[Study of Urinary excretion of total, free, and non-dialysable conjugated hydroxyproline in paraplegics]

Eighteen paraplegics with or without neurogenic osteo-arthropathy (POAN) were evaluated for variations in their urinary excretion levels of total (T), and free (L) hydroxyproline and its non-dialysable (ND) and dialysable (D) peptide fractions. Increases in urinary hydroxyproline, moderate rises in free hydroxyproline and more substantial increases in dialysable and non-dialysable peptide fractions could be observed in these patients who all were affected with osteoporosis of disuse. Only variations in dialysable hydroxyproline could be used to differentiate between POAN + and POAN - patients. Of the various ratios which were analyzed (ND/T, L/ND, and D/ND), the D/ND ratio appears to be the most useful for diagnosis and monitoring of patients with POAN.