Me: This is one of those posts that puts ideas into one’s head on what is possible biomedically. The study shows that one can transplant epiphyseal plates into host bodies as long as it is kept vascularized. The term vascularized just means that it has blood vessels going in and out of it keeping it feed with incoming nutrients and has a way to remove the waste. One big question I have had since reading Dr. Brighton’s detailed description of the plates was exactly how the blood vessels are distributed along the layers of the plate. We know that the resting zone is the most critical since it is where everything starts and is also the true determining area for how much longitudinal growth is possible. It also has at least 2 growth factors which determine the chondrocytes to start stacking in columns when they get to the proliferative zone.
There was 4 ways the researchers were testing to see the longitudinal growth.
- Serial roentgenograms – a time distribution of photographs made with x-rays
- Histological examination – using microscope to analyze the cells
- Fluorescent bone-labeling – sounds just like what it is
- Microangiography – Radiography of the minute blood vessels of an organ obtained by injection of a contrast medium and enlargement of the resulting radiograph
Implications: This study has proved that growth plate transplantation is completely possible, as long as you keep the chondrocytes fed through vascularization.
J Bone Joint Surg Am. 1984 Dec;66(9):1421-30.
Free microvascular epiphyseal-plate transplantation. An experimental study in dogs.
To evaluate the feasibility of transplanting vascularized epiphyseal plates while maintaining normal growth in the recipient site, twenty-two puppies from known, large breeds were divided into one control and three experimental groups of four animals each and one long-term group of six animals. The control group underwent insertion of a radiopaque marker in the fibular metaphysis bilaterally, and, in addition, a fibular osteotomy was performed on one side. In the experimental groups, a fibular switch was carried out, selecting one fibula as a vascularized graft and the other as a non-vascularized graft. Both the controls and the experimental groups were evaluated using serial roentgenograms, histological examination, fluorescent bone-labeling, and microangiography. One week, six weeks, three months, and seven months postoperatively, animals from each group were killed. Continuous growth was observed in the vascularized epiphyseal transplants and in the controls, with no statistical difference noted, whereas the non-vascularized transplants exhibited considerably less or no growth. Vascularized transplants demonstrated an average 21.2-millimeter increase in length while non-vascularized transplants showed a 6.6-millimeter increase. Histological examination, fluorochrome bone-labeling, and microangiography confirmed the continued viability of the vascularized epiphyseal transplants in contrast to the non-vascularized transplants.
- PMID: 6501338 [PubMed – indexed for MEDLINE]