This occurs in two forms the less common syndromic variant and the more common sporadic variant. The defect in these patients is a 'G-protein anomaly' which for some reason prevents the stem cells in that area from forming bone. This of course means following removal it is best not to fill it in with the patient's own bone as the same defect will cause more fibrous tissue to form there. It is recommended that any other bone substitute except the patient's own tissue be used. Some form of a static fixation device is then necessary to allow the bone graft substitutes to incorporate well.
Syndromic fibrous dysplasia
In this condition an entire bone (mono-ostotic) or multiple bones (poly-ostotic) may be involved in multiple limbs (polymelic) or a a single limb (monomelic). Interestingly, the monomelic forms can happen in a 'ray' extending from , say, the shoulder to humerus, one forarm bone and one finger. If associated with precocious puberty the syndrome is typically refered to as McCune Albright syndrome. Girls in this condition may have reached menarche at the age of 5. Considerations for treatment generally centre around endocrine issues.
Non-syndromic fibrous dysplasia
These are very common conditions. They typically occur around the hip which therefore has a tendency to deform plastically over time. Historically, with a tendency to fracture and heal, the hip became shaped like a shepherd's crook. These deformities are much rarer now as they are managed in a timely fashion.
Figure. This case represents an isolated instance of fibrous dysplasia that was prone to cracking in the hip. To prevent further deformity we removed the tumor and filled it with cadaveric bone. An angled blade plate was used to stabilised the construct. This is the best evidence supported approach to this common problem.