Three months after a Colles fracture treated in a cast, a 55-year-old woman has a swollen, glossy, stiff hand with burning pain. X-ray shows patchy porosis of the carpus. The single most useful confirmatory investigation is:

• A Serum calcium and phosphate levels
• B Nerve conduction studies of the median nerve
• C MRI of the wrist with contrast
• D Three-phase technetium bone scintigraphy ✓

Explanation

This is complex regional pain syndrome type 1, classically called Sudeck's atrophy. A three-phase bone scan showing diffuse increased periarticular uptake in the affected limb supports the diagnosis early, before plain films show the characteristic patchy demineralisation. Serum calcium and phosphate are normal, distinguishing it from metabolic bone disease, and nerve conduction studies are normal because there is no identifiable nerve injury in type 1 disease.

Reference: Apley's System of Orthopaedics and Fractures, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.