System

Why the system as a whole?

Because with a system, efforts can be directed toward a solution of the challenges:

  • In that the individual biomechnics of the patient, is reconstructed (no change of the position of the femur to the acetabulum – retaining the offset) and therefore no change to bone quality
  • By reducing wear to below 0.05 mm per year over time, through further development of polyethylene to vitamys (vitamin E reduces the aging process of the polyethylene
  • Through further development of medical ceramics to optimise the bearing

optimys – RM Pressfit vitamys – ceramys

optimys

01

Individual solution for the patient

The optimys was developed to enable the individual reconstruction of the patient’s anatomy, whereby the main construct is the femoral neck. The centre of rotation and the offset are independently retained, irrespective of the initial situation (varus or valgus of the femoral neck).

The design of the short stem and the reconstruction of the individual anatomy enable an improvement of the force distribution in the bone and reduce the stress shielding 1.

optimys in a nutshell

Medial curvature

  • To reconstruct the individual anatomy 2,3,8,9

Triple Taper and CaP coating

  • To achieve a good primary stability and reduce the risk of subsidence 1
  • Secondary stability due to improved osseointegration 4,5,6
  • Good short term results 7

Curved design

  • To preserve as much bone as possible 8,9,10
  • More physiological proximal femoral strain pattern 1

Latest ODEP rating can be found onwww.odep.org.uk

References

1 Bieger R.I., A.;Reichel, H.;Durselen, L. Biomechanics of a short stem: In vitro primary stability and stress shielding of a conservative cementless hip stem. J Orthop Res, 2013. 31(8): p. 1180-6.

2 Kutzner K.P., Kovacevic M.P., Roeder C., Rehbein P., et al. Reconstruction of femoro-acetabular offsets using a short-stem. Int Orthop, 2015. 39(7): p. 1269-75.

3 Kutzner KP,Freitag T, Donner S, Kovacevic MP,·Bieger R et al Outcome of extensive varus and valgus stem alignment in short stem THA: clinical and radiological analysis using EBRA-FCA. Arch Orthop Trauma Surg, DOI 10.1007/s00402-017-2640-z

4 Overgaard S. Calcium phosphate coatings for fixation of bone implants: Evaluated mechanically and histologically by stereological methods. Acta Orthopaedica Scandinavica, 2000. 71(6): p. 1-74.

5
Kutzner K.P., Pfeil D., Kovacevic M.P., Rehbein P., et al. Radiographic alterations in short-stem total hip arthroplasty: a 2-year follow-up study of 216 cases. Hip Int, 2016. 26(3): p. 278-83.

6
Szmukler-Moncler S., Perrin D., Ahossi V., Pointaire P. Evaluation of BONIT®, a fully Resorbable CaP Coating Obtained by Electrochemical Deposition, after 6 Weeks of Healing: A Pilot study in the Pig Maxilla. Key Eng Mater, 2001. 192-195: p. 395-398

7 5A* rating for optimys (ODEP)

8
Jerosch J. Kurzschaftendoprothesen an der Hüfte. 2017: Springer. 315

9
Kutzner K.P., Donner S., Schneider M., Pfeil J., et al. One-stage bilateral implantation of a calcar-guided short-stem in total hip arthroplasty. Operative Orthopädie und Traumatologie, 2017: p. 1-13.

10
Hochreiter J., Hejkrlik W., Emmanuel K., Hitzl W., et al. Blood loss and transfusion rate in short stem hip arthroplasty. A comparative study. Int Orthop, 2016.

RM_Pressfit_CAD

RM Pressfit vitamys

02

Innovation based on clinical evidence

Robert Mathys senior was the first to describe the isoelasticity of standard polyethylene cups, titanium RM cups and human bone. The wear resistance was further improved through the introduction of vitamys (2009) reducing oxidation of polyethylene, by which osteolysis in the long term is virtually ruled out.

RM PRESSFIT cup in a nutshell

Isoelasticity

  • Preservation of bone thanks to elasiticity 1,3
  • Backside wear can be avoided via monobloc design 1,4
  • Lower revision rate for RM Classic and RM Pressfit compared to the average of all uncemented cups in NZ Registry 10
  • Good mid- and long-term clinical data with the RM philosophy 7,8,9

vitamys

  • Wear rate of vitamys is 80% ( in vitro) or 65% (in vivo) lower than the standard UHMWPE 2,5,6
  • In vitro tests proved to be long-term oxidation and ageing resistant 2

Latest ODEP rating can be found onwww.odep.org.uk

References

1 Ihle M., Mai S., Pfluger D., Siebert W. The results of the titanium-coated RM acetabular component at 20 years: a long-term follow-up of an uncemented primary total hip replacement. J Bone Joint Surg Br, 2008. 90(10): p. 1284-90.

2 Beck M., Delfosse D., Lerf R., Becker R., et al. Oxidation Prevention with Vitamin E in a HXLPE Isoelastic Monoblock Pressfit Cup: Preliminary Results, in Total Hip Arthroplasty, K. Knahr, Editor. 2012, Springer Berlin Heidelberg. p. 21-31.

3 Kastius A., Schoeniger R., Beck M. Acetabular osseointegration and bone density one year after RM Pressfit vitamys cup implantation, in SGOT. 2012: Basel, Switzerland.

4 Halma J.J., Eshuis R., Vogely H.C., van Gaalen S.M., et al. An uncemented iso-elastic monoblock acetabular component: preliminary results. J Arthroplasty, 2015. 30(4): p. 615-21.

5 Scemama C., Anract P., Dumaine V., Babinet A., et al. Does vitamin E-blended polyethylene reduce wear in primary total hip arthroplasty: a blinded randomised clinical trial. Int Orthop, 2016.

6 Data on File at Mathys Ltd Bettlach

7 10A* rating for RM Classic (ODEP)

8 10A* rating for RM Pressfit (ODEP)

9 7A* rating for RM Pressfit vitamys (ODEP)

10 The New Zealand Joint Registry – Eighteen year report January 1999 to December 2016 (NZJR)

ceramys

03

A pearl of ceramics

The quality of medical ceramics and the better wettability virtually rule out wear on ceramic-ceramic bearings and reduce the wear against standard PE to 1/10th. The advantage of the ceramic-ceramic bearing with regard to wear is counteracted by the need for an additional metal fixation, with the consequence that there is an increase in stress shielding. Thus today as an optimum solution Mathys recommends  the hard-soft coupling, i.e. ceramys head and RM Pressfit vitamys (highly crosslinked PE stabilised with vitamin E).

ceramys in a nutshell

High product safety

  • Superb fracture resistance 1
  • Reduced risk of inlay chipping in case of CoC 2,3

Decreased risk of squeaking

  • Reduced risk of surface roughening in case of recurrent luxation 2,3

Excellent ageing resistance

  • Similar burst strength and wear rate before and after accelerated ageing 4
References

1 Al-Hajjar M, Jennings LM, Begand S, Oberbach T, Delfosse D, Fisher J et al. Wear of novel ceramic-on-ceramic bearings under adverse and clinically relevant hip simulator conditions. Biomed Mater Res B Appl Biomater. 2013 Nov;101(8)

2 Data on File at Mathys Ltd Bettlach

3
Oberbach T., Begand S., Glien W., Kaddick C. Luxation Test of Different Ceramic on Ceramic Coupling. Key Eng Mater, 2007. 330-332: p. 1235-1238.

4
Begand S.O., T;Glien, W. ATZ – A new material with a high potential in joint replacement Key Eng Mater, 2005. 284-286: p.;983-986.

chsha V1-2.30.010-01_VARIA

QUESTIONS?

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Whether on individual products, the system as a whole or our anatomy workshops – I will be happy to answer your questions.

Christian Hein

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