Overview
McCune‑Albright syndrome (MAS) is an ultra‑rare, mosaic genetic disorder that often presents with painful bone lesions, hormonal imbalances, and distinctive skin pigmentation. A recent case report detailed a 15‑year‑old boy with a severe, fibrous‑dysplasia‑related deformity of the left femur who was treated with multiple osteotomies, massive curettage, intramedullary nail fixation, and synthetic bone grafting. The report demonstrated measurable improvement in function, as captured by the Lower Extremity Functional Scale (LEFS), and highlighted a surgical strategy that may be applicable to other patients with polyostotic fibrous dysplasia (FD) secondary to MAS.
Because limb deformity and length discrepancy are among the most disabling features of MAS, understanding the outcomes of this combined approach is essential for patients, families, and clinicians who are weighing surgical options. The case provides real‑world data on the feasibility of aggressive corrective surgery, the durability of the correction, and the types of complications to anticipate.
What This Study Examined
The authors described a single‑patient, retrospective analysis of a complex reconstructive procedure performed at a tertiary orthopedic center. The intervention consisted of (1) three sequential osteotomies to straighten the femur, (2) extensive curettage of the dysplastic bone tissue, (3) placement of a locked intramedullary nail (IM nail) for axial stability, and (4) filling of the defect with a synthetic bone graft substitute. Functional outcomes were assessed pre‑ and post‑operatively using the LEFS questionnaire.
Why This Matters for Patients
Patients with MAS often face recurrent deformity because the bone that regenerates after an osteotomy is itself dysplastic. This case shows that a combined strategy—multiple osteotomies, removal of the abnormal tissue, rigid intramedullary fixation, and grafting—can provide a more durable correction than osteotomy alone. For families confronting the prospect of multiple surgeries, the report offers concrete evidence that functional gain is achievable, and it clarifies the risk profile associated with each component of the procedure.
Medical Background
MAS results from post‑zygotic activating mutations of the GNAS gene, leading to constitutive activation of the G‑protein signaling pathway. The classic triad includes FD of bone, café‑au‑lait macules (CALM), and precocious puberty. When FD involves multiple bones (poly‑FD), the affected limbs may develop angular deformities, bowing, and length discrepancy that impair gait, cause pain, and increase fracture risk.
Traditional treatments range from observation to limited osteotomies, external fixation, or intramedullary stabilization. However, the dysplastic bone often remodels into the same abnormal shape, leading to recurrence. Recent advances emphasize the use of an intramedullary nail to provide continuous internal support, while massive curettage removes the bulk of the fibro‑osseous tissue, creating a more favorable environment for bone graft incorporation.
How the Procedure Works
1. Multiple osteotomies: The surgeon makes precise bone cuts at strategic levels to realign the shaft and correct angular deviation. 2. Massive curettage: Using curettes and high‑speed burrs, the abnormal fibro‑osseous matrix is scraped away, leaving a clean cancellous cavity. 3. Intramedullary nail fixation: A locked IM nail is inserted through the medullary canal, spanning the osteotomy sites and providing rigid internal support that resists bending forces. 4. Bone grafting: A synthetic graft (e.g., calcium sulfate or hydroxyapatite‑based) is packed into the defect to promote new bone formation and stabilize the construct.
Who Is a Candidate?
Ideal candidates are adolescents or young adults with MAS‑related poly‑FD who have (a) a clinically significant angular deformity (>30°) or leg‑length discrepancy (>2 cm), (b) pain or functional limitation despite non‑operative management, and (c) sufficient residual healthy bone stock to accommodate a nail. Contraindications include active infection, severe cardiopulmonary disease precluding anesthesia, or inability to comply with postoperative weight‑bearing restrictions.
Clinical Summary
- Procedure: Multiple femoral osteotomies, massive curettage of dysplastic bone, locked intramedullary nail placement, synthetic bone graft augmentation.
- Typical Duration: 3–5 hours of operative time, depending on the number of osteotomies and extent of curettage.
- Recovery: Partial weight‑bearing with crutches for 6–8 weeks; full return to sport often at 4–6 months.
- Success Rate (general): In poly‑FD, intramedullary fixation combined with grafting shows functional improvement in 70‑80 % of cases (based on series of similar patients).
Study Methodology
The authors performed a retrospective case review of a single patient treated at a university orthopedic department. Radiographs, intra‑operative photographs, and LEFS scores were collected pre‑operatively, at 3 months, and at 12 months post‑surgery. The primary aim was to assess whether the combined technique could achieve lasting correction of femoral bowing and improve functional capacity.
Patient Selection Criteria
Inclusion required a confirmed diagnosis of MAS (presence of FD, CALM, and precocious puberty), a documented femoral angular deformity >30°, and a history of a previously healed fracture that contributed to persistent bowing. Exclusion criteria were active infection, non‑ambulatory status, and inability to give informed consent.
Outcome Measures
The study employed two objective metrics: (1) radiographic measurement of the femoral mechanical axis (degrees of lateral bowing) and (2) the Lower Extremity Functional Scale (LEFS), a 20‑item questionnaire ranging from 0 (worst) to 80 (best) that quantifies lower‑extremity disability.
Results & Findings
Post‑operative radiographs demonstrated a reduction of the lateral bow from 42.6° to 8.3° at the 12‑month follow‑up, representing an 80 % correction. The LEFS score improved from a pre‑operative 31 to a post‑operative 66, indicating a clinically meaningful functional gain.
Key Outcomes
- Significant angular correction (≈80 %) maintained at 12 months.
- Improved functional status as measured by LEFS (increase of 35 points).
- No radiographic signs of recurrent dysplastic remodeling within the 12‑month period.
- Successful integration of the synthetic bone graft without graft‑related infection.
Complications & Risks
The authors reported no intra‑operative fractures, neurovascular injuries, or deep infections. However, they noted the following potential risks, consistent with the broader literature on intramedullary fixation in FD:
- Hardware irritation or prominence requiring secondary surgery for nail removal.
- Transient postoperative pain at osteotomy sites.
- Potential for incomplete graft incorporation leading to delayed union.
- Recurrence of deformity over time if residual dysplastic bone continues to remodel.
All complications were managed conservatively, and the patient returned to full weight‑bearing without assistive devices by eight weeks.
Key Takeaways for Patients
- Combined osteotomies, curettage, intramedullary nailing, and grafting can achieve marked correction of MAS‑related femoral bowing.
- Even after an aggressive surgical approach, some risk of hardware irritation or future deformity persists; long‑term follow‑up is essential.
- Recovery typically involves 6–8 weeks of protected weight‑bearing followed by gradual return to activity.
- Functional improvement can be substantial, often translating into a higher quality of life and ability to participate in sports.
- Ask your surgeon about the durability of the correction, the type of bone graft used, and the plan for postoperative monitoring.
Frequently Asked Questions
- What is McCune‑Albright syndrome and how does it affect the bones?
- MAS is a genetic mosaic disorder that causes abnormal bone growth called fibrous dysplasia, leading to weak, misshapen bones that can bow, fracture, or grow at uneven rates.
- Why are multiple osteotomies needed instead of a single cut?
- Because the femur may be bowed at several points, multiple cuts allow the surgeon to straighten each segment precisely and achieve overall alignment.
- What is an intramedullary nail and why is it preferred for MAS?
- An intramedullary nail is a metal rod placed inside the marrow canal of the bone; it provides strong internal support that resists bending and reduces the chance of the bone returning to its abnormal shape.
- Is bone grafting necessary after curettage?
- Grafting fills the cavity left after removing the dysplastic tissue, promotes new healthy bone formation, and helps stabilize the construct while the nail heals.
- How long will I be in a cast or using crutches after this surgery?
- Most patients use crutches for 6–8 weeks with limited weight‑bearing; a short‑term removable splint or cast may be applied for additional support during the early healing phase.
(Source: PubMed / Europe PMC)