Ultrasound bone mass in paraplegic patients

Study design: A cross-sectional study. Objective: To clarify the existing controversy with regard to whether paraplegic patients suffer a loss of bone mass in the upper limbs. Setting: Madrid, Spain. Methods: We evaluated bone mass by phalangeal ultrasonography in 35 male patients with paraplegia (mean age 49 +/- 12 years), and 25(OH)D3 and PTH to exclude the presence of osteomalacia and secondary hyperparathyroidism. Spasticity was evaluated according to the Ashworth scale. Patients were compared with a control group of 35 healthy male subjects (mean age 48 +/- 13 years). Results: The patients had lower 25(OH)D3 levels and amplitude-dependent speed of sound (Ad-SOS) than controls (both P<0.001), and higher PTH levels (P<0.05). There was a statistically significant negative association between PTH and 25(OH)D3 levels (r = -0.52, P<0.0001, Cl -0.73 to -0.22) and between 25(OH)D3 and injury duration (r = 0.34, P<0.05, Cl -0.60 to -0.01). There was no correlation between Ad-SOS values, levels of PTH or 25(OH)D3, and the injury duration. No significant difference in Ad-SOS values was found in patients grouped according to low-to-normal 25(OH)D3 level or according to normal-to-high PTH level. There were no differences in relation to muscle tone. Only alkaline phosphatase and tartrate-resistant acid phosphatase levels were higher in patients than in controls (both P<0.001). Conclusion: Paraplegic patients had a loss of phalangeal bone mass that was unrelated to the levels of vitamin D or PTH, or to muscle tone, so it seems to be related to increased bone resorption rather than to deficient bone formation.