Evaluation of Changes in Hip Morphology in a Rabbit Model of Patellar Dislocation via Computed Tomography Imaging

BACKGROUND Although early patellar dislocation induces morphological changes in the patellofemoral joint, its potential influence on hip morphology during growth remains unclear. This study evaluated changes in hip morphology via computed tomography (CT) imaging in a rabbit model of patellar dislocation. MATERIAL AND METHODS Thirty female New Zealand White rabbits (2 months old) were included. The left hindlimbs of rabbits (n = 28 after 2 postoperative deaths) underwent patellar dislocation surgery and comprised the study group. Contralateral right hindlimbs (n = 28), which underwent no surgical procedure, served as the control group. Anteroposterior pelvic radiographs and CT scans were obtained immediately after surgery and 4 months later. Central edge angle, acetabular abduction angle, acetabular version, pubic relative length, ischiac relative distance (IRD), and femoral version were measured and analyzed. RESULTS No significant differences were observed immediately after surgery. Four months later, acetabular version (study group: 24.83±5.50°; control group: 16.14±5.15°; P<0.001), IRD (study group: 1.85±0.08 mm; control group: 1.77±0.11 mm; P=0.002), and femoral version (study group: -3.11±4.17°; control group: 4.15 ± 5.02°; P<0.001) significantly differed between groups. Acetabular version showed a negative correlation with femoral version (r=-0.813, P<0.001) and a positive correlation with IRD (r=0.563, P<0.001). CONCLUSIONS Early patellar dislocation in growing rabbits led to significant alterations in acetabular version, femoral version, and IRD, suggesting that patellar dislocation can influence hip development during growth.