重度の膝側副靱帯損傷と膝前十字靱帯損傷に合併した膝蓋腱損傷の2例

Neglected Patellar Tendon Disruption Associated with Anterior Cruciate Ligament and Collateral Ligament Injuries. Reports of Two Cases

　膝側副靱帯損傷を伴った膝前十字靱帯（ACL）損傷に膝蓋腱損傷を合併した2例を経験した．膝蓋腱損傷は，術中に移植腱として膝蓋腱を採取した際に判明した．術前のMRIでは膝蓋腱の不連続性が認められていたが，術前評価の時点でこの変化は見逃されていた．両症例ともに術前に明らかな膝伸展不全徴候は認められなかったため，膝蓋腱の再建は行わず，術式を変更してACL再建術のみを行った．膝側副靱帯損傷を伴うACL損傷においては，膝蓋腱損傷が合併している可能性を念頭に置いて理学所見や画像所見の評価を行う必要がある．

　We report two cases of simultaneous rupture of the patellar tendon, anterior cruciate ligament (ACL), and collateral ligament. Case 1 was in a 29-year-old man who injured his right knee when he jumped from the loading platform of a truck, and we made a preoperative diagnosis of ACL, lateral collateral ligament, and medial meniscus injury. Case 2 was in a 34-year-old man who injured his left knee while skiing, and we made a preoperative diagnosis of injury of the ACL, medial collateral ligament, and medial meniscus. We failed to diagnose patellar tendon rupture before surgery in either of these cases, because there was no clear dysfunction of the extensor mechanism clinically. However, retrospective examination of the MRI images revealed discontinuity of the patellar tendon in both cases. Although this combination of injuries is rare, rupture of a patellar tendon should always be kept in mind in patients with ACL injury, and careful clinical examination and interpretation of the MRI scans is necessary.