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

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.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.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.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

Are patellofemoral joint alignment and shape associated with structural magnetic resonance imaging abnormalities and symptoms among people with patellofemoral pain?

Background: Patellofemoral malalignment has been observed among people with patellofemoral pain (PFP) and may be associated with the presence of imaging features of osteoarthritis, symptoms, and function. Purpose: To determine whether patellofemoral joint alignment and bony shape are associated with (1) cartilage, bone, and soft tissue morphological abnormalities defined on magnetic resonance imaging (MRI) and (2) reported symptoms and function among people with PFP. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Participants (mean ± SD age, 30.2 ± 9.5 years; range, 14-50 years; 78 females, 58.6%) completed questionnaires regarding demographics, pain, symptoms, and function and underwent a 3-T MRI scan of their more symptomatic eligible knee. Structural MRI abnormalities were scored with the MOAKS (Magnetic Resonance Imaging Osteoarthritis Knee Score), and MRI alignment and shape were measured with standardized methods. Associations among MOAKS features, PFP symptoms, and alignment and shape measures were evaluated with regression analyses (α =.05). Results: Minor cartilage defects were present in 22 (16.5%) participants, patellar osteophytes in 83 (62.4%), anterior femur osteophytes in 29 (21.8%), Hoffa synovitis in 81 (60.9%), and prefemoral fat pad synovitis in 49 (36.8%). A larger Insall-Salvati ratio was significantly associated with the presence of patellar osteophytes (odds ratio [OR], 51.82; 95% CI, 4.20-640.01), Hoffa synovitis (OR, 60.37; 95% CI, 4.66-782.61), and prefemoral fat pad synovitis (OR, 43.31; 95% CI, 4.28-438.72) in the patellofemoral joint. A larger patellar tilt angle was significantly associated with the presence of minor cartilage defects (OR, 1.10; 95% CI, 1.00-1.20), the presence of patellar osteophytes (OR 1.12; 95%CI 1.02-1.22), and prefemoral fat pad synovitis (OR, 1.11; 95% CI, 1.03-1.20) in the patellofemoral joint. Finally, a larger bisect offset was significantly associated with the presence of minor cartilage defects (OR, 1.05; 95% CI, 1.00-1.11) and patellar osteophytes (OR, 1.07; 95% CI, 1.01-1.14) in the patellofemoral joint. The majority of patellofemoral alignment measures were not associated with symptoms or function. Conclusion: For people with PFP, the presence of morphological abnormalities defined on MRI appears to be related to particular patellofemoral alignment measures, including higher Insall-Salvati ratio (indicating patella alta), larger patellar tilt angle (indicating greater lateral tilt), and larger bisect offset (indicating greater lateral displacement). Hardly any associations were found with symptoms or function. So there might be a distinct subgroup of PFP that is more prone to developing patellofemoral osteoarthritis later in life, as particular alignment measures seem to be associated with the presence of patellar osteophytes. Prospective studies are required to investigate the longitudinal relationship between alignment or bony shape and morphological abnormalities defined on MRI in this patient population

Structural Abnormalities on Magnetic Resonance Imaging in Patients With Patellofemoral Pain

Background: Structural abnormalities of the patellofemoral joint might play a role in the pathogenesis of patellofemoral pain (PFP), a common knee problem among young and physically active individuals. No previous study has investigated if PFP is associated with structural abnormalities of the patellofemoral joint using high-resolution magnetic resonance imaging (MRI). Purpose: To investigate the presence of structural abnormalities of the patellofemoral joint on high-resolution MRI in patients with PFP compared with healthy control subjects. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients with PFP and healthy control subjects between 14 and 40 years of age underwent high-resolution 3-T MRI. All images were scored using the Magnetic Resonance Imaging Osteoarthritis Knee Score with the addition of specific patellofemoral features. Associations between PFP and the presence of structural abnormalities were analyzed using logistic regression analyses adjusted for age, body mass index (BMI), sex, and sports participation. Results: A total of 64 patients and 70 control subjects were included in the study. Mean SD age was 23.2 +/- 6.4 years, mean BMI +/- SD was 22.9 +/- 3.4 kg/m(2), and 56.7% were female. Full-thickness cartilage loss was not present. Minor patellar cartilage defects, patellar bone marrow lesions, and high signal intensity of the Hoffa fat pad were frequently seen in both patients (23%, 53%, and 58%, respectively) and control subjects (21%, 51%, and 51%, respectively). After adjustment for age, BMI, sex, and sports participation, none of the structural abnormalities were statistically significantly associated with PFP. Conclusion: Structural abnormalities of the patellofemoral joint have been hypothesized as a factor in the pathogenesis of PFP, but the study findings suggest that structural abnormalities of the patellofemoral joint on MRI are not associated with PFP