*smith&nephew SBG Anatomical Hip Stem Prosthesis. Product Information

Transcription

1 Product Information *smith&nephew SBG Anatomical Hip Stem Prosthesis

2 For a Perfect Fit Because Anatomy Matters On account of its anatomical shape the cementless SBG stem, which has been used successfully since 1990, conforms to the natural features of the proximal femur. Its hydroxyapatite coating promotes rapid growth of bone onto the surface of the prosthesis. With its design and user-friendly instrument set, also for minimal invasive approaches, the system meets the demands made of a safe hip endoprosthesis. 1. Stem Design The CCD angle is 130. The predefined antetorsion angle of 7 comes closer to physiologic al, anatomical conditions. In conjunction with correct pos itioning and orientation of the appropriate acetabular compon ent this makes it possible to reduce any dislocation tendency. For precision adaptation to the anatomy there are 12 standard sizes available, each with left and right versions. 2. Surface The proximal area of the prosthesis is coated with a layer of hydroxyapatite 65 μm thick. Accelerated osseointegration due to the hydroxyapatite also allows rapid full loading even if bone quality is inferior. The longitudinal grooves over the entire surface enlarge the surface area available for bone growth and absorb torsional forces. 3. Material The SBG stem is made of a high-strength titanium alloy, Ti6Al4V. The distal stem is rough-blasted with special fused alumina. «The SBG stem is also ideal for minimal invasive surgery and in terms of technique it is easy to implant. The special design conforms to the «fit and fill» philosophy. Design-related high primary stability and a HA-coated surface allow not only immediate loading, even if bone quality is inferior, but also rapid, long-lasting osseointegration for the implant. Moreover, this implant is very «forgiving», in order to avoid leg-lenghtening a slight varus implantation is possible and was done several times in our hospital without observing any stem failure.» Prof. Dr. med. Reinhard Graf Stolzalpe General and Orthopaedic Regional Hospital, Austria 02 Product Information This Document is not for distribution in the United States.

3 SBG Modelled on anatomy The SBG stem follows the endomedullary curvature of the femur. As a result of its anatomical shape the prosthesis seeks optimum fit conforming to anatomical conditions. Adaptation creates extensive bone-implant contact whilst avoiding pressure peaks. 03

4 Histology Histological tests on an SBG prosthesis after six months in situ, removed owing to a periprosthetic fracture: osseointegration the entire circumference of the prosthesis. The micrograph clearly shows resorption pits. The areas containing partially resorbed hydroxyapatite have been refilled with bone tissue (Lintner 2001) Design features Longitudinally the stem profile is rotated by approx. 30. With a gentle twisting motion the stem fits precisely into the prosthetic bed, which has been prepared with anatomically shaped rasps. The antetorsion angle of 7 matches the features of the natural femoral neck. Cross-section The medially and laterally flattened oval cross-sections create a conical body which absorbs axial forces. The oval cross-section is equivalent to an «anatomical rectangle» so it absorbs torsional forces. 04 Product Information

5 SBG Confidence Created by Excellent, Confirmed, Long-term Results Clinical results Long-term clinical results for the SBG stem can be described as excellent, with a high level of patient satisfaction. The very high primary stability of the SBG stem usually allows immediate full-load capacity. By using a hydroxyapatite coating in the main anchorage area, which has been grown through within approx. six weeks, the implant can always be fitted by the cementless method even with inferior bone quality and in elderly patients. Another reason for the excellent implantability of the SBG stem is that it seeks the optimum path in the femoral tube on its own and achieves optimum press fit. In a publication by H. Effenberger, R. Graf, M. May et al. 1 the following Kaplan- Meier survival curve is shown which serves to confirm the excellent long-term clinical outcome with a result of 99.5 %. Survival function Cumultive survival rate Follow-up period (months) Kaplan-Meier survival curve, with revision of the stem component as the end point with a survival curve of 99.5% (95% CI ) after 10 years. 1 H. Effenberger, MD, Asst. Prof., R. Graf, MD, Prof., M. May, MD, M. Lojpur, MD, M. Imhof, F. Lintern, MD, Prof. 05

6 The Cemented IPA Stem The cemented IPA stem has been used successfully for implan tation since Its anatomical shape is based on the positive experience gained with the cementless SBG stem and follows the natural features of the proximal femur. The femur is prepared using the same rasp system. The IPA and SBG stems therefore offer a complete range of prostheses for cemented and cementless treatment. 1 Stem design The CCD angle is 130. The given antetorsion angle of 10 is close to physiological, anato mical conditions. In combination with correct positioning and orientation of the corresponding cup component, this helps to reduce any possible tendency to dislocation. The IPA stem system is available in eight sizes in left and right versions. Materials and surface The anatomical IPA stem is made from CoCrMo cast alloy as per ISO Its surface is cor un dum-blasted for ideal cement adhesion. This gives a middle roughness Ra of μm. Using this CoCr material, which has been tried and tested over many years, renders this cemen t ed stem extremely safe. 2 3 Cement thickness It is essential to aim for a homo geneous and unbroken cement mantle with the appropriate thickness and meshing in the bone. The philosophy of the IPA stem is to have a 2 3 mm cement layer at least. Modelled on the real anatomy The IPA stem follows the natural intramedullary shape of the pro ximal end of the femur, with the stem profile twisted 30 in its longitudinal axis. The size of the anatomically shaped IPA stem is increased harmoniously in all three planes so that it can be perfectly matched to the internal mor phology of the proximal end of the femur. This enables a uniform cement mantle to be achieved. 06 Product Information

7 SBG Simplicity and Efficiency The straight-forward and user-friendly instrument set results in an easy surgical technique, saving valuable operating time and achieving reproducible results. The curvature of the prosthesis bed is produced with special anatomically shaped rasps that precisely match the stem design. Various offset-adapters accommodate the possibility for minimal invasive approaches. Offset-Adapter 10 mm Offset-Adapter 25 mm Double Offset-Adapter, left 13/17 mm Double Offset-Adapter, right 13/17 mm Modular Rasps left and right Modular Necks 07

8 Manufacturer Smith & Nephew Orthopaedics AG Erlenstrasse 4a 6343 Rotkreuz Switzerland For further information please contact our local sales office. Trademark of Smith & Nephew Lit. No e Ed. 08/08 EU 0123