Responsiveness of Subcutaneous Fat, Intermuscular Fat, and Muscle Anatomical Cross-Sectional Area of the Thigh to Longitudinal Body Weight Loss and Gain: Data from the Osteoarthritis Initiative (OAI).

Thigh subcutaneous (SCF) and intermuscular (IMF) fat have been associated with joint health and function. Here, we explore the (sex-specific) responsiveness of SCF, IMF, and muscle during longitudinal weight loss and gain, as well as the change in questionnaire-based and physical performance-based knee function measures. This exploratory study included 103 Osteoarthritis Initiative (OAI) participants, who displayed a ≥10% weight loss or gain between baseline (BL) and 2-year (Y2) follow-up (and maintained half of that weight loss until year 4) and had axial 3T magnetic resonance images (MRI) for measuring SCF, IMF, and muscle cross sectional areas (CSAs).

Responsiveness of Infrapatellar Fat Pad Volume Change to Body Weight Loss or Gain: Data from the Osteoarthritis Initiative.

Obesity is a potent risk factor for knee osteoarthritis (OA) that is driven by mechanical and potentially endocrine mechanisms, and it affects women more frequently than men. The infrapatellar fat pat (IPFP) represents a potential link between obesity, intra-articular inflammation and structural pathology. Here we investigate whether the IPFP is responsive to body weight loss/gain in women and how its responsiveness to weight change compares to that of subcutaneous fat (SCF) of the thigh.

Variance in infra-patellar fat pad volume: Does the body mass index matter?-Data from osteoarthritis initiative participants without symptoms or signs of knee disease.

The infra-patellar fat pad (IPFP) has been proposed to represent an endocrine link between obesity and knee osteoarthritis (OA). The purpose of the current study has been to explore the extent to which IPFP volume is related to body mass index (BMI). A total of 152 participants (age 56±7 years) without knee OA were studied.

Validation of an active shape model-based semi-automated segmentation algorithm for the analysis of thigh muscle and adipose tissue cross-sectional areas.

Objective: To validate a semi-automated method for thigh muscle and adipose tissue cross-sectional area (CSA) segmentation from MRI.

Materials And Methods: An active shape model (ASM) was trained using 113 MRI CSAs from the Osteoarthritis Initiative (OAI) and combined with an active contour model and thresholding-based post-processing steps. This method was applied to 20 other MRIs from the OAI and to baseline and follow-up MRIs from a 12-week lower-limb strengthening or endurance training intervention (n = 35 females).

Thigh Muscle Specific-Strength and the Risk of Incident Knee Osteoarthritis: The Influence of Sex and Greater Body Mass Index.

Objective: To determine whether lower thigh muscle specific-strength increases the risk of incident radiographic knee osteoarthritis (RKOA), and whether there exists a sex-specific relationship between thigh muscle specific-strength and body mass index (BMI).

Methods: A total of 161 Osteoarthritis Initiative participants (62% female) with incident RKOA (Kellgren/Lawrence grade 0/1 at baseline, developing an osteophyte and joint space narrowing grade ≥1 by year 4) were matched to 186 controls (58% female) without incident RKOA. Thigh muscle anatomical cross-sectional areas (ACSAs) were determined at baseline using axial magnetic resonance imaging scans.

Quantitative relationship of thigh adipose tissue with pain, radiographic status, and progression of knee osteoarthritis: longitudinal findings from the osteoarthritis initiative.

Objective: The aim of this study was to explore the relationship of thigh subcutaneous fat (SCF) and intermuscular fat (IMF) content with knee osteoarthritis (KOA) cross-sectionally and longitudinally, using quantitative magnetic resonance imaging. Specifically, we examined relationships with frequent knee pain, various radiographic strata, and structural progression status of KOA.

Materials And Methods: Subjects who showed between-knee discordance of frequent versus no pain (n = 48), osteophyte versus no radiographic KOA (n = 55), and radiographic joint space narrowing versus no joint space narrowing (n = 44) were selected from the Osteoarthritis Initiative.

Longitudinal sensitivity to change of MRI-based muscle cross-sectional area versus isometric strength analysis in osteoarthritic knees with and without structural progression: pilot data from the Osteoarthritis Initiative.

Object: Biomechanical measurement of muscle strength represents established technology in evaluating limb function. Yet, analysis of longitudinal change suffers from relatively large between-measurement variability. Here, we determine the sensitivity to change of magnetic resonance imaging (MRI)-based measurement of thigh muscle anatomical cross sectional areas (ACSAs) versus isometric strength in limbs with and without structural progressive knee osteoarthritis (KOA), with focus on the quadriceps.

Thigh muscle cross-sectional areas and strength in advanced versus early painful osteoarthritis: an exploratory between-knee, within-person comparison in osteoarthritis initiative participants.

Objective: To compare cross-sectional and longitudinal side differences in thigh muscle anatomic cross-sectional areas (ACSAs), strength, and specific strength (strength/ACSA) between knees with early versus advanced painful radiographic osteoarthritis in the same person.

Methods: Forty-four of 2,678 Osteoarthritis Initiative participants (31 women and 13 men) met the inclusion criteria of bilateral frequent knee pain, medial joint space narrowing (JSN) in 1 knee, and no medial (or lateral) JSN in the contralateral knee. Thigh muscle ACSAs of the quadriceps, hamstrings, adductors, and individual quadriceps heads at consistent locations were determined using magnetic resonance imaging.