Radiographic patellar height assessment of knee osteoarthritis

Area of Science:

• Orthopedics
• Radiology
• Biomedical Imaging

Background:

• Abnormal patellar height is linked to knee instability and osteoarthritis development.
• Current imaging methods lack standardized protocols for reliable patellar height assessment.
• Limited research exists on patellar height in relation to different knee compartments.

Purpose of the Study:

• To evaluate patellar height using various radiographic measurement methods.
• To compare the correlation and inter-observer reliability of these methods.
• To investigate the association between patellar height measurements and compartmental knee osteoarthritis.

Main Methods:

• Retrospective cross-sectional study of knee X-rays from January 2022 to December 2023.
• Independent evaluation of images by two radiologists.
• Application of Insall-Salvati Index, Modified Insall-Salvati Index, Caton-Deschamps Index, and Blackburne-Peel Index for patellar height assessment.

Main Results:

• 362 subjects included in the analysis.
• Most patellar height measurements were lower in the osteoarthritic group compared to the normal group (P < 0.05).
• Caton-Deschamps Index showed excellent inter-observer reliability (ICC = 85%).
• Strongest correlation observed between Insall-Salvati and Modified Insall-Salvati indices (r = 0.69).

Conclusions:

• Patellar height indices correlate with knee osteoarthritis severity.
• The Caton-Deschamps method offers the highest inter-observer reliability for patellar height assessment.
• Radiographic patellar height measurements can aid in staging knee osteoarthritis severity using the KL grading system.