Increased distraction rates favor chondrogenesis in the rat

摘要

For nearly a century, it has been known that orthopaedic tissues are sensitive to the mechanical environment and can adapt to their physical surroundings. Pauwels, Carter, and others have postulated that precursor tissue differentiation anddevelopment might be governed by local deformation states [1,6]. Perren has proposed that the mechanical environment plays a permissive role during bone repair [7]. These studies and others support the notion that physical forces interact closely withphysiology during tissue regeneration and healing.Mechanical influences on tissue repair are very pronounced during distraction osteogenesis (DO). During this technique, an osteotomy is performed and the two bony ends are distracted to achieve a certain lengthening goal. Over time, the gap createdbetween the two bony ends is filled with mesenchymal-type tissue, which is eventually converted to mature lamellar bone. During the distraction period, the mesenchymal-like gap tissue is repeatedly stretched and. perhaps, damaged as tension accumulates.In addition, this tissue is exposed to a combination of compressive and bending strains from functional activity.Numerous authors have reported the presence of various amounts of cartilaginous and fibrous tissues within the gap [2,3,5,9]. We hypothesize that the local strain environment plays a critical role in determining the distribution of tissue types. Toaddress this hypothesis, we have developed a bilateral rat model of DO. This study was designed to determine whether or not increased distraction rates favored the development of cartilaginous tissues.