Osteoarthritis of the hip (grading)

Last revised by Joachim Feger on 22 Aug 2020

Osteoarthritis of the hip can be graded according to its severity.


Plain radiograph

Different grading schemes are described for plain radiographs of the hip:

  • grade 0: normal
  • grade 1: possible joint space narrowing and subtle osteophytes
  • grade 2: definite joint space narrowing, defined osteophytes and some sclerosis, especially in the acetabular region
  • grade 3: marked joint space narrowing, small osteophytes, some sclerosis and cyst formation and deformity of femoral head and acetabulum
  • grade 4: gross loss of joint space with above features plus large osteophytes and increased deformity of the femoral head and acetabulum
Tönnis classification for osteoarthritis of the hip

The original Tönnis classification consists of three degrees of degenerative changes featuring osteoarthritis of the hip. Grade 0 was added later 2,3.

  • grade 0: no signs of osteoarthritis
  • grade 1: minor joint space narrowing, subchondral sclerosis of the femoral head and/or acetabulum, small osteophytes
  • grade 2: moderate joint space narrowing, small subchondral cysts of the femoral head and/or acetabulum, moderate loss of sphericity of the femoral head
  • grade 3: severe joint space narrowing or obliteration, large subchondral cysts, severe deformity of the femoral head
Croft score for hip osteoarthritis

The Croft score uses different compositions of the following features for the grading of hip osteoarthritis: osteophytes, joint space narrowing, subchondral sclerosis, subchondral cysts 4,5.

  • grade 1: only osteophytic changes
  • grade 2: only joint space narrowing
  • grade 3: two of the above mentioned radiographic features
  • grade 4: three of the above mentioned radiographic features
  • grade 5: femoral head deformity plus three of the above mentioned radiographic features
  • grade 0: normal
  • grade 1: inhomogeneous high signal intensity in cartilage (T2WI)
  • grade 2: inhomogeneity with areas of high signal intensity in articular cartilage (T2WI); indistinct trabeculae or signal intensity loss in femoral head and neck (T1WI)
  • grade 3: criteria of grade 1 and 2 plus indistinct zone between femoral head and acetabulum; subchondral signal loss due to bone sclerosis
  • grade 4: above criteria plus femoral head deformity

See also

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Cases and figures

  • Figure 1: anatomy of the hip joint
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  • Figure 2: changes in osteoarthritis
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  • Case 1: grade 3 on CT
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  • Case 2: grade 3 on plain film
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  • Case 3: grade 2
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