Abstract
Introduction: The triple tapered polished cemented C-stem has evolved from the study on long-term results of the Charnley design, when first fractures of the stem and then proximal strain shielding of the femur and stem loosening were identified as the continuation of the same process. The design utilises the common engineering principle of male (stem) and female (cement) tapers engaging under load, loading the proximal femur.
Methods and Results: The C-stem was tested extensively and introduced into clinical practice in December 1993. Up to the end of October 2007, 4558 have been implanted in primary operations.
None of the 4558 stems have been revised for aseptic loosening or fracture.
The patient’s mean age at surgery was 48 years (range 15–76), and 171 hips with a mean follow-up of 11 years (range 10–13.7) have now passed 10 years. There were 97 females and 64 males in this group with 10 patients having bilateral C-stems. The main underlying pathologies were Primary Osteoarthritis 30%, Developmental Dysplasia of the hip 27% and Avascular Necrosis of the hip 19%.
Clinical outcome graded according to d’aubigne and postel for pain, function and movement has improved from 3.1, 3.1 and 2.9 to 5.9, 5.7 and 5.6 respectively.
A good quality proximal femur had been maintained in 47.1% and improved in a further 29.9%.
Discussion: The results achieved with the C-Stem design and technique are encouraging and support the concept of loading the proximal femur, but place a demand on the understanding of the technique and its execution at surgery.
Correspondence should be addressed to Mr Peter Howard, Editorial Secretary, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE, England.
