La fijación del componente tibial en las artroplastias de rodilla

The loosening of the tibial component is the most frequent cause for the failure of the total knee Arthroplasty.An experimental study has been planned in dogs in order to know the histological behaviour of the bone tissue using different materials and methals clinically used to fix thetibial component into the upper end of the tibia.Two different miniature" special designs of the component tibial prothesis for dogs, have been used, one of them made of politetrafluorethilene (P.T.F.) with a peg screwedwith flanges, another one made of methal Aisi 316 Lum with a plain p~g of six holes.Three different series 'of dogs were used: In the first series of twelve dogs a P.T.F. cemented prothesis was implanted over the lateral tibial plateau; on the second group of telve dogs the same prothesis but uncemented, and in the third series of twelve dogs the Aisi616 Lum prothesis uncemented was used.The dogs were sacrified along different periods of one to twenty four weeks; each specimen oí the upper end oí the tibia was studied by radiology, optical microscopy and fluorescence under microscopy view.AH cemented prothesis provoqued progresivefibrous reactions into the bed and fibrocartilaguewhich lead to its loosening.The uncemented P.T.C. prothesis showed a sinking by elastic deformity but were well fixed into the bone tissue.Finally, the metalic prothesis had no displacement at aH and the bone grew intimately along the surface of the peg and also across the holes. The fixation was quite solid. This method of uncemented fixation seems to be the most adecuate. Our experience with the Ring prothesis is in accordance to the convenience of the method.

The loosening of the tibial component is the most frequent cause for the failure of the total knee Arthroplasty.An experimental study has been planned in dogs in order to know the histological behaviour of the bone tissue using different materials and methals clinically used to fix thetibial component into the upper end of the tibia.Two different miniature" special designs of the component tibial prothesis for dogs, have been used, one of them made of politetrafluorethilene (P.T.F.) with a peg screwedwith flanges, another one made of methal Aisi 316 Lum with a plain p~g of six holes.Three different series 'of dogs were used: In the first series of twelve dogs a P.T.F. cemented prothesis was implanted over the lateral tibial plateau; on the second group of telve dogs the same prothesis but uncemented, and in the third series of twelve dogs the Aisi616 Lum prothesis uncemented was used.The dogs were sacrified along different periods of one to twenty four weeks; each specimen oí the upper end oí the tibia was studied by radiology, optical microscopy and fluorescence under microscopy view.AH cemented prothesis provoqued progresivefibrous reactions into the bed and fibrocartilaguewhich lead to its loosening.The uncemented P.T.C. prothesis showed a sinking by elastic deformity but were well fixed into the bone tissue.Finally, the metalic prothesis had no displacement at aH and the bone grew intimately along the surface of the peg and also across the holes. The fixation was quite solid. This method of uncemented fixation seems to be the most adecuate. Our experience with the Ring prothesis is in accordance to the convenience of the method.