A Closer Look At The Future Of Total Ankle Arthroplasty
- Volume 22 - Issue 5 - May 2009
- 17979 reads
- 0 comments
These systems rely on three separate components for the ankle joint rather than two components. The tibial and talar components remain, but rather than these components having contact, there is a third polyethylene insert (called the mobile bearing) between these components to allow for freedom of translation and rotation.
Normal biomechanics of the ankle cause shear forces on the classic two-component systems. This shear leads to accelerated breakdown of the polyethylene inserts and high amounts of stress at the osseous component interface, which can ultimately result in failure of the device.
With the inclusion of a fully replaceable mobile bearing in the design of these implants, the prevailing thinking is there will be less stress passing through the prosthesis and its osseous interface. In turn, this will hopefully lead to a longer life for the device. Furthermore, allowing for translation and rotation should allow for more natural ambulation for the patient.
Total ankle implants are becoming more widely used by podiatric surgeons in the U.S. and abroad. With a better understanding of biomechanics and learning from previous failures and successes in total joint replacement implants in other areas of the body, perhaps the total ankle implant may soon become the procedure of choice for chronic ankle conditions as opposed to arthrodesis.
Dr. Johnson is a first-year resident at the Hennepin County Medical Center in Minneapolis.
Dr. Burks is a Fellow of the American College of Foot and Ankle Surgeons, and is board-certified in foot and ankle surgery. He is in private practice in Little Rock, Ark.
For further reading, see “A New Solution For The Arthritic Ankle” in the December 2005 issue, “Inside Insights On Ankle Replacement Surgery” in the March 2008 issue, “Total Ankle Arthroplasty: Do The Risks Decrease With Experience?” in the July 2006 issue and “Are Ankle Implants Worth Another Look?” in the April 2003 issue of Podiatry Today.
To check out the archives or get information on reprints, visit the Web site at www.podiatrytoday.com.
1. Stauffer RN. Total joint arthroplasty. The ankle. Mayo Clin Proc 1979; 54(9):570-5.
2. Bolton-Maggs BG, Sudlow RA, Freeman MA. Total ankle arthroplasty. A long-term review of the London hospital experience. J Bone Joint Surg Br 1985; 67(5):785-90.
3. Jensen NC, Kroner K. Total ankle joint replacement: a clinical follow up. Orthopedics 1992; 15(2):236-9.
4. Kitaoka HB, Patzer GL. Clinical results of the Mayo total ankle arthroplasty. J Bone Joint Surg Am 1996; 78(11):1658-64.
5. Takakura Y, et al. Ankle arthroplasty. A comparative study of cemented metal and uncemented ceramic prostheses. Clin Orthop Relat Res 1990; 252:209-16.
6. Bauer TW, et al. Hydroxyapatite-coated femoral stems. Histological analysis of components retrieved at autopsy. J Bone Joint Surg Am 1991; 73(10):1439-52.
7. Geesink RG. Osteoconductive coatings for total joint arthroplasty. Clin Orthop Relat Res 2002; 395:53-65.
8. Conti S, Lalonde KA, Martin R. Kinematic analysis of the Agility total ankle during gait. Foot Ankle Int 2006; 27(11):980-4.
9. Leszko F, et al. In vivo kinematics of the Salto total ankle prosthesis. Foot Ankle Int 2008; 29(11):1117-25.
10. Wright TM, Bartel DL. The problem of surface damage in polyethylene total knee components. Clin Orthop Relat Res 1986; 205:67-74.
11. Bartel DL, et al. The effect of conformity and plastic thickness on contact stresses in metal-backed plastic implants. J Biomech Eng 1985; 107(3):193-9.
12. Gill LH. Challenges in total ankle arthroplasty. Foot Ankle Int 2004; 25(4):195-207.