Research Summary Research topic:
Investigating how outcomes of revision ankle arthroplasty compare with primary arthroplasty outcomes and with the outcomes of ankle fusion for treating a failed total ankle arthroplasty Research results:
Understanding of whether the outcomes of revision ankle arthroplasty are as good as they are for primary total ankle arthroplasty or if an ankle fusion is better for treating failed total ankle arthroplasty Patient care application of results:
Understanding of what can be done non-surgically—such as physical therapy and activity modification—to get revision ankle arthroplasty patients back to moving and lower their risk of needing another surgery Simplified patient care application:
More cost effective revision ankle replacements that have better outcomes
Failed total ankle arthroplasty:
OREF grant recipient assesses treatment options
Jay D. Lenn
End-stage ankle arthritis results in severe pain, deformity and functional disability. Both ankle fusion and total ankle arthroplasty can result in less pain and improved quality of life. Arthroplasty has become more common, however, because it preserves mobility in the ankle and may protect surrounding joints from increased wear.
Although studies have shown that survival rates of ankle implants have improved over the years, there is still little to no information about best practices following an implant failure. How do the outcomes of revision ankle arthroplasty compare with primary arthroplasty outcomes? And how do the outcomes of revision arthroplasty compare with ankle fusion for treating a failed total ankle arthroplasty?
To begin addressing these questions, Robin M. Queen, PhD, former director of the Michael W. Krzyzewski Human Performance Lab (K-Lab) and assistant professor of orthopaedic surgery at Duke University Medical Center, was awarded a 2014 Orthopaedic Research and Education Foundation (OREF) Research Grant in Revision Related to Total Ankle Arthroplasty. The grant, for which funding is made possible by Wright Medical, provides $100,000 over two years. Dr. Queen is completing this work as the director of the Kevin P. Granata Biomechanics Lab (Granata Lab) and associate professor of biomedical engineering and mechincs at Virginia Tech.
One assessment tool that Dr. Queen and her colleagues at the Granta Lab brought to these research questions was 3-D motion-capture technology. A biomedical engineer by training, Dr. Queen noted that this technology provides relevant biomechanical data that helps them evaluate postoperative changes in functional abilities.
Dr. Queen explained, “We used a technology similar to what is used to make video games or movies to look at how somebody moves. We put small reflective markers on the patients and recorded their movement using a large motion-capture system. With this system, we calculated such things as the amount of force that was being imparted on the pateints’ bodies and their joint position while walking, sitting or standing.”
She stated that this technology was valuable not only in their investigations but also for patient education. She said, “We showed patients a visual representation of how they were walking before surgery and after. They think it's great when they can see they don't have the same limp or that they're not walking as slowly.”
Comprehensive assessment of outcomes
The motion-capture, biomechanical data provided just one component of a comprehensive database of functional and clinical outcomes following primary total ankle arthroplasty at Duke University Medical Center. The OREF-funded study built upon this work with the outcomes of revision arthroplasty or fusion—either ankle fusion or tibiotalar calcaneal fusion (fusion of the talar bone in the ankle joint to both the tibia and the heel bone).
The expansion of this database captured preoperative and one-year postoperative information. The assessments included:Motion-capture, biomechanical data Physical examination by the treating physician Multiple scales for patient-reported functional abilities and pain Mulitple standard functional assessments, such as timed get-up-and-go, single-leg stance, walking speed and the Short Physical Performance Battery
The first aim of the research project was to compare and characterize the outcomes of the primary and revision arthroplasty. The researchers compared outcomes of 20 patients in each treatment group matched by age, sex and body mass index.
Dr. Queen observed, “We anticipate that these findings can be used to refine patient education, to explain what the postoperative course will look like, what their limitations may be and what their expectations should be.”
She hopes that ultimately the research will inform efforts to alter the postoperative course with nonoperative interventions, such as physical therapy and activity modifications. “That's where my research melds with orthopaedic surgery. After the surgeon has performed this great procedure, what can we do to augment that in an attempt to get the patient back to moving better or to lower the risk for another surgery?”
Cost-effectiveness of treatment options
The second aim of this study was to assess the economic outcomes of revision ankle arthroplasty and ankle fusion to treat a failed ankle implant. The researchers took into account not only the direct medical costs of the procedures but also indirect costs related to treatment outcomes and functional status, such as the ability to work, changes in earnings, number of days missed from work and disability payments. They will collect data from 30 patients in each of the treatment groups.
Dr. Queen noted that the benefit of this investigation may be two-fold. First, it would lay a foundation for determing best practices in treating failed ankle implants. Second, better outcomes and more cost-effectiveness with revision arthroplasty—if observed—might inform alterations in implant designs and surgical procedures that better accommodate revision surgery.
Benefits of OREF
The value of OREF, according to Dr. Queen, extends beyond funds for conducting investigations and gathering pilot data for grants from the National Institutes of Health (NIH). Another benefit is OREF's grant-writing workshops. “I had the opportunity to sit down with researchers who are highly funded,” she stated. “They gave us feedback that has helped us make the strongest proposal we can to secure NIH grants.”
Dr. Queen also noted that OREF grants have enabled her to train junior level researchers in her lab. “The students and residents get to understand the importance of doing research and doing it correctly and ethically. OREF has fostered my role in helping them move toward their own goals of becoming surgeons or PhDs in orthopaedic research. ”
Dr. Queen is now an associate professor in the Department of Biomedical Engineering and Biomechanics, Kevin P. Granata Biomechanics Lab at Virgina Tech College of Engineering. She also holds affliated positions in the Edward Via College of Osteopathic Medicine, the Department of Health Sciences at Virginia Tech as well as in the Department of Orthopedic Surgery at Virginia Tech–Carilion School of Medicine.
Jay D. Lenn is a contributing writer for OREF. He can be reached at firstname.lastname@example.org