Background: This study aims to provide biomechanical data on the effect of patella height in the setting of medial patellofemoral ligament (MPFL) reconstruction using finite element analysis. The study will also examine patellofemoral joint biomechanics using variable femoral insertion sites for MPFL reconstruction.
Methods: A previously validated finite element knee model was modified to study patella alta and baja by translating the patella a given distance to achieve each patella height ratio. Additionally, the models were modified to study various femoral insertion sites of the MPFL (anatomic, anterior, proximal, and distal) for each patella height model, resulting in 32 unique scenarios available for investigation.
Results: In the setting of patella alta, the patellofemoral contact area decreased, resulting in a subsequent increase in maximum patellofemoral contact pressures as compared to the scenarios with normal patellar height. Additionally, patella alta resulted in decreased lateral restraining forces in the native knee scenario as well as following MPFL reconstruction. Changing femoral insertion sites had a variable effect on patellofemoral contact pressures; however, distal and anterior femoral tunnel malpositioning in the setting of patella alta resulted in grossly elevated maximum patellofemoral contact pressures as compared to other scenarios.
Conclusions: Patella alta after MPFL reconstruction results in decreased lateral restraining forces and patellofemoral contact area and increased maximum patellofemoral contact pressures. When the femoral MPFL tunnel is malpositioned anteriorly or distally on the femur, the maximum patellofemoral contact pressures increase with severity of patella alta.
Clinical Relevance: When evaluating patients with patellofemoral instability, it is important to recognize patella alta as a potential aggravating factor. Failure to address patella alta in the setting of MPFL femoral tunnel malposition may result in even further increases in patellofemoral contact pressures, making it essential to optimize intraoperative techniques to confirm anatomic MPFL femoral tunnel positioning.
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View Article and Find Full Text PDFBackground: Medial patellofemoral ligament reconstruction (MPFLR) is an excellent surgical option for patients with recurrent patellar instability. This technique has demonstrated significant improvements in patient-reported outcomes, high rates of return to sport, and low rates of failure. However, there is debate regarding the use of isolated MPFLR in the setting of concomitant pathoanatomic features such as patella alta, trochlear dysplasia, or a lateralized tibial tubercle.
View Article and Find Full Text PDFPatella height ratios diagnose the same healthy knees differently.
Sci Rep
January 2025
University of Turin, CTO Hospital (C.T.O. Centro Traumatologico Ortopedico), Via Gianfranco Zuretti, 29, Torino, 10126, TO, Italy.
Article Synopsis
- The study evaluates whether the Insall-Salvati and Caton-Deschamps ratios align with normal distribution patterns in healthy knees, using data from 434 CT-scanned knees.
- Results showed that while the Insall-Salvati ratio identified the 98th centile correctly for patella alta, it overdiagnosed patella baja, while the Caton-Deschamps index also revealed discrepancies in diagnosing patella baja at the 5th centile.
- Overall, the study found poor inter-rater reliability between the two ratios, as indicated by a kappa coefficient of 0.01.
What's up with patella alta?
Curr Opin Pediatr
February 2025
Hospital for Special Surgery, New York, New York.
Purpose Of Review: Patella alta, which describes an abnormally proximally positioned patella, has become of particular interest as it has been identified as a potential factor in patellofemoral instability (PFI) and other common pediatric orthopedic conditions. The purpose of this review is to describe the condition, measuring techniques, and its association with pediatric orthopedic conditions, and to evaluate methods of correction of patella alta.
Recent Findings: Recent literature has explored the etiology of patella alta by investigating patellar height as age increases, with inconclusive findings as to whether the condition is congenital or acquired over time.
A novel assessment of the differences in various measurements in patients with patella alta and baja: a retrospective cross-sectional study.
Quant Imaging Med Surg
December 2024
Department of Radiology, Basaksehir Cam and Sakura City Hospital, İstanbul, Turkey.
Background: Insall-Salvati index (ISI) is widely used to evaluate patella position, the specific relationship between quadriceps patellar tendon angle (QPA) and patellofemoral measurements remains unclear. Understanding this relationship could provide valuable insights into diagnosing and treating knee pain, instability, and patellofemoral pathologies more effectively. In this study, we aimed to assess whether there was a significant difference between the patients with patella alta and baja in terms of many patellofemoral measurements and pathologies.
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