Caton-Deschamps index (knee)
Citation, DOI, disclosures and article data
At the time the article was created Juan Delgado had no recorded disclosures.View Juan Delgado's current disclosures
At the time the article was last revised Henry Knipe had the following disclosures:
- Radiopaedia Events Pty Ltd, Speaker fees (past)
- Integral Diagnostics, Shareholder (ongoing)
- Micro-X Ltd, Shareholder (ongoing)
These were assessed during peer review and were determined to not be relevant to the changes that were made.View Henry Knipe's current disclosures
The Caton-Deschamps index is used to measure patellar height and identify patella alta and patella baja. The Caton-Deschamps index relies upon the length of the patellar articular surface and its distance from the tibia, reducing erroneous measurements in those with long patella bodies, as measured in the Insall-Salvati ratio.
The Caton-Deschamps index can be measured on a lateral radiograph or sagittal knee CT or MRI. For measurement, it is considered ideal that the knee is flexed at an angle of 30º, although for the original study by Caton-Deschamps the flexion angles were between 20º and 80º.
- A: distance between the anterior angle of the tibial plateau, to the most inferior aspect of the patellar articular surface
- B: patellar articular surface length
Caton-Deschamps index = A / B
- normal range: 0.6-1.3
- patella alta: >1.3
- patella baja: <0.6
The Caton-Deschamps ratio can also be applied to children, but age correction should be applied because patellar ossification begins at its proximal side 1.
- 1. Thévenin-Lemoine C, Ferrand M, Courvoisier A, Damsin J-P, Pointe HD le, Vialle R. Is the Caton-Deschamps Index a Valuable Ratio to Investigate Patellar Height in Children? J Bone Joint Surg Am. 2011 Apr 20;93(8):e35.
- 2. Seil R, Müller B, Georg T, Kohn D, Rupp S. Reliability and interobserver variability in radiological patellar height ratios. Knee Surg Sports Traumatol Arthrosc. 2000;8(4):231–6.
- 3. van Duijvenbode D, Stavenuiter M, Burger B, van Dijke C, Spermon J, Hoozemans M. The reliability of four widely used patellar height ratios. Int Orthop. 2016 Mar;40(3):493–7.
- 4. Munch JL, Sullivan JP, Nguyen JT, Mintz D, Green DW, Shubin Stein BE, et al. Patellar Articular Overlap on MRI Is a Simple Alternative to Conventional Measurements of Patellar Height. Orthop J Sports Med. 2016 Jul;4(7):2325967116656328.
- 5. Narkbunnam R, Chareancholvanich K. Effect of patient position on measurement of patellar height ratio. Arch Orthop Trauma Surg. 2015 Aug;135(8):1151–6.