Prevalence of radiographic and MRI features of patellofemoral osteoarthritis in young and middle-aged adults with persistent patellofemoral pain.

OBJECTIVE: In adults with persistent patellofemoral pain (PFP), (i) describe the prevalence of radiographic features of patellofemoral osteoarthritis (PFOA); (ii) describe the prevalence of magnetic resonance imaging (MRI) PFOA and compare to age- and sex-matched controls; and (iii) explore radiographic and MRI prevalence across age, sex and body mass index (BMI) groups.

METHODS: This cross-sectional study included 84 individuals with PFP ≥3 months duration, and 26 age- and sex-matched controls. PFP participants underwent posteroanterior, lateral and skyline radiographs. Radiographic OA features were scored using Kellgren & Lawrence (KL) criteria and a radiographic atlas, with KL grade ≥2 defined as OA, and KL 1 as early OA. Both groups underwent 3.0 Tesla MRI scans, scored using the MRI Osteoarthritis Knee Score. Compartmental prevalence of MRI OA features was based on cartilage lesions, bone marrow lesions (BMLs) and osteophytes.

RESULTS: 20 (24%) participants with PFP had radiographic PFOA (KL≥2), and 25 (30%) had early PFOA (KL1). MRI PFOA was more prevalent in PFP (16-29%) than controls (4-12%), irrespective of how PFOA was defined. Within the PFP group, the prevalence of PFOA on radiograph and MRI was greater in those of older age, female sex, or with higher BMI.

CONCLUSIONS: Radiographic and MRI PFOA features were evident in 20-30% of adults aged 26-50 years with persistent PFP, with greater prevalence observed in those who were older, female, or with higher BMI. MRI PFOA was more prevalent in individuals with PFP than pain-free controls, especially when defined as a full-thickness cartilage lesion with BML. This article is protected by copyright. All rights reserved.