Clinical Aspects of Insufficiency Fracture in Chronic Inflammatory Joint Disease

Yun, Bo Ra; Lee, Myung Ho; Lee, Hye Sun; Choi, Yoon Young; Kim, Tae Hwan; Jun, Jae Bum; Bae, Sang Cheol; Yoo, Dae Hyun

Abstract

OBJECTIVE
Insufficiency fracture (IF) occurs when normal or physiological muscular activity stresses a bone that is deficient in mineral or elastic resistance. We studied clinical characteristics of IF in patients with chronic inflammatory joint diseases in Korea.
METHODS
Between Aug. 1997 and Feb. 2003, thirty five patients with 77 fractures were studied at the authors' institution when they were being treated for their rheumatic diseases. The clinical and laboratory data were collected by review of medical record retrospectively.
RESULTS
All patients except four were postmenopausal women (mean age 63.0+/-10.0 years) with long disease duration (mean 14.2+/-11.6 years). Thirty three patients had rheumatoid arthritis, 1 ankylosing spondylitis and 1 systemic lupus erythematosus. Twenty nine patients (85.7%) were receiving regular steroid treatment (mean dose 4.0+/-2.3 mg/day, mean duration 6.1+/-4.2 years). Twenty four patients were treated with methotrexate. The significant reduction in their bone mineral density was found 27 patients based on BMD or QCT. Eight patients without osteoporosis were treated with steroid or MTX. Twenty three patients were ever used for osteoporosis treatment. Most patients except four presented with pain in the low back, groin, hip, pelvic, leg and knee. Initial simple radiography was positive in only 7 patients, with vertebral compression fracture in 11 patients and no effect on mobility except ten. Diagnosis was delayed (mean duration of symptom until diagnosis was 45.6+/-64.5 days). IF was confirmed using the bone scan. Sacrum and pelvic bone was most frequently affected site. The other sites were SI joint, iliac wing, symphysis pubis, acetabulum and femur neck. Twenty nine patients required in-patient stay (mean 17.4 days). All but one patient showed an uneventful recovery with conservative treatment.
CONCLUSION
The low grade nature of symptoms, minimal effect on mobility, absence of significant trauma and missed on initial plain radiography make diagnosis difficult and delayed. IF should be suspected in cases of unexplained pain with local tenderness in patients of chronic inflammatory joint diseases. The technetium-99m diphosphonate bone scintigraphy was valuable diagnostic tool in the early recognition of IF.