New implantable shock absorber relieves pain, delays knee replacement in osteoarthritis patients

USA: Knee pain is a chronic condition that affects approximately 14 million Americans of all ages. Total knee replacement is the last remedy if physical therapy, over-the-counter pain medication and injections don't relieve the pain.

Researchers at The Ohio State University Wexner Medical Center, have found in a recent study that  a new implantable shock absorber can relieve pain and improve function in patients with knee pain commonly caused by osteoarthritis.

Results from a multi-center clinical trial, presented today at an orthopedic symposium in Boston, show a new implantable shock absorber can relieve pain and improve function. Dr. David Flanigan, an orthopedic surgeon at The Ohio State University Wexner Medical Center, enrolled patients in the trial at the medical center and was the first in the U.S. to implant the MISHA Knee System made by Moximed.

"There really hasn't been much to offer for knee arthritis between the more basic options like medications, therapy, and injections all the way to joint replacement," said Flanigan, who is also a professor of orthopedics at the Ohio State College of Medicine"This shock absorber could be in-between step patients need."

The device involves a piston that anchors to the inner side of the femur and tibia bones with a small plate. Trial data showed a significant reduction in pain scores and improvement in function scores for more than 90% of the 81 trial participants. The shock absorber had a success rate of 86% compared to the most common procedure, high tibial osteotomy, which has a success rate of 66% and is typically used to treat symptomatic osteoarthritis of the medial compartment of the knee.

"When you're walking, doing activities, it's going to take away about 30% of that shock or stress on the knee every time you put weight on your leg," said Flanigan. "You see patients who are struggling just to walk and have pain on a daily basis. They have this device, go through rehabilitation and then they're walking and getting back to activities that are really important to them."

Chuck Stenger of New Albany, Ohio was the first person to receive the shock absorber device three years ago. Today, the retired firefighter says he's doing exceptionally well and is grateful he had the opportunity to try the device.

"Before participating in the clinical trial, I was told I was probably a candidate for a knee replacement, and I didn't think I was quite ready for that yet," Stenger said. "Three days after the implant procedure I was walking around, and with a little therapy I'm back to golfing, taking long walks and just living life without constant pain in my knees."

The two-year collective clinical trial data has been submitted to the U.S. Food and Drug Administration and is under regulatory review.