The ties between the College of Engineering and  Weill Cornell Medical College in New York City have  been close since the late 1970s, when Sibley School  of Mechanical and Aerospace Engineering Professor  Donald Bartel began work with biomechanical  engineers at the Hospital for Special Surgery, the  orthopedic affiliate of Weill Cornell.

Bartel analyzes and designs bone-implant systems,  including replacements of joints that have been damaged by osteoarthritis or rheumatoid arthritis.

“The design of joint replacements involves both  structure and function,” Bartel says. “The components  have to remain securely attached to the bone, and the  wear between the artificial articulating surfaces, which  often consist of a polished metal rubbing against ultrahigh  molecular weight polyethylene, must be minimized.  Functionally, the joint has to provide normal motions  and transmit normal loads.”

Bartel is a co-inventor on patents for hip and  knee prostheses, and he is currently researching  replacements for the shoulder and elbow. He also is  extending his work to evaluate the relative influence of  prosthesis design variables and patient and surgical  variables on bone-implant system performance.

Bartel’s research is a collaborative effort between  the Sibley School and the Biomechanics Department  of the Hospital for Special Surgery, where he has a dual  appointment as a senior scientist.

To date, manufactured joints have not solved the  problem of wear. Whenever artificial joints rub together,  the friction creates microscopic particulate debris.  Biomedical Engineering Professor Larry Bonassar,  who has a joint appointment in Mechanical and  Aerospace Engineering, is addressing this issue by  attempting to grow bone, tendon, cartilage, and  ligament tissues. His ultimate aim: to create implants  that have the complicated contours of originals and the  potential to renew and remodel themselves, just like  original parts.

“We’ve developed methods based on traditional  materials processing that are analogous to injection  molding and sintering (fusing), but which enable living  cells to survive,” Bonassar says. “I believe we are the  only group taking this approach. And we’re on the  leading edge in developing analytical techniques to  devise biodegradable scaffolds that will support the  shape of new tissues and then be absorbed into the  body.” 

Bonassar is working with Professor Abe Stroock  in Chemical and Biomolecular Engineering on artificial  vasculature to support these new biomaterials.

Professor Marjolein van der Meulen, another Cornell  biomechanical engineer in Mechanical and Aerospace  Engineering, is an expert on the structure and strength  of long bones—the femur and tibia—and vertebral  bones. With colleagues at the Hospital for Special  Surgery, she aims to regenerate bone tissue that has  been lost to osteoporosis or other disease.

“We are interested in the role that mechanical  stimuli play in regulating bone mass,” says van der  Meulen. “In particular, we have been developing  approaches to apply dynamic mechanical loads to  the skeleton, with the intent of inhibiting and ultimately  treating bone loss in skeletal diseases such as  osteoporosis.”

Mechanical and Aerospace Engineering Professor  Francisco Valero-Cuevas combines mechanics,  mathematics, and neurophysiology to understand  neuromuscular function.

“Anatomists have studied the hand for thousands  of years, but we know precious little about how the  hand works. We know even less about how to restore  hand function, in a biomechanically optimal way, after  disease or injury,” says Valero-Cuevas, director of the  Neuromuscular Biomechanics Laboratory.

Through collaborations with neuroscientists,  computer scientists, clinicians, and Cornell’s program  in nonlinear systems, Valero-Cuevas seeks to  understand how the musculoskeletal and nervous  systems complement each other to produce  mechanical function.