Abstract
Generally cemented total hip arthroplasty (THA) has become an extremely successful operation with excellent long-term results. Although it always remained a popular choice for the elderly patients in many countries, recent trends show an increased use of noncemented stems in all age populations in many national registries. So far, there has been no clear age associated recommendation, when a cemented stem should be used. Described major complications including periprosthetic fractures are usually associated with age >75 years, in many registries. Uncemented stems perform better than cemented stems in recent registries; however, unrecognised intra-operative femoral fractures may be an important reason for early failure of uncemented stems. Experimental studies have indicated that intra-operative fractures do affect implant survival, it has been shown that intra-operative and direct post-operative fractures increase the relative risk of revision during the first 6 post-operative months significantly. In addition it has been clearly shown, that uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 post-operative years than cemented stems.
Based on the overall femoral bone quality, especially in female patients >70 years, cemented fixation has a lower fracture risk. Based on the implant fixation type: metaphyseal vs. diaphyseal of various uncemented stems, major attention should be drawn to the intra-operative bone quality during the broaching process, especially for metaphyseal fixation stem types. Although cementless distal fixation can be achieved in thick cortices still in many patients, the incidence of associated thigh pain needs to be considered for some implant types. Furthermore small femoral canals might generate certain implant-bone size mismatch in relation to the proximal femur.
In any cemented THA, a proper cementing technique is of major importance to assure longevity of implant fixation. This also includes proper implant sizing/templating, ensuring an adequate cement mantle thickness, which might be restricted in a small diameter femur. The desired outcome is a cement interdigitation into cancellous bone for 2–3 mm and an additional mantle of 2 mm pure cement. Consequently proper planning in small diameter patients, prevents sizing problems, while in few cases special/individualised stem sizes might be considered.
