Running, Knee Joint Loading, Gait Changes and Clinical Assessment

A 2017 systematic review of more than 100,000 people found hip and knee osteoarthritis in 3.5% of recreational runners, 10% of non-runners and 13% of elite competitive runners. A long-term study of older runners also found lower prevalence than in controls. The data do not support running as a cause, and runners whose symptoms do not flare can keep running. The knee adduction moment is a proxy for medial compartment load and predicts progression. Greater knee flexion at heel strike may shift load onto cartilage not adapted to it, which makes restoring knee extension important. Increased medial muscle co-contraction was linked to faster progression, lateral co-contraction to less cartilage loss. Assessment covers red flags, range of motion, strength, gait and five recommended function tests, including the 30-second chair stand, 40 m fast-paced walk and timed up and go. Radiographic severity matches pain poorly. About 30% of people with osteoarthritis show central sensitization, suggested by moderate to severe pain, pain out of proportion to damage and spreading pain.