A client arrives to the emergent care clinic describing pain, tenderness, and swelling of the right knee and an inability to bear weight on the leg. The nurse obtains a history from the client that a popping sound was suddenly heard in the right knee while playing tennis. Based on the history and assessment, which injury should the nurse expect has occurred?

Choice A reason: Tendonitis is inflammation of a tendon, usually caused by repetitive strain or overuse. It presents with gradual onset of pain and tenderness, not with a sudden popping sound or acute inability to bear weight. Therefore, tendonitis does not match the acute presentation described. Choice B reason: A fracture of the patella would cause severe pain, swelling, and inability to extend the knee. However, the history of a popping sound during activity is more characteristic of ligament injury rather than bone fracture. Fractures are typically associated with direct trauma rather than sudden twisting or pivoting movements. Choice C reason: A rotator cuff tear involves the shoulder joint, not the knee. This option is irrelevant to the client’s presentation, as the symptoms are localized to the knee. Choice D reason: A ligament sprain, particularly of the anterior cruciate ligament (ACL), often occurs with a sudden popping sound, acute pain, swelling, and inability to bear weight. The mechanism of injury described (playing tennis, sudden movement) is consistent with ligament injury. This is the most likely diagnosis based on the history and assessment.