Male patient had twist injury of his knee with tear of the ACL and was operated. After the surgery he suffered acute lumbalgia. Twelve days later he was re-admitted for knee effusion and elevated body temperature, and arthrolysis and joint washing were performed. Following the procedure he complained of hypoesthesia of the proximal lower left limb and knee. EMG reveled L4 and S1 root damage, and MRI showed reduced lumbar lordosis and different disc lesions. In case of compression neuropathy (tourniquet), the expert recommends symptomatic only treatment.