Quantitative assessment of para-osteo-arthropathy and its maturation on serial radionuclide bone images

Paraplegics whose range of motion is limited by para-osteo-arthropathy (POA) may have difficulty in becoming independent unless the heterotopic bone mass is removed. The recurrence rate is high if the bony mass is not mature at the time of surgery. Radiography and alkaline phosphatase correlations are not trustworthy. In 3 paraplegics with POA, radiolabeled osteotropic agents demonstrated a steady decrease in the uptake ratio (heterotopic/normal bone) followed by a steady-state plateau, reflecting the most useful index of maturation and allowing surgical removal of bone without recurrence.