Hi, this is Sagar Wagle, one of the musculoskeletal radiology fellows at Stanford University. We have a case of a 64 year old male with low back pain with a left hip component. Radiographs show osteoarthritis of both hips. In left hip there is joint space narrowing and we can also see osteophytes. On the right hip the joint space is relatively preserved, but there is osteophyte in the acetabulum. And here we can see the left hip on a different view where you can see the joint space narrowing and the acetabular osteophyte. There are different grading system for hip osteoarthritis and radiographs and one of them is Thonis system. In this grade 0 refers to normal hip without any osteoarthritis. In grade 1 there is mild joint space narrowing. In grade 2 there is moderate joint space narrowing and there can be small subchondral cysts. In grade 3 there is severe joint space narrowing. There can be loss of sphericity of the femoral head. There can be large subchondral cysts and avascular necrosis. On the right we have image of a 26 year old male. The joint spaces are completely normal. So this is Thonis grade 0. There is no osteoarthritis. In this case in the left hip there is some joint space narrowing and we can see this when we compare it to the right hip. Some people may call this mild joint space narrowing. Some people may call this moderate. So there is some subjectivity. There is also osteophyte. In this case we'll just call this moderate joint space narrowing and give this grade 2. In this case, there is complete loss of joint space and the lucency in the femoral head. This represents subchondral cyst and we can also see sclerosis in the acetabulum. So this is grade 3. Here there is complete loss of joint space and there are subchondral cysts on the femoral head and acetabulum. There is also subchondral sclerosis. So this is also example of grade 3. If we go back to our original case, some people could call this mild joint space narrowing. Some people could call this moderate. So depending on the person they could give this a grade 1 or grade 2 and one thing to keep in mind is that sometimes osteoarthritis can appear severe on imaging but the symptoms could be mild and at other times the imaging findings could be really mild and the symptoms could be really severe. In this case, the patient underwent arthroplasty of the left hip. Thank you for watching the video.

3rd Edition, CASE 25

3rd Edition

Hip

musculoskeletal radiology

osteoarthritis

Thonis grading system

hip arthroplasty

imaging correlation