Osteitis condensans ilii: a significant association with sacroiliac joint tenderness in women

To determine whether subjects with radiological evidence of osteitis condensans ilii exhibit symptoms and signs in common with sacroiliitis when compared with an age-matched control group and to examine demographic features.

The Dunedin Hospital radiology database was searched for all subjects with changes of osteitis condensans ilii over a 10-year period. An age-matched control group with plain X-rays of the pelvis was recruited from the same database. All subjects were sent a questionnaire enquiring about back pain and details of previous pregnancies. Those who responded to the questionnaire were invited for clinical assessment.

Thirty-five individuals with osteitis condensans ilii were identified over the 10-year period. All were female and reported prior pregnancy supporting an association between osteitis condensans ilii and pregnancy. Stress testing of the sacroiliac joints was associated with greater tenderness in the osteitis condensans ilii group with a mean of 1.8 positive tests out of a possible 4, compared to 0.8 in the control group (Wilcoxon rank-sum test P = 0.02). Comparison between the two groups showed no difference in number of pregnancies, newborn weight, presence of back pain, back pain assessed by the Oswestry Low Back Pain Questionnaire or loss of function using the Bath Ankylosing Spondylitis Functional Index (BASFI).

Osteitis condensans ilii is associated with tenderness during sacroiliac joint compression tests and should be considered in the differential diagnosis when sacroiliac joint tenderness is elicited.