A 37 year old multiparous female with a few weeks history of back pain and left groin pain.
This 37 year old multiparous female presented with a few weeks history of back pain and left groin pain. A CT abdomen was requested to exclude left renal colic. The CT showed bilateral symmetric sclerosis of the iliac aspects of the sacro-iliac joints, with extension of the sclerosis into the sacral aspect of the left sacro-iliac joint. A subsequent AP pelvis radiograph illustrates these findings on plain film. Blood tests including inflammatory markers, bone profile, thyroid function tests and HLA-B27 were normal. Clinical examination of the sacro-iliac joints was also normal and it was felt that the symptoms were related to mechanical back pain. The symptoms improved with analgesics.
Osteitis condensans ilii is a benign condition mainly seen in young multiparous women. It affects 2% of the population and is thought to be a stress reaction from pregnancy, but it may also occur in males and nulliparous females. The underlying pathophysiology is likely benign bone remodelling from response to stress. The radiographic appearances are characterized by a dense triangular sclerosis on the iliac side of the sacro-iliac joints. Joint space and articular surfaces are not involved. Clinical examination of the sacro-iliac joints and laboratory blood tests are typically normal. The condition is not related to the HLA-B27 antigen. CT is superior to plain radiography in detecting early joint abnormalities in sacro-iliitis and can differentiate between early sacro-iliitis and osteitis condensans ilii if clinical examination is unhelpful. Quantitative scintigraphy has proved non-specific in this regard. Previous authors have suggested that on plain radiography, what sometimes appears to be sclerotic involvement of the sacral aspect is no more than sclerosis in the auricular portion of the ilium itself. However, CT has since confirmed that sacral sclerosis can occur and is normally wider than 3 mm. It is debatable whether osteitis condensans ilii can be a cause of symptoms such as back pain. Many feel that the condition is an incidental finding. Some patients with symptoms are treated with physiotherapy and/or analgesics. The prognosis is good in any case. Our patient's symptoms improved with analgesics, but whether the symptoms were due to the osteitis condensans ilii or to another cause is debatable. There is no differential diagnosis of the radiologic findings, particularly given the clinical and laboratory findings.
Osteitis condensans ilii.
On the anteroposterior (AP) pelvic X-ray and sacroiliac joint CT images, the following observations can be noted:
Conditions similar to sacroiliitis (e.g., ankylosing spondylitis) usually involve erosions of the articular surface, irregular sclerosis, or changes in the joint space, often accompanied by relevant laboratory abnormalities (such as HLA-B27 positivity or elevated inflammatory markers). In this case, there are no clear signs of articular surface involvement or erosion, and neither clinical nor laboratory findings suggest such changes.
Localized bone sclerosis can be found in bone islands or conditions leading to increased bone density, but the typical location and shape may differ from the findings in this case. The lesion here is located near the sacroiliac joint margin on the iliac side, consistent with a characteristic triangular sclerosis.
Commonly seen in multiparous women and may be related to repeated stress on the pelvic region and hormonal changes. If the joint space and surrounding soft tissues are not affected, it generally indicates benign reactive sclerosis.
Taking into account the patient's age, sex, history of childbirth, clinical symptoms (low back pain and left groin pain), a localized sclerotic triangle on the iliac side of the sacroiliac joint evident on imaging, and normal laboratory results, the most likely diagnosis is:
Given the generally benign nature of this condition and the favorable prognosis for most patients:
1) Moderate rest and avoidance of excessive load bearing, combined with oral or topical analgesics and anti-inflammatory medications (e.g., NSAIDs).
2) Physical therapy if necessary (e.g., hot compresses, ultrasound, or low-frequency electrical stimulation).
Initially focus on alleviating local pain and strengthening the core muscles, gradually introducing the following exercises:
Examples include planks and bridge exercises, each held for 10–20 seconds, gradually increasing duration and number of sets as tolerated.
Avoid sudden or vigorous twisting movements, and progressively work on flexibility.
Including small-range gluteal bridge leg lifts and side-lying leg lifts, gradually increasing resistance or repetitions based on pain tolerance.
It is recommended to follow the FITT-VP principle (Frequency, Intensity, Time, Type, Volume, Progression) to individualize the exercise routine:
For patients with significant symptoms who do not respond to conservative treatments, discuss interventional therapy with orthopedic or pain specialists. However, the vast majority of cases do not require surgical intervention.
Disclaimer: This report is intended for reference only and is not a substitute for in-person clinical evaluation or professional medical advice. If you have further questions or if symptoms worsen, please seek medical attention promptly.
Osteitis condensans ilii.
