スポーツにより発症した𦙾骨内果疲労骨折偽関節の1例

Nonunion of a Medial Malleolus Stress Fracture : Case Report

　抄録：𦙾骨内果疲労骨折偽関節の1例を経験したので報告する．症例はサッカー歴4年の16歳，男性．高校のサッカー部員であり，右足関節内側部痛を主訴とした．近医にて𦙾骨内果骨折を指摘され，明らかな外傷歴がなかったため，𦙾骨内果疲労骨折と診断された．しかし積極的な治療を拒否し，通常通りサッカーを続けた．6カ月後疼痛改善を認めず，当科を紹介受診した．遠位骨片の転位が増大しており，𦙾骨内果疲労骨折偽関節と診断し，観血的骨接合術を施行した．意図にそぐわず，術後6週にて全荷重歩行を行っていた．その後，骨癒合の遷延を認めるようになったが疼痛が消失したため，術後7カ月より運動を開始し，9カ月後には完全復帰した．術後1年6カ月の現在，受傷前と同程度の運動が可能である．

　本症例の特徴として，水平な骨折線があげられる．これまでに報告されている症例とは異なった足関節の不安定性によるものと推察された．

　This is a report of a case of nonunion of a medial malleolus stress fracture in a high school soccer player. The patient went to another orthopaedic clinic complaining of medial ankle pain, and a diagnosis of stress fracture was made based on the history and radiographic evidence. But he refused medical treatment, and continued playing soccer as usual. Six months later the pain had not improved, and he came to our hospital. Radiographs of the right ankle revealed greater displacement of the medial malleolus fracture. We made a diagnosis of nonunion of a medial malleolus stress fracture and treated it by open reduction and internal fixation. The patient unintentionally placed his full body weight on the ankle 6 weeks postoperatively. There was a delay in healing of the fracture, but the patient did not experience any pain. He gradually started exercising 7 months after surgery, and returned to playing soccer 9 months postoperatively. At present, 1.5 years after surgery, he can function as well as before the injury.

　Our case was characterized by a horizontal fracture of the medial malleolus, and we speculate that it was caused by ankle joint instability, different from other cases.