2023 ISAKOS Biennial Congress ePoster
Magnetic Resonance Imaging Overestimates Patellar Height Compared With Radiographs
Juan Pablo Martinez-Cano, MD, MSc, PhD, Cali, Valle del Cauca COLOMBIA
Riccardo Gomes Gobbi, MD, PhD, São Paulo, SP BRAZIL
Pedro N. Giglio, MD, São Paulo, SP BRAZIL
Elizabeth A. Arendt, MD, Minneapolis, MN UNITED STATES
Giovanna Babikian Costa, MD, São Paulo, SP BRAZIL
Betina B. Hinckel, MD, PhD, Troy, MI UNITED STATES
Fundación Valle del Lili, Cali, Valle, COLOMBIA
FDA Status Not Applicable
Summary
MRI can overestimate patellar height compared to CR, it is recommended to use the CR as the preferred method when measuring patellar height.
ePosters will be available shortly before Congress
Abstract
Purpose
To evaluate the inter-observer and inter-method reliability for patellar height
measurements between conventional radiographs (CR) and magnetic resonance
imaging (MRI) using 1 or 2-slices.
Methods
Reliability study; with 60 patients divided in two groups: 30 patients with
patellar instability (patella group) and 30 patients with anterior cruciate ligament or
meniscus injury (control group). CR and MRI were evaluated by two independent
observers. Insall-Salvati index (IS) and Caton-Deschamps index (CD) were measured
using three different methods: CR, 1-slice MRI or 2-slices MRI. Intra-class correlation
coefficients (ICC) were calculated for inter-observer reliability and inter-method
reliability. Bland-Altman agreement was also calculated.
Results
The inter-observer reliability was very good for the IS with ICCs of 0.93, 0.84
and 0.82, for the CR, 1-slice MRI and 2-slices MRI, respectively. Similarly, for the CD
the ICCs were good, 0.76, 0.80 and 0.75 for the CR, 1-slice MRI and 2-slices MRI,
respectively. No differences were found between the patella and the control group. The
inter-method analysis results were: ICCs for IS (0.83, 0.86, 0.93) and CD (0.72, 0.82,
0.83), for the comparisons of CR/1-slice MR, CR/2-slices MRI and 1-slice MRI/ 2-slices
MRI, respectively. The Bland-Altman mean differences showed an 8% and a 7%
increase on IS values with 1-slice MRI and 2-slices MRI compared to CR results, while
the increase was of 9% and 1% in CD for the respective comparisons with CR.
Conclusion
MRI can overestimate patellar height compared to CR, as much as an 8%
increase in Insall-Salvati values when using 1 or 2-slices MRI measurements, and up to
a 9% increase in Caton-Deschamps value when using the 1-slice MRI method. It is
recommended to use the CR as the preferred method when measuring patellar height.