What is the management of fibrous dysplasia?

Management of Fibrous Dysplasia

For symptomatic fibrous dysplasia of bone, initiate bisphosphonate therapy (pamidronate 180 mg IV every 6 months) to reduce bone pain and improve radiological appearance, reserving surgery for pathological fractures, severe deformity, or lesions at high fracture risk. 1, 2

Medical Management

Bisphosphonate Therapy

• Pamidronate is the primary medical treatment, administered at 180 mg intravenously every 6 months in adults 1
• Bisphosphonates relieve bone pain in approximately 50% of patients and improve radiological appearance (filling of lytic lesions, cortical thickening) 1
• Treatment increases bone mineral density at affected sites and decreases bone resorption markers 1
• Zoledronic acid (4 mg IV every 6 months) has been studied but shows no substantial improvement in patients resistant to pamidronate 1
• Alendronate has also been used in open studies with similar benefits to pamidronate 1

Adjunctive Medical Therapy

• Calcium and vitamin D supplementation should be provided to patients with deficiency to limit secondary hyperparathyroidism, which can worsen fibrous dysplasia lesions 1, 3
• Phosphorus supplementation is indicated for patients with polyostotic disease and renal phosphate wasting, which commonly occurs in this population 1, 3

Surgical Management

Indications for Surgery

Surgery is indicated for: 2, 4, 5

• Pathological fractures
• Severe bone deformity requiring correction
• Persistent pain despite medical therapy
• Large lesions with high fracture risk
• Prevention of progressive deformity

Monostotic Disease

• Small, asymptomatic circumscribed lesions require only monitoring without intervention 4
• Symptomatic circumscribed lesions should be treated with curettage, cryosurgery, and bone grafting with or without internal fixation depending on size and location 2, 4
• Large lesions (>5 cm) or those in weight-bearing bones require internal fixation in addition to curettage and bone grafting 2

Polyostotic Disease

• Large lesions with deformity or high fracture risk require curettage, bone grafting, and rigid internal fixation 2, 4
• Corrective osteotomies with internal fixation are necessary for established bony deformities 2, 4
• Proximal femoral nail anti-rotation (PFNA) or intramedullary nailing is preferred for femoral lesions with deformity 2
• For shepherd's crook deformity, intertrochanteric valgus osteotomy with angled blade plate fixation followed by cephalomedullary nail stabilization achieves 71-91% success rates 5

Surgical Technique Considerations

• Avoid bone grafting in patients younger than 18 years as 75% of grafts fail to incorporate and are resorbed in this age group 5
• Strut allografts show 54% revision-free survival at 20 years for proximal femoral disease 5
• Intramedullary nails should be used for large lesions to prevent deformity and treat fractures 2

Disease-Specific Considerations

McCune-Albright Syndrome

• Avoid radiotherapy in patients with McCune-Albright syndrome and skull base fibrous dysplasia due to risk of sarcomatous transformation 6
• Surgical outcomes are uniformly poor in McCune-Albright syndrome compared to isolated fibrous dysplasia 4
• Alternative medical and surgical treatments should be prioritized over radiotherapy for growth hormone excess in these patients 6

Monitoring and Follow-up

• Annual noninvasive imaging of affected bones initially to detect progression, with frequency reduced once stability is confirmed over 2-3 years 7
• Monitor for complications including pathological fracture, progressive deformity, and rarely malignant transformation 3
• Assess for renal phosphate wasting in polyostotic disease with serum phosphorus and tubular reabsorption of phosphate 3

Important Caveats

• The clinical course is highly variable, ranging from asymptomatic incidental findings to severe progressive disease 4, 3
• Bisphosphonate efficacy data comes from open studies without controls; randomized controlled trials are needed 1
• Surgical recurrence rates are significant, particularly in younger patients and those with polyostotic disease 2, 5
• Diagnosis requires correlation of radiographic findings with histopathology to exclude malignancy 3