Abstract
The purpose was to investigate morphological changes of the hip joint in patients
with recurrent dislocation of the patella combined with trochlear dysplasia. There
was a retrospective analysis of 148 patients and 150 control subjects. The selection
of participants was randomized. Hip and knee data for all participants were obtained
from X-ray or computed tomography measurements. Nine values, that is, central edge
angle (CEA), acetabulum index angle (AIA), femoral neck-shaft angle, sharp angle,
the depth of the acetabulum, femoral anteversion angle (FAA), anterior acetabular
section angle (AASA), posterior acetabular section angle (PASA), and sulcus angle,
were measured to evaluate differences between the control group and the patient group
and analyze the correlation of the sulcus angle in patients to FAA and CEA. Patients
with recurrent dislocation of the patella had less acetabular coverage and are more
likely to develop developmental dysplasia of the hip than the hips of patients with
normal knees. For the patient group, three values, that is, CEA (27.68 ± 5.25 vs.
34.30 ± 3.51 degrees, p < 0.001), AASA (57.14 ± 6.17 vs. 63.08 ± 7.23 degrees, p < 0.001), and PASA (89.53 ± 6.51 vs. 99.63 ± 5.94 degrees, p < 0.001), were decreased. The sharp angle (43.77 ± 3.23 vs. 39.28 ± 3.19 degrees,
p < 0.001), AIA (11.52 ± 4.41 vs. 3.73 ± 2.51 degrees, p < 0.001), and FAA (24.68 ± 3.44 vs. 18.49 ± 3.55 degrees, p < 0.001) were increased. The acetabulum became shallower in-depth (7.05 ± 2.18 vs.
10.45 ± 1.61 mm, p < 0.001). There was a weak correlation between the sulcus angle and CEA (r = − 0.302, p < 0.001) and FAA (r = 0.212, p = 0.022). Recurrent patellar dislocation combined with trochlear dysplasia may be
associated with the hip morphology. Developmental disorders of the knee joint, and
hip joint should be considered in the treatment of patients with recurrent dislocation
of the patella.
Keywords
recurrent patellar dislocation - trochlear dysplasia - developmental dysplasia of
the hip - morphological analysis of hip joint