School of Medicine and Health Sciences Poster Presentations

Title

ACL Growth with Age in the Skeletally Immature: An MRI study

Poster Number

192

Document Type

Poster

Status

Medical Student

Abstract Category

Clinical Specialties

Keywords

orthopeadics, sports medicine, anterior cruciate ligament

Publication Date

Spring 2018

Abstract

Background: The current knowledge of morphological changes during growth of the ACL in the skeletally immature patient is limited.

Purpose: To establish normal ACL growth trajectories in skeletally immature patients utilizing serial magnetic resonance imaging (MRI) examinations.

Materials and Methods: A retrospective review of patients aged 0 to 18 years who had undergone at least two serial magnetic resonance imaging (MRI) examinations of the same knee for reasons other than ACL tear was performed. A total of 365 MRIs were reviewed. The parameters measured included physeal status, sagittal length of the ACL, diameter of the ACL in the sagittal and coronal plane, ACL-tibial inclination angle, femoral transcondylar width and intercondylar notch width, the anterior and posterior borders of the ACL attachment, anterior-to-posterior dimension of the tibia, and tibial epiphyseal height. A Pearson correlation coefficient was calculated to determine the direction and strength of each measurement taken compared to age. Growth curves were created for individual parameters by calculating average growth vectors across quarter year age intervals. This produced a predictive model for the rate of growth for ACL parameters at different ages.

Results: Of the 147 patients included, 50.3% were female. Ages at time of MRI ranged 1.3 to 21.7 years, inclusive of all MR images available (average 13.5 years, SD 3.60). The Pearson correlation coefficient for each measurement examined showed statistically significant relationship relative to age, with varying degrees of strength. The ACL grows in length and diameter with age, and younger patients had more oblique, anteriorly attached ACLs compared to older patients. The ACL length growth model shows three distinct phases of growth: patients age 1.5 to 5.75 years average 2.25 mm of growth per year (mm/yr); patients aged 6 to 11.5 average 1.46 mm/year; and growth begins to plateau at age 11.75, reaching 0 mm/year by age 18.5 years. The ACL sagittal diameter growth model shows an average of 0.45 mm/year between 1.5 and 14.5 years old, after which growth slows until it stops at age 18.75.

Conclusion: In the skeletally immature patient, the ACL grows in length and diameter in the coronal and sagittal planes in an approximately linear fashion until age 18. Additionally, the tibial insertion of the ACL becomes more posterior and the orientation of the tibial insertion more vertical with age. This model aids clinicians in predicting normal ACL parameters for reconstruction procedures in the skeletally immature patient, specifically in very young patients.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Open Access

1

This document is currently not available here.

Share

COinS
 

ACL Growth with Age in the Skeletally Immature: An MRI study

Background: The current knowledge of morphological changes during growth of the ACL in the skeletally immature patient is limited.

Purpose: To establish normal ACL growth trajectories in skeletally immature patients utilizing serial magnetic resonance imaging (MRI) examinations.

Materials and Methods: A retrospective review of patients aged 0 to 18 years who had undergone at least two serial magnetic resonance imaging (MRI) examinations of the same knee for reasons other than ACL tear was performed. A total of 365 MRIs were reviewed. The parameters measured included physeal status, sagittal length of the ACL, diameter of the ACL in the sagittal and coronal plane, ACL-tibial inclination angle, femoral transcondylar width and intercondylar notch width, the anterior and posterior borders of the ACL attachment, anterior-to-posterior dimension of the tibia, and tibial epiphyseal height. A Pearson correlation coefficient was calculated to determine the direction and strength of each measurement taken compared to age. Growth curves were created for individual parameters by calculating average growth vectors across quarter year age intervals. This produced a predictive model for the rate of growth for ACL parameters at different ages.

Results: Of the 147 patients included, 50.3% were female. Ages at time of MRI ranged 1.3 to 21.7 years, inclusive of all MR images available (average 13.5 years, SD 3.60). The Pearson correlation coefficient for each measurement examined showed statistically significant relationship relative to age, with varying degrees of strength. The ACL grows in length and diameter with age, and younger patients had more oblique, anteriorly attached ACLs compared to older patients. The ACL length growth model shows three distinct phases of growth: patients age 1.5 to 5.75 years average 2.25 mm of growth per year (mm/yr); patients aged 6 to 11.5 average 1.46 mm/year; and growth begins to plateau at age 11.75, reaching 0 mm/year by age 18.5 years. The ACL sagittal diameter growth model shows an average of 0.45 mm/year between 1.5 and 14.5 years old, after which growth slows until it stops at age 18.75.

Conclusion: In the skeletally immature patient, the ACL grows in length and diameter in the coronal and sagittal planes in an approximately linear fashion until age 18. Additionally, the tibial insertion of the ACL becomes more posterior and the orientation of the tibial insertion more vertical with age. This model aids clinicians in predicting normal ACL parameters for reconstruction procedures in the skeletally immature patient, specifically in very young patients.