In this case, a patellofemoral prosthesis, more commonly called a kneecap prosthesis, will be used. This prosthesis will be composed of a polythene piece that replaces the knee cap cartilage which will articulate with a femoral metal chain guard which replaces the other part of the articulation.

The human anatomy of the patellofemoral articulation that lags behind the function with an arthrosis that develops at this level is most often due to a congenital malformation. Thus the prostheses that will be used will have a design that will not follow the normal anatomy. It is this paradox that will assure their effectiveness and stability.

The operation should be carried out by a surgeon who is familiar with this particular type of surgery. It involves about one week of hospitalisation and two months of rehabilitation. This prosthesis will permit a restoration of the complete functioning of the knee and in particular concerning mobility, stability and pain.

Under the condition of using this prosthesis only in primary knee cap arthrosis without an axis deviation of the inferior member, excellent results have been obtain in more than ninety percent of the cases that already have a ten year hindsight.