25 & 30 years: CLS® Spotorno and Alloclassic® Zweymüller® Hip Stem
Backed by Decades of Documented Success [1;2].
Press Release May, 2009
The 1980s saw a revolution in total hip replacement procedures, shifting
from conventional cemented implants to uncemented endoprostheses. While a
large number of uncemented designs were introduced during this time period,
very few can claim 25 years or more of continuous use and such an amount of
clinical data. The Alloclassic Zweymüller and CLS Spotorno
hip systems, with their optimized design details, inspired many emulators.
However, documented evidence demonstrates that even minor deviations from
the original implants with respect to design or material properties can
affect the longevity of the implants [1].
The Alloclassic Zweymüller hip stem was first implanted 30 years ago and the CLS Spotorno hip stem, 25 years ago. Since then, these stems have become two of the most frequently used — and most successful — uncemented total hip replacement systems. Their continued clinical success is attributed to Zimmer’s expertise in tribology, development and sophistication in manufacturing joint replacement solutions. Over the years, through close collaboration with accomplished joint replacement surgeons, the CLS Spotorno and Alloclassic Zweymüller hip stems were optimized to provide enhanced stability, wear characteristics, and range of motion. In the last 25 years, a level of quality has been achieved that would be very difficult to exceed, as expressed in the markedly low revision rates of the prostheses [2;3].
Long-term results
Independent data published in the world-renowned Swedish Hip Arthroplasty
Registry demonstrated that the CLS Spotorno hip stem had a survival
rate of 99% after 13 years [2]. Thus, only 1% of the clinically documented
endoprostheses required revision before an in-situ time of 13 years.
Similarly good survival rates of up to 100% at 13 years postoperative are
documented for the Alloclassic Zweymüller hip stem [3]. Even in
younger patients (mean age of 52 years), where the implant is subjected to
increased physical activity, a survival rate of 95% at 18 years
postoperative was reported [4]. It is clear that in more than 25 years, the
CLS Spotorno and Alloclassic Zweymüller hip stems have set a standard for
quality that is distinguished by low revision rates and long-term
survivorship.
Unmatched quality
The successes of the original CLS Spotorno and Alloclassic Zweymüller hip stems have led others to copy these two prostheses. Yet, the long-term results of uncemented hip implants depend on specific designs and material properties. Even minimal deviations from the original can lead to different clinical results [1]. A replica of a product design does not include all clinically relevant details, because the expertise in material and process technologies simply cannot be copied. The excellent documented clinical results apply only to the original CLS Spotorno and Alloclassic Zweymüller implants, and not to replications of their designs.
Conclusion
Thanks to their sophisticated designs, precise manufacturing and further optimization, the Alloclassic Zweymüller and CLS Spotorno hip stems have achieved clinical success for 30 years and 25 years, respectfully. Surgeons worldwide have reported high levels of satisfaction and outstanding survivorship rates with these uncemented systems. Because the clinically relevant details of material and design cannot be copied, the long-term results of these two original implants do not apply to replications.
References
[1] Lester DK, Wick M. J Bone Surgery (Br) 2004; 86-B: 1108-1114
[2]
www.jru.orthop.gu.se
[3] Pieringer H et al. J Arthoplasty 2006; 21:
967-974
[4] Reigstad O et al. Acta Orthopaedica 2008; 79: 194-202
