The degree of patella alta in newborns shows strong correlations with patellofemoral parameters and is influenced by the intrauterine position – An ultrasound-based correlation study

Background

Studies suggest that the development of a suitable patellar groove is highly dependent on a regular patellar position imprinting the patellofemoral joint. Furthermore, previous studies have shown that breech position also has an influence on the patellofemoral joint shape. The aim of this study is to exploratively analyze influences on patellar sagittal height in newborns.

Methods

In this ultrasound-based study, parameters influencing patellar height will be exploratively examined (i.e. patellofemoral joint parameters, hip dysplasia, sex, body and age characteristics of the parents and the newborn, intrauterine position). 98 newborns born between June 2023 and November 2023 at the University Hospital receiving an ultrasound hip screening examination received additional standardized ultrasounds of their knees.

Results

For all 3 measured patellar height indices patellar height was lower for newborns after breech positions. For one of the measured indices this result was significant (p = 0.018). Patellofemoral trochlear configuration also showed significant relationships to patellar height. A high sulcus angle and a lower internal rotation of the trochlea are significantly related to lower patellar heights (multiple linear regression model, model fit: p = 0.002, Coefficients: Sulcus angle p = 0.007, Trochlea angle p = 0.028).

Conclusions

Breech position, high sulcus angle and lower internal rotation of the trochlea are significantly related to lower patellar heights. This is the first study to describe these relationships in newborns and increases clinical awareness. As the exact nature of the relationships remains unclear further research should be conducted.