Valgus bracing brings offloading, functional benefits in medial compartment OA

Deformity correction and load balancing may help gait and augment other cartilage treatment.

A small clinical biomechanics study shows that valgus bracing for medial compartment knee osteoarthritis can bring positive changes in angulation, adduction and gait.

The results of the evaluation of the effects of a valgus brace on the three-dimensional movements and the impact on a knee from ground forces during gait were presented to the 6th Symposium of the International Cartilage Repair Society. Jim Richards, PhD, professor at the University of Central Lancashire, England, reported on management of medial compartment osteoarthritis (OA) of the knee in active individuals who do not yet require surgery, or who are unsuitable for surgery due to associated medical conditions.

A normal person walking transmits 60% of the load onto the medial compartment, he said. “But in medial compartment knee OA, this is much closer to 100%.”

To assess the effects of the brace on the biomechanics of the knee, Richards and colleagues at the University of Central Lancashire and the University of Salford, also in England, used an eight-camera motion analysis system with markers utilizing the Calibrated Anatomical System Technique (CAST) protocol on six subjects with Kellgren-Lawrence Grade 2-4 OA and no anterior cruciate ligament (ACL) deficiency.

“The CAST technique is very important for dealing with the immensely complex biomechanical problems that we are presented with,” Richards said. “We use four markers on each segment of the limb. Without it we cannot correctly measure the coronal plane movement or the transverse plane movement, which are very important in biomechanical studies,” he said.

5° of correction

The researchers analyzed the subjects while they walked five 10-meter walks with and without the brace. “We used a twin-hinged OA brace,” Richards said, “which is basically a three-point pressure system that aims to support and correct the deformity.” They used a standardized correction of 5° for all patients. Richards and his coworkers recorded data for the knee adduction angle, knee adduction moments and ground-reaction forces.

Richards said he saw significant improvements in the angulation of the knee in the coronal plane and the knee adduction moment during the stance phase with the brace. The ground reaction forces showed an increase in loading with the brace and a greater push-off force.

“It is very important to also note that we are actually getting lower pain and greater function,” he said. “This indicates the brace has a corrective effect and enables the subjects to have a more normal gait pattern with a reduction in pain.

“My final thought is that using bracing for cartilage repair is common,” Richards added. “But how many postoperative bracing scenarios actually incorporate some form of varus correction to offload or even out loading on the medial and lateral compartments, which should theoretically help any repair we might do?”

For more Information:
Richards JD, Jones RK, Kim WY. Biomechanical changes in the conservative treatment of medial compartment OA of the knee using valgus bracing. #7a-3. Presented at the 6th Symposium of the International Cartilage Repair Society. Jan. 8-11, 2006. San Diego.