Instructions: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: A case of bilateral patella tendon rupture in an otherwise healthy 38-year-old man who sustained relatively minor trauma is presented. A flexion moment against a contracted or contracting quadriceps muscle is thought to have been the mechanism of injury. A survey of the literature yielded reports of three other cases of otherwise healthy patients who had had bilateral simultaneous disruption of the patella tendons.
Output:
Adult