Brief Answer: You must have injured your ankle also Detailed Answer: Hi thanks for your question. the only explanation is that you injured your left ankle at the same time as your right knee. it is impossible for a right knee injury to cause bruising and swelling of the left ankle. if you are not in any pain in your left ankle and you do not have a limp then this injury must be fairly minor and should improve spontaneously however if you have pain or a limp depending on the severity you may want to see a dr and arrange an X-ray of your ankle to ensure no fracture. best wishes

---

Brief Answer: Common to find bruising at ankle with knee injury Detailed Answer: Hi, That makes more sense, sorry I misinterpreted your question. As your ankle and foot is the most dependant part of your leg then swelling and bruising from an injury on any part of your leg can track down to the ankle and or foot under gravity. This is very common and nothing to worry about. If you elevated you leg particularly at night when your are sleeping you will find that by the morning the swelling has improved. The bruising will resolve over a few weeks. Best wishes

---