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PS is an elderly gentleman who walked into our office this afternoon after having his right knee replaced last year on the west coast. He soon noticed that his left hip and knee began to hurt after the right knee was replaced. When I first observed him standing in the office, I knew there wasn’t something quite right. In order to stand straight, he needed to bend his right knee and when he straightened his right knee, his left would lift off the ground.

I then immediately knew what had happened, which is a great illustration of our orthopedics 2.0 philosophy. PS is short, all of about 5 foot 5 inches tall, but regrettably he had a right knee prosthesis installed that was meant for a much larger person. The images above show that the right thigh is now too long. Image #1 is with him seated, looking from above. Note that the right leg is now about 3/4 of inch longer. I had to grab a medical textbook that was 3/4 of an inch thick to allow him to stand normally (the two pictures to the right, #2 and #3). Note that the top of the knee cap on the left is about 3/4″ higher than the right (blue dashed lines). The amazing part? Once PS was standing without the book, his right hip and knee ached (he had since been diagnosed with right hip and knee arthritis), but when he was standing on the book, his hip and knee hurt much less.

The upshot? We’ve seen many smaller patients get prostheses sized for larger patients and end up with a body part that’s too long. What happens when you suddenly make one leg almost an inch longer than the other? The short leg will get much more pressure and wear and tear causing arthritis, which I’ve blogged about in the past. So not only does PS need stem cells to help his hip and knee arthritis pain, but he also desperately needs a big heel lift!

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile