Knee Osteoarthritis: Why Exercise Is Treatment, Not Just Fitness

A head-to-head treatment trial

One of the more interesting kneeosteoarthritis studies was published in the New England Journal of Medicine in2020. Researchers randomly allocated 156 people with knee osteoarthritis toeither a course of physical therapy or a glucocorticoid injection. At one year,the physical-therapy group had better overall pain and function scores than theinjection group. This does not mean injections are never useful, nor that everypatient will respond in the same way. It does, however, reinforce an importantmessage: rehabilitation is not simply an optional add-on while we wait for thejoint to deteriorate. Exercise can be a central treatment for symptoms andfunction.

What a physiotherapist is trying tochange

Knee osteoarthritis is not managed bystrengthening the quadriceps in isolation. We consider knee movement, legstrength, hip and calf capacity, walking tolerance, stairs, balance,confidence, sporting or work goals and the amount of activity the knee iscurrently tolerating. The exercise dose is then matched to the person. For onepatient that may begin with sit-to-stand and short walks; for another it mayinclude heavy leg strengthening, cycling, hills or gym work. Manual therapy maysometimes be used to make movement more comfortable, but the longer-term aim isusually to improve the knee and the person around it, not simply to providetemporary relief.

Testing gives us more than a pain score

Objective measures are particularly usefulin osteoarthritis because pain naturally fluctuates. Timed sit-to-stand, steptests, walking speed, range of motion and strength testing can show improvementeven during a temporary pain flare. Where appropriate, more detailed tools suchas dynamometry or force-based testing can quantify side-to-side differences andhelp set meaningful targets. Regular review matters because exercise must beprogressed to remain an adequate training stimulus. It also allows us to identifywhen swelling, loss of movement, night pain or a sudden change in symptomsneeds medical review. The most useful question is often not "How worn ismy knee?" but "What can we improve so this knee does more with lessdifficulty?"

Selected research

1. Deyle GD, Allen CS, Allison SC, et al. Physical Therapy versusGlucocorticoid Injection for Osteoarthritis of the Knee. New England Journal ofMedicine. 2020;382:1420-1429. doi:10.1056/NEJMoa1905877.

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