Sex‐specific biomechanics and morphology of the anterior cruciate ligament during skeletal growth in a porcine model

Howe, Danielle; Cone, Stephanie G.; Piedrahita, Jorge A.; Collins, Bruce; Fordham, Lynn Ansley; Griffith, Emily H.; Spang, Jeffrey T.; Fisher, Matthew B.

doi:10.1002/jor.25207

Cited by 9 publications

(22 citation statements)

References 48 publications

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“…With this conversion, castration can also decrease serum estrogens in males. With other studies showing that females have higher joint laxity than males, which is a known risk factor for ACL injury [46,47,52], the previous work in this pig model showing a 38% greater APTT for female pigs at 18-months [30], and this work showing similar normalized laxity values for boars and barrows, the future work should focus on the need to directly measure multiple hormonal factors in females.…”

Section: Discussionmentioning

confidence: 87%

“…Six of each age group were left sexually intact (boars), while the other six were castrated (barrows) at an early age (n=6 animals/age/treatment). The boar data presented in this study has been re-analyzed from a previous study [30] to be compared directly with barrow data. All animals were bred at the North Carolina State University Swine Education Unit, and all experimental protocols were approved by the NC State University IACUC.…”

Section: Methodsmentioning

confidence: 99%

“…We have shown similar size and functional changes within the human and porcine ACL, making this a good model to study changes during adolescence [23,29]. The size of the porcine ACL diverges in males and females around the point of sexual maturity, mainly within the two distinct bundles of the ACL, the anteromedial (AM) and posterolateral (PL) bundles [30]. The AM bundle in males and females increase in size throughout adolescence, yet the PL bundle size plateaus near the onset of puberty.…”

Section: Introductionmentioning

confidence: 99%

“…The AM bundle in males and females increase in size throughout adolescence, yet the PL bundle size plateaus near the onset of puberty. Functionally, there is also a shift in bundle function when resisting anterior loads, where the AM bundle becomes the primary stabilizer over the PL bundle in both males and females [30]. The time of these changes is sex-dependent, with the plateau in PL bundle size occurring earlier and functional changes occurring later in females.…”

Section: Introductionmentioning

confidence: 99%

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Neo-natal castration leads to subtle differences in porcine anterior cruciate ligament morphology and function in adolescence

Thompson

Howe

Griffith

et al. 2023

Preprint

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Female adolescent athletes are at a higher risk of tearing their anterior cruciate ligament (ACL) than male counterparts. While most work related to hormones has focused on the effects of estrogen to understand the increased risk of ACL injury, there are other understudied factors, including testosterone. The purpose of this study was to determine how surgical castration in the male porcine model influences ACL size and function across skeletal growth. Thirty-six male Yorkshire crossbreed pigs were raised to 3 (juvenile), 4.5 (early adolescent), and 6 months (adolescent) of age. Animals were either castrated (barrows) within 1-2 weeks after birth or were left intact (boars). Post-euthanasia, joint and ACL size were assessed via MRI, and biomechanics were assessed via a robotic testing system. Joint size increased throughout age, yet barrows had smaller joints than boars (p<0.001 for all measures). ACL cross-sectional area (CSA), length, volume, and stiffness all increased with age (p<0.0001), as did ACL anteromedial (AM) bundle percent contribution to resisting applied loads (p=0.012). Boar ACL and AM bundle volumes were 18% (p=0.003) and 24% (p=0.004) larger than barrows across ages. However, CSA, stiffness, and bundle contribution were similar between boars and barrows (p>0.05). The barrows had smaller temporal increases in AM bundle percent function than boars, but these data were highly variable. Thus, early and sustained loss in testosterone leads to subtle differences in ACL morphology, but may not influence measures associated with increased injury risk, such as CSA or bundle forces in response to applied loads.

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Section: Discussionmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Neo-natal castration leads to subtle differences in porcine anterior cruciate ligament morphology and function in adolescence

Thompson

Howe

Griffith

et al. 2023

Preprint

Self Cite

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“…The median T2* relaxation time was calculated for each ACL bundle. Additionally, the volume of each segmented tissue was recorded, and the cross-sectional area (CSA) of the AM and PL bundles, the complete ACL, MCL, and LCL were calculated as previously described ( 17 , 18 ). Briefly, each segmented tissue was exported as a surface mesh, and analyzed using a MATLAB script.…”

Section: Methodsmentioning

confidence: 99%

Degenerative changes are associated with severity of anterior cruciate ligament injury within the skeletally immature joint

Howe

Thompson

Teeter

et al. 2022

Preprint

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Pediatric anterior cruciate ligament (ACL) injuries are a major problem in the pediatric and adolescent populations. Approximately one-quarter of these injuries only extend through only part of the tissue cross-section. Yet, there is very limited data to inform clinical treatments for pediatric partial ACL tears. In particular, understanding how injury severity impacts long-term degenerative changes in the joint is unknown. In this study, we leverage a skeletally immature preclinical porcine model to evaluate joint biomechanics, tissue remodeling, and degeneration after partial (isolated anteromedial (AM) or posterolateral (PL) bundle) or complete (full thickness) ACL injury. Six months after injury, joint laxity increases were minimal for PL bundle injury, minor for AM bundle injury, and major for ACL injury. In both partial injury cases, the remaining bundle remodeled through an increase in CSA to attempt to restore ACL function and stabilize the knee joint. Joint degeneration (evaluated by cartilage T1 relaxation, macroscopic cartilage degeneration, and meniscal hypertrophy) was minimal after PL bundle injury, moderate after AM bundle injury, and substantial after ACL injury. Further analysis with subjects grouped by Lachman grade (indicating the extent of joint destabilization) indicated that degeneration was associated with the extent of biomechanical destabilization, irrespective of the injury type. These findings point to the importance of considering the results of joint laxity exams when creating treatment plans for young patients with significant growth remaining, particularly those with partial ACL injuries.

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3D characterization of the triple‐bundle Achilles tendon from in vivo high‐field MRI

Cone

Kim

Thelen

et al. 2023

Journal Orthopaedic Research

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The Achilles tendon consists of three subtendons that transmit force from the triceps surae muscles to the calcaneus. Individual differences have been identified in Achilles subtendon morphology and twist in cadavers, which may have implications for triceps surae mechanics and function. High‐field magnetic resonance imaging (MRI) can be used to identify boundaries within multi‐bundle tissues, which could then enable studies of subtendon structure−function relationships in humans. The objective of this study was to use high‐field MRI (7T) to image and reconstruct Achilles subtendons arising from the triceps surae muscles. We imaged the dominant lower leg of a cohort of healthy human subjects (n = 10) using a tuned musculoskeletal sequence (double echo steady state sequence, 0.4 mm isotropic voxels). We then characterized the cross‐sectional area and orientation of each subtendon between the MTJ and calcaneal insertion. Image collection and segmentation was repeated to assess repeatability. Subtendon morphometry varied across subjects, with average subtendon areas of 23.5 ± 8.9 mm2 for the medial gastrocnemius, 25.4 ± 8.9 mm2 for the lateral gastrocnemius, and 13.7 ± 5.9 mm2 for the soleus subtendons. Repeatable subject‐specific variations in size and position of each subtendon were identified over two visits, expanding on prior knowledge that high variability exists in Achilles subtendon morphology across subjects.

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Sex‐specific biomechanics and morphology of the anterior cruciate ligament during skeletal growth in a porcine model

Cited by 9 publications

References 48 publications

Neo-natal castration leads to subtle differences in porcine anterior cruciate ligament morphology and function in adolescence

Neo-natal castration leads to subtle differences in porcine anterior cruciate ligament morphology and function in adolescence

Degenerative changes are associated with severity of anterior cruciate ligament injury within the skeletally immature joint

3D characterization of the triple‐bundle Achilles tendon from in vivo high‐field MRI

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