Effects of weight bearing rehabilitation after microfracture surgery studied
12:34 p.m., Feb. 25, 2013--In the body, bones are padded with a smooth cartilage layer at the ends, allowing smooth motion where two bones meet and form a joint. When cartilage around the bone becomes degenerated or lost due to osteoarthritis or traumatic injury, however, joint mobility decreases and can become painful.
Young athletes suffering from trauma induced cartilage loss are typically treated with microfracture surgery, a minimally invasive procedure that creates tiny punctures in the bone to stimulate bone marrow to the damaged area and the creation of new articular cartilage by the stem cells in bone marrow.
Diamond in the rough
After surgery, rehabilitation therapy is a crucial component of patient outcomes. Traditional physical therapy procedures, however, limit weight bearing for the first eight weeks, particularly the application of weight to the joint.
X. Lucas Lu, assistant professor in the University of Delaware’s Department of Mechanical Engineering, is principal investigator of a new grant investigating whether weight bearing during microfracture rehabilitation will enhance the deposition and quality of newly repaired tissue at the injury site. Lynn Snyder-Mackler, Alumni Distinguished Professor in the Department of Physical Therapy, is a co-investigator on the project.
The project is funded through a $96,276 Junior Investigator Grant from the Musculoskeletal Transplant Foundation.
Under the grant, Lu and Snyder-Mackler will develop a unique bioreactor system to simulate micro-fracture surgery in the laboratory. Using a novel mechanical loading device, they will subject 3D organic cartilage-bone replicas to weights resembling those applied shortly after surgery. Lu will measure and compare the longitudinal changes in the biomechanical and biochemical properties of the repaired tissue generated by the stem cells.
“If successful, the system could provide a low-cost, yet powerful tool to study the repair mechanisms of microfracture surgery,” said Lu.
In particular, it could provide new details on:
- The interaction between bone marrow and surrounding cartilage;
- The role of controlled-release of growth factors in the development of cartilage; and
- The effects of different rehabilitative treatment protocols on cartilage recovery.
“This system has the potential to fill a critical gap in knowledge regarding cartilage lesion repair in microfracture surgery and to further improve the design of rehabilitation protocols,” remarked Suresh G. Advani, George W. Laird Professor and chair of the Department of Mechanical Engineering.
About the professors
X. Lucas Lu joined the UD faculty in 2010 as an assistant professor in mechanical engineering. Lu’s research at UD focuses on soft tissue biomechanics, joint lubrication, osteoarthritis prevention and the involvement of bone marrow in cartilage repair. He holds joint appointments with the Center for Biomedical Engineering Research and the Biomechanics and Movement Science Program (BIOMS).
Lynn Snyder-Mackler, Alumni Distinguished Professor in the Department of Physical Therapy, joined the UD faculty in 1989. Known for her expertise and research of sports related knee and shoulder injuries, she has extensive experience in post-surgery knee rehabilitation, with over 100 published peer-reviewed papers in related areas. In 2012, the National Institutes of Health honored Snyder-Mackler with the MERIT award for research on the rehabilitation of knee injuries.
Article by Sarah E. Meadows
Photo by Kathy F. Atkinson