“It was surprising that the presence of pain predicted the higher than normal joint loads,” says Dr. Wimmer. “We thought that the presence of structural changes would have been the indicator that something was seriously wrong with the knee joints.”
Dr. Wimmer says that his group’s work highlights the importance of knee joint alignment and mechanical loading. “Mechanical loading may be even more important than radiographic disease state in determining who is likely to progress to moderate and severe stages of disease.”
The presence of pain related to structural changes in the knee calls for a biomechanical intervention, and while it might seem intuitive to strengthen the knee muscles, this strategy only reduces pain; excess medial compartment loading still occurs.
“Presently non-surgical interventions for knee OA are directed towards alleviating knee pain but no conservative intervention exists that can significantly and reliably affect biomechanical risk factors for progression of knee OA,” says Dr. Wimmer. That’s why they considered an alternative.
Since the hip muscles control the body’s relative center of gravity, they also indirectly dictate balanced movement at the knee. Consequently, Dr. Wimmer and colleagues decided to pilot a novel exercise regimen directed at strengthening the hip abductor muscles.
They enrolled six OA patients with knee disease and strengthened their hip muscles for four weeks.
“The idea was that the patients improve their upper body position during gait and thus lower their knee adduction moments,” says Dr. Wimmer. The treatment seemed to work; all patients reduced their knee adduction moments and also experienced pain relief.
Dr. Wimmer presented details on this trial at the ACR/ARHP Annual Scientific Meeting in November.
Megan White is a medical journalist based in Boston.
