Not a Traditional "Short Stem"
ARC Hip Stem is not a shortened version of a traditional stem, but rather built from the ground up to preserve tissue.
Many other bone preserving designs are based on previous traditional stems, and essentially built with a smaller profile. The ARC stem was designed with a new philosophy: load healthy medial bone, and promote proximal bone remodeling.
Healthy Bone Engagement
The ARC's unique design not only conserves tissue, but engages healthy medial bone to encourage additional proximal strength.2
The proximal conical flare is designed to transfer hoop tension in the femoral neck and proximal femur into compressive loads to maintain stress on the medial calcar, in order to promote bone remodeling, helping to ensure long term fixation.2 FEA modeling has demonstrated improved proximal strain patterns to the retained femoral neck.*
Engaging the medial calcar stimulates boney ingrowth, instead of the resorption that you may see in some distally loading systems. Hydroxyapatite coating is applied to the porous coating, enhancing the early fixation of the component, which has a positive effect on femoral remodeling and bone density.3
Approach-Friendly Surgical Technique
The unique stem shape is conducive to any surgical approach, including direct anterior.
The femoral preparation for the ARC utilizes a hand-rasping system. By following the natural curve of the medial cortex, the femoral preparation for the ARC is achievable using any surgical approach.
The Solution for Young, Active Patients
Femoral neck sparing design preserves healthy bone and tissue.
The ARC hip stem conserves bone in the proximal femur making it a good choice for younger, more active patients. The ARC's design requires less bone to be removed during surgery, providing the opportunity for surgeons to dissect fewer soft tissues. It also loads the proximal femur in such a way as to provide an environment where bone could be preserved over time.
Using Gruen Zones1 as a reference, the ARC is designed to conserve bone in Zones 1, 3, 4, 5, and 7 as shown in this figure.
Monoblock Standard, Modularity When Necessary
ARC hip stem is available in fixed monoblock design, as well as a proven modular design for greater versatility.
The ARC has two stem types: monoblock, and modular. The monoblock construct is available in neutral, and varus orientation. If more varus/valgus or ante/retroversion adjustment is needed, the modular stem can be used with one of several neck options.
The Modular ARC stem features a cremescoli tapered neck junction, with maximized taper engagement to limit risk of corrosion or fretting. The use of modular necks allow intra-operative adjustment of joint stability, leg length, offset, and version.
- Gruen, T. A.; McNeice, G. M.; and |and |Amstutz, H. C.: "Modes of failure" of cemented stem-type femoral components. A radiographic analysis of loosening”, Clin. Orthop., 141: 17-27, 1979.
IOF World Congress on Osteoporosis, May 5-8, 2010 Florence, Italy, Poster Exhibit, “Neck Sparing Total Hip Arthroplasty Lessons Learned”
By: T. McTighe, I. Woodgate, A. van der Rijt, A. Turnbull, J. Harrison, D. Brazil, L. Keppler, J. Keggi, K.J. Keggi, R. Kennon , S.D. Stulberg, L.E. Rubin
- Effect of Circumferential Plasma-Spray Porous Coating on the Rate of Femoral Osteolysis After Total Hip Arthroplasty, ROGER H. EMERSON, JR., M.D. , STEVEN B. SANDERS, M.D. , WILLIAM C. HEAD, M.D. and LINDA HIGGINS, PH.D. , PLANO, TEXAS The Journal of Bone and Joint Surgery 81:1291-8 (1999), © 1999 The Journal of Bone and Joint Surgery, Inc.
* - Data on file at OMNIlife science, inc.