Open Access Research article

Association between obesity and magnetic resonance imaging defined patellar tendinopathy in community-based adults: a cross-sectional study

Jessica Fairley1, Jason Toppi1, Flavia M Cicuttini1, Anita E Wluka1, Graham G Giles123, Jill Cook4, Richard O’Sullivan56 and Yuanyuan Wang1*

Author Affiliations

1 School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Melbourne VIC 3004, Australia

2 Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Carlton VIC 3053, Australia

3 Cancer Epidemiology Centre, Cancer Council Victoria, Carlton VIC 3053, Australia

4 Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Frankston VIC 3199, Australia

5 Healthcare Imaging Services, MRI Department, Epworth Hospital, Richmond VIC 3131, Australia

6 Department of Medicine, Central Clinical School, Monash University, Melbourne, Australia

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BMC Musculoskeletal Disorders 2014, 15:266  doi:10.1186/1471-2474-15-266

Published: 7 August 2014

Abstract

Background

Patellar tendinopathy is a common cause of activity-related anterior knee pain. Evidence is conflicting as to whether obesity is a risk factor for this condition. The aim of this study was to determine the relationship between obesity and prevalence of magnetic resonance imaging (MRI) defined patellar tendinopathy in community-based adults.

Methods

297 participants aged 50–79 years with no history of knee pain or injury were recruited from an existing community-based cohort. Measures of obesity included measured weight and body mass index (BMI), self-reported weight at age of 18–21 years and heaviest lifetime weight. Fat-free mass and fat mass were measured using bioelectrical impedance. Participants underwent MRI of the dominant knee. Patellar tendinopathy was defined on both T1- and T2-weighted images.

Results

The prevalence of MRI defined patellar tendinopathy was 28.3%. Current weight (OR per kg = 1.04, 95% CI 1.01-1.06, P = 0.002), BMI (OR per kg/m2 = 1.10, 95% CI 1.04-1.17, P = 0.002), heaviest lifetime weight (OR per kg = 1.03, 95% CI 1.01-1.05, P = 0.007) and weight at age of 18–21 years (OR per kg = 1.03, 95% CI 1.00-1.07, P = 0.05) were all positively associated with the prevalence of patellar tendinopathy. Neither fat mass nor fat-free mass was associated with patellar tendinopathy.

Conclusion

MRI defined patellar tendinopathy is common in community-based adults and is associated with current and past history of obesity assessed by BMI or body weight, but not fat mass. The findings suggest a mechanical pathogenesis of patellar tendinopathy and patellar tendinopathy may be one mechanism for obesity related anterior knee pain.

Keywords:
Obesity; Patellar tendinopathy; Body mass index; Weight; Fat mass; Magnetic resonance imaging