ABSTRACT
BACKGROUND: Animal models of peripheral partial epiphyseal plate closure are commonly used in related trials.OBJECTIVE: To modify the original animal models of distal femoral partial epiphyseal plate closure.DESIGN, TIME AND SETTING: A self-controlled trial was performed at the Experimental Animal Center of General Hospital of Chinese PLA from March to October 2007.MATERIALS: Twenty healthy New Zealand rabbits of 4-6 weeks old weighing 1.0-1.5 kg were selected.METHODS: A straight incision about 2 cm was made in lateral knee of 20 rabbits. The subcutaneous tissues and knee capsule were cut open to expose distal femoral condyle. The condylar plate line was clear. Two holes were drilled in the fight lateral condyle, about 3.0-4.0 mm deep, and partial normal epiphyseal plate (about 33%-44% of the total growth plate) was removed. An incision deep to periosteum was created in the left side and regarded as self-control.MAIN OUTCOME MEASURES: Femoral length, valgus angle of the distal femur, and femoral deformity were detected by X-ray photograph, and gross observation. Bone bridge formation of bilateral femora was observed by histological examination.RESULTS: One rabbit died of diarrhea 31 days after surgery, and 19 were included in final analysis. ①Radiographs showed that the mean length of left femur (control side) was significantly longer but valgus angle was significantly smaller than the right side (experimental side) 4 months after surgery (P ＜ 0.01). The left distal femur averagely grew for 2.27 cm,accounted for 57.6% of the overall femoral growth, and the right side averagely grew for 0.45 cm, accounted for 21.4% of the overall femoral growth.②Four months after surgery, femoral appearance of the control side was normal, with smooth and complete condylar and facies articularis patellae. While, the experimental side femur was significantly shortened, and severe vaigus deformity was observed in the distal femur. ③Five weeks after surgery, layer cells of the epiphyseal plate arranged regularly in the control side. Bone trabecula with many fibers was found in bone defect cavity of the experimental side, and the cell layer of the remnant epiphyseal plate was decreased. The epiphyseal plate was closed in the control side,and bone trabecula of the experimental side was thickened 10 weeks postoperatively.CONCLUSION: This modeling method is simple, efficient, and easy to manipulate; in addition, the bone bridge area is controllable. The models can meet the study demands for peripheral partial epiphyseal plate closure, and are significant for filling material selection during treatment.
ABSTRACT
Objective Congenital dislocation of the patella is rare and produces varying degrees of knee disability with the growth of the child. It should be managed as soon as the diagnosis is made. The purpose of this paper is to describe the procedure and to assess the results of congenital dislocation of patella treated with medial transfer of patellar tendon and lateral transfer of medial fascio muscular flap. Methods Five children with congenital dislocation of patella were treated with medial transfer of patellar tendon and lateral transfer of medial fascio muscular flap between June 1994 and June 1998. There were two boys and three girls. The age of the patients at the surgery varied from 4 to 10 years. Four of them were unilateral and one was bilateral without any other deformities. An S-shaped incision is made to expose the distended medial fascio muscular flap, dislocated patella and well developed vastus medialis. The patellar tendon is detached from its insertion and released from the surrounding retinacula. A hole corresponding to the width of the patella is made in the membrane and another one is made through the synovial membrane and the fibrous capsule. The patellar tendon was sutured into the hole in the tibial metaphysis through the two membrane holes. The iliotibial band was lengthened and the biceps tendon was turned over the abundant medial retinaculum with a part of the vastus medialis to the lateral side of the synovial membrane. The patient was kept in a long leg cast and immobilized for 6 weeks. Results The average period of follow up was three years(range, one year and six months to five years). Four cases were able to extend the knee completely and one case had minus ten degrees in extention. Knee valgus in two patients disappeared after operation and one had a lower patella, but the function of knee was normal without any symptoms and signs. There were no complications in this series. Conclusion The patients with congenital dislocation of patella which is permanent and irreducible must be interfered with operation. Five patients were successfully treated with medial transfer of patellar tendon and lateral transfer of medial fascio muscular flap with less invasive and no complications, therefor it is worthwhile to be recommended for the treatment of congenital dislocation of patella.