Patients with OA pain need to understand that ‘joint pain’ is probably not due to the amount of cartilage present or lost. Zhang states we should only study people with actual joint symptoms, because not all people who have OA on X-ray actually have any pain or dysfunction, and not all people with symptoms show radiographic OA.
Let’s look at study done by Hannan etal in 2000. They examined 6880 persons aged 25-74 finding:
319 subjects (3.7%) had radiographic grade 2-4 (obvious) knee OA
Yet only 47% of these 319 people reported knee pain,
53% of subjects with grade 2-4 knee OA reported no knee pain
1. knee pain was reported by 1004 subjects (14.6%),
2. but only 15% had radiographic grade 2-4 OA changes.
3. That means 85% of people with knee pain had grade 0 or 1 level radiographic changes.
0. no radiographic features of OA are present
1. doubtful ‘joint space narrowing (JSN) and possible osteophytic lipping’
2. definite osteophytes and possible JSN on anteroposterior weight-bearing radiograph
3. multiple osteophytes, definite JSN, sclerosis, possible bony deformity
4. large osteophytes, marked JSN, severe sclerosis, definite bony deformity
Other things may need to be considered:
- Pain definitions need to be standardised & disability measures included
- Some causes of knee pain have nothing to do with OA e.g. ligament injury, tendonitis which explains some of the 85% of knee pain sufferers with nil or little OA.
- Using more (3 different) X-ray views in persons with knee pain improves identification of OA to 70% of cases
- Osteophytes better predict pain than cartilage volume
- The higher the radiographic OA grade, the likelier pain
Even so, we need to ask why 30-53% of grade 2-4 knee OA cases report no knee pain?
When we understand that cartilage debris activate inflammatory pathways, and that higher rates of cartilage breakdown almost certainly trigger the initial events leading to joint pain and loss of function we can also understand why total cartilage volume likely has little bearing on symptoms. The question we really need to ask is why can’t peoples’ bodies maintain strong cartilage?
Article Written + Submitted by:
Andreas Klein Nutritionist + Remedial Therapist from Beautiful Health + Wellness
P: 0418 166 269