Fibrous dysplasia of bone is a rare condition where normal, healthy bone tissue is gradually replaced with weaker, fibrous tissue that resembles scar tissue. This replacement weakens the affected bones and makes them more vulnerable to fractures, deformities, and pain throughout life.

Understanding Treatment Goals and Approaches

The primary goal when treating fibrous dysplasia of bone is to manage symptoms, prevent complications, and maintain the best possible quality of life for patients. Because this condition weakens bones and can cause pain and deformity, treatment focuses on protecting bone strength, reducing pain, correcting deformities when they occur, and preventing fractures. The approach to treatment is highly individualized and depends on several factors including which bones are affected, how many bones are involved, the severity of symptoms, and the patient’s age and overall health.^[1]

Treatment strategies vary widely because fibrous dysplasia presents differently in each person. Some individuals discover they have the condition only by accident during X-rays for unrelated issues and experience no symptoms at all. Others face significant challenges including repeated fractures, bone pain, and visible deformities that affect their daily activities and mobility. The number of affected bones also plays a crucial role in determining treatment intensity—those with monostotic fibrous dysplasia (affecting one bone) typically require less intervention than those with polyostotic fibrous dysplasia (affecting multiple bones).^[2]

Medical societies and expert groups have developed guidelines to help healthcare providers deliver consistent, high-quality care for this rare condition. These recommendations emphasize the importance of regular monitoring, coordinated care between different specialists, and tailored treatment plans. While standard treatments approved by medical authorities exist for managing symptoms and complications, researchers continue to explore new therapeutic approaches through clinical trials. These investigations aim to find better ways to slow disease progression, reduce bone turnover, and improve outcomes for people living with fibrous dysplasia.^[15]

Standard Treatment Approaches

Standard treatment for fibrous dysplasia follows a stepwise approach that begins with careful observation and progresses to more active interventions only when necessary. Many patients, especially those with monostotic fibrous dysplasia who experience minimal or no symptoms, may not require any immediate treatment beyond regular follow-up appointments with their healthcare provider. During these visits, doctors monitor bone health through physical examinations and imaging tests to watch for any changes that might require intervention.^[1]

When symptoms do occur, pain management becomes a primary concern. Bone pain in fibrous dysplasia can result from the expansion of abnormal fibrous tissue within the bone, pressure on surrounding nerves, or small fractures within weakened bone. Healthcare providers often start with basic pain relief measures, but when pain becomes more significant, they may prescribe medications specifically designed to strengthen bones and reduce pain.

Bisphosphonates are the most commonly used medications for fibrous dysplasia. These drugs, which are also used to treat osteoporosis, work by slowing down the process of bone breakdown and resorption. In fibrous dysplasia, abnormally high bone turnover contributes to bone weakness and pain. Bisphosphonates target large, overactive cells called osteoclasts that break down bone tissue. By reducing the activity of these cells, bisphosphonates help stabilize the bone and can significantly reduce pain in many patients. Clinical experience has shown that approximately half of patients with fibrous dysplasia who take bisphosphonates experience meaningful pain relief. These medications also help reduce bone turnover markers that can be measured in blood tests.^[14]

The duration of bisphosphonate therapy varies depending on the individual patient’s response and needs. Some patients receive intermittent courses of treatment when symptoms flare up, while others may benefit from longer-term therapy. The medication can be given as oral tablets or through intravenous infusions, depending on the specific drug chosen and the patient’s circumstances. Healthcare providers monitor patients during treatment through blood tests that measure markers of bone turnover and assess kidney function, as bisphosphonates are processed through the kidneys.

Side effects of bisphosphonates can include flu-like symptoms after the first dose, particularly with intravenous forms, as well as digestive upset with oral preparations. More serious but rare complications include jaw problems and unusual fracture patterns with very long-term use. However, for most patients with fibrous dysplasia, the benefits of pain reduction and bone stabilization outweigh these risks when the medication is used appropriately.

For patients with bone deformities or those at high risk of fractures, bracing may provide important support. Braces help stabilize weakened bones and can guide proper bone growth in children. They are particularly useful for bones in the legs and arms that bear weight or are subject to repeated stress during daily activities. While bracing does not reverse the underlying condition, it can prevent deformities from worsening and reduce the risk of fractures.^[1]

Surgical intervention becomes necessary when patients experience fractures, significant bone deformities that affect function, or complications from bone expansion that impairs nearby organs or structures. The most common surgical procedures include fixing broken bones with internal hardware like plates and screws, removing sections of abnormal bone, and performing bone grafts. In a bone graft procedure, surgeons may replace abnormal fibrous bone with healthy donor bone (called allograft bone) or with synthetic bone substitute materials made from calcium-based compounds. However, there is a recognized risk that the fibrous dysplasia may recur in the grafted area, particularly if the patient’s own bone is used. The choice of graft material and surgical technique depends on the location and extent of disease.^[6]

Surgery for fibrous dysplasia requires careful planning because the affected bone often has an unusually rich blood supply, which can lead to significant bleeding during the procedure. Patients may need blood transfusions during or after surgery. The surgical approach also depends on the specific bone involved—procedures on skull and facial bones require specialized craniofacial expertise, while operations on long bones of the arms and legs fall under orthopedic surgery. Some patients require multiple surgeries over time as the condition progresses or as deformities recur.^[10]

For patients with craniofacial fibrous dysplasia (affecting bones of the skull and face), additional treatments may be needed to address complications like vision loss, hearing impairment, or nasal congestion. When expanding bone lesions compress the optic nerves or narrow the auditory canals, surgical decompression may be necessary to preserve sensory function. Timing of these interventions is critical—waiting too long can result in permanent damage, while operating too early in a child’s development might lead to regrowth of abnormal bone.^[11]

Patients with McCune-Albright syndrome, a form of polyostotic fibrous dysplasia associated with hormonal problems and skin changes, require additional specialized care from endocrinologists. Hormonal disturbances in this syndrome can include early puberty, overactive thyroid, excess growth hormone, and abnormal phosphate levels that further weaken bones. Treatment of these endocrine problems is essential for overall disease management and may include medications to control hormone production or surgery to remove overactive glands.^[3]

Emerging Treatments in Clinical Trials

Researchers have been actively investigating new treatment approaches for fibrous dysplasia through clinical trials conducted at specialized centers. One of the most promising recent developments involves a medication called denosumab, which works differently from bisphosphonates to reduce bone turnover.

Denosumab is a medication already approved by the U.S. Food and Drug Administration for treating bone loss in osteoporosis and certain cancer-related bone problems. In fibrous dysplasia, scientists recognized that elevated levels of a protein called RANKL (receptor activator of nuclear factor kappa-B ligand) contribute to excessive bone turnover. Denosumab works by blocking RANKL, thereby reducing the activity of osteoclasts and slowing the destructive bone remodeling process that characterizes fibrous dysplasia.^[13]

A Phase 2 clinical trial conducted at the National Institutes of Health in the United States evaluated denosumab in eight adult women with fibrous dysplasia. This trial was carried out by researchers from the National Institute of Dental and Craniofacial Research (NIDCR). Participants received high doses of denosumab over a six-month treatment period. The results were encouraging: at the end of treatment, bone biopsies and scans showed a marked reduction in bone turnover within the fibrous lesions. Blood tests measuring proteins associated with bone turnover also dropped to normal levels, indicating that the medication successfully improved bone quality and strength.^[13]

Patients in the trial reported meaningful improvements in disease-related complications. One participant with fibrous dysplasia affecting her ribs experienced increased lung function, likely because the stabilization of abnormal bone reduced pressure on her lungs. Another patient with skull involvement noticed improvements in vision, suggesting that reducing bone expansion helped relieve pressure on the optic nerves. These clinical improvements demonstrated that denosumab may do more than just alter laboratory values—it may genuinely improve patients’ quality of life and reduce disability.^[13]

However, the trial also revealed an important limitation: when patients stopped taking denosumab, abnormal bone turnover returned in all but one participant. Even more concerning, in four patients, bone turnover actually exceeded pre-treatment levels after stopping the medication—a phenomenon known as rebound effect. This finding suggests that denosumab may need to be given continuously or in carefully planned intermittent doses to maintain its benefits, and that stopping treatment requires close monitoring. Researchers and clinicians must carefully consider these risks when deciding whether to use denosumab for fibrous dysplasia patients.^[13]

This clinical trial represents the culmination of 25 years of research at the National Institute of Dental and Craniofacial Research aimed at understanding the biological mechanisms underlying fibrous dysplasia and identifying promising treatments. The trial demonstrates how laboratory research into disease mechanisms can lead to new therapeutic approaches. Phase 2 trials like this one are designed to evaluate whether a treatment shows enough promise in terms of effectiveness to warrant larger studies that compare the new treatment to current standard approaches.

While the denosumab trial results are promising, it’s important to understand that this medication is not yet a standard treatment for fibrous dysplasia, and more research is needed to determine the optimal dosing, treatment duration, and patient selection. The decision to use denosumab would need to carefully balance potential benefits against risks, including the rebound effect seen when treatment stops.

Beyond denosumab, researchers continue to investigate other aspects of fibrous dysplasia treatment. Clinical trials are exploring better ways to predict which patients are most likely to develop severe complications, optimal timing for surgical interventions, and improved techniques for bone reconstruction. Some research focuses on understanding the genetic mutation (in the GNAS gene) that causes fibrous dysplasia, with the long-term hope that treatments targeting this fundamental defect might one day be possible. However, gene therapy or other mutation-specific treatments remain in early research stages and are not yet ready for clinical testing in patients.^[3]

Clinical trials for fibrous dysplasia often take place at specialized centers with expertise in rare bone diseases, including the National Institutes of Health in the United States and major academic medical centers in Europe and other regions. Patients interested in participating in research studies should discuss this option with their healthcare providers, who can help determine eligibility and provide information about available trials. Participating in clinical trials not only gives patients potential access to new treatments but also contributes valuable knowledge that may help future patients.

Most common treatment methods

• Observation and monitoring
  • Regular follow-up appointments with healthcare providers to watch for changes in bone health
  • Periodic imaging tests including X-rays, CT scans, or MRI to track disease progression
  • Blood and urine tests to monitor bone turnover markers
  • Particularly suitable for patients with minimal symptoms or monostotic disease
• Medication therapy
  • Bisphosphonates to strengthen bones and reduce pain by decreasing bone turnover
  • Available in oral tablet form or intravenous infusion
  • Can reduce pain in approximately half of patients
  • Treatment duration varies based on individual response
• Supportive devices
  • Bracing to support weakened bones and prevent deformities
  • Particularly useful for long bones in arms and legs
  • Helps guide proper bone growth in children
• Surgical interventions
  • Fracture repair with internal fixation using plates and screws
  • Bone grafting to replace abnormal bone with donor bone or synthetic substitutes
  • Removal of diseased bone sections
  • Decompression surgery for craniofacial involvement affecting vision or hearing
  • Correction of bone deformities to improve function and appearance
• Pain management
  • Standard pain relief medications for mild symptoms
  • Bone-strengthening medications that also reduce pain
  • Physical therapy to maintain mobility and function
• Endocrine therapy
  • For patients with McCune-Albright syndrome who have hormonal abnormalities
  • Medications to control early puberty, thyroid overactivity, or other hormone problems
  • Requires coordination with endocrinology specialists