Researchers at Children’s Hospital of Philadelphia (CHOP) demonstrated how trochlear anatomy evolves during pediatric development with and without recurrent patellofemoral instability (PFI), a condition where the kneecap repeatedly slips out of its groove, causing pain, swelling and difficulty with physical activity. The findings, recently reported in a landmark study in the American Journal of Sports Medicine, highlighted that PFI in growing children worsens trochlear dysplasia, which can result in further kneecap instability, while those without PFI experienced natural improvements.
Trochlear dysplasia, a structural condition when the groove in a person’s thigh bone is too shallow or uneven and makes the kneecap more likely to slip out of position, is a consistent risk factor for PFI. However, until now, researchers had limited understanding of how the trochlea developed during growth. A research team, led by Brendan A. Williams, MD and J. Todd Lawrence, MD, PhD, attending pediatric orthopedic surgeons with CHOP’s Orthopedic Center and the Sports Medicine and Performance Center, along with Jie Nguyen, MD, MS, a pediatric radiologist and Director of the Section of Musculoskeletal Imaging with CHOP’s Department of Radiology, aimed to bridge the knowledge gap by analyzing and defining critical changes in trochlear anatomy over time in developing patients with and without PFI.
In the study, the researchers analyzed 128 pediatric patients including 98 with PFI and 30 without. The team reviewed the MRIs of each patient at two separate time points to evaluate a variety of measurements and assessments that quantify the severity of trochlear dysplasia. They found that patients with PFI experienced worsening of trochlear dysplasia, with moderate to severe dysplasia increasing from 67% to 89%. In contrast, children without PFI showed encouraging improvement, with normal trochlear characteristics increasing from 53% to 87% at follow-up.
The CHOP team’s findings add to a growing body of evidence that the patellofemoral joint is constantly changing and adapting during childhood and adolescence, shaping how youth develop and function over time. Future studies will explore whether early stabilization techniques, such as medial patellofemoral ligament (MPFL) reconstruction, can promote normal trochlear development and prevent recurrent instability.
“Understanding the relationship between patellar instability and trochlear development is critical to improving care for these young patients,” said Williams. “Our research highlights the potential to intervene during a crucial period of skeletal growth to optimize long-term outcomes.”
Williams et al. “Trochlear Morphological Changes in Skeletally Immature Patients Across Consecutive MRI Studies.” American Journal of Sports Medicine. Online January 24, 2025. DOI: 10.1177/03635465241312168.
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Researchers at Children’s Hospital of Philadelphia (CHOP) demonstrated how trochlear anatomy evolves during pediatric development with and without recurrent patellofemoral instability (PFI), a condition where the kneecap repeatedly slips out of its groove, causing pain, swelling and difficulty with physical activity. The findings, recently reported in a landmark study in the American Journal of Sports Medicine, highlighted that PFI in growing children worsens trochlear dysplasia, which can result in further kneecap instability, while those without PFI experienced natural improvements.
Trochlear dysplasia, a structural condition when the groove in a person’s thigh bone is too shallow or uneven and makes the kneecap more likely to slip out of position, is a consistent risk factor for PFI. However, until now, researchers had limited understanding of how the trochlea developed during growth. A research team, led by Brendan A. Williams, MD and J. Todd Lawrence, MD, PhD, attending pediatric orthopedic surgeons with CHOP’s Orthopedic Center and the Sports Medicine and Performance Center, along with Jie Nguyen, MD, MS, a pediatric radiologist and Director of the Section of Musculoskeletal Imaging with CHOP’s Department of Radiology, aimed to bridge the knowledge gap by analyzing and defining critical changes in trochlear anatomy over time in developing patients with and without PFI.
In the study, the researchers analyzed 128 pediatric patients including 98 with PFI and 30 without. The team reviewed the MRIs of each patient at two separate time points to evaluate a variety of measurements and assessments that quantify the severity of trochlear dysplasia. They found that patients with PFI experienced worsening of trochlear dysplasia, with moderate to severe dysplasia increasing from 67% to 89%. In contrast, children without PFI showed encouraging improvement, with normal trochlear characteristics increasing from 53% to 87% at follow-up.
The CHOP team’s findings add to a growing body of evidence that the patellofemoral joint is constantly changing and adapting during childhood and adolescence, shaping how youth develop and function over time. Future studies will explore whether early stabilization techniques, such as medial patellofemoral ligament (MPFL) reconstruction, can promote normal trochlear development and prevent recurrent instability.
“Understanding the relationship between patellar instability and trochlear development is critical to improving care for these young patients,” said Williams. “Our research highlights the potential to intervene during a crucial period of skeletal growth to optimize long-term outcomes.”
Williams et al. “Trochlear Morphological Changes in Skeletally Immature Patients Across Consecutive MRI Studies.” American Journal of Sports Medicine. Online January 24, 2025. DOI: 10.1177/03635465241312168.
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