Abstract
Cemented total hip arthroplasty (THA) has become an extremely successful operation with excellent long-term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Various older and recent studies presented excellent long-term results, for cemented fixation of the cup as well as the stem.
Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed.
Preoperative steps as proper implant sizing/ templating, ensuring an adequate cement mantle thickness, and hypotensive anesthesia, minimising bleeding at the bone cement interface, are of major importance.
First the fossa pyriformis should be clearly identified, including the posterolateral entry point of the prosthesis. The femoral neck cut is usually 1.5cm to 2cm above the minor trochanter, based on the preoperative planning and implant type. Opening of the canal is done with an awl or osteotome, followed by any blunt tipped instrument, to follow the intramedullary direction. A box osteotome opens the lateral portion of the femoral neck, gently to preserve as much cancellous bone as possible. Sequential broaching follows carefully and according to the planning, to ensure preservation of 2mm to 3mm cancellous bone for interdigitation. Some systems might require over-broaching by one size. Trialing is done with the broach. Following, irrigation using a long nozzle pulsatile lavage, reduces the chance for fat embolism. A cement restrictor is then placed 1.5cm to 2cm distal to the tip of the stem, to ensure an adequate cement mantle distally. A second complete pulsatile irrigation of the canal follows, to minimise bleeding, followed by a dry sponge. Cement mixing is vacuum based in the meantime, usually 60–80g. We prefer the use of low dose antibiotic laden cement in our set up. Two to three minutes after mixing, the cement is applied rapidly in a retrograde technique, with a cement gun placing the nozzle tip against the cement restrictor. The gun is “pushed” out during the application, rather than being withdrawn from the canal. Proximal pressurization is first done by thumb, then with a proximal seal for 1 minute. The stem is inserted slowly using steady manual pressure, in the center of the cement mantle, however should never be impacted. The stem is aligned with the previously defined lateral entry point and is held in position until the cement hardens. The desired outcome is a cement interdigitation into cancellous bone for 2mm to 3mm and an additional mantle of 2mm pure cement.
