Interaction of Mechanical and Biological Factors in Knee Osteoarthritis

Principal Investigator: Thomas P. Andriacchi, PhD

Objective: This is a study to identify possible mechanisms by which OA develops and progresses by examining the interaction of in vivo functional mechanical and biological factors in patients with medical compartmental knee OA and healthy subjects.

Specific Aims

Aim 1: To determine if a defined walking exercise will lead to temporal increases in serum biomarker concentration

Aim 2: To evaluate the relationship between in vivo load at the major joints of the lower extremity during normal gait and serum biomarker concentration.

Progress during 2006

Work Accomplished

• Recruited and collected data for 53 patients and control subjects
• Processed gait data for 53 patients and control subjects
• Processed MRI data and serum samples for a subset of patients and control subjects
• Submitted two abstracts and one manuscripts on subsets of data

Main Findings

Older adults show changes in serum COMP concentration before and after a walking exercise that is similar to those previously reported for younger adults. Male patients had much higher baseline COMP concentrations than male control subjects and than female patients. Studies show that changes in serum COMP concentration before and after a walking exercise differed between patients with knee OA and control subjects, and regional cartilage variation was related to kinematic and loading characteristics in overweight and obese control subjects.

Plan for Subsequent Years

• Recruit and collect data for 25 patients with knee OA and 5 control subjects
• Process gait data for all 25 patients with knee OA and 5 control subjects
• Process MRI data and serum samples for 60 patients with knee OA and control subjects

Data Analysis

• Quantify changes in serum COMP and MMP concentrations before and after exercise
• Relate changes in serum COMP and MMP concentration before and after exercise to total load at the joints of the lower extremity during normal gait
• Relate cartilage thickness variation to in vivo load at the knee during normal gait
• Determine differences in these relationships between patients with knee OA andcontrol subjects
• Submit two abstracts and two manuscripts on subsets of data

Presentation

Jessica L. DeMarre, Lars Muendermann, Thomas P. Andriacchi, Annegret Muendermann. A mechanism to lower the knee adduction moment during walking: gait retraining as intervention for knee OA, American Society of Biomechanics Meeting, Blacksburg, VA, September 6-9, 2006.

Funding Source: NIH