Postgraduate Medical Journal 2005;81:65-67
© 2005 Fellowship of Postgraduate Medicine
University Hospitals of Leicester NHS Trust, Leicester General Hospital, Leicester, UK
Department of Orthopaedics, Leicester General Hospital, Gwendolen Road, Leicester LE5 4PW, UK; firstname.lastname@example.org
Submitted 24 September 2003
Accepted 29 March 2004
Keywords: back pain; osteitis condensans ilii; ankylosing spondylitis; pregnancy
Backache is a common symptom in women in pregnancy and during the postpartum period. Ligamentous laxity and extra mechanical stress have been attributed as the main cause for back pain during pregnancy.1,2 In a small group of patients the persistent pain during the postpartum period may be secondary to osteitis condensans ilii (OCI). This case report highlights the salient features and discusses the differential diagnosis and management of this benign condition.
Clinically, her body mass index was 32. She had a slightly increased lumbar lordosis and her gait was normal. She had no wasting of muscles. She was able to do a tiptoe and heel walking without any difficulty. Flexion, extension, rotation, and lateral bending of her lumbar spine were normal. On palpation, she had no specific bony or paraspinal muscle tenderness. She could demonstrate a straight leg raise up to 90 degrees on both sides and sciatic stretch test and femoral stretch test were negative. Power, tone, reflexes, and sensation were normal bilaterally. The FABER test (Flexion-ABduction External Rotation) or the figure of four test provoked the pain in her buttocks. This test is also known as Patrick’s test and is performed with the patient supine on the examination table. The limb to be examined is guided into figure of four position with the ipsilateral ankle resting across the contralateral thigh. The examiner then presses downwards on the ipsilateral knee with one hand while providing counterpressure with the other hand on the contralateral anterior superior iliac spine. This manoeuvre tends to stress the sacroiliac joint on the side being tested. Sacroiliac joint pathology typically produces posterior hip pain and in an arthritic hip pain is usually felt anteriorly in the groin. Table 1 shows her baseline blood investigations, which were all normal. An anteroposterior plain radiograph of her lumbar spine is shown in fig 1.
Treatment in OCI is conservative with physiotherapy and analgesia as required. Our patient had a course of physiotherapy and made a satisfactory recovery.
A study among the Swedish women between the ages of 38 and 64 showed that two thirds of them had experienced back pain at some time, but only a small group reported that it started during pregnancy.3,4 Current reports show that the back pain experienced during pregnancy can be intense and may persist after pregnancy. One third of women who experience pain during the postpartum period have reported that their back pain affects their day-to-day activities, and in about 10% of them it prevents them from working.3
Most back pain settles after pregnancy with simple measures. In a small group of patients back pain may persist and can hinder their normal daily activities. Extensive investigations including magnetic resonance imaging not only increase anxiety but are of little benefit. Correct diagnosis and reassurance with simple treatment measures can yield satisfactory results in this group of patients. Primary care physicians and other specialists who deal with patients suffering from back pain need to be aware of these uncommon benign disorders, of which OCI is one.
Current orthopaedic and rheumatology literature reveals very little information regarding OCI and there is hardly any mention of it in the publications commonly referred to by primary care physicians for their everyday practice.
OCI is a benign condition typically seen after pregnancy and is not associated with any inflammatory arthritis.5,6 It is essentially a radiological diagnosis. The iliac bone adjacent to the sacroiliac joint is predominantly affected and usually, although not invariably, it is a bilateral and relatively symmetric process. It is more common in women of childbearing age group. Rarely, nulliparous women and men may be affected and it can be unilateral. The radiological appearance in OCI is characteristic with well defined triangular sclerosis on the iliac aspect of the sacroiliac joint. The bony eburnation involves the inferior portion of the bone and the apex of the sclerosis can extend up to the auricular portion of the ilium. In OCI, the joint space is preserved and the articular margins are intact, unlike in other forms of sacroiliitis. These radiological features may vary in extent and may even resolve with time.7 The radiological features and the clinical history are diagnostic of OCI, but other differential diagnoses include seronegative spondyloarthropathies, renal osteodystrophy, lymphoma, Paget’s disease, and primary hyperparathyroidism. Normal blood parameters and seronegativity exclude the majority of these disorders. Polyarthralgia in peripheral joints have been noted in a small group of patients with OCI, although significant inflammatory articular findings are generally absent.
The aetiology of OCI is not clear and many theories have been postulated. It is suggested that the increased mechanical stress across the sacroiliac joint coupled with increased vascularity during pregnancy leads to the changes seen on the iliac bone. However, OCI seen in nulliparous women and in men is not consistent with this theory, although it is assumed that mechanical stress from a different causation may be operational in this group of patients. Some authors have postulated that OCI and ankylosing spondylitis may be inter-related; however the aetiopathology of ankylosing spondylitis is different from OCI (table 2).8 Singal et al in their comparative studies between OCI and ankylosing spondylitis in female patients have concluded that OCI is not a variant of ankylosing spondylitis.9,10
To conclude: OCI is a benign self limiting condition seen after pregnancy in young women with low back pain. It is important to recognise this entity as it may potentially be confused with sacroiliitis from other disorders like ankylosing spondylitis and inflammatory arthritis. Conservative treatment with analgesics and physiotherapy are the mainstay of management in OCI.