A Patient with Focal Fibrocartilaginous Dysplasia in the Distal Femur and Review of the Literature

A Patient with Focal Fibrocartilaginous Dysplasia in the Distal Femur and Review of the Literature

AKIRA ANDO,¹ MASAHITO HATORI,¹ MASAMI HOSAKA,¹ YOSHIHIRO HAGIWARA,¹ ATSUSHI KITA,² TATSUHIRO OCHIAI³ and EIJI ITOI¹

¹Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine
²Department of Orthopaedic Surgery, Japanese Red Cross Sendai Hospital
³Department of Orthopaedic Surgery, Miyagi Takuto Medical Center

Focal fibrocartilaginous dysplasia (FFCD) is a rare and benign bone lesion that induces bowing deformity of the long bones in young children. Excessive production of fibrocartilage by abnormal differentiation in the metaphysis or by trauma during delivery or after birth is thought to cause growth disturbance. Radiologically, the lesion is characterized by a lucent defect with marginal sclerosis in the medial metaphysis of the long bone. However, there have been few reports about the initial radiological changes of FFCD before bowing started. We report a patient with FFCD in the left distal femur in whom the radiological changes were serially observed during the course of the disorder. A 2-week-old boy first visited our hospital because of left thigh pain. Plain radiographs did not show any abnormal findings at that time. At 10 weeks, a well-defined lucent defect with bony fragment inside was observed in the distal femoral medial cortex. At 1 year, this bony fragment gradually vanished but varus deformity progressed and reached approximately 40 degrees at the age of 2. After removal of the lesion, osteotomy and immobilzation was performed with Ilizarov external fixator comprising rings, rods and wires. Complete bone union was achieved 3 months after operation. It is noteworthy that we could observe the initial radiological changes of FFCD before varus deformity occurred. As far as we know, there have been no descriptions of the bony fragment inside a lucent defect of the lesion. Radiological features may vary in the early phase of FFCD.

keywords —— focal fibrocartilaginous dysplasia; femur; osteotomy; Ilizarov external fixator.

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Tohoku J. Exp. Med., 2008, 215, 307-312

Correspondence: Masahito Hatori, Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.

e-mail: mhato@mail.tains.tohoku.ac.jp