title: Recreational runners with patellofemoral pain exhibit elevated patella water content.
abstract: Increased bone water content resulting from repetitive patellofemoral joint overloading has been suggested to be a possible mechanism underlying patellofemoral pain (PFP). To date, it remains unknown whether persons with PFP exhibit elevated bone water content. The purpose of this study was to determine whether recreational runners with PFP exhibit elevated patella water content when compared to pain-free controls. Ten female recreational runners with a diagnosis of PFP (22 to 39years of age) and 10 gender, age, weight, height, and activity matched controls underwent chemical-shift-encoded water-fat magnetic resonance imaging (MRI) to quantify patella water content (i.e., water-signal fraction). Differences in bone water content of the total patella, lateral aspect of the patella, and medial aspect of the patella were compared between groups using independent t tests. Compared with the control group, the PFP group demonstrated significantly greater total patella bone water content (15.4±3.5% vs. 10.3±2.1%; P=0.001), lateral patella water content (17.2±4.2% vs. 11.5±2.5%; P=0.002), and medial patella water content (13.2±2.7% vs. 8.4±2.3%; P<0.001). The higher patella water content observed in female runners with PFP is suggestive of venous engorgement and elevated extracellular fluid. In turn, this may lead to an increase in intraosseous pressure and pain.
authors.affiliation: Department of Physical Therapy, University of Nevada, Las Vegas, Las Vegas, NV, USA.
authors.forename: Kai-Yu
authors.initials: KY
authors.lastname: Ho
authors.affiliation: Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA; Department of Radiology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Houchun H
authors.initials: HH
authors.lastname: Hu
authors.affiliation: Department of Radiology, University of Southern California, Los Angeles, CA, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Colletti
authors.affiliation: Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA. Electronic address: powers@usc.edu.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Powers
mesh_terms: D000328:Adult; D001834:Body Water / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D010329:Patella / Q000378:metabolism*; D046788:Patellofemoral Pain Syndrome / Q000378:metabolism*; D011998:Recreation; D015203:Reproducibility of Results; D012420:Running / Q000293:injuries*; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Bone water content; Patella; Patellofemoral pain; Runner