ORIGINAL ARTICLE Growth Plate Behavior After Desepiphysiodesis Experimental Study in Rabbits Jean-Luc Jouve, MD, Jean-Marc Guillaume, MD, Patrick Frayssinet, MD, Franck Launay, MD, Elke Viehweger, MD, Michel Panuel, MD, and Ge ´rard Bollini, MD Abstract: The aim of this work was to study the potential healing of the growth plate in the case of a central desepiphysiodesis. A central defect was made in the distal femoral growth plate of thirty 3-week- old rabbits. In group A the growth plate defect was left empty as con- trol. The defects of group B were implanted with a polymeric cylinder fixed in the metaphysis with a pin. In group C the cylinder was fixed in the epiphysis. Two months after implantation, clinical, radiologic, and histologic analyses were carried out. In group A, the mean short- ening was 12.63%; it was 4.9% in group B and 1.54% in group C. Histologic analysis showed constant appearance of an epiphysiodesis after migration of the implant in the metaphysis. No regeneration of the growth plate was observed. Prevention of migration of the inter- positional material is recommended to avoid recurrence of an epiph- ysiodesis. Key Words: growth plate, epiphysiodesis, shortening (J Pediatr Orthop 2003;23:774–779) G rowth plate lesions frequently cause epiphysiodesis bone bridges, which in turn can be at the origin of bone length abnormalities as well as variations in the bone axes, depending on the location and width of the bone bridge. 1,4,5 Once the bridge is formed, numerous authors have described the possi- bility of removing the bone bar. In all cases exogenous mate- rial must be inserted to avoid its reconstruction. 7,11,12,18,21 Dif- ferent materials, either natural (fat, frozen hyaline cartilage, muscle) or synthetic (silicon, methacrylate, wax) have been described in the literature. 2,3,7,8,13,14,15,16,21 Numerous reports have shown possible growth recovery, depending on the ma- terial implanted, and possible healing of the altered growth plate after bone bridge removal. 19,20 The results are varied, depending of the size, location, and efficiency of the remaining growth plate. Discussion still exists as to the nature of the in- terpositional material and the possibility of growth plate regen- eration after these techniques. The goal of this experiment was to study the potential healing of a central growth plate defect after migration of syn- thetic interpositional material in the metaphysis. We studied the clinical incidence of binding of the implanted material in a growth plate defect and compared the results with those ob- tained after migration of the material. Then a histologic study was carried out to assess the growth plate behavior in these different procedures. METHODS The aim was to create a growth cartilage defect large enough to have a significant impact on bone length growth. To eliminate any interference linked with a lesion of the perichon- dral and/or periosteal region, a central circular defect was pro- duced to generate a length growth failure without axial defor- mity. Thirty 3-week-old white female New Zealand rabbits were used in this study. The right femur was used as control in each animal and was not operated. Each rabbit was anesthe- tized with 5 mg ketamine and 0.25 mg chlorpromazine. The knee was reached by an external approach. The patella and extensor muscles were dislocated inwards to make available the femoral trochlea and the whole femoral distal extremity. A central hole was drilled through the cartilage with a 4.5-mm- diameter drill. The entry was located in front of the intercon- dylar opening. Once the epiphysis and growth plate had been perforated, the drill stopped in the bone marrow cavity. The hole was hand-made rather than machine-made to avoid any heating of the tissues through a mechanical drill. The hole was Study conducted at the UMRC 6578, CNRS-Universite ´ de la Me ´diterrane ´e, Marseille, France. From UMRC 6578, CNRS-Universite ´ de la Me ´diterrane ´e, Unite ´ d’anthropologie: Adaptabilite ´ biologique et culturelle, Faculte ´ de me ´de- cine, Marseille, France (Drs Jouve and Panuel); Service d’Orthopédie Pe ´- diatrique Ho ˆ pital Enfants La Timone, Marseille, France (Drs. Guillaume, Launay, Viehweger, and Bollini); Urodelia, Le Gaillard, St. Lys, France (Dr Frayssinet). None of the authors received financial support for this study. Reprints: Jean-Luc Jouve, MD, Service d’Orthope ´die Pe ´diatrique, Ho ˆpital En- fants La Timone, 264 rue St-Pierre, 13385 Marseille Cedex 05, France (e-mail: Jean-luc.Jouve@mail.ap-hm.fr). Copyright © 2003 by Lippincott Williams & Wilkins 774 J Pediatr Orthop • Volume 23, Number 6, November/December 2003