Femoral trochlear dysplasia after patellar dislocation in rabbits

The aim of this study was to investigate the effects of patellar dislocation on the development of the trochlear groove in rabbits.

Eighty knees from forty one-month-old white rabbits were divided into three groups (sham surgery, experimental, control). Lateral patellar dislocation was established in the experimental group and the effect on the development of the trochlear groove was compared with that in the sham surgery and control groups. Computed tomography (CT) scans were conducted to measure the angle, width and depth of the trochlear groove one month and six months after surgery. Gross specimen examination, cross-sectional anatomy and histological observation were conducted to investigate the anatomical configuration of the femoral trochlea and the changes in cartilage tissue of the trochlear groove at six months after surgery.

At six months after surgery, CT scans showed a significant difference between the sham surgery group and the experimental group in the angle, width and depth of the trochlear groove. There were no significant differences between the sham surgery group and the control group. Gross specimen examination and cross-sectional anatomy indicated low lateral femoral trochlea and reduced height at the trochlear groove in the experimental group. The femoral trochlea was of normal appearance in the other two groups. Histological investigations showed that there were degenerative changes in the cartilage tissue of the femoral trochlea in the experimental group.

Secondary femoral trochlear dysplasia may be caused by patellar dislocation in a normally developing femoral trochlea. Patellar dislocation may be one of the causes of femoral trochlear dysplasia.