Atypical insufficiency fractures confused with Looser zones of osteomalacia

Area of Science:

• Bone Metabolism and Radiology
• Skeletal Diseases

Background:

• Osteopenia and insufficiency fractures can suggest osteomalacia.
• Looser zones are characteristic radiographic findings often associated with osteomalacia.

Purpose of the Study:

• To evaluate atypical insufficiency fractures that resemble Looser zones.
• To propose refined radiographic criteria for Looser zones.
• To outline a diagnostic strategy for similar future cases.

Main Methods:

• Radiographic assessment of insufficiency fractures.
• Bone densitometry (single-energy photon absorptiometry).
• Biochemical indices and bone histomorphometry.
• In vivo double tetracycline labeling.

Main Results:

• Six women presented with osteopenia and fractures at typical Looser zone sites.
• Biochemical and histomorphometric analyses excluded osteomalacia.
• In vivo labeling showed variable bone turnover.
• Vertebral compression fractures were noted in two patients.

Conclusions:

• Atypical insufficiency fractures can mimic Looser zones but are not necessarily indicative of osteomalacia.
• More stringent radiographic criteria are proposed for defining Looser zones.
• A diagnostic strategy is outlined for differentiating these fractures.