Deformity of the proximal femur in fibrous dysplasia
leads to deviation of the mechanical axis of the hip, which may lead
to the development of secondary osteoarthritis (OA). This study
investigated the prevalence and predisposing factors for the development
of OA in patients with fibrous dysplasia of the proximal femur.
We reviewed the records of 209 patients from our institutional database
with fibrous dysplasia of the proximal femur, investigating possible predisposing
factors including patient demographics, the extent of the coxa vara
deformity, the presence of peri-articular disease, and the overall
burden of skeletal disease. Of the 209 patients, 24 (12%) had radiological
evidence of OA in the ipsilateral hip. The prevalence was significantly
higher in patients with polyostotic fibrous dysplasia compared with
those with monostotic disease (p <
0.001). In a subgroup analysis of
patients with polyostotic disease, the extent of deformity (quantified
using the neck–shaft angle), and the presence of peri-articular
disease (whether in the head of the femur or the acetabulum) were
significant predictors of osteoarthritis (neck–shaft angle likelihood
ratio (LR) = 0.847 per 1° increase, p = 0.004; presence of lesion
in the head of the femur LR = 9.947, p = 0.027; presence of lesion
in the acetabulum LR = 11.231, p = 0.014). Our data suggest that patients with polyostotic fibrous dysplasia
have a high risk of developing secondary OA of the hips. This risk
is higher in patients with peri-articular disease, and those with
a more severe deformity of proximal femur. Cite this article:
