Description
The cooperation with Prof. M. E. Müller and Robert Mathys Senior led to the development of one of the most successful implants of the past 40 years – the Müller straight stem. Even today, it is among the most widely used stem concepts and, as the CCA stem, it is a key portfolio component at Mathys.
The design of the CCA stem according to the Müller philosophy is a self-centring wedge (AP), allowing the implant to independently centre and lock in the femur. This can reduce the risk of the stem being implanted in a varus or valgus position.1
Additional anchoring is achieved by the cement mantle being equally divided ventrally and dorsally due to its flat stem cross-section. The rib structure supports the rotation stability of the implant.2
The Müller straight stem is still important today in the field of hip replacements due to its good to excellent clinically proven medium and long-term results.1,3,4,5,6 Registry data 7,8 of the CCA stem and clinical data 9 demonstrate the reliability of this concept in practice.
BENEFIT OF THE CCA STEM ACCORDING TO THE MÜLLER PHILOSOPHY:
Benefit
- Two material designs: CoCrMo and stainless steel
- Medullary-space-filling (shape-closed, composite beam) at the AP level 1,10
- Self-centring due to wedge angle and wide tip (no centralise necessary) 1
- Rib structure for improved rotational stability 2
- Small collar for cement compression 2
- The CCA stem is awarded with a 10A* (10-year high evidence) in the British ODEP ratings 11
1 Clauss, M.; Luem, M.; Ochsner, P. E.; Ilchmann, T., Fixation and loosening of the cemented Muller straight stem: a long-term clinical and radiological review. J Bone Joint Surg Br, 2009. 91(9): p. 1158-1163.
2 Nowakowski, A.M.; Lüem, M.; Ochsner, P. E., Cement collar and longitudinal groove: the effects on mechanical stability with aseptic loosening in Müller straight-stem implants. Arch Orthop Trauma Surg, 2008. 128(7): p. 745-750.
3 Stucinskas, J. et al, Long-Term femoral bone remodeling after cemented hip arthroplasty with the Müller straight stem in the operated and nonoperated Femora.The Journal of Arthroplasty, 2012. Vol. 27 No. 6: p. 927-933.
4 Stucinskas, J. et al, Dynamics of femoral bone remodelling in well fixed total hip arthroplasty. A 20-year follow-up of 20 hips. Hip Int, 2014. Vol 24(2): p. 149-154.
5 Clauss, M. et al, Similar effect of stem geometry on radiological changes with 2 types of cemented straight stem. Acta Orthop. April, 2016; 87(2): p. 120-125.
6 Erivan, R. et al.; RM Pressfit cup: good preliminary results at 5 to 8 years follow-up for 189 patients. Hip Int, 2016. 25,26 (4): p. 386-391.
7 The New Zealand Joint Registry - Eighteen Year Report - January 1999 to December 2016.
8 Australian Orthopaedic Association – National Joint Replacement Registry - Annual Report 2017.
9 Poolman, R.W. et al., Finding the right hip implant for patient and surgeon: the Dutch strategy-empowering patients. Hip Int, 2015. 25(2): p. 131-137.
10 Langlais, F; Kerboull, M.; Sedel, L.; Ling, R. S.M., The 'French paradox.'. J Bone Joint Surg Br, 2003. 85(1): p. 17-20.
11 Latest ODEP ratings can be found at www.odep.org.uk.