John C. Clohisy, MD, FAAOS (center), accepted the Kappa Delta Elizabeth Winston Lanier Award on behalf of the Academic Network of Conservative Hip Outcomes Research (ANCHOR) group at the AAOS 2024 Annual Meeting in San Francisco. Dr. Clohisy is pictured with Francis Young-In Lee, MD, PhD, FAAOS, Orthopaedic Research and Education Foundation Research Awards co-chair (left), and Kristin Power, Kappa Delta Foundation Board member (right).


Published 5/29/2024

Kappa Delta Elizabeth Winston Lanier Award Presented to ANCHOR for Pre-Arthritic Hip Conditions Research

The 2024 Kappa Delta Elizabeth Winston Lanier Award was presented to the Academic Network of Conservative Hip Outcomes Research (ANCHOR) group for 20 years of research to improve the quality of care for adolescent and young adult patients suffering from the three most common pre-arthritic hip conditions: femoroacetabular impingement (FAI), developmental dysplasia of the hip (DDH), and residual Legg-Calve-Perthes disease. Their research has helped the orthopaedic community better understand the basic pathophysiology of hip osteoarthritis (OA), disease natural history, diagnosis, surgical treatment, and predictors of treatment outcomes for young patients who often live with hip dysfunction for years or even decades with eventual progression to advanced OA.

OA is a common condition that affects 27 million Americans with costs that are projected to increase by $185.5 billion per year. Hip OA is particularly problematic due to associated disability. Over time, the pre-arthritic conditions of FAI, DDH, and Legg-Calve-Perthes disease wear down the articular cartilage that covers the hip joint surface and lead to hip OA, which is associated with pain, limited function, and reduced quality of life.

“In the early 2000s, the orthopaedic community lacked an understanding of pre-arthritic hip disease diagnoses and treatments. Variable patient age at presentation, lack of generalizable surgical treatments, and limited clinical outcomes reporting for hip-preservation procedures were major challenges,” said lead researcher John C. Clohisy, MD, FAAOS, Daniel C. and Betty B. Viehmann Distinguished Professor of Orthopaedic Surgery at Washington University in St. Louis. “Due to a lack of knowledge of pre-arthritic hip disease and a limited number of surgeons to treat these diseases, the average wait time for an accurate pre-arthritic hip diagnosis was 3 to 5 years. This was clearly an underserved patient population.”

Early contributions by Reinhold Ganz, MD, and his colleagues in Switzerland helped transform hip surgery with the introduction of new surgical techniques and concepts regarding the causes of hip OA. However, these refined concepts and surgical strategies were initially viewed as untraditional, unproven, and technically challenging. “We wanted to understand, investigate, and implement Dr. Ganz’s concepts to advance the quality of care for these patients, and we established three goals as the basis of our research: improving the individual healthcare experience of the patient; improving the health of populations; and lowering per-capita healthcare costs for populations,” said Dr. Clohisy.

The ANCHOR group, coordinated from Washington University, initially enrolled two cohorts—FAI-1 and PAO-1 (periacetabular osteotomy), totaling 3,168 surgical cases—to detail population characteristics of FAI and DDH patients and to investigate the safety and efficacy of surgical treatments. Data collection of clinical presentation, diagnosis, patient-reported outcome measures (PROMs), radiographic imaging, surgical procedure details, and intraoperative disease classification set the foundation for subsequent investigations. This dataset enabled the group to examine several key performance indicators to provide quantitative measurement of improved patient outcomes.

Timely diagnosis
The ANCHOR group performed a series of foundational studies to describe the clinical presentation and epidemiology of patients with FAI, DDH, and labral tears. Findings of the studies included:

  • There was a predominance of DDH in young, active females, who often presented with significant hip dysfunction and symptoms, including groin or lateral hip pain. Clinical presentation was accelerated with high activity levels and more severe deformity.
  • Females with FAI had greater symptomatology and milder morphologic abnormalities, whereas males had higher activity levels, larger morphologic abnormalities, and more extensive intra-articular disease. Both groups presented with activity-related groin pain and tended to have restricted hip range of motion and progressive symptoms over time.

Patient satisfaction
The ANCHOR group measured patient-reported satisfaction with standardized methodology to provide feedback on the patient experience associated with surgery for FAI. The findings included:

  • FAI patients self-reported high overall satisfaction rates (>91 percent) and low rates of dissatisfaction (>9 percent). Long-term mean 10-year follow-up of the FAI-1 cohort was recently completed (unpublished data) and demonstrated maintenance of these high satisfaction rates (91 percent).
  • Most patients studied who underwent PAO surgery demonstrated marked clinical improvement and returned to sport, and only a small percentage had activity limitations from surgical hip symptoms (<11 percent). overall patient satisfaction in pao patients was also consistently more than 90 percent.>

Treatment indication and complication risk
These studies aimed to identify appropriateness in patient selection and precise surgical technique. The ANCHOR group determined that hip arthroscopy procedures are best utilized in the treatment of FAI with accessible FAI morphology. Alternatively, outcomes of isolated hip arthroscopy in the setting of acetabular dysplasia or advanced articular disease are not favorable.

The initial literature on surgical procedures in the young population was not standardized and lacked risk and complication reporting. The group analyzed the safety of PAO, hip arthroscopy, and surgical hip dislocation. The researchers found that the complication risk ranged from 1 to 5 percent, depending on the procedure. Additionally, permanent disability related to any of these procedures was <1 percent.>

Early skepticism among the orthopaedic community related to the diagnosis of FAI, its association with hip OA, indications for surgery, and efficacy of surgery required critical investigation of these new concepts. ANCHOR’s findings included:

  • Preoperative PROM score was a strong, highly significant predictor of all outcomes. More recent analyses have determined that competitive athletes had superior outcomes and lower failure rates compared with non-athletes (after controlling for important covariates). For FAI surgery, a lower risk of clinical failure was associated with participation in competitive athletics (P = 0.01) and male sex (P <0.001).>
  • Longer chronicity of preoperative symptoms, patients aged >40 years requiring acetabular microfracture, and revision surgery were independently associated with inferior clinical outcomes. Subgroup analysis of adolescent patients identified females, mild cam FAI deformities, and lack of sports participation to be associated with higher rates of treatment failure.

The ANCHOR group developed a consensus document to standardize radiograph evaluation of the young adult hip and more recently have emphasized the important role of 3D imaging. It includes a comprehensive review of radiographic technique and image interpretation that has served as a cornerstone contribution for surgeons, radiologists, radiology technicians, and orthopaedic/radiology trainees. ANCHOR’s findings concluded that 3D imaging plays a fundamental role in the evaluation of young adult hip disorders. Additionally, low-dose CT scanning is an excellent tool to precisely determine acetabular and femoral morphology as well as femoral version.

“Over the past 20 years, access to quality care for young patients with pre-arthritic hip disease has markedly improved,” said Dr. Clohisy. “We now have surgeons and healthcare teams who can deliver a comprehensive approach to manage the full spectrum of pre-arthritic hip disease. While we’ve made great strides, we’re continuing to improve by better defining and diagnosing the conditions, determining the best indications for surgery, and optimizing our surgical techniques.”