Fig 1.
3D models were created for tissues such as the anterior cruciate ligament (ACL) using MRI scans and segmentations of individual tissues.
Images shown for newborn (0 month), early adolescent (4.5 month), and late adolescent (18 month) joints, scale bars are 10 mm. Length and cross-sectional area (CSA) calculation methods described for an ACL.
Fig 2.
Allometric growth within or between tissues can be assessed by plotting data on a log-log graph (A) and comparing to the slope of an isometric line. Isometric slopes are listed for all possible combinations of CSA and length (B).
Fig 3.
Length (A) and CSA (B) increase several fold in the ACL, PT, MCL, and LCL from birth through skeletal maturity. Data for individual specimens are presented as points while mean and 95% confidence intervals are represented by dashes and lines. Bars represent significant differences between consecutive age groups (p<0.05).
Fig 4.
Tissue length data compared across tissues at each age normalized to the late adolescent group.
Data for individual specimens are presented as points while mean and 95% confidence intervals are represented by dashes and lines. * denotes p<0.05 from ACL, + denotes p<0.05 from PT.
Fig 5.
Tissue CSA data compared across tissues at each age normalized to the late adolescent group.
CSA is significantly greater in the ACL compared to the other tissues (p<0.05) at ages including 0, 3, and 4.5 months. Data for individual specimens are presented as points while mean and 95% confidence intervals are represented by dashes and lines. * denotes p<0.05 from ACL.
Fig 6.
Assessment of allometric growth within each tissue.
Comparisons of CSA and length for the ACL and LCL reveal allometric growth whereas the PT and MCL exhibit isometric growth. In these plots, the dashed line represents the line of isometry while the solid line represents the line of best fit for the data (R2 values provided, p<0.05 denote statistical difference from isometric line, slopes denote standard and best fit lines).
Fig 7.
Comparisons of tissue length reveal differing rates of growth between the tissues.
In these plots, the dashed line represents the line of isometry while the solid line represents the line of best fit for the data points (R2 values provided, p<0.05 denote statistical difference from isometric line, slopes denote standard and best fit lines).
Fig 8.
Comparisons of tissue CSA show differing rates of growth between tissues, specifically between the ACL and the other three.
In these plots, the dashed line represents the mathematical line of isometry while the solid line represents the line of best fit for the data points (R2 values provided, p<0.05 denote statistical difference from isometric line, slopes denote standard and best fit lines).