A prospective, multicenter study from Hospital for Special Surgery (HSS) and NYU Langone Health, both in New York, has been honored with the 2021 Otto Aufranc Award from The Hip Society. The study, “A simple Hip-Spine Classification for total hip arthroplasty,” represents the largest literature series evaluating the relationship between hip-spine pathology and the risk of dislocation after THA.
Co-author Jonathan M. Vigdorchik, M.D., a hip and knee replacement surgeon at HSS, explained to OTW the importance of the hip-spine connection to complication rates and patient outcomes. “The hip-spine relationship is currently the most important topic in hip replacement surgery and for the prevention of the most common complication of a hip replacement, dislocation.”
“Since 1978, hip surgeons have been performing the operation with the same targets in terms of position of the components, and only using one static X-ray to understand the condition. We know from previous work that about 50% of revision hip replacement surgery is potentially avoidable, so reducing risks whenever possible is of utmost importance.”
“Although hip replacement has been a tremendously successful procedure, certain patients are at higher risk than others for complications. We have begun to understand those risks, and to identify preoperatively how to do things differently during a hip replacement to avoid those risks and reduce the potential for complications.”
“Our goal was to simplify this problem so that the classification and treatment algorithm could be understood and implemented by all. It establishes four categories of patients, based on a radiographic analysis of two X-rays, and then depending on the category, establishes a recommendation for a particular hip replacement component position.”
OTW asked Dr. Vigdorchik if existing classification systems can help ameliorate the risk of dislocation. Dr. Vigdorchik explained, “There are two other classification systems, but they have not been adopted because they are too complex/complicated and have not been linked to an easy solution during surgery.”
In the study itself, the research team enrolled 2,081 patients. According to the team: “There were 987 patients enrolled in group 1A, 232 patients in group 1B, 715 patients in group 2A, and 147patients in group 2B.”
“Seventy patients were treated with lumbar spine fusion and most had fusion at the L4-5 levels (16; 23%) or L4-S1 levels (12; 17%) fusions. Fifty-one patients (73%) had one or two levels fused, and 19 (27%) had greater than three levels fused. Dual mobility (DM) components were used in 166 patients (8%), including all of those in group 2B and with greater than three level fusions.”
“Using the hip-spine classification,” explained Dr. Vigdorchik to OTW, “we were able to show a 99.2% survivorship free of dislocation in an otherwise high-risk group. In the highest risk group, those with a spinal deformity and stiff spine, we showed a significant reduction in dislocation rate compared to prior literature.”
“Information is available today to simplify the understanding of the hip-spine relationship to help surgeons identify high-risk patients, and then guide surgeons on what to do differently during the operation to prevent risk. A surgeon must ask themselves, ‘What am I willing to do to determine the proper position of the hip replacement for my patient.’ Is it one X-ray? Well then, we can only give you so much information, the same amount of information we had in 1978. If you get two more X-rays, I can give you a lot more information. If you get two X-rays and a CT scan, then we can develop 3D models and run impingement analyses. Each bit of information increases your ability to do a better job at the hip replacement, increases the success and optimizes the outcome for your patients.”
