The semitendinosus tendon regenerates after resection - A morphologic and MRI analysis in 6 patients after resection for anterior cruciate ligament reconstruction

Recently, the surprising observation has been made, supported by clinical a nd MRI findings, that the semitendinosus tendon can regenerate after being harvested in its whole length and thickness for anterior cruciate ligament reconstruction. We studied 6 patients with previous anterior cruciate ligam ent reconstruction, using a quadruple semitendinosus tendon autograft. In 5 of these, physical examination and MRI showed that the tendond had regener ated. In all 6 patients, the findings were documented macroscopically by op en surgical exploration and in the 5 regenerated tendons, also morphologica lly by biopsies. Macroscopically, histologically and immunohistochemically the regenerated tendons closely resembled normal ones with focal scar-like areas. Our present findings and earlier studies show that full length and t hickness harvesting of the semitendinosus tendon in most cases result in fu ll-length tendon regeneration with tissue closely resembling the normal ten don.