Acute injury of anterior cruciate ligament during karate training

A 38-year-old black-belt karate practitioner presented with acute disabling injury of his knee after swift-withdrawal of a reverse-roundhouse-kick. Examination confirmed the diagnosis of grade III ACL tear. Although there are reports documenting injury rate in modern karate, no previous cases of karate-related ACL injuries have been reported. The trauma mechanism is different than ACL injuries during other non-contact and contact sports. The current case report indicates that ACL injury can occur without any contact of the lower limb as a result of dynamic muscular forces during karate training.