Does immobilization influence the systemic acceleratory phenomenon that accompanies local bone repair?

Authors

  • Martina Mueller,

    1. Klinik der Furstenhof, Center of Endocrinology, Metabolic Bone Diseases, and Gynecology, Bad Pyrmont, Germany
    Search for more papers by this author
  • Tobias Schilling,

    1. Klinik der Furstenhof, Center of Endocrinology, Metabolic Bone Diseases, and Gynecology, Bad Pyrmont, Germany
    Search for more papers by this author
  • Helmut W. Minne,

    Corresponding author
    1. Klinik der Furstenhof, Center of Endocrinology, Metabolic Bone Diseases, and Gynecology, Bad Pyrmont, Germany
    • Klinik Der Fürstenhof Center of Endocrinology, Metabolic Bone Diseases, and Gynecology P.O. Box 1660 D3280 Bad Pyrmont, Germany
    Search for more papers by this author
  • Reinhard Ziegler

    1. Klinik der Furstenhof, Center of Endocrinology, Metabolic Bone Diseases, and Gynecology, Bad Pyrmont, Germany
    Search for more papers by this author

Abstract

The rate of remodeling in the region of a bone defect exceeds normal tissue activity. It was Frost who described this reaction as the regional acceleratory phenomenon (RAP). We previously showed that restoration of a local bone defect in the rat leads not only to RAP but also leads to a systemic acceleration of osteogenesis (systemic acceleratory phenomenon, SAP) in distant sites of the skeleton. In this study we investigated the impact of immobilization of the defect-bearing extremity on the development of SAP. A hole 1.2 mm in diameter was drilled in the diaphysis of the left tibia of female rats. In the experimental group (n = 15), a knee tenotomy was performed in the defect-bearing left hind leg. We examined both femora, both tibiae, and the fourth lumbar vertebra by computed x-ray densitometry on day 7 postoperatively. Immobilization of the defect-bearing limb led to a decrease in x-ray density not only of the immobilized (p lt; 0.0001) but also of the contralateral tibia (p lt; 0.0001). Both femora (p lt; 0.001) and the fourth lumbar vertebra (p lt; 0.025) of the experimental group also showed a significant decrease in x-ray density. We previously showed that SAP leads to an increase in x-ray density of both femora. This increase is no longer detectable in animals after immobilization of the defect-bearing limb. Thus we conclude that immobilization interferes with SAP. This suggests the possible dependence of SAP on mechanical load. Furthermore, these data suggest a possible impact of local immobilization on the rest of the skeleton.

Ancillary