Sagittal Plane Tibial Slope All Influence ACL Related Knee Kinematics and Increase Forces on the Native and Reconstructed Anterior Cruciate Ligament: A Systematic Review of Cadaveric Studies

ObjectiveTo investigate the risk of new meniscal tears after treatment for anterior cruciate ligament (ACL) injury, in children and adults with and without ACL reconstruction.DesignPrognosis systematic review (PROSPERO registration number CRD42016036788).MethodsWe searched Embase, Ovid Medline, Cochrane, CINAHL, SPORTDiscus, PEDro and Google Scholar from inception to 3rd May 2018. Eligible articles included patients with ACL injury (diagnosis confirmed by MRI and/or diagnostic arthroscopy), reported the number of meniscal tears at the time of ACL injury diagnosis/start of treatment and reported the number of new meniscal tears that subsequently occurred. Articles with fewer than 20 patients at follow-up, and articles limited to ACL revision surgery or multi-ligament knee injuries were excluded. Two independent reviewers screened articles, assessed eligibility, assessed risk of bias and extracted data. We judged the certainty of evidence using the Grading of Recommendations Assessment Development and Evaluation (GRADE) working group methodology.ResultsOf 75 studies included in the systematic review, 54 studies with 9624 patients and 501 new meniscal tears were appropriate for quantitative analysis. Heterogeneity precluded data pooling. The risk of new meniscal tears was 0%–21% when follow-up was <2 years, 0%–29% when follow-up was 2 to 5 years, 5%–52% when follow-up was 5 to 10 years and 4%–31% when follow-up was longer than 10 years. The proportion of studies with high risk of selection, misclassification and detection bias was 84%, 69% and 68%, respectively. Certainty of evidence was very low.ConclusionNew meniscal tears occurred in 0%–52% of patients between 4 months and 20 years (mean 4.9±4.4 years) following treatment for ACL injury. The certainty of evidence was too low to guide surgical treatment decisions. This review cannot conclude that the incidence of new meniscal tears is lower if ACL injury is treated with surgery compared with treatment with rehabilitation only.

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Tibial Slope and Its Effect on Force in Anterior Cruciate Ligament Grafts: Anterior Cruciate Ligament Force Increases Linearly as Posterior Tibial Slope Increases

The American Journal of Sports Medicine ◽

10.1177/0363546518820302 ◽

2019 ◽

Vol 47 (2) ◽

pp. 296-302 ◽

Cited By ~ 26

Author(s):

Andrew S. Bernhardson ◽

Zachary S. Aman ◽

Grant J. Dornan ◽

Bryson R. Kemler ◽

Hunter W. Storaci ◽

...

Keyword(s):

Anterior Cruciate Ligament ◽

Linear Relationship ◽

Sagittal Plane ◽

Cruciate Ligament ◽

Tibial Slope ◽

Tibial Osteotomy ◽

Acl Graft ◽

Posterior Tibial ◽

Axially Loaded ◽

Anterior Cruciate

Background: Previous work has reported that increased tibial slope is directly correlated with increased anterior tibial translation, possibly predisposing patients to higher rates of anterior cruciate ligament (ACL) tears and causing higher rates of ACL graft failures over the long term. However, the effect of changes in sagittal plane tibial slope on ACL reconstruction (ACLR) graft force has not been well defined. Purpose/Hypothesis: The purpose of this study was to quantify the effect of changes in sagittal plane tibial slope on ACLR graft force at varying knee flexion angles. Our null hypothesis was that changing the sagittal plane tibial slope would not affect force on the ACL graft. Study Design: Controlled laboratory study. Methods: Ten male fresh-frozen cadaveric knees had a posterior tibial osteotomy performed and an external fixator placed for testing and accurate slope adjustment. Following ACLR, specimens were compressed with a 200-N axial load at flexion angles of 0°, 15°, 30°, 45°, and 60°, and the graft loads were recorded through a force transducer clamped to the graft. Tibial slope was varied between −2° and 20° of posterior slope at 2° increments under these test conditions. Results: ACL graft force in the loaded testing state increased linearly as slope increased. This effect was independent of flexion angle. The final model utilized a 2-factor linear mixed-effects regression model and noted a significant, highly positive, and linear relationship between tibial slope and ACL graft force in axially loaded knees at all flexion angles tested (slope coefficient = 0.92, SE = 0.08, P < .001). Significantly higher graft force was also observed at 0° of flexion as compared with all other flexion angles for the loaded condition (all P < .001). Conclusion: The authors found that tibial slope had a strong linear relationship to the amount of graft force experienced by an ACL graft in axially loaded knees. Thus, a flatter tibial slope had significantly less loading of ACL grafts, while steeper slopes increased ACL graft loading. Our biomechanical findings support recent clinical evidence of increased ACL graft failure with steeper tibial slope secondary to increased graft loading. Clinical Relevance: Evaluation of the effect of increasing tibial slope on ACL graft force can guide surgeons when deciding if a slope-decreasing proximal tibial osteotomy should be performed before a revision ACLR. Overall, as slope increases, ACL graft force increases, and in our study, flatter slopes had lower ACL graft forces and were protective of the ACLR graft.

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