Clinical Orthopaedics Clin Orthop Relat Res (2014) 472:1558–1567 and Related Research® DOI 10.1007/s11999-013-3380-1 A Publication of The Association of Bone and Joint Surgeons® CLINICAL RESEARCH Radiographic Classification of Coronal Plane Femoral Deformities in Polyostotic Fibrous Dysplasia Ernesto Ippolito MD, Pasquale Farsetti MD, Alison M. Boyce MD, Alessandro Corsi MD, Fernando De Maio MD, Michael T. Collins MD Received: 4 July 2013 / Accepted: 5 November 2013 / Published online: 19 November 2013 Ó The Association of Bone and Joint Surgeons1 2013 Abstract interobserver reliability; and (3) to characterize the radio- Background Fibrous dysplasia of bone is a skeletal dys- graphic progression of polyostotic fibrous dysplasia in a plasia with a propensity to affect the femur in its population of patients with the condition who were treated polyostotic form, leading to deformity, fracture, and pain. with a variety of approaches at several centers. The proximal femur is most commonly involved with a Methods We retrospectively reviewed radiographs of 127 tendency to distal progression, thereby producing the typ- femurs from 84 adult patients affected by polyostotic ical shepherd’s crook deformity. However, there are few fibrous dysplasia. Fifty-nine femurs had undergone one or data on the spectrum and progression of femoral deformi- more operations. The radiographs were evaluated in the ties in polyostotic fibrous dysplasia. coronal plane for neck-shaft angle and angular deformities Questions/purposes The purposes of this study were (1) along the whole femoral shaft down to the distal epiphysis. to develop a radiographic classification for polyostotic Four observers evaluated each film two times at intervals; fibrous dysplasia; (2) to test this classification’s intra- and intra- and interobserver reliability testing was performed using the kappa statistic. Eighty-nine femurs (70%) were available for followup to evaluate for progression at a mean Each author certifies that he or she, or a member of his or her of 10 years (range, 6–20 years). immediate family, has no funding or commercial associations Results Six reproducible patterns of deformity were (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection identified in both untreated and operated femurs: with the submitted article. type 1 (24%), normal neck-shaft angle with altered shape of All ICMJE Conflict of Interest Forms for authors and Clinical the proximal femur; type 2 (6%), isolated coxa valga with Orthopaedics and Related Research editors and board members neck-shaft angle[140°; type 3 (7%), isolated coxa vara with are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research neither advocates neck-shaft angle\120°; type 4 (20%), lateral bowing of the nor endorses the use of any treatment, drug, or device. Readers proximal half of the femur associated with normal neck-shaft are encouraged to always seek additional information, including angle; type 5 (14%), like in type 4 but associated with coxa FDA-approval status, of any drug or device prior to clinical use. valga; and type 6 (29%), like in type 4 but associated with Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted coxa vara. Interobserver and intraoberver kappa values were in conformity with ethical principles of research, and that informed excellent, ranging from 0.83 to 0.87. In 46 of the 89 femurs consent for participation in the study was obtained. (52%) for which longitudinal radiographic documentation This work was performed at the University of Rome Tor Vergata, was available, there was progressive worsening of the Rome, Italy. E. Ippolito (&), P. Farsetti, F. De Maio A. Corsi Department of Orthopaedic Surgery, University of Rome Department of Molecular Medicine, University of Rome Tor Vergata, c/o PTV, Viale Oxford 81, 00133 Rome, Italy La Sapienza, Rome, Italy e-mail: [email protected] A. M. Boyce, M. T. Collins National Institutes of Health, Bethesda, MD, USA 123 Volume 472, Number 5, May 2014 Classification of Femur Deformities in PFD 1559 original deformity, although the pattern remained the same; Patients and Methods types 1 and 2 tended not to progress, whereas types 3 to 6 did. Conclusions A reproducible radiographic classification of Demographics polyostotic fibrous dysplasia-associated femoral deformi- ties is proposed, which can serve as a tool for assessing and We searched the databases of three treatment centers from treating these deformities. After reviewing the radiographs 1994 to 2009 to identify all patients with polyostotic of 127 femurs, we identified six reproducible patterns of fibrous dysplasia treated at those centers during that femoral deformities. time. We found 92 patients (138 femurs), of whom Level of Evidence Level III, diagnostic study. See 84 (127 femurs) had records complete enough to begin our Guidelines for Authors for a complete description of levels analysis; to be considered complete, a medical record had of evidence. to have a good-quality AP radiograph of the hip, the chart notes with diagnosis, and the treatment records of any surgery performed The treatment centers were the National Institute of Introduction Health, Bethesda, MD, USA, and the Department of Orthopaedic Surgery, University of Tor Vergata, Rome, Polyostotic fibrous dysplasia is an uncommon skeletal dis- Italy. ease caused by somatic activating mutations in the cAMP- Of the 84 patients, 38 were male and 46 female; 43 had regulatory protein Gsa [19, 22]. Normal bone and bone bilateral femoral involvement and 41 had unilateral marrow are replaced by abnormal proliferative osteogenic involvement. Fifty-nine patients had McCune-Albright precursors [1, 17, 18], leading to deformity, fracture, syndrome and 25 polyostotic fibrous dysplasia alone. At functional impairment, and pain [2, 9, 13, 14]. Polyostotic the time of the last radiographic examination, all the fibrous dysplasia may occur in association with cutaneous femurs were skeletally mature. The mean age of the hyperpigmentation and hyperfunctioning endocrinopathies, patients at the time of the last radiograph was 30 years including hyperthyroidism, precocious puberty, growth (range, 16–52 years). For 89 femurs (57 patients, 70% hormone excess, hypercortisolism, and fibroblast growth of the initial study cohort), weightbearing radiographic factor-23-mediated hypophosphatemia. The combination of documentation was available from a mean of 10 years polyostotic fibrous dysplasia and one or more extraskeletal before the final followup radiographs (range, 6–20 years), manifestations is termed McCune-Albright syndrome. whereas for 38 femurs, only weightbearing radiographs The proximal femur is one of the most frequently taken at the final followup were available. In subjects with affected sites in individuals with polyostotic fibrous dys- radiographic documentation spanning several years before plasia [3, 6–8, 10, 21]. Mechanical stress and repeated the final followup, only the last radiograph of the femur fractures result in progressive varus and bowing, leading to was selected for the classification. the classical shepherd’s crook deformity first described by von Reklingausen in 1891 as reported by Ulligan [20]. Management of these deformities is challenging, because Radiographic Evaluation they vary from case to case and they often tend to progress despite surgical intervention [3, 5, 7, 10–12]. However, to The femoral radiographs were examined twice by four of our knowledge, no radiographic grading system has been the authors (EI, PF, AC, FDM) with an interval of 6 weeks. validated using intra- and interobserver reliability testing or Of the four authors who read the radiographs, three were found to be useful in terms of predicting progression of orthopaedic surgeons and one was a pathologist. The osseous deformity. readers who were blinded to each other had postfellowship In this study, we performed a retrospective radiographic professional experience ranging from 10 to 40 years. The review in a large cohort of patients with polyostotic fibrous following parameters were evaluated: [1] location of dysplasia to classify the variety of femoral deformities and fibrous dysplasia (FD) lesions within the femur; FD was to correlate the deformity pattern with the surgical cor- identified by the presence of at least one of the following rection required. We therefore sought to [1] develop a features: (a) typical ‘‘ground glass’’ appearance, (b) radiographic classification for polyostotic fibrous dyspla- increased or decreased radiodensity, (c) bone cysts, or (d) sia; [2] test this classification’s intra- and interobserver enlargement and/or irregularity of the femoral profile; [2] reliability; and [3] characterize the radiographic progres- presence and extent of the shaft cortices and the medullary sion of polyostotic fibrous dysplasia in a population of canal; [3] neck-shaft angle measurement on the AP view; patients with the condition who were treated with a variety the angle was measured between the axis of the femoral of approaches at several centers. neck and the anatomical axis of the femur. When a lateral 123 1560 Ippolito et al. Clinical Orthopaedics and Related Research1 bowing deformity was present in the proximal femoral shaft below the lesser trochanter (shepherd’s crook defor- mity), the neck-shaft angle was identified by the inter- section of the axis