Lindsey Vonn's younger sister, Karin Kidlow, has sustained a torn anterior cruciate ligament barely six weeks after her elder sibling suffered the same injury during this year's Winter Olympics.

America's legendary Alpine ski racer ruptured her left ACL before the Games even began and then broke that same leg during a crash that required four surgeries due to the fracture's complexity. Karin was in Cortina d'Ampezzo to watch Vonn compete. She also stayed by her sister's bedside while in hospital.

Both are now back in the United States. Vonn, though, is now the one supporting her injured sibling as they recover.

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Vonn posted about Kidlow's plight on Instagram. Sharing a video of her sister walking on crutches with a braced right knee, she said: "Karin joins the rehab programme!"

She tags Kidlow in the clip, captioning it "Patient #2 - torn ACL," and adds: "Welcome to the Vonn rehab centre." Kidlow later posted her own video of Vonn testing out the movement in her sister's knee cap.

Responding to what she is doing, Kidlow says: "OK, that's not even that bad. Vonn then explains: "OK, just got back and forth like this," moving Kidlow's right knee cap between both of her thumbs and index fingers.

However, after trying to move the kneecap vertically rather than horizontally, Kidlow reacts in pain. "Ah! No joke, that hurts a little bit.

Vonn continues to move the kneecap regardless, explaining: "OK, I know, because you've got these two portals right here." Kidlow responds: "Yeah, and your fingers are on them. Her sister says: "I know. If you touch them, they're chunky." Kidlow, at this point, cannot help but laugh and stops recording Vonn.

The caption reads: "First appointment with my new physical therapist. Vonn reposted the video on her account and then asked whether she should charge her sister.

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Hours later, Vonn posted progress on her own recovery. She shared a video of her riding a scooter outside while her Cavalier King Charles Spaniel, Chance, walked around her on a lead.

Vonn captioned the post: "Look out world! Here we come." She also added that it was her "first time outside in over a month!"

The scooter is named 'Speedy' as Vonn revealed in a previous post after riding it inside. She said: Got some new wheels! This is as fast as I'm going to go for a while, but it's better than the wheelchair! I'm naming him 'Speedy'."