Traumatic radial nerve injury in humeral shaft fracture is the most common traumatic nerve injury in long-bone fracture, with overall prevalence 2-18%, ranging from traction to complete transection. Spontaneous recovery may reach 88%. The aim of the study is to assess the sensitivity & specificity of the ultrasound to detect the radial nerve injury and to see if this can be used as a diagnostic test. This is a prospective study on 17 adult patients with a closed fracture of the humeral shaft, dividing into two groups, the first group of 7 patients had signs and symptoms of radial nerve palsy at presentation and the second group of 10 patients had intact radial nerve function was considered as a control group. All these patients had at least one indication to fix their fractured humerus, then all patients had evaluated with high-resolution ultrasound(7 Mhz) to assess the radial nerve by the same radiologist with three weeks of injury. Then all the patients have been treated with open reduction and internal fixation with an exploration of the radial nerve and the results were compared. The use of high-resolution ultrasound shows a low sensitivity and specificity (66.6% and 63.6% respectively) with low overall accuracy (64%). Our conclusion is the high-resolution ultrasound cannot be used as a diagnostic test for radial nerve injury associated with closed humeral shaft fracture, but still can show some traumatic pathology which may benefit from early surgical exploration.
