Data used in the preparation of this article were obtained from the Osteoarthritis Initiative (OAI) database, which is available for public access at http://www.oai.ucsf.edu/ . Specific OAI datasets used were baseline clinical dataset 0.2.2, baseline imaging datasets 0.E.1 and 0.C.2, 24 month follow-up clinical dataset 3.2.1, and 24 month follow-up imaging datasets 3.E.1 and 3.C.2.
We studied the right knees of 142 subjects selected from the OAI incidence and normal control subcohorts. Subjects in the normal control subcohort had no radiographic findings of OA (defined as a definite tibiofemoral osteophyte) in either knee at baseline and had no OA risk factors at baseline. Subjects in the incidence subcohort did not have symptomatic knee OA, defined as frequent symptoms and radiographic OA in the same knee, in either knee at baseline, but had at least one of the following OA risk factors at baseline: knee symptoms (“pain, aching, or stiffness in or around the knee” in the past 12 months), overweight or obesity, history of knee injury, history of knee surgery, family history of total knee replacement or Heberden nodes.
Specific inclusion criteria for the subjects from both subcohorts for this study were: 45-55 years of age, body mass index (BMI) of 19-27kg/m2, Western Ontario and McMaster University (WOMAC) pain score of zero in both knees at baseline, and Kellgren-Lawrence (KL) score ≤1 (based on an additional reading done for the present study) in the right knee at baseline. In addition, baseline and 24 month follow-up right knee MR images had to be available and useable. These specific inclusion criteria were applied to exclude obesity as an OA risk factor and to focus on younger, relatively asymptomatic subjects. Based on these criteria, 101 subjects with OA risk factors (50 males, 51 females) and 41 subjects without OA risk factors (15 males, 26 females) were eligible and included in the study.
The study protocol, amendments and informed consent documentation were reviewed and approved by the local institutional review boards.
We studied the right knees of 142 subjects selected from the OAI incidence and normal control subcohorts. Subjects in the normal control subcohort had no radiographic findings of OA (defined as a definite tibiofemoral osteophyte) in either knee at baseline and had no OA risk factors at baseline. Subjects in the incidence subcohort did not have symptomatic knee OA, defined as frequent symptoms and radiographic OA in the same knee, in either knee at baseline, but had at least one of the following OA risk factors at baseline: knee symptoms (“pain, aching, or stiffness in or around the knee” in the past 12 months), overweight or obesity, history of knee injury, history of knee surgery, family history of total knee replacement or Heberden nodes.
Specific inclusion criteria for the subjects from both subcohorts for this study were: 45-55 years of age, body mass index (BMI) of 19-27kg/m2, Western Ontario and McMaster University (WOMAC) pain score of zero in both knees at baseline, and Kellgren-Lawrence (KL) score ≤1 (based on an additional reading done for the present study) in the right knee at baseline. In addition, baseline and 24 month follow-up right knee MR images had to be available and useable. These specific inclusion criteria were applied to exclude obesity as an OA risk factor and to focus on younger, relatively asymptomatic subjects. Based on these criteria, 101 subjects with OA risk factors (50 males, 51 females) and 41 subjects without OA risk factors (15 males, 26 females) were eligible and included in the study.
The study protocol, amendments and informed consent documentation were reviewed and approved by the local institutional review boards.
