Historic Hinge Prosthesis GUEPAR

On 1968 seven residents and one orthopaedic surgeon professor working in a French hospital in-stitution called «Assistance Publique des Hôpitaux de Paris» meet themselves to concept and realize a new hinge prosthesis.
This group and the prosthesis will be called GUEPAR (in French: Groupe pour l’Utilisation et l’Etude des Prothèses ARticulaires).
First one was implanted in 1970, cemented and with a mechanic particularity with a backwards and overraised to 15mms position of the flexion axis relative to the joint line.
This particular design allows a complete flexion with smooth running tibia under femur.
Also exists a patellar pathway close to the anatomy with lever arm convenient for quadriceps strength.
Moreover this prosthesis needs a total economic bone resection tibia and femur for only 18mms to make easier fusion procedure if sometimes necessary.
On 1981, a 5 years follow up review with 183 knees was reported. 5 patients deceased with cardi-ac complications and 2 with assesed fat embolism. 27% patients had lateral patellar misalignments, only 10% needs correction.
As far infection worries are concerned, 15 deep infections cases (8,3%) difficult to manage. 26 aseptic loosening (16%), only 10 knees (6%) need prosthesis replacement.
Since 1975 prosthesis modifications appeared, mainly to adapt bone anatomy in the trend to de-crease patellar misalignment and intra medullar cementation leading the concept of «Guepar 2* hinge prosthesis» .
Another review on 1989 with a lot of 155 hinge Guepar 2* prosthesis was published. Among these 155 knees, 58 had previous knee prosthesis (35,04%). On the whole series, infection rate appeared high (8,3%) and also difficult to heal.
As aseptic loosening it seemed that enlarged and more effectively adapted to the morphological metaphysis anatomy decreased aseptic loosening rate. Only 2 femoro tibial loosening (1,4%) appeared. Moreover patellar problems concerned 6 patellar button loosening with 3 of them patellar fractures. Functional results of this series for knees operated between 1977 to 1984 with an 3,5 years average follow up (40 cases have more than 5 years follow up) shows very good and good results (84%) with Guepar 2*, (75% for revision of 44 knee prosthesis), face to only 60% with the original Guepar.
As conclusion the hinge Guepar prosthesis was formerly well known during the 70ths and used in France and foreign countries. Since 1980 indications of this type of prosthesis decreased face to the development of semi constrained knees. Nevertheless this type of hinge prosthesis, mainly rota-tory, keeps some indications for «ruined» knees with complete bony destruction loss and with poor ligaments.