The aims were to investigate the general and specific effects of mild traumatic brain injury (mTBI), and if people with orthopaedic injuries who had sustained their injuries through exposure to acceleration/deceleration force could have sustained a brain injury. The Rapid Screen of Concussion and Digit Symbol Substitution Test were given to patients with mTBI (89 male, 23 female), and patients with orthopaedic injuries that did (27 male, 5 female) or did not (27 male, 15 female) involve deceleration forces within 24 hours of injury. A group of uninjured people (31 male, 12 female) were also tested. Compared to all other groups, patients with mTBI recalled fewer words and correctly answered fewer orientation questions. Patients with either mTBI or deceleration orthopaedic injuries showed slower speed of information processing than patients with nondeceleration orthopaedic injuries or participants without injury. Nondeceleration patients and uninjured participants did not differ. These results suggest that there are both general injury effects and specific mTBI effects on efficiency of cognitive functioning. The results also highlight the probability that patients with a diagnosis of orthopaedic injury who were exposed to acceleration/deceleration forces may have suffered a mild brain injury as well.