Mineralisation of tubular bones is affected differently by low phosphorus supply in growing-finishing pigs.

BACKGROUND: Phosphorus (P) supply is essential for bone mineralisation. Reduced P may result in osteopenia, whereas excessive P may result in environmental impacts. The objective was to study the long-term effect of three dietary P levels on net bone mineralisation in growing-finishing pigs. Eighteen female pigs were fed low P (LP (4.1)), medium P (MP (6.2)) or high P (HP (8.9 g P kg-1 DM)) from 39.7 until 110 kg. Trabecular, cortical and overall bone mineral density (BMD), ash, calcium (Ca) and P were determined after slaughter. RESULTS: The LP diet generally reduced the BMD, ash, Ca and P in all bones, though all measures were markedly lowered in femur compared with humerus. The trabecular BMD in LP pigs was only different in the distal section compared to the MP-fed pigs (P < 0.05). In addition, ash, Ca and P were lower in the proximal and distal sections. No significant effect of HP was seen. Conclusively, LP caused lower net bone mineralisation, mainly of femur. The trabecular tissue of the distal bones seems to be most metabolically active. CONCLUSIONS: The MP level was sufficient for net bone mineralisation. Femur is recommended for studying bone fragility whereas humerus seems useful to study increased P retention. © 2019 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Thermal epiphysiodesis performed with radio frequency in a porcine model.

BACKGROUND AND PURPOSE: Current techniques for epiphysiodesis involve opening of cortical windows; use of staples, screws, and tension devices; and fusion with curettes or drills. Complications may have serious consequences. There is a need for a more reliable, precise, and less traumatic procedure that overcomes the known complications from existing techniques. We analyzed a new epiphysiodesis technique using radio-frequency ablation (RFA) in a porcine model. METHODS: Six 35-kg and two 25-kg immature pigs were used. 1 hind leg of each animal was randomly selected and the proximal tibia growth plate was ablated laterally and medially. The contralateral leg was used as a control. MR images were obtained immediately after the ablation and 12 weeks later for 6 animals, and 24 weeks later for the other 2 animals. CT was done for the 2 animals that were followed for 24 weeks for proof of bone bridges. RESULTS: Both tibias were equal in length initially. At the 12-week follow-up, there was an average leg length discrepancy of 3.9 mm (95% CI: 3.0-4.8), and at 24 weeks the difference was 8.4 mm and 7.5 mm. No damage to the adjacent tissue was found. Bone bridges and physeal closure were found after 24 weeks. The pigs showed no discomfort after the intervention. INTERPRETATION: We found RFA to be feasible for epiphysiodesis in a pig model. The method is minimally invasive and recovery may be quick compared to conventional methods. We recommend that the method should be tested in larger-scale safety studies before clinical application.