Disclosures: Neil A. Segal, MD, MS: Flesion Therapeutics (Products/Services: No) (Research Grant or Support)Pacira (Products/Services: No) (Research Grant or Support)

Objective: The patellofemoral joint is frequently affected by osteoarthritis (PFOA) and is incompletely imaged on radiographs. Weight-Bearing CT (WBCT) could offer advantages for visualization. This study determined the sensitivity, specificity, and accuracy of WBCT and radiographs (XR) for detection of PFOA features in comparison with cartilage damage on MRI.

Design: Prospective Cohort StudySetting : Ancillary study to the Multicenter Osteoarthritis Study (MOST) at University of Iowa siteParticipants : 60 right knees of older adults from Existing and New MOST Cohort who had fixed-flexion radiographs (AP/lateral), WBCT, and 1.5T MRI at 144 month visit were randomly selected for analysis.

Interventions: N/A

Main Outcome Measures: WBCT and radiographs were read for OARSI JSN score and MRI was read for MOAKS cartilage score by two experienced musculoskeletal radiologists blinded to subject. Using MOAKS scoring on MRI (referent standard), the sensitivity, specificity and accuracy of patellofemoral OARSI JSN scores based on WBCT and XR were compared.

Results: The mean±SD age and BMI for the 60 participants included (66.7% women) were 67.6±9.8 years and 30.0±5.3 kg/m2 respectively. WBCT demonstrated significantly greater sensitivity (.85–.97 on WBCT vs. .47–.57 on XR) and accuracy (.85–.92 on WBCT vs. .48–.57 on XR) for all parameters except lateral full-thickness cartilage loss (McNemar’s test p-values all < 0.001). There was fair-to-moderate and none-to-slight agreement between PFOA findings on WBCT and XR, respectively, and semi-quantitative scores of PF cartilage on MRI. Inter-rater reliability for XR JSN [kappa=0.83 (0.64, 1.0)], WBCT JSW [kappa=0.60 (0.48, 0.72)] and MRI MOAKS-CM [kappa=0.70 (0.61, 0.79)] readings were good.Conclusions: WBCT demonstrates significantly greater sensitivity and accuracy than radiographs for identification of PFOA features. Given the same Relative Radiation Level as XR and improved visualization, WBCT holds promise to improve understanding of the weight-bearing patellofemoral joint.

Level of Evidence: Level II

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/clinical-value-of-weight-bearing-ct-and-radiographs-for-detecting-patellofemoral-cartilage-damage-visualized-by-mri-in-the-most-study/