The ilioischial line, also known as the Köhler line, is a radiologic feature seen in the AP pelvis view and serves to assess the posterior acetabular column 1-4.
If the acetabular fossa touches or medially extends the ilioischial line this is a finding of coxa profunda 2,3, which itself can be seen in different hip pathologies such as acetabular dysplasia or pincer morphology 5, and also in asymptomatic or normal hips 3.
If in addition, the femoral head is medial or close to the ilioischial line and medial to the acetabular walls this is a sign of protrusio acetabuli 4, which itself can be seen in osteoarthritis, rheumatoid arthritis, post-traumatic hip joints 4, osteogenesis imperfecta 6, or Paget disease.
Disruption of the ischioanal line is considered a sign for a posterior column fracture 1.
- 1. Adult Hip Radiography: Lines and angles. doi:10.1594/essr2017/P-0209
- 2. Anderson LA, Kapron AL, Aoki SK, Peters CL. Coxa profunda: is the deep acetabulum overcovered?. (2012) Clinical orthopaedics and related research. 470 (12): 3375-82. doi:10.1007/s11999-012-2509-y - Pubmed
- 3. Fujii M, Nakamura T, Hara T, Nakashima Y, Iwamoto Y. Does radiographic coxa profunda indicate increased acetabular coverage or depth in hip dysplasia?. (2015) Clinical orthopaedics and related research. 473 (6): 2056-66. doi:10.1007/s11999-014-4084-x - Pubmed
- 4. Leunig M, Nho SJ, Turchetto L, Ganz R. Protrusio acetabuli: new insights and experience with joint preservation. (2009) Clinical orthopaedics and related research. 467 (9): 2241-50. doi:10.1007/s11999-009-0853-3 - Pubmed
- 5. Boone G, Pagnotto MR, Walker JA, Trousdale RT, Sierra RJ. Radiographic features associated with differing impinging hip morphologies with special attention to coxa profunda. (2012) Clinical orthopaedics and related research. 470 (12): 3368-74. doi:10.1007/s11999-012-2539-5 - Pubmed
- 6. Violas P, Fassier F, Hamdy R, Duhaime M, Glorieux FH. Acetabular protrusion in osteogenesis imperfecta. (2002) Journal of pediatric orthopedics. 22 (5): 622-5. Pubmed