Citation, DOI, disclosures and article data
Citation:
Chmiel-Nowak M, Hacking C, Jones J, et al. Patellotrochlear index. Reference article, Radiopaedia.org (Accessed on 05 Aug 2024) https://doi.org/10.53347/rID-78481
Disclosures:
At the time the article was last revised Craig Hacking had the following disclosures:
- Philips Australia, Paid speaker at Philips Spectral CT events (ongoing)
These were assessed during peer review and were determined to
not be relevant to the changes that were made.
View Craig Hacking's current disclosures
Patellotrochlear index (PTI) is one of the methods to determine patellar height.
Measurement
The patellotrochlear index is measured on a sagittal MR image with the maximal patellar cartilage thickness and the maximal craniocaudal diameter of the patella.
Two measurements are made:
Patellotrochlear index (PTI) = A/B
Interpretation
There is significant heterogeneity in what is considered normal/abnormal using this index 1-3:
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1. Biedert R & Albrecht S. The Patellotrochlear Index: A New Index for Assessing Patellar Height. Knee Surg Sports Traumatol Arthrosc. 2006;14(8):707-12. doi:10.1007/s00167-005-0015-4 - Pubmed
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2. Ali S, Helmer R, Terk M. Patella Alta: Lack of Correlation Between Patellotrochlear Cartilage Congruence and Commonly Used Patellar Height Ratios. AJR Am J Roentgenol. 2009;193(5):1361-6. doi:10.2214/AJR.09.2729 - Pubmed
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3. Bailey M, Metcalfe A, Hing C, Eldridge J. Consensus Guidelines for Management of Patellofemoral Instability. The Knee. 2021;29:305-12. doi:10.1016/j.knee.2021.02.018 - Pubmed
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