Osteoarthritis Studies

Current Projects | Completed Projects

Current Projects

Pilot Study of Strength and Gait Training for Older Adults with Knee Osteoarthritis and Varus Malalignment

This pilot study is testing a novel intervention of tailored strength training and gait retraining among older adults with knee osteoarthritis (OA) and varus malalignment (i.e., "bow-legs"). Specific aims are to: 1.) assess the feasibility of the intervention, 2.) collect data to inform sample size estimates for a larger study, 3.) measure the sensitivity of specific biomarkers in this context and select those most appropriate for a larger study. Participants will include 15 adults age 65 years and younger with medial compartment knee OA and varus malalignment (>5°), recruited from Duke University Medical Center. A clinical assessment will be used as a preliminary determination of varus malalignment, and digital postero-anerior knee radiographs will assess the degree of malalignment, as well as radiographic OA severity. All participants will be involved in a 12-week intervention, consisting of eight individual visits with a physical therapist. The physical therapist will instruct participants in strength training exercises tailored for knee OA and varus malalignment, and participants will be asked to perform these exercises at home, three times weekly. The physical therapist will also instruct participants in a newly developed "medial thrust gait" pattern, which helps to decrease adduction moments during walking and therefore off-loads the medial portion of the knee, which is typically over-loaded among individuals with varus malalignment. This gait pattern involves bringing the knees closer to the midline of the body during stance phase. The primary outcome will be peak knee adduction moment during gait (normal walking speed), assessed via an eight camera real-time motion capture system and force plates. Secondary outcomes will include the Western Ontario and McMaster Universities Osteoarthritis Index (measuring lower extremity pain, stiffness, and function), the Short Physical Performance Test Protocol (a battery of five functional tests), and serum biomarkers (before and after acute exercise), including serum cartilage oligomeric matrix protein, hyaluronan, C-reactive protein, matrix metalloproteinase-3, and C2C. Statistical analyses will focus on comparison of pre- and post-intervention values for primary and secondary outcomes.

Current Status:

Data collection began in January 2009

Biomechanics and Inflammation in Osteoarthritis

Osteoarthritis (OA) is one of the most prevalent rheumatic diseases, with OA of the knee affecting over 10% of adults age 55 and older. Consequently, there is a great need for methods for treatment of the disease as well as understanding its progression. This project is a longitudinal clinical study to develop more effective exercise and weight-loss therapies to reduce the pain, physical disability, and psychological distress experienced by overweight patients with persistent osteoarthritic knee pain.

We will study 280 patients over four years. Subjects are currently being recruited and each year groups of 70 patients will be organized into those receiving normal care, those receiving weight management procedures, those receiving behavioral therapy, and those receiving a combination of weight management and therapy. Initial baseline data will be collected before treatment and then gait data will be collected immediately after the 24-week treatment phase and then at 6 and 12 months following treatment.

We expect that all of our subjects will initially exhibit differences in gait; we intend to explore these differences in two ways. First, we will explore changes in walking speed associated with different treatments and see how stride length, frequency, knee ROM, and forces increase with speed for the different treatment classes. Second we will compare stride length, stride frequency, knee ROM, peak forces, loading rates, and bending moments at comparable (size-adjusted) speeds across different treatment classes.

Current Status:

Data collection has been completed for cohorts 1, 2, 3 and 4.

Abstracts:

Ershela L. Sims, Mary Beth Nebel, Virginia B. Kraus, Francis J. Keefe, Jennifer Pells, Farshid Guilak, Jessica Tischner, Daniel Schmitt. Gait Mechanics of Knee Osteoarthritis. Biomedical Engineering Society Annual Meeting, Chicago 2006, IL.

Ershela L. Sims, Mary Beth Nebel, Francis J. Keefe, Jennifer Pells, Jessica Tischner, Virginia B. Kraus, Farshid Guilak, Daniel Schmitt. Severity of Knee Osteoarthritis and its Effect on Gait Mechanics in Walking. American Society of Biomechanics Annual Meeting 2006, Blacksburg, VA.

Jennifer Pells, Kim Dixon, James Blumenthal, Jessica Tucker, David Caldwell, Virginia Kraus, Daniel Schmitt, Ershela Sims, and Francis Keefe. Self-efficacy for pain and weight management among overweight patients with osteoarthritis: Relationship to pain, physical disability, and psychological distress. American Pain Society Annual Scientific Meeting 2006. San Antonio, TX.

Articles:

A manuscript on the baseline gait data for cohorts 1-6 is currently being prepared. It will be submitted in the near future.

T J Somers, F J Keefe, J J Pells, K E Dixon, S Waters, P Riordan, J A Blumenthal, D McKee, L LaCaille, J M Tucker, D Schmitt, D S Caldwell, V B Kraus, E L Sims, R A Shelby, J R Rice. Pain Catastrophizing and Pain-Related Fear in Overweight and Obese Osteoarthritis Patients: Relationships to Pain and Disability J. Pain and Symptom Management (In Press)

Completed Projects

The Relationship between Self-reported Disability and Gait Parameters in Osteoarthritis

Osteoarthritis (OA) affects more than 20 million Americans. While a growing body of clinical evidence suggests that pain and other psychosocial factors modulate OA treatment efficacy, the mechanisms through which these factors influence joint function in obese OA patients have not been fully explored. The impact of self-assessed severity of pain and ability to function on gait mechanics was investigated in 181 obese patients with knee OA of varying radiographic degree. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) VA3.1 was used to characterize pain intensity, stiffness, and level of physical function while the Arthritis Impact Measurement Scales (AIMS) were used to determine physical, emotional, and social well-being. OA severity was characterized through Kellgren-Lawrence (K/L) grading. 3-D kinematic data were collected using a motion capture system. Subjects performed five walking trials at two, self-selected speeds, normal and fast. Correlation between WOMAC scores, AIMS scores, BMI, K/L grade, and gait variables were evaluated using Pearson’s correlation coefficient (r). Regression analysis was used to determine the contributions of WOMAC, AIMS, BMI, and K/L grade to variations in gait. These analyses were performed at both speeds. BMI was inversely correlated with walking velocity, stride length, peak vertical force (PVF), and knee range of motion (KROM) at both speeds and with support time at the normal speed. Physical disability as measured by the AIMS was correlated with walking velocity and stride length at the normal speed, but was inversely correlated with these two variables and KROM at the fast speed. Similarly, WOMAC function score was correlated with stride length at the normal speed, but was inversely correlated with velocity, stride length, and stride frequency at the fast speed. WOMAC pain score was also inversely correlated with walking velocity at the fast speed. K/L grades were inversely correlated with velocity, PVF, and KROM at both fast and normal speeds, and with stride length at the normal speed. Regression analysis revealed that BMI and AIMS physical disability scores were the greatest contributors to variation in walking velocity, stride length, KROM, and PVF at both speeds. For each of these variables, AIMS physical disability was a greater contributor to variance at the fast speed than at the normal speed and was the greatest overall contributor to variance at fast speed, suggesting that altered gait patterns may be more strongly influenced by perceived degree of disability than by the radiographic presence of knee OA, and that this influence increases with task difficulty. In this light, it appears crucial to address perception of physical disability when designing osteoarthritis intervention strategies.

Current Status:

Abstracts:

Mary Beth Nebel, Ershela L. Sims, Virginia B. Kraus, Jennifer Pells, Jessica Tischner, Farshid Guilak, Francis J. Keefe,and Daniel Schmitt. Influence of Psychosocial Parameters on Altered Gait Mechanics Associated with Osteoarthritis and Obesity. American Society of Biomechanics South East Regional Conference 2007. Durham, NC.

Articles:

Manuscript is currently under review at Osteoarthritis & Cartilage.

Racial Differences in Pain, Physical Function, and Gait Mechanics Associated with Knee Osteoarthritis

This study sought to determine the relationship between race and certain psychosocial variables as well as gait mechanics in obese patients with knee osteoarthritis of varying radiographic degree. We hypothesized that black patients experience higher levels of OA, higher perceived pain, lower levels of positive feelings about their disease, and altered gait mechanics compared to white patients. These relationships were determined by examining the impact of race on arthritis self efficacy, perceived pain, psychological, and physical disability, as well as kinematic and kinetic gait variables in a cohort of 175 subjects with knee OA.

Current Status:

Abstracts:

Ershela L. Sims, Francis J. Keefe, Virginia B. Kraus, Farshid Guilak, and Daniel Schmitt. Racial Differences in Pain, Physical Function, and Gait Mechanics Associated with Knee Osteoarthritis. Osteoarthritis and Cartilage. Volume 15 Supplement C: 2007.

Articles:

Manuscript is in review at Ethnicity & Disease.

Biomechanical Perspectives on Gender Differences in Knee Osteoarthritis

Osteoarthritis of the knee is seen more frequently in females than males. It has been determined that gender differences in gait biomechanics exist, however the origin of these differences is not fully understood. The purpose of this study was to examine the influence of anthropometrics, radiographic disease severity (rOA), and self-report measures of pain and disability on gender differences in gait mechanics in patients with knee osteoarthritis. Outcome measures including velocity, stride length, stride frequency, support time, knee angle, and vertical ground reactions forces were determined from 3-D kinematic and kinetic data collected on 26 male and 30 female subjects walking at self-selected normal and fast velocities. Anthropometric data, rOA, and self-report measures of pain and disability were also collected. Although male and female participants did not differ significantly in rOA, women were younger and had a lower BMI than men. Females walked with a significantly higher stride frequency although they essentially walked at the same speed as the males. However, when asked to walk fast, the significant difference in stride frequency was not present. Within female subjects variations in gait mechanics were primarily explained by weight, BMI and self-reported physical disability. In males, variations in gait mechanics were primarily explained by pain and self-reported physical disability.

Current Status:

Ershela L Sims, Julie M. Carland, Francis J. Keefe, Virginia B. Kraus, Farshid Guilak, and Daniel Schmitt. Biomechanical gender differences in knee osteoarthritis. Journal of Women & Aging. (In Press)