Introduction
Short femoral stems, also named metaphyseal stems, have been designed and introduced into the surgical practice in order to improve the results of the standard non-cemented stems. A wide range of short stems are available, with differences in design, surgical technique, and published outcomes.
Rationale
Several advantages have been advocated in favor of short stems over standard non-cemented stems. Short stems:
- Preserve the proximal femoral bone stock
- Decrease stress shielding
- Decrease the tight pain rate
- Ease minimally invasive surgical procedures
- Improve long-term stem survival
- Ease the surgical procedure during revision
Classification
There are two main groups of short stems, those that are neck-preserving and those that do not preserve the femoral neck. Another feature that differentiates them in the availability of modularity.
List of short stems
Mayo Conservative Stem (Zimmer) - Non-neck preserving and no modularity
CFP - Neck-preserving, no modularity
Metha (Aeesculap) - Neck-preserving, modularity
Cut (ESKA) - Neck-preserving, no modularity
Taperlock Microplasty (Biomet) - Neck-preserving, no modularity
Nanos (Smith and Nephew) - Neck-preserving and no modularity
Proxima Stem (DePuy) - Can be neck-preserving, no modularity
Silent (DePuy) - Neck-preserving, no modularity
Mini Hip (Corin) - Neck-preserving, no modularity
Collo-MIS (Lima) - Neck-preserving, no modularity
Outcome
Mayo Conservative Stem (Zimmer)
- Survival 98.2% without mechanical loosening at 5 and 10 years (Morrey et al, 2000)
CFP
- Survival 97% at 3 years (Gill et al, 2010)
- Survival 100% at 3,1 years (Pons, 2010)
Cut (ESKA)
- Survival 98% at 6.6 years (Steens et al, 2010)
Metha
- Survival 100% at 1 year (Synder et al, 2009)
Proxima Stem (DePuy)
- Survival 100% at 8 years (Santori et al, 2010, reporting the precursor stem of the Proxima)
- Survival 100% at 2.1 years (Tóth et al, 2010)
- Survival 100% at 1.7 years (Ghera et al, 2009)
Complications
List of complications related to each implant here.
Pearls and Pitfalls
- Routine radiographic controls during the surgery is recommended during the learning curve.
- The use of short anatomical stems in hip dysplasia can lead to an excessive anteversion of the femoral component that can predispose to dislocation. Careful planning must be done for these cases, and a standard stem allowing to control femoral version has to be available as an alternative option during the surgical procedure.
- A short stem can be a valuable option in cases with severe femoral deformity or presence of previous implants, or even to ease the revision of a fractured hydroxyapatite fully coated femoral stem (a case report about this last option has been described by Sangüesa-Nebot et al, 2010)
Controversy
- Many of the medium- and long-term results published to date correspond to the author or authors of the implant; the results have to be observed carefully.
- The learning curve of this stem is assumed to be equal to conventional stems, but no series address it.
- The influence of conditions such as obesity, metabolic bone diseases, or osteoporosis on the stem survival rate is yet to be defined.
- The failure pattern of these stems is yet to be known; it still has to be proved that the surgical revision is eased and that the revision can be done with a primary conventional stem.
References
- Morrey BF, Adams RA, Kessler M. A conservative femoral replacement for total hip arthroplasty. A prospective study. J Bone Joint Surg Br. 2000;82(7):952-8.
- Hube R, Zaage M, Hein W, Reichel H. Early functional results with the Mayo-hip, a short stem system with metaphyseal-intertrochanteric fixation. Orthopade 2004; 33 (11): 1249-58.
- Ghera S, Pavan L. The DePuy Proxima hip: a short stem for total hip arthroplasty. Early experience and technical considerations. Hip International 2009; 19(3): 215-220.
- Gilbert RE, Salehi-Bird S, Gallacher PD, Shaylor P. The Mayo Conservative Hip: experience from a district general hospital. Hip Int 2009 Jul-Sep; 19 (3): 211-4.
- Goebel D, Schultz W. The Mayo cementless femoral component in active patients with osteoarthritis. Hip Int 2009 Jul-Sep; 19 (3): 206-10.
- Pons M. Learning curve and short-term results with a short-stem CFP system. Hip Int 2010; 20 (Suppl 7) (S7): 52-57.
- Briem D, Schneider M, Bogner N, Botha N, Gebauer M, Gehrke T, Schwantes B. Mid-term results of 155 patients treated with a collum femoris preserving (CFP) short stem prosthesis. Int Orthop. 2011 May;35(5):655-60
- Tóth K, Mécs L, Kellermann P. Early experience with the Depuy Proxima short stem in total hip arthroplasty. Acta Orthop Belg. 2010 Oct;76(5):613-8.
- Sangüesa-Nebot MJ, Soriano FC, Gabarda RF, Valverde C. Revision hip arthroplasty with a short femoral component in fractured hydroxyapatite fully coated femoral stem. J Arthroplasty 2010; 25: 1168.e13;Epub 2009 Sep 2
- Steens W, Skripitz R, Schneeberger AG, Petzing I, Simon U, Goetze C. [Cementless femoral neck prosthesis CUT--clinical and radiological results after 5 years]. Z Orthop Unfall. 2010 Aug;148(4):413-9.
- Boyle C, Kim IY. Comparison of different hip prosthesis shapes considering micro-level bone remodeling and stress-shielding criteria using three-dimensional design space topology optimization. J Biomech. 2011 Apr 15. [Epub ahead of print]
- Gill IR, Gill K, Jayasekera N, Miller J. Medium term results of the collum femoris preserving hydroxyapatite coated total hip replacement. Hip Int 2008; 18(2):75-80
- Santori FS, Santori N. Mid-term results of a custom-made short proximal loading femoral component. J Bone Joint Surg Br. 2010 Sep;92(9):1231-7.
- Synder M, Drobniewski M, Pruszczy?ski B, Sibi?ski M. Initial experience with short Metha stem implantation. Ortop Traumatol Rehabil. 2009;11(4):317-23
