Fibrous dysplasia: Clinical features, deformities, management, and outcomes

The aim of this study was to evaluate the rate of proximal femoral involvement and the incidence of shepherd's crook deformity in patients with fibrous dysplasia (FD) and to identify possible factors associated with the development of shepherd's crook deformity.

Between January 1990 and December 2022, a total of 158 consecutive patients (78 males, 80 females; mean age: 23.8 ± 15.0 years; range, 3 to 71 years) diagnosed with FD were retrospectively analyzed. Presenting symptoms, lesion location, radiological findings, treatment modalities, development of deformity, postoperative complications, and the need for secondary surgery were recorded.

The mean follow-up was 64.2 ± 38.4 (range, 24 to 210) months. Among the patients, 125 had monostotic and 33 had polyostotic lesions. Of the 215 lesions identified, 83 were treated surgically, while 132 were managed with clinical observation. Shepherd's crook deformity was observed in nine of 75 proximal femoral lesions. The deformity was significantly more common in polyostotic than in monostotic lesions (25.0% vs. 5.9% respectively; p = 0.026). McCune-Albright syndrome (MAS) was present in two patients, both exhibiting shepherd's crook deformity, whereas the rate was 9.6% among patients without MAS. Valgus osteotomy was performed in all nine patients with shepherd's crook deformity, improving the mean neck-shaft angle from 90.5° (range, 85 to 105°) preoperatively to 125.6° (range, 120 to 130°) postoperatively. In six of these patients, no marked loss in the postoperative neck-shaft angle was observed, while three patients required secondary surgery due to recurrence of the deformity.

Most lesions can be managed successfully with observation, while surgery is indicated for the eradication of symptomatic lesions, prevention of pathological fractures, and correction of deformities. Shepherd's crook deformity seems to be more common in patients with polyostotic lesions and MAS. Although valgus osteotomy can achieve radiographic improvement, recurrence of deformity and the need for multiple surgeries are not uncommon.