A 13-year-old girl presented with pain and swelling on the medial aspect of the proximal leg, which she had noticed for several years. Her height and body weight were 161 cm and 64 kg, respectively. She had no past medical history related to the lesion. There was no history of trauma or injury. On physical examination, the non-mobile hard lesion was palpable with slight tenderness on the medial side of the proximal tibia. Plain radiographs showed a lesion protruding from the bone with continuity to the underlying bone (Fig. ). The size of the lesion was 2.0 cm on a plain radiograph. MRI depicted a protuberant bone lesion with continuity to normal bone. However, an overlying cartilaginous cap or surrounding inflammation was not apparent (Figs. ). Surgically, the lesions were approached posterior to the conjoint tendon, and resected using a curved chisel (Fig. ). The lesion was composed of lamellar bone trabeculae with fatty marrow and a covering cartilaginous component, compatible with osteochondroma. There was no evidence of malignancy. Six months after surgery, the preoperative symptoms had disappeared.
A 13-year-old girl had noticed pain for six months when she ran, but no pain while she walked. She also noticed snapping at the medial site of the proximal leg on knee flexion. Her height and body weight were 150cm and 42kg, respectively. She had no past medical history related to the lesion. On physical examination, a small hard lesion was palpable. Tenderness at the medial side of the proximal tibia was observed. The snapping phenomenon was reproduced on knee flexion. Plain radiographs showed a small 0.5 cm osseous lesion on the antero-posterior radiographic view (Fig. ). CT depicted a small protuberant bone lesion with continuity to normal bone (Fig. ). Surgically, the lesions were approached posterior to the conjoint tendon, and resected with a curved chisel while retracting the attachment of the pes anserinus. The lesion was composed of a hyaline cartilaginous cap and underlying lamellar bone trabeculae and fatty marrow (Fig. ). There was no evidence of malignancy. Six months after the surgery, the symptoms had disappeared.