Fig. 2. Needle electromyography of the left medial vastus muscle at 3 months postoperatively. The y-axis indicates the voltage in 50 microvolts per division (μV/D). The x-axis indicates the time in 20 milliseconds per division (ms/D). This examination revealed high-voltage dense-frequent denervation activities (fibrillations and sharp waves), consistent with an acute lesion. The assessment of the right medial vastus muscle at 3 months showed unchanged results compared with the primary electromyography.