著明な滑膜炎を合併したvalgus extension overload syndromeの1例

Valgus Extension Overload Syndrome Accompanied by Severe Synovitis : Case Report

　抄録：Valgus extension overload syndromeでは，投球時の肘関節外反伸展により後方のインピンジメントが生じ，肘関節後内側に骨軟骨障害や遊離体形成がみられる．今回筆者らは，本症に合併して多数の骨軟骨片と著明な滑膜炎が存在した1例を経験した．症例は16歳，女性のソフトボール選手である．主訴は投球時の右肘関節痛であった．肘関節に腫脹がみられ，伸展-25°，屈曲125°，前腕回内70°，回外70°と制限がみられた．単純X線にて，5個の遊離体を認めた．超音波では滑車の後内側に剝離骨軟骨片を認めた．滑膜切除と剝離骨片切除を行った．病理組織では，滑膜内に多数の軟骨片や骨軟骨片が認められた．術後3カ月の時点で伸展-25°，屈曲130°，前腕回内90°，回外90°に改善，内野手レギュラーとして復帰している．本例では多数の関節内遊離体と著明な滑膜炎が合併し滑膜性軟骨腫症が強く疑われたが，本症に特徴的な軟骨のcloningがなかった．したがって滑膜性軟骨腫症は否定され，著明な滑膜炎を合併したvalgus extension overload syndromeと診断された．

　The term “valgus extension overload syndrome” is usually used to describe a condition consisting of medical compartment distraction, lateral compartment compression, and posterior compartment impingement. The impingement produces degenerative changes in the posterior compartment of the elbow as a result of forces imposed on the elbow during repetitive throwing. We report a case of 16-year-old female softball player in which this syndrome was accompanied by several loose bodies and severe synovitis. The patient's chief complaint was right elbow pain while pitching. The right elbow was swollen, and its range of motion was limited to-25 degrees of extension, 125 degrees of flexion, 70 degrees of pronation, and 70 degrees of supination. Ultrasonography showed a detached osteochondral fragment in the posteromedial aspect of the trochlea. The patient was treated by synovectomy of the elbow with fragment removal. Pathological examination of the surgical specimen revealed many osteochondral fragments in the synovium. Three months after the operation, elbow motion had increased to-25 degrees of extension, 130 degrees of flexion, 90 degrees of pronation, and 90 degrees of supination. The patient had resumed softball as a regular field player. In this case, primary synovial chondromatosis was initially suspected because of the presence of many loose bodies and severe synovitis in the elbow joint. However, the pathological analysis did not show any evidence of cloning, which is a characteristic of synovial chondromatosis. Therefore, the final diagnosis was valgus extension overload syndrome accompanied by severe synovitis.