Space Technology Gets a Leg Up

Rehab is the answer to preventing problems after knee surgery. Activities and exercise prevent muscle wasting and scar tissue from forming. Rehab helps keep the heart and lungs in shape. The bottom-line in rehab is: restore function in the shortest time possible. This study looks at another way to speed up rehab and meet that goal: lower body positive-pressure exercise.

A special device called the lower body positive pressure (LBPP) chamber was used. The LBPP is a waist high box with a treadmill inside. It's been used by NASA for astronaut training. Pressure inside the chamber can be reduced to decrease the effects of gravity. This means less load on the bones and joints while walking on the treadmill.

Fifteen knee patients were included. Nine patients had part of the meniscus taken out via arthroscopy. The rest had an anterior cruciate ligament (ACL) repair.

Pressure inside the chamber was increased to unload the joints by 40 percent and then by 80 percent. Each patient walked for two minutes under three different conditions: normal body weight, then 40, and 80 percent unloaded. Ground reaction force (GFR) is the amount of force from the ground up through the leg when walking. GFR was measured along with knee range of motion and pain levels.

This was the first study to use LBPP with patients who had knee surgery. The goal was to see if LBPP could decrease GFR comfortably during walking after knee surgery. The results showed LBPP not only decreased bone and joint loads, but also decreased muscle activity further unloading the knee joint.

The authors suggest that the LBPP exercise chamber may be a good device to rehab patients. It could be used with anyone who needs to get up and walking but can't put weight on the leg. This could include strokes, spinal cord injuries, amputees, and orthopedic patients after surgery.



References: Robert K. Eastlack, MD, et al. Lower Body Positive-Pressure Exercise after Knee Surgery. In Clinical Orthopaedics and Related Research. February 2005. Vol. 431. Pp. 213-219.