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Background: Little is known on how meniscal morphology develops during skeletal growth and maturation and its subsequent relationship with the corresponding bony anatomy. Hypotheses: (1) Meniscal dimensions and morphology would change by age during skeletal growth and maturation in different ways in boys compared with girls. (2) Morphological features of the medial and lateral menisci would correlate to medial and lateral femoral condyle curvatures. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Anatomic features of the medial and lateral menisci were measured on magnetic resonance imaging scans from 269 unique knees (age, 3-18 years; 51% female) with no prior history of injury, congenital or growth-related skeletal disorders, or bony deformities. Morphological shape-based measurements were normalized to tibial plateau width or determined as ratios of meniscal dimensions. The association between age and anatomy was analyzed with linear regression. Two-way analysis of variance with the Holm-Šídák post hoc method was used to compare anatomy between sexes in different age groups. Linear regression was used to evaluate the relationship between femoral condyle curvature radius and meniscal morphology in each compartment after adjusting for age and sex. Results: Meniscal length, width, horn distance, mean cross-sectional area (CSA), and mean height increased with age in both sexes (R 2 > 0.1; P <.001). Age-related changes in meniscal morphology were seen in normalized length, width, horn distance, and mean height; width-to-length ratio; horn distance-to-length ratio (lateral meniscus only); normalized mean CSA (except lateral meniscus in girls); and mean tip angle (R 2 > 0.04; P <.02). Sex-based differences were also found, with some morphological differences (normalized length and height) throughout development (P <.03) and size differences (length, width, and mean CSA) in later development (P <.01). After adjusting for age and sex, there were significant correlations between medial condyle curvature radius and normalized width, width-to-length ratio, horn distance, horn distance-to-length ratio, mean CSA, and mean height of the medial meniscus (P ≤.041) and between lateral condyle curvature radius and normalized length, mean height, and mean tip angle of the lateral meniscus (P ≤.004). Conclusion: Age-related changes in meniscal dimensions and morphology, most notably a nonuniform growth pattern in meniscal geometry, occurred during skeletal growth and maturation, with different trends in boys than in girls. [ABSTRACT FROM AUTHOR]

Background: Several tibiofemoral anatomic features have been repeatedly associated with increased anterior cruciate ligament (ACL) injury risk. Previous studies have highlighted age and sex differences among these anatomic risk factors, but little is known about the normal and pathologic development of these differences during skeletal maturation. Purpose: To investigate differences in anatomic risk factors at various stages of skeletal maturation between ACL-injured knees and matched controls. Study Design: Cross-sectional study; Level of evidence, 3. Methods: After institutional review board approval, magnetic resonance imaging scans from 213 unique ACL-injured knees (age, 7-18 years, 48% female) and 239 unique asymptomatic ACL-intact knees (age, 7-18 years, 50% female) were used to measure femoral notch width, posterior slope of the lateral and medial tibial plateau, medial and lateral tibial spinal height (MTSH, LTSH), medial tibial depth, and posterior lateral meniscus-bone angle. Linear regression was performed to assess change in quantified anatomic indices with age for male and female patients in the ACL-injured cohort. Two-way analysis of variance with Holm-Sidak post hoc testing was performed to compare anatomic indices between ACL-injured knees and ACL-intact controls in each age group. Results: In the ACL-injured cohort, notch width, notch width index and medial tibial depth increased with age (R 2 > 0.1; P <.001) in both sexes. MTSH and LTSH increased with age only in boys (R 2≥ 0.09; P ≤.001), whereas meniscus-bone angle decreased with age only in girls (R 2 = 0.13; P <.001). There were no other age differences in quantified anatomic indices. Patients with ACL injury consistently had a significantly higher lateral tibial slope (P <.01) and smaller LTSH (P <.001) as compared with ACL-intact controls across all age groups and sexes. When compared with age- and sex-matched ACL-intact controls, ACL-injured knees had a smaller notch width (boys, 7-18 years; girls, 7-14 years; P <.05), larger medial tibial slope (boys and girls, 15-18 years; P <.01), smaller MTSH (boys, 7-14 years; girls, 11-14 years; P <.05), and larger meniscus-bone angle (girls, 7-10 years; P =.050). Conclusion: The consistent morphologic differences throughout skeletal growth and maturation suggest a developmental role in high-risk knee morphology. The observed high-risk knee morphology at an earlier age preliminarily suggests the potential of knee anatomy measurements in identifying those with a predisposition toward ACL injury. [ABSTRACT FROM AUTHOR]

Background: The cross-sectional area (CSA) of the anterior cruciate ligament (ACL) and reconstructed graft has direct implications on its strength and knee function. Little is known regarding how the CSA changes along the ligament length and how those changes vary between treated and native ligaments over time. Hypothesis: It was hypothesized that (1) the CSA of reconstructed ACLs and restored ACLs via bridge-enhanced ACL restoration (BEAR) is heterogeneous along the length. (2) Differences in CSA between treated and native ACLs decrease over time. (3) CSA of the surgically treated ACLs is correlated significantly with body size (ie, height, weight, body mass index) and knee size (ie, bicondylar and notch width). Study Design: Cohort study; Level of evidence, 2. Methods: Magnetic resonance imaging scans of treated and contralateral knees of 98 patients (n = 33 ACL reconstruction, 65 BEAR) at 6, 12, and 24 months post-operation were used to measure the ligament CSA at 1% increments along the ACL length (tibial insertion, 0%; femoral insertion, 100%). Statistical parametric mapping was used to evaluate the differences in CSA between 6 and 24 months. Correlations between body and knee size and treated ligament CSA along its length were also assessed. Results: Hamstring autografts had larger CSAs than native ACLs at all time points (P <.001), with region of difference decreasing from proximal 95% of length (6 months) to proximal 77% of length (24 months). Restored ACLs had larger CSAs than native ACLs at 6 and 12 months, with larger than native CSA only along a small midsubstance region at 24 months (P <.001). Graft CSA was correlated significantly with weight (6 and 12 months), bicondylar width (all time points), and notch width (24 months). Restored ACL CSA was significantly correlated with bicondylar width (6 months) and notch width (6 and 12 months). Conclusion: Surgically treated ACLs remodel continuously within the first 2 years after surgery, leading to ligaments/grafts with heterogeneous CSAs along the length, similar to the native ACL. While reconstructed ACLs remained significantly larger, the restored ACL had a CSA profile comparable with that of the contralateral native ACL. In addition to size and morphology differences, there were fundamental differences in factors contributing to CSA profile between the ACL reconstruction and BEAR procedures. Registration: NCT 02664545 (ClinicalTrials.gov identifier). [ABSTRACT FROM AUTHOR]