CORR Insights ® : What Is the Role of Allogeneic Cortical Strut Grafts in the Treatment of Fibrous Dysplasia of the Proximal Femur?

Abstract

B one deformities in patients with fibrous dysplasia can be potentially disabling and difficult to treat. When involving the proximal femur, fibrous dysplasia is often progressive; resulting in pain, varus angulation of the hip (shepherd’s crook deformity) and potentially, pathological fractures [6, 7]. The disease process is caused by a postzygotic (somatic) mutation of the GNAS gene, manifesting in poorly functioning osteocytes, which produce an inferior quality fibro-osseous bone [9]. The extent of the disease, as well as its extraskeletal manifestations (such as McCune–Albright Syndrome), depends upon the eventual location of the migrating, abnormal embryonic cells [2, 10]. Traditional treatment with curettage and grafting has been associated with resorption of the graft and replacement with newly formed, dysplastic bone produced by the persistent population of abnormal osteoblasts [7]. Enneking and colleagues [3] have suggested that cortical allografts may provide superior outcomes when treating lesions of the femoral neck. The suggestion was that incorporation (or replacement) of the cortical bone would be limited in comparison to cancellous grafting thus maintaining structural support the femoral neck. Evaluation of retrieved bulk allografts, previously implanted for tumor reconstructions confirmed (at least adjacent to normal bone) that allografts demonstrated delayed and incomplete incorporation [4]. Such findings suggest that the premise might also be valid in fibrous dysplasia. Shortly after the Majoor and colleagues paper was accepted for publication, a similar article was published—also from a national referral center (NIH)—maintaining a longitudinal database for patients with fibrous dysplasia [5]. Leet and colleagues reviewed surgical management of long bone lesions in their patients, comparing various grafting techniques including cortical allografts. They identified no differences in outcome comparing patients treated with the cortical grafts versus other techniques, concluding that both allografting and autograft are of ‘‘limited value in ablating lesions of fibrous dysplasia’’ [5]. This CORR Insights is a commentary on the article ‘‘What Is the Role of Allogeneic Cortical Strut Grafts in the Treatment of Fibrous Dysplasia of the Proximal Femur?’’ by Majoor and colleagues available at: DOI: 10.1007/s11999-016-4806-3. The author certifies that he, or a member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/ licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. This CORR Insights comment refers to the article available at DOI: 10.1007/s11999-0164806-3.