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Understanding Changes to Acetabular Coverage During Skeletal Growth Using 3D Modeling

June 7, 2021

Pediatric orthopaedic surgeon Michael P. McClincy, MD, and collaborators from the Department of Radiology at the University of Pittsburgh School of Medicine published results from a new study that uses 3-dimensional computed tomography modeling to assess and characterize the size and developmental changes of the acetabular lunate cartilage at various ages during development in a cohort of adolescents aged 10 to 18 years. 

The study was published in March in the Journal of Pediatric Orthopaedics.

"The acetabulum is a highly complex anatomic structure, and visualizing it in three-dimensional studies is difficult with traditional imaging techniques. How the acetabulum develops over time, the morphological changes at different ages is significant for hip preservations specialists to more fully understand," says Dr. McClincy. "A more thorough understanding of what the three-dimensional nature of acetabulum looks like at different ages during development, and if there are distinct differences based on the sex of the patient is what we sought to determine with this new study."

Study Highlights and Findings

Dr. McClincy's research team created a series of 62 3-D computed tomography reconstructions of CT pelvis scans from a cross-section of children and adolescents aged 10 to 18 who had normal hip anatomy without signs of pathology (e.g., dysplasia; impingement.) They stratified the cohort into groups by sex and age – 10-12; 13-15; 16-18 years. The 3-D hip reconstructions were then analyzed, and the area of acetabular lunate cartilage was determined. They also examined the lunate cartilage as a whole and in sections – superior, anterior, and posterior.

Females were found to have a decrease in femoral head coverage by the lunate cartilage as age increased. Most of the changes in femoral head coverage occurred between the ages of 10 and 15 years. Male subjects overall did not exhibit a decrease as age increased, but there were decreases noted when examining the anterior and superior aspects of the acetabulum and its lunate cartilage.

“We clearly appreciated differences in developmental changes between sexes, with female subjects indicating femoral head growth happens faster than cartilage development,” says Dr. McClincy. “This was an unexpected finding, but an important one, along with the global and regional changes during aging for females and males, respectively. This information will add to the diagnostic clarity in determining whether pathology exists, and to what degree.”

Future Studies

On a broader note, Dr. McClincy has embarked on collaborative studies with colleagues in the Department of Radiology and the 3-D Printing Laboratory at the University of Pittsburgh that combines the use of 3-D modeling and printing techniques coupled with artificial intelligence and machine learning to improve reconstructive surgical approaches of the acetabulum to maximize stability and function for patients with developmental dysplasia of the hip and femoroacetabular impingement.


1. Herman M, Krivoniak A, Ruh E, Thakrar D, Bosch P, Wylie JD, Ghodadra A, McClincy MP. Acetabular Coverage Decreases at the End of Skeletal Growth: A 3DCT Study of Healthy Hips. J Pediatr Orthop. 2021 March 1; 41(3): e232-e239.

More About Dr. McClincy

Michael P McClincy MDMichael P. McClincy, MD, is an assistant professor of orthopedic surgery. Dr. McClincy earned his medical degree and completed his residency training at the University of Pittsburgh School of Medicine. He then completed fellowships in pediatric sports medicine and pediatric and adolescent hip preservation, both at Boston Children’s Hospital, before returning to Pittsburgh to join UPMC Children's in 2018. Prior to medical school, Dr. McClincy graduated from Dartmouth College with a degree in mathematics. While at Dartmouth, he also was a member of the football team, playing four years as a defensive lineman.

Dr. McClincy’s clinical areas of focus are hip preservation surgery, arthroscopic knee and shoulder surgery, and sports medicine. Fellowship training allowed Dr. McClincy to study and practice sophisticated hip preservation techniques, such as hip arthroscopy and osteotomies of the acetabulum and proximal femur. His research is focused mainly on the study of hip pathology and improving interventional capabilities for patients with a variety of hip morphologies, from dysplasia to impingement. His interests extend to exploring the biomechanics of the hip in young athletes, especially those that fall between the spectrums of impingement and instability. Dr. McClincy has active research interests in femoroacetabular impingement and hip dysplasia surgery in adolescents and young adults.