EFFICIENCY OF DISTAL CENTRALIZERS IN COLLARLESS, POLISHED, TAPPERED FEMORAL COMPONENTS

Abstract

Introduction: Recently many total hip arthroplasty systems have the optional use of a distal femoral stem centralising mechanism in order to ensure on adequate circumferantial distal cement mantle. The purpose of this study was to evaluate, in a clinical setting, the potential benefit of centralizers on stem centralization and alignment of polished tapered femoral components. Material and
Method: Forty cemented primary total hip arthroplasties performed between 1993- 1997 were reviewed retrospectively. The thickness of the cement mantle at the level of the lesser trochanter and distal tip of the stem, and the alignment of the stem were measured. All values were normalized using the 28 mm femoral head as a magnification reference.
Results: The mean stem alignment was 0.28 degree in valgus. Results indicate that minimum 3 mm cement thickness was provided in both distal mediolateral and AP planes. In proximal medial region the cement mantle thickness is 2.7 mm in average.
Discussion: When compared with the results of the literature, distal centralizing mechanism of collarless tapered polished femoral components allowed adequate proximal and distal cement mantle thickness even in minimum values and a valgus alignment in average.