Clinical presentation and treatment strategies of proximal femoral fibrous dysplasia without deformity

Background The treatment for proximal femoral fibrous dysplasia (FD) without deformity remains controversial. This study investigated clinicopathologic factors and treatment outcomes in patients with proximal femoral FD without deformity to highlight factors relevant to clinical decision-making. Results From 2007 to 2023, 41 patients with proximal femoral FD without deformity (20 men, 21 women) were identified at three institutions. We examined the age, BMI, Denis Pain Scale scores, occurrence patterns, imaging findings, surgical intervention, and follow-up data. The median patient age was 32 years (range 7–73), and the median BMI value was 21.0 (range 14.5–29.1). The occurrence patterns included 36 single-bone single lesions, two single-bone multiple lesions, one multiple-bone case, and two McCune-Albright syndromes. The lesions varied from the neck-trochanter to subtrochanteric regions, with a median size of 2,000 mm 2 . Radiographs showed cortical thinning (29 patients), marginal sclerosis (26 patients), and pathological fractures (four patients). Cystic changes were observed in 12 patients, aneurysmal bone cyst (ABC) changes in six, and both changes in four. The initial Denis Pain Scale scores were grade 1 (nine patients), grade 2 (22 patients), grade 3 (nine patients), grade 4 (no patients), and grade 5 (one patient). The median follow-up was 49 months. The pain scores correlated with cortical thinning ( p = 0.0219), which in turn correlated with lesion size ( p = 0.0357), extensive location ( p = 0.0357), and changes in ABC ( p = 0.0342). Of the 21 patients treated a combination of curettage, bone grafting, and internal fixation, 18 showed improvements in their pain scores. A comparison of preoperative and postoperative scores revealed a statistically significant reduction following surgery ( p < 0.0001). Curettage and bone grafting alone caused early pathologic fractures in two out of two cases. Conclusions Depending on cortical thinning, lesion size, extensive location, and the presence of ABC changes, surgical stabilization may alleviate pain in symptomatic proximal femoral FD. In such cases, internal fixation should be considered essential to prevent complications such as pathologic fractures and to achieve adequate pain control, whereas curettage and bone grafting alone appear insufficient.