Obesity Negatively Impacts Success of Total Ankle Replacement

Long-term follow-up of obese recipients of ankle implants shows higher failure rate


ROSEMONT, Ill. (March 7, 2016)  Obese patients receiving total ankle arthroplasty (TAA), also known as total ankle replacement, face an increased long-term risk of ankle implant failure if the implant has been in the patient more than five years, according to new research from Foot & Ankle International (FAI) presented at AOFAS Specialty Day on March 5.
The retrospective study reviewed the charts of TAA patients and separated them into two groups according to BMI. The reference group included patients with a BMI of less than 30, and 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.
When the groups were compared, 97 ankle replacements were found to have had a minimum five-year follow-up of their implants, and 49 of these implants were in obese patients. These patients had received total ankle replacements for various arthritic conditions, including osteoarthritis, post-traumatic arthritis and inflammatory arthritis.
Results suggest that obesity may negatively influence ankle replacement outcomes. Although there was little difference in five-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 five-year follow-up to evaluate the impact of obesity on TAA implant failure rates,” says Steven L. Haddad, MD, senior author. “Obese patients with primary osteoarthritis treated with TAA were found to have lower five-year implant survivorship compared to 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, adds Haddad, that the ankle implants used in most of the patients in this study were an older type that may not reflect accurate data with today’s modern implants. Thus, important results such as these must be looked at as a part of the evolving world of total ankle arthroplasty.
The study Effect of Obesity on Total Ankle Arthroplasty Outcomes was published in January 2016. A podcast of the study is also available. Other authors included Oliver Schipper, MD; Sahitya Denduluri, BA; and Ying Zhou, PhD. FAI is published by the American Orthopaedic Foot & Ankle Society (AOFAS).
About the AOFAS
The AOFAS promotes quality, ethical and cost-effective patient care through the education, research and training of orthopaedic surgeons and other health care providers. The Society creates public awareness for the prevention and treatment of foot and ankle disorders, provides leadership, and serves as a resource for government and industry as well as the national and international health care communities.

About Orthopaedic Foot and Ankle Surgeons

Orthopaedic foot and ankle surgeons are medical doctors (MD and DO) who specialize in the diagnosis and treatment of musculoskeletal disorders and injuries of the foot and ankle. These specialists use medical, physical and rehabilitative methods as well as surgery to treat patients of all ages. Relying on four years of medical school training, five years of post-graduate training and often a fellowship in foot and ankle care, orthopaedic foot and ankle surgeons perform reconstructive procedures, treat sports injuries and manage foot and ankle trauma.
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