Abstract
BACKGROUND: This study was performed to investigate the effects of hip dislocation on the morphological development of the acetabulum and femoral trochlear groove utilizing an animal model. METHODS: A total of 128 newborn Wistar rats were randomly assigned to a control group (CG, n=48) and an experimental group (EG, n=80). The EG underwent induced hip dislocation via one week of swaddling. At the 4 and 8-week marks, 16 rats from the CG and half from the EG were euthanized. Morphometric parameters included acetabular width (AW) and depth (AD), the diameter of the femoral head (DFH), the femoral anteversion angle (FAA), and the angle, depth, and width of the trochlear groove (ATG, DTG, and WTG, respectively). Histological analysis was performed to evaluate the maturation of the femoral head and trochlear cartilage. RESULTS: Compared with the CG, the EG exhibited shallower trochlear grooves, smaller and more irregular femoral head morphology, and shallower acetabula. Significant differences were observed between the CG and EG in the AW, AD, DFH, and FAA (P<0.001). Additionally, the EG also showed significant differences in the WTG (P=0.045), DTG (P<0.001), and ATG (P=0.005). The FAA was positively correlated with the ATG and negatively correlated with the LCL and DTG. Histological analysis revealed notable cartilage degeneration and subchondral bone alterations in the femoral heads of the EG, whereas no significant histopathological changes were observed in the femoral trochlea. CONCLUSION: Hip dislocation not only leads to developmental dysplasia of the hip, but also impairs the maturation of the femoral trochlea, with the pathological changes of both DDH and trochlear dysplasia becoming more pronounced over time.