Chronic low back and leg pain caused by thickening of the bone density in the lower 1/2 to 2/3 of the iliac portion of the sacroiliac joint is called osteitis condensans ilii. It may be related to pregnancy, strain, or focal inflammation.

bubble_chart Etiology

During the late stage of pregnancy (third stage), due to endocrine effects, tendons and ligaments often become relaxed, leading to loosening of the sacroiliac joint and loss of stability. As a result, the sacroiliac joint may frequently experience abnormal stimulation or injury, particularly with a higher likelihood of injury to the iliac portion of the sacroiliac joint. It may also be related to body weight, chronic strain, or trauma.

bubble_chart Pathological Changes

In 1963, Glogowski first reported that pathological examination revealed significant degeneration of articular cartilage with infiltration of inflammatory cells. There was an inflammatory reaction around the trabecular bone beneath the cartilage, and osteoblasts exhibited normal or active growth. The bone marrow cavity showed fibrosis. Osteocytes were present in lacunae, and scattered cartilage islands were found near the articular surface, but no iliac bone necrosis was observed.

bubble_chart Clinical Manifestations

This condition is commonly seen in married women aged 20-30 who have given birth, and occasionally in men. Patients are generally in good health, with their main complaint being lower back and leg pain. The pain is usually mild, but some may experience no symptoms or more severe pain. The pain is chronic and intermittent, often worsening with pregnancy or increased number of childbirths. In most cases, the lesions occur bilaterally in the iliac region of the sacroiliac joints, presenting with localized tenderness or grade I muscular rigidity. The pelvic separation and compression tests are positive, while laboratory findings are mostly within normal ranges.

X-ray findings: The anteroposterior view of the sacroiliac joint shows a neat and clear joint space. The iliac side of the bone near the middle and lower two-thirds of the sacroiliac joint surface exhibits abnormally dense bone tissue, forming a uniform dense band where the trabecular texture completely disappears. The edges are clear without bone destruction, and the sacral side is not involved. This lesion is mostly symmetrical but can also occur unilaterally. The local area may appear triangular, crescent-shaped, or pear-shaped. The sclerotic zone can be up to 3 cm wide.

This condition should be differentiated from early ankylosing spondylitis sacroiliitis, focal joint and sacroiliac joint subcutaneous nodules, etc.

bubble_chart Treatment Measures

Patients with this condition should temporarily avoid pregnancy, reduce physical labor, and apply local heat therapy, physiotherapy, or block therapy and acupuncture as needed. Bed rest for 2 to 4 weeks may be necessary if required. When preparing to leave bed after symptoms have alleviated or disappeared, a lumbar support should be worn for protection, and activity levels should be gradually increased. If symptoms do not improve with the above treatments, consideration should be given to removing the lesion or performing sacroiliac joint fixation.