RESULTS OF THE C-STEM POLISHED TRIPLE TAPERED FEMORAL COMPONENT

Abstract

The use of polished femoral implants employing the taper-slip philosophy now dominates the cemented portion of the hip arthroplasty market in the United Kingdom. Despite this fact, there have been very few published or presented series reporting the medium to long-term results of double tapered implants and only one previously reported series looking at the results of the triple tapered stem.

We present the results of 500 consecutive polished triple tapered C-stem femoral components performed in 455 patients.

All operations were performed using a posterior appproach, with cemented all polyethylene acetabular components and the use of third generation femoral cementing techniques, restrictors, centralisers and Pala-cos-R cement.

There were 282 female patients (62%) and 173 males (38%). The average age at the time of surgery was 68.3 years (23 to 92), with an average duration of follow-up of 71 months (36 to 112). 47 patients (51 hips) died during the follow-up period at an average of 54 months (1–87).

There were 3 dislocations, 2 on one occasion and one twice, at an average of 4 years. There were 2 deep infections, one of which required revision, and 4 non-fatal pulmonary emboli. There were 3 undisplaced trochanteric cracks treated by cerclage wiring and 3 nerve palsies: 2 femoral (temporary) and one sciatic (permanent). There was only one case of significant heterotopic ossification (Brooker Class 4).

The stem was neutral in 89% of cases, varus in 7% and valgus in 4%. Subsidence within the cement mantle occurred in 79% of cases, with an average of 0.87mm. 9 stems subsided 2 to 4mm but all stopped at 2 years and there was no further subsidence thereafter.

One hip was revised for deep infection but none of the remaining implants demonstrated any progressive radiolucencies in any Gruen zones and none demonstrated any features suggestive of current or future loosening. There was no evidence of negative bone remodelling.

The data was collected prospectively and the study is ongoing.