Introduction: The effects of dynamic loading on growth are presently poorly understood. Studies investigating static/dynamic loadings do not use matched and normalized loading parameters.
Objectives: This study aimed at characterizing the effects of static/dynamic loading of growth plate explants, matched in terms of average strain, on the histomorphometry.
Methods: Growth plate explants were extracted from distal ulnae of 4-week-old swine. Four groups were implemented: normal, culture control, static loading, matched dynamic loading. Normal samples were immediately fixed. The static samples underwent 10% strain. The dynamic samples underwent equivalent cyclic strain at 0.1 Hz. Matched control samples were kept in identical conditions. Sections were made from methymetacrylate embedded samples and stained with Toluidine Blue. The total growth plate thickness and the combined thickness of the hypertrophic/proliferative zones were measured.
Results: The chondrocytes columnar arrangement from the dynamic samples was disorganized, especially in the hypertrophic/proliferative zones, when compared to the other groups. A decrease was observed in all parameters when comparing the static/dynamic groups to the control group. These reductions were statistically significant for the static group only.
Conclusion: Explants responded differently to static/dynamic loading. The loss of columnar arrangement was more severe in the dynamically loaded explants, but decreases in all histological parameters were more significant following static loading. Complementary mechanobiological data is required to fully interpret these results.
Significance: The exact response of the physis to static/dynamic stresses will help improve current treatment approaches and develop new approaches for the treatment of pediatric musculoskeletal deformities, such as scoliosis.