Patellar Morphology and Osteoarthritis: A Cadaveric Analysis

Area of Science:

• Orthopedics
• Anatomy
• Radiology

Background:

• Patellofemoral osteoarthritis is a common condition.
• Previous studies on patellar morphology and osteoarthritis used small sample sizes.
• Characterizing patellar morphology is crucial for understanding osteoarthritis development.

Purpose of the Study:

• To investigate the relationship between patellar morphology and patellofemoral osteoarthritis in a large cadaveric cohort.
• To evaluate the reliability and validity of two methods for grading patellar morphology: Wiberg classification and lateral-to-medial facet ratio.

Main Methods:

• Analyzed 1,032 cadaveric patellae.
• Characterized morphology using Wiberg's concavity patterns and lateral-to-medial facet ratio.
• Graded osteoarthritis based on osteophytic burden.
• Performed regression analysis to assess associations.

Main Results:

• Wiberg type II showed a correlation with patellofemoral arthritis (p=0.003).
• Wiberg system demonstrated poor intra- and inter-rater reliability (kappa values 0.43 and 0.27).
• Lateral-to-medial facet ratio had high reliability (ICC 0.91 and 0.85) but no association with osteoarthritis.

Conclusions:

• No patellar morphology grading system was found to be both reliable and valid for association with patellofemoral osteoarthritis in this study.
• The Wiberg system's clinical utility is questionable due to poor reproducibility and unexpected correlations.
• The lateral-to-medial facet ratio, while reliable, does not appear to be a valid indicator of osteoarthritis.