Obesity Negatively Impacts Success of Total Ankle Replacement
Obese patients who undergo total ankle arthroplasty (TAA) face an increased long-term risk of ankle implant failure if the implant has been in the patient more than 5 years, according to research published in Foot & Ankle International and presented at the AOFAS Specialty Day in Orlando.
The retrospective study reviewed the charts of TAA patients and separated them into 2 groups according to BMI:
The reference group included patients with a BMI of less than 30
The obesity group included patients with a BMI greater than or equal to 30, which is the World Health Organization’s definition of obesity.
In this study, the mean BMI was 33.5kg/m2, which is significantly higher than the non-obese patients, who averaged 24.8kg/m2.
Of the 97 ankle implants that had a minimum 5-year follow-up, 49 were in obese patients. These patients had undergone TAA for various arthritic conditions, including osteoarthritis, post-traumatic arthritis, and inflammatory arthritis.
Results of the study suggest obesity may negatively influence ankle replacement outcomes. Although there was little difference in 5-year implant failure between the BMI groups, there was a significantly higher probability of failure in obese patients at their final follow-up averaging 7.9 years from the time of the surgery. The mean time to revision ankle replacement surgery in both groups was 4.8 years from the date of surgery.
“Ours is the first comparative study with a minimum 5-year follow-up to evaluate the impact of obesity on TAA implant failure rates,” said senior author Steven L. Haddad, MD.
“Obese patients with primary osteoarthritis treated with TAA were found to have lower 5-year implant survivorship compared with obese patients with other types of arthritis who were similarly treated. These patients should be counseled appropriately when they are deciding between TAA and arthrodesis, or fusion.”
It is important to note, Dr. Haddad noted, that the ankle implants used in most patients in this study were an older type that may not reflect outcomes with today’s modern implants. Thus, important results such as these must be looked at as a part of the evolving world of TAA.
Shipper ON, Denduluri SK, Zhou Y, Haddad SL. Effect of obesity on total ankle arthroplasty outcomes. Foot Ankle Int 2016 Jan;37(1):1-7. doi: 10.1177/1071100715604392. Epub 2015 Sep 16.
Ankle image from: Pagenstert G, Hintermann B. Simultaneous bilateral total knee and ankle arthroplasty as a single surgical procedure. BMC Musculoskeletal Disorders 2011, 12:233 doi:10.1186/1471-2474-12-233. Accessed 3/20/16. © 2011 Pagenstert and Hintermann; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.