Abstract
Conventional wisdom holds that aseptic failure of proximal ingrowth femoral stems should be addressed by revision to a longer femoral stem dependent upon more distal fixation. This is a reliable and time-honoured strategy with a high likelihood of success provided secure initial fixation of the revision stem is obtained. Yet, stems reliant upon more distal diaphyseal fixation are accompanied by a greater risk of physiologic thigh pain attributable to the differential in flexural stiffness of the femoral shaft compared with the prosthetic stem.
Contemporary proximal ingrowth femoral stems have become the most popular device used in total hip arthroplasty and are traditionally reserved for primary procedures. Nevertheless, the flat tapered design offers a tight fit between the medial and lateral endosteal cortices of the femur, unimpeded by an increasing anteroposterior dimension of the stem, and provides a secure geometrical block to rotational movement of the stem. In instances when the primary stem is not fit to the endosteal cortex on the anteroposterior radiograph, such as with the Corail or SROM devices, the opportunity may exist for revision with a flat tapered proximal ingrowth stem that is upsized to abut the endosteal femoral cortex. Such a strategy preserves the diaphyseal femur for subsequent revision in these typically young patients and avoids the issue of thigh pain in this active population. Likewise, revision of a well-fixed long stem that is associated with unrelenting thigh pain may be similarly accomplished by revision to a flat proximal ingrowth stem provided the integrity of the upper femur can be maintained during the revision. A prophylactic cerclage wire around the proximal femur is a helpful adjunct when using flat tapered proximal ingrowth stems in the revision setting.
