Abstract
Elderly femoral neck fractures are often treated with cemented stems according to the reason that bone quality of the patients is not good enough to obtain the initial stability for supporting press fit cementless stem. Some elderly patients also have medullary expanding so called stovepipe canals which make initial stability of press fit stems difficult. Stems with lateral flare have some mechanical advantages to obtain proximal fixation compare to the straight stems without lateral flare. Concerning to initial stability, their vertical loads can be supported not only by proximal medial cortex but also by proximal lateral cortex. The stems also have rotational stability because of the proximal high fit and fill. As lateral flare is a transverse extension in axial section, the stem occupies the proximal canal widely. So it provides strong rotational stability. The purpose of this study was to evaluate the outcome of press fit cementless stem with lateral flare for elderly femoral neck fractures with poor bone quality and with medullary expanding.
We performed a retrospective review of the clinical records and radiograghs of consecutive 42 patients (42 hips) of femoral neck fracture operated with cement-less stems with lateral flare in 2005 and 2006. In this period, all displaced femoral neck fractures were operated using cementless stems with lateral flare (Revelation Hip System, DJO, USA) in our hospital. We could follow 24 patients for over one year. 12 of 24 patients had so called stovepipe canals according to Canal Flare Index< 3.0 (Noble et al). Minimum follow up duration was one year. The mean age of the patients at the time of operation was 78.2 years. The mean duration of follow-up was one year and three month. At the time of final follow-up, stem subsidence, stem fixation, spot welds and demarcation line at distal part of stem are assessed on radiograph. And operation time, blood loss at operation and complaint of thigh pain through all the follow up period are also investigated on clinical record.
There was no stem subsidence over 2mm and demarcation line in two cases. All stems were assessed bone-grown fixation. We could find at least one spot welds in all patients around porous coated part of the stem. The mean operation time was 60.1 min. and mean blood loss was 240.5 ml. There was no patient who complaints of thigh pain after operation.
Cementless stems with lateral flare were seemed to obtain good initial stem fixation for elderly femoral neck fracture patients even they have poor bone quality and medullary expanding.
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