Where the Loading Goes: Why the Inner Side of Your Knee Bears the Brunt of Osteoarthritis
May 2026
If you've been told that knee osteoarthritis (OA) is "a load problem", that's true – but it's only half the picture. The more useful question, and the one that's quietly reshaping how knee OA is treated, isn't just how much load your knee carries. It's where that load goes.
For most people with knee osteoarthritis, the answer is strikingly consistent: too much of it lands on the inner side of the knee (known as the medial compartment).
Why the inner knee gets overloaded
Picture the line of force that travels up through your leg each time your foot hits the ground as you walk. In most people, that line passes slightly to the inside of the knee rather than straight through its centre. That small offset acts like a lever, creating a turning force that pushes extra pressure onto the inner (or medial) compartment of the joint.
The further that line of force sits from the centre of the knee, the longer the lever, and the greater the load on that inner compartment. It's the same principle as a spanner: the longer the handle, the more force it applies. Over years of walking, that's a lot of repeated pressure concentrated in one spot. Which is exactly where wear and tear so often shows up.
The key insight: that loading isn't fixed
Here's the part that changes things. For a long time it was assumed that this load was simply a fact of your anatomy – just something to be managed. But research shows that it can actually be redirected.
This is the principle behind the AposHealth treatment we offer at the clinic. The device – a pair of shoes fitted with adjustable convex pods under the foot – lets your clinician fine-tune where pressure falls as you walk. Nudging that pressure slightly towards the outside of the foot shifts the line of force closer to the centre of the knee, shortening the lever and easing the load on the overworked medial compartment.
A study of patients with medial-compartment knee osteoarthritis tested exactly this. Shifting the pressure outward reduced the load on the medial compartment by roughly 10% to 14%. Shifting it the other way increased that load, which (although not the goal) proved an important point: the pressure on the inner knee can be turned up or down directly and predictably. The total load accumulated across each step came down by a similar margin too, and that cumulative load may matter just as much as the peak for the long-term health of the joint.
You don't have to relearn how to walk
One of the most reassuring findings from the study is what didn't change.
Patients' walking speed, stride length and rhythm all stayed the same. They weren't consciously altering their gait or concentrating on doing anything differently; the mechanics adjusted first, quietly, while they simply walked as normal.
You don't have to retrain yourself; the system does the work.
Why being able to act early matters
While many of the most valuable things you can do for knee OA – building strength, managing weight – are genuinely worthwhile, they also take time to pay off and can be hard to sustain when your knee already hurts.
Redirecting load is different: it can ease pressure on the joint from day one.
This early relief isn't just welcome in itself. It can create a window: a more comfortable starting point that makes it easier to engage with the rest of your care, including the strengthening and lifestyle work that supports your knee over the long term.
Apos is best thought of as a springboard, not a substitute, for those other approaches.
AposHealth can help even in more advanced osteoarthritis
Some conservative treatment options, such as standard insoles, tend to lose their effect as osteoarthritis advances. Encouragingly, the research suggests this kind of load reduction remains achievable even in people with more advanced disease, not only those in the early stages.
Treating the drivers, not just the symptoms
Because persistently high load on the inner knee is closely linked with how osteoarthritis progresses, easing that load isn't only about feeling better today. By addressing the mechanical force that's driving the wear, there's reason to believe it may help slow the joint's decline and, for some people, delay the point at which surgery comes onto the table.
That's a question researchers are continuing to study, but the underlying logic is sound: shift the pressure off the part of the knee that's struggling, and you change the conditions the joint has to cope with.
To put it another way, managing knee osteoarthritis is sometimes less about doing more, and more about placing the force in the right place.
Could AposHealth help you?
If you're living with knee osteoarthritis – especially the kind that bites on the inner side of the joint — it may be worth understanding how the load is travelling through your knee, and whether it can be eased. The right starting point is a proper assessment of how you move.
You can get in touch with our team to arrange a gait assessment, and we'll talk you through whether AposHealth (or another part of our musculoskeletal care) is the right next step for you.
This article is for general information only and does not constitute medical advice. The research described examines how knee load can be changed and may not reflect every individual's results. Always seek the guidance of a qualified healthcare professional regarding any medical condition or treatment.
