A young man was involved in a road traffic accident. He was riding a motorbike when he collided with a car. He was taken from the scene of the accident to an accident and emergency department in a hospital at 10 pm. The injuries he sustained involved a laceration to his left knee and a small laceration to his chin. He had no head injury, and the significant injury was a 15 cm laceration over the anterior aspect of his left knee. This was a deep laceration, down to the patella, with muscles and other structures exposed in the base of the wound. X-rays taken at the time showed no bony injury, and clinical examination of the knee joint showed no injury to the ligaments. Xrays were also taken of his skull and spine, to exclude fractures. Under a general anaesthetic the following day, his chin laceration was cleaned and sutured. His wound over the knee was debrided, irrigated and closed primarily with two layers of sutures. Following this, he was put into an above knee plaster cast and remained in hospital for four days. Two days following his discharge, he was admitted with an acutely swollen leg. Clinical diagnosis of a deep vein thrombosis was made and this was confirmed by venography. A clot was noted in the calf veins below the knee. He was fully anticoagulated with heparin, then switched to warfarin and remained hospitalised for a further eight days. He was discharged home with a support bandage and continued to attend physiotherapy for further period of six weeks.