Background Insufficiency fractures may occur in patients with long-standing inflammatory joint diseases (IJD). Activity of the disease, immobilisation and prolonged corticosteroid treatment are the main predisposing factors. In most cases the fractures are easily diagnosed, in others the diagnosis is delayed, as they may mimic exacerbation of the underlying disease or other pathological conditions.

Objectives To evaluate the clinical profile of patients with initially misdiagnosed insufficiency fractures and to investigate the causes of the diagnostic delay.

Methods The files of 12 patients with IJD who were referred for presumed exacerbation of the rheumatic disease and were subsequently diagnosed as suffering from insufficiency fractures were reviewed and relevant parameters were analysed.

Results Most of the patients were aged (mean 68.5 years) and were suffering from IJD for long periods of time (mean 16.6 years). All of them received prolonged corticosteroid therapy (mean 9.5 years) in doses up to 15 mg prednisone a day). Five patients had previous insufficiency fractures. The new fractures were located in the distal tibia, femoral neck, head of humerus, lesser trochanter of the femur, sacrum, pubic rami, acetabulum and metatarsus. The initial diagnosis was: acute synovitis (8 patients), trochanteric bursitis (1), radiculopathy (1), tendinitis (1) and avascular necrosis of bone (1). The diagnostic delay was one to eight weeks (mean 2.7). In seven patients the correct diagnosis was reached by initial radiographs and in five by bone scintigraphy and CT. Treatment with bed rest, non weight bearing, NSAID (all patients) and calcitonin (7 cases) resulted in partial (8 patients) or complete recovery (4 patients).

Conclusion Insufficiency fractures can mimic disease activity or other musculoskeletal pathological conditions in patients with IJD. Clinician’s awareness may prevent unnecessary investigations and therapy.

References

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