Abstract: On February 10, 2011, an employee was operating a backhoe with bucket attachment to break up pieces of concrete at a construction site. To break up larger chunks of concrete, the employee needed to change the end attachment to pneumatic steel puncher. He drove over to the staging area and parked the backhoe by the shaker steel plates by the entrance of the lot. The shaker steel plates were used to strip mud and dirt off incoming vehicles' tires. According to the employee, these shaker plates were unusually high, about four inches. The employee walked over these plates and, tripped. He crushed his left knee onto a shaker plate and fractured it in three places. The employee was transported by paramedics to California Hospital, where he had surgery and was hospitalized.