Medtech Miracles and Tragedies: Sandra Liddy

In the mid-1990s, Los Angeles Police Department Officer Sandra Liddy injured both her knees while participating in a riot-control and firearm-suppression training. The 47-year-old underwent two arthroscopic procedures on her right knee and one on her left to repair the damage, but nothing helped. She turned to multiple pain medications, physical therapy, and even steroid injections as a last ditch effort.

“I couldn’t walk. I was limping. I couldn’t sit for a long time. [If I ended up] sitting for a long time, I couldn’t stand up. It was just very, very painful,” she says.
She knew it was time for knee replacement surgery. Liddy was referred to orthopedic surgeon Jaime Hernandez, who used a Stryker knee navigation software system that helps position the implant properly and make accurate implant sizing decisions on her.

“The usual way is to insert metal rods into the tubes of the bone and then calculate [using an eyeball method] the knee,” Hernandez explains. “It’s not as accurate [as a software system], and there’s more blood loss.”

Another technology Hernandez uses in knee replacements is OrthoSensor’s VeraSense Knee System, which is a pressure sensor that is inserted into the knee to check the pressure on the two sides of the knee to make sure they are equal. It enables the physician to make any final adjustments to the knee.

Liddy had her right knee replaced in November 2013, and in March 2014 she decided to have the left knee replaced via the same method. Today, Liddy marvels at the fact that she walks without a limp and can go to the gym and even hike, although she can’t kneel yet. “I always wanted to feel normal, but I couldn’t,” she says. “I was limping, popping pills, in pain. I had no motivation to be fit. Now, I have scars, but I am kind of proud of them.

“I am back to work,” she says. “I have been off of the pain medication for two months. Even my boss last week said, ‘Look at you go, now that you have new knees,’” she says. “I am like Speedy Gonzalez now compared to where I was before.”