SUPRAPATELLA IN RATS

Objectives: Researches have focused their attention on articular cartilage of various bones but neglected suprapatella so this study was designed to study the histological changes in fibrocartilage of suprapatella in rats while studying immobilization. Data Source: 20 male Sprague Dawley rats were procured from animal house NIH Islamabad. Design of Study: Experimental. Setting: The study was carried out at the animal house College of Physician and Surgeons Islamabad. Duration: The duration of study was 6 weeks from 01-06-2009 to 05-07- 2009. Materials & Methods: A total of 20 male Sprague Dawley rats 3 months old were used. They were divided into two groups. Each group contained 10 animals. Group 1consisted of control animals that were not immobilized. Group 2 were immobilized for four weeks. The right hind limbs of rats were immobilized with plaster of Paris cast. Care was taken to cover the knee joint completely. At the end of experimental period the rats were anaesthetized with chloroform. The skin over knee joint was dissected and the joint along with supra patella was exposed. The knee joint was cut in sagittal plane. It was stored in 10% formalin for 48 hours. Specimen was decalcified using Ethylene diamine tetra acid (EDTA). After processing for making paraffin blocks 10μm and 7 μm sections were cut from the same block and stained as given below. Mallory Trichrome stain was used for 10μm thick sections to demonstrate collagen content. H & E stain was used for 7 μm thick sections to study routine histology of supra patellar articular cartilage. Results: On four weeks immobilization small necrotic areas were observed in the suprapatella and splits were also observed. Conclusions: It is therefore concluded that suprapatella can be as prominent as the patella itself. It shows necrotic changes on immobilization and is present in a number of animals that are highly significant in orthopedic research.