膝前十字靱帯再建術における採取腱の再生―術後超早期のMRIによる経時的前向き検討

Hamstring Tendon Regeneration after Harvesting for Anterior Cruciate Ligament Reconstruction. : A Prospective Study with Early Post-operative MRI.

　MRIで術後早期の膝屈筋腱の再生過程を前向きに検討した．前十字靱帯再建術を受ける連続する20膝を対象とした．MRIを術後12週以内に5回撮り，関節面高位とその5cm近位の2カ所で，再生腱の出現率，出現週数と信号強度の変化を調査した．結果，早い症例では2週以内に再生腱が認められ，6週では80％以上の症例に認められた．6週までに認められない症例では，その後も認められなかった．また，腱再生は関節面高位より5cm近位で先行していた．本研究より，膝屈筋腱の旺盛な再生能が確認され，再生するかどうかは術後6週以内に決定されると考えられた．

　This prospective study used early postoperative magnetic resonance imaging (MRI) to evaluate hamstring regeneration after harvesting for anterior cruciate ligament (ACL) reconstruction. MRI scans were performed five times within a twelve-week postoperative period in 20 consecutive patients who underwent ACL reconstruction. MRIs of the joint line and 5cm proximal to the joint line were obtained, and the time required for regenerative tendons to appear and the signal intensity to change was evaluated. Regenerative tendons appeared within 2 weeks after operation in some early cases and were recognized in over 80％ of the cases at 6 weeks after operation. Among the cases in which regenerative tendons were not recognized within 6 weeks after operation, no evidence of regenerative tendons was seen at 12 weeks after operation. The possibility of hamstring regeneration was confirmed to be quite high, furthermore, the outcome of hamstring regeneration can be predicted at an early stage, within 6 weeks after operation.